Switch to Lithium without DC to DC or Li-BIM?

[Grey Goose]

On 7/22/2024 at 7:57 AM, Tom Cherry said:

Thanks for the qualification. Monaco was still switching around or maybe the Bean Counters were controlling. I LIKE MAGNUM. I understand it. It is a TANK. BUT, I would NOT trust my 15 YO nor purchase a new one if I decided to go down that path.

BUT, I would also use the same LOGIC.  Would I TRUST the substantial investment in Li to a 20 year old inverter? NO for the obvious reasons I stated. I just got 25 years out of a GE Dishwasher that had an expected life span of 15. I knew what to fix or replace when it "gave me a signal" before it was terminal. I can go on about keeping computers and appliances and cars...LOL, running.  WAY past their normal life.

BUT, Li will NOT tolerate even a BOBBLE.  We have a resident in a town some 10 miles away. He took the "Lithium" battery out of his Tesla. YES, for a period of time...maybe still, Tesla used a MEMORY BATTERY.  It looked like a regular starting battery. Tesla got flack for using a wet cell or maybe even an AGM. So, they popped in a Lithium. It died. The owner watched a YouTube. Yanked it out.  Put it on the Granite counter top in is almost $1,000,000 residence.  Hooked up a 12/6 V 6/2 A charger....got a beer...watched a Saturday afternoon basketball game. 

Later BOOM.  Neighbor tried to extinguish it with a 2 3/4 #. FD arrived....they carted it out....in a blanket or whatever containment. Remodeling will be in excess of $100K.

I also have a buddy that has TORN APART a Mercedes Benz Hybrid Battery (his future SIL is the Service Manager at a MB dealer and they store the FAILED in the 2 rented PODS outback.). He constructed a "12 VDC" home emergency battery. He is like the guy in the VIDEO. A brilliant engineer with a curiosity...like tearing apart an old Radio Shack computer...just to see how it was made.

He is FULLY aware of all the cell balancing and such. He tested each "bank" or matrix and then matched them back up. He keeps it inside a container....

We, he used to be my boss, were the PTB for making decisions on new equipment or manufacturing systems vs MAKE DO or REPAIR. We had to include RELIABLITY as the criteria.  Like replacing a $50K "Press" rather than rebuilding as it was the Weak Link in a multimillion department....and that product line was our bread and butter with nice margins cash cow...

Good Luck....   

Sorry I meant to quote another user. 

Edited August 14 by Grey Goose

[Mocephus]

9 hours ago, Biljol said:

The battery Isolation Manager may possibly have a max amps rating that is limiting the current.

In regards to battery boost to start, you can still use it kind of. When you boost you are connecting the two banks together. So what I have done is link them together for say 20 min this allows the lithium to charge the chassis battery. Then you can remove the boost and start.

 

 

Thanks Burke, good thought. Also the current I’m seeing going into the battery (via the BMS app) is the NET current after the refrigerator, panel lights, microwave clock/display, inverter, chassis batteries and other system components have taken their share of the alternators output. I noted this to be about 20A during my tests.

[Grey Goose]

On 8/12/2024 at 10:25 PM, Mocephus said:

UPDATE: After much research and consultation with others, I elected to make the switch to lithium without purchasing a new "lithium compatible" inverter, or a new "lithium compatible" solar charge controller or a DC to DC charger. I simply removed the 8 FLA batteries and cables, cleaned and repainted the battery trays, changed the charge profiles on my inverter and solar charge controller...and hooked up the new EPOCH 300AH lithium house battery.

Here's how it all came together:

I started with 8 - 6v Trojan batteries rated at 225AH for a total of 900AHs (12v). Because you can only discharge FLAs and AGMs to 50% SOC, the effective AH rating of the Trojans is actually 450AH.

 

My inverter (Xantrex RV3012)  does not have a custom charge profile feature. It only has settings for FLA, AGM and GEL batteries. The charge profile for GEL batteries shows a BULK VDC of 14.1, ABSORB of 14.1 and FLOAT of 13.6. That setting also does not do an equalizing charge (which would damage a lithium battery).

I called EPOCH and gave them the charging profile for the GEL setting on my inverter and the technician assured me that it would be fine to use that profile and that it would not damage the battery. He did say that there was a chance the inverter may not charge the battery to 100%.

Following a forum member's advice, I changed my solar charge controller to its AGM setting which also charges in the same range as the Xantrax inverter's GEL setting, and also does not perform an equalization charge when set to AGM. 

Starting at a 50% SOC, I installed the battery and let it charge overnight while plugged into shore power. The next morning the battery was charged to 98%.

There had been a fair amount of concern that I would burn up my alternator if I did not install a DC to DC charger, so I tested it out. I first drained the lithium down to 13%. Then I cranked the engine and let it run at high idle for over half an hour while monitoring the charge going into the battery. The highest it ever got was 32A. The Neece-Leville alternator on our rig is rated at 270A. The battery has a max charge rating of 200A.

So, I'm going to see how the battery performs under the above scenario. If all goes well, here's what I see as the pros and cons:

PROS

- No more dealing with the hassle of maintaining water levels in the FLA batteries, or the recommended "exercising" of AGMs, if I had gone that route.

- No more concerns about corrosion and rust caused by the off-gassing of the FLAs.

- Went from 12 cable connections (and the requisite maintenance of those) to 2 cables.

- Reduced the weight of the house batteries by 438 lbs.

- Gained an extra storage bay tray that once housed 4 of the FLAs.

- Max 80% (recommended) use of the AH rating as opposed to FLA and AGM, of which only 50% is useable.

- Constant voltage output throughout the discharge cycle.

- Longer lifespan (11 year warranty)

- Faster charging times

- Lower cost over the life of the battery

CONS

 

- Sacrificed approximately 210 AHs by going to just one 300 AH lithium battery....assuming an 80% max discharge for the lithium (300ah *.8 = 240 effective AH vs 450 for the FLAs). If I need more, I can easily add up to three additional lithiums.

- Up-front Cost: If I had added a second battery to get closer (apples to apples) to the 450 effective AH rating of the FLAs, my cost would have been approximately $657 higher than replacing all 8 FLAs. By adding just the one battery, my cost was actually $355 less.

- Lost the ability to use the battery boost feature in case the chassis batteries became weak. The Lithium battery does not have the cranking amps required to start the engine and attempting to do so could damage the battery. I could, however, use the battery boost switch to charge the chassis batteries from the house batteries....or carry jumper cables.

I'll be watching the battery's performance and I'll do an update if any issues arise but please let me know if you see something that I'm missing!

Congratulations! One of the primary reasons I switched to Lithium last year is that I got tired of looking at and dealing with the lead acid units and they were approaching the end of life anyway. 

I would not worry too much about your inverter/charger as you already know your battery has a BMS that manages the charging and discharge of the battery. And guess what? Some of the "approved LI" chargers are really nothing more than a regulated dc power supply that simply charge the battery until the BMS stops the charge cycle when fully charged. I have verified this many times using amp/meter, amp clamps, and DC voltage meters so this is not something I just read about on the internet.

I am very curious about your alternator test though. How did you determine how much current from the alternator was going into the LI battery during this test? How did you confirm the battery SOC was at 13%? The reason I ask these questions is that your alternator should have provided more current in this scenario providing your chassis batteries were fully charged AND if there was not an additional load on your inverter. Is it possible you had a load on your house batteries while you were doing this charge test? 

24 minutes ago, Mocephus said:

Thanks Burke, good thought. Also the current I’m seeing going into the battery (via the BMS app) is the NET current after the refrigerator, panel lights, microwave clock/display, inverter, chassis batteries and other system components have taken their share of the alternators output. I noted this to be about 20A during my tests.

My 2007 chassis alone used quite a bit more than 20 AMPs when I tested it over a 400 mile trip. This was during the daytime so I was not running the headlights. Are you able to turn the inverter function off during this test to eliminate the additional load on the house battery? If you did this and the charge going into the house battery goes up it would give an indication that the alternator output is the limit and not something the BIM is doing.

Edited August 14 by Grey Goose
additional clarity

[Mocephus]

40 minutes ago, Grey Goose said:

Congratulations! One of the primary reasons I switched to Lithium last year is that I got tired of looking at and dealing with the lead acid units and they were approaching the end of life anyway. 

I would not worry too much about your inverter/charger as you already know your battery has a BMS that manages the charging and discharge of the battery. And guess what? Some of the "approved LI" chargers are really nothing more than a regulated dc power supply that simply charge the battery until the BMS stops the charge cycle when fully charged. I have verified this many times using amp/meter, amp clamps, and DC voltage meters so this is not something I just read about on the internet.

I am very curious about your alternator test though. How did you determine how much current from the alternator was going into the LI battery during this test? How did you confirm the battery SOC was at 13%? The reason I ask these questions is that your alternator should have provided more current in this scenario providing your chassis batteries were fully charged AND if there was not an additional load on your inverter. Is it possible you had a load on your house batteries while you were doing this charge test? 

Hi Jeff, yes I was tired of looking at the mess from the FLAs too!

I determined the charge going into the lithium battery and the SOC by watching it on the battery’s BMS app. I did turn on the headlights during part of the test but you are right. The APP shows the net current going into the battery after other components (refrigerator, inverter, microwave display, maybe chassis batteries, etc.) have taken their share from the alternator. I measured the base draw at about 20A. 

18 minutes ago, Grey Goose said:

Congratulations! One of the primary reasons I switched to Lithium last year is that I got tired of looking at and dealing with the lead acid units and they were approaching the end of life anyway. 

I would not worry too much about your inverter/charger as you already know your battery has a BMS that manages the charging and discharge of the battery. And guess what? Some of the "approved LI" chargers are really nothing more than a regulated dc power supply that simply charge the battery until the BMS stops the charge cycle when fully charged. I have verified this many times using amp/meter, amp clamps, and DC voltage meters so this is not something I just read about on the internet.

I am very curious about your alternator test though. How did you determine how much current from the alternator was going into the LI battery during this test? How did you confirm the battery SOC was at 13%? The reason I ask these questions is that your alternator should have provided more current in this scenario providing your chassis batteries were fully charged AND if there was not an additional load on your inverter. Is it possible you had a load on your house batteries while you were doing this charge test? 

My 2007 chassis alone used quite a bit more than 20 AMPs when I tested it over a 400 mile trip. This was during the daytime so I was not running the headlights. Are you able to turn the inverter function off during this test to eliminate the additional load on the house battery? If you did this and the charge going into the house battery goes up it would give an indication that the alternator output is the limit and not something the BIM is doing.

That’s a good idea. Yes, I can turn it off at the remote. I’ve also ordered a clamp style AC/DC multimeter so I can measure the actual current coming out of the alternator and into the battery. 

[Grey Goose]

22 minutes ago, Mocephus said:

Hi Jeff, yes I was tired of looking at the mess from the FLAs too!

I determined the charge going into the lithium battery and the SOC by watching it on the battery’s BMS app. I did turn on the headlights during part of the test but you are right. The APP shows the net current going into the battery after other components (refrigerator, inverter, microwave display, maybe chassis batteries, etc.) have taken their share from the alternator. I measured the base draw at about 20A. 

That’s a good idea. Yes, I can turn it off at the remote. I’ve also ordered a clamp style AC/DC multimeter so I can measure the actual current coming out of the alternator and into the battery. 

How did you measure the base draw without an amp clamp?

[Mocephus]

59 minutes ago, Grey Goose said:

How did you measure the base draw without an amp clamp?

I watched the battery app with no charging source connected. Granted, I was not able to measure any draw from the chassis side since the engine was not running during that test. Knowing that, I knew I needed an amp clamp. 

[Grey Goose]

On 8/6/2024 at 10:14 PM, cbr046 said:

I'm curious how many amps a TYPICAL stock coach alternator puts out with a fresh start, lights on, AC fan on max and, of course, all the engine and transmission circuits . . . . basically everything the alternator MIGHT put out before charging the coach batteries. 

Every model & chassis will be different, but it might give a WAG as to how big of a DC-DC charger (for coach side) might be possible.

Or if someone has taken actual measurements . . . .

- bob

I confirmed that my coach chassis uses 30-35 amps min. Turn on the headlights while towing a TOAD it was at least another 20 amps. This was over a 400 mile stretch and did not include charging the chassis battery. It is a bit of a long story how/why ended up testing this out.

On 8/13/2024 at 7:28 AM, Tom Cherry said:

Coincidentally, I was doing my EXERCISE of my Trojans yesterday and some interesting...seemingly strange things occurred.  I did some further experiments and then talked to two other members who have electronics backgrounds and we have theorized a few things....which explains why we are seeing the recent high failure rates of the Magnum inverters.  AGAIN...I like Magnum and I have spent time from the first year I owned (purchased new) it in 2009 and then as a moderator started helping folks in 2010 or 11 and also noting why we are seeing the uptick in failures.  OLD AGE...

I ran my batteries down to about 60% SOC the first time.  All was well.  Then I put the MH back in the normal state and left it to recharge overnight. Sometime in the middle of the recharge a fault occurred.  I know that as the Microwave and refrigerator and coffee maker snitched. The power was off.  It was NOT the 50A service.  I have had the MH in storage for a long time and left if for several days as I put it back in covered storage when Debby passed on NC.

Then I ran down the batteries even more yesterday. I won't delve in to what I also confirmed about the Low Battery Cut Off setting and I will be updating the Battery 101 and Magnum setup files. That in itself is a separate topic....but the load or the spikes of your load will dictate exactly WHERE and WHY the LBCO should be set lower than most folks "THINK"...and this has been confirmed by Magnum.

OK....during the recharging yesterday, same thing.  Lost power internally...as he LED's were flashing.  The Magnum Remote was in a ERROR STATE. The inverter was overheating.  When that happens, the charging as well as the pass through 120 VAC to the GFCI and the Refrigerator and the MIcrowave shuts down. The Inverter will restart after the FET's cool oll.

The settings were the same as I had been using all the years.  BUT, in a confession, I had left the MH in storage and we did not travel.  SO, this is all catch.

WHY DID THE FET's OVERHEAT?  This has NOT occurred before...  The charging rate was set to 80% which is 10% LOWER than Magnum recommends....FOR A NEW UNIT. 

After talking to the other two members....one theorized....and has had experience with this phenomenon when he repaired mother boards for a PC as well as general knowledge. There are two BANKS, if you will, in the Magnum.  On the PCB, there are FET's.  These are the HEART of the Magnum.  If you go into the Technical function of the remote there are several ways of checking on the Magnum and Magnum tech support usually has you scroll through and read back the information.

The Magnum has two cooling fans and two sensors.  One for each bank of FET's.  My FET's were NOW OVERHEATING.  They had never done this before and I had exercised and recharged the batteries many times....like one should do.

The RATIONALE...  The Magnums and the MH's we have here are getting older. As I have stated, we have had MORE total Magnum failures requiring a new inverter in the past two years than during the prior 3 or 4 years...since we set up the new site.  WHY?  SIMPLE.

When the FET's are mounted on the PCB or the MAIN BOARD, there is an array of heat sinks or maybe one massive one.  Matters NOT.  The heatsink is on the board and the FET is mounted on top of it...The heat sink is to dissipate HEAT...the CAUSE of MOST FAILURES.  Every PC or electronic system with a large processing chip or FET's whatever have a HEAT Sink and a Fan. All desktop has such. Over the years if you have ever gone inside, you may find a separate fan and coiling system for the main chip.  NOW, in the Magnum, the FET's are "BEDDED" or there is a layer of Thermal Conductive Heat Sink Compound.  Some call it PASTE....some GREASE.  It is used to provide HEAT TRANSFER from the FET body to the HEAT Sink. It ENHANCES or is there for 100% HEAT transfer from the FET to the Heat Sink. Then there is a sensor and a cooling fan. Thermal Conductive Heat Sink Compound is NOT A 100% GOOD until Gabriel blows the Trumpet. It eventually deteriorates or breaks down and starts to crystalize.  Therefore, it is losing it's ability to TRANSFER the FET heat to the heat SINK.  COMMON PROBLEM.  Many folks have tools to remove the FET and then clean and replace the Heat Sink Compound.  BUT, if the FET is damaged or one does not catch that in time.  BINGO...a DEAD FET.

That is what happened to me and what is going on inside it. This is NOT something new and revolutionary.  Magnum suggests allowing cooling or air circulation where the Inverter is located. Many of our old timers have, occassionally experienced this and we open the bays or some put a small fan down there during times of high temps.

SO...my comments about the AGING of the Magnums now is a valid conclusion.  

SO...back to the gist of the comments. Magnum told me....  Lithiums AIN'T our Thing.  OK..  BUT, if one decides or has experimented and they have an older Magnum and it seems to charge their banks OK.  FINE.  BUT, my experience ALSO tells me that the Remotes are MORE vulnerable.  I would PERSONALLY purchase a NEW REMOTE...on GENERAL principles...as the Remotes change the setup parameterss... DRASTICALLY.  Magnum says that.  I know that....mine failed.

THEN...my point is.  If there is a known failure of one component...the REMOTE...and then if there is the AGING factor or the breakdown of the Thermal Heat Sink Paste and the Inverter is running HOTTER....why would you want to risk destroying the Li Bank?

The SOLUTION...as most will say... CUT BACK ON THE CHARGE RATE.  I will now throttle mine back to 50%. I KNOW it worked fine in the past at 80. SO for inverters older than the 15 or so years...I am recommending cutting it back and will update the files.

That's my logic.  One of the members that I talked to yesterday has 10 YO Trojans and they will still, after exercising, go back to 100 SOC.  His inverter is 17 Years old. He know how to convert to Lithiums and had researched and watched videos and also commented here. His "PLAN"...subject to change...WHEN (NOT IF) his Magnum fails, he will probably NOT replace it.  He will do the upgrade to Lithiums with a Victron and also the other required MOD's...which have been posted in all the topics and are working today. 

That's my point. I am NOT anti-Lithium.  I an AITI-WASTING money or gambling on 15 - 20 year old electronics that have TWO KNOWN Failures....  And the failures COULD, as well as WILL destroy the Lithiums.  We have had at least 20 odd occasions of just "Popped in Lithiums" and did very little or maybe was told NOT to make any changes.  Three to five YEARS is when the fail...some have went out in less than TWO. They MAY have purchased the lower end...Frank McElroy posted, I think, a Video on Lithiums and all Lithiums AIN'T the same.  Just like all batteries are NOT THE SAME.  The Trojan's are the GOLD standard.  Many brands are NOT that well made.  

So...that's it.  Color me what you want....but make sure it is NOT ANTI-LITHUM....but is ANTI-GAMBLING...  

Hope this clears it up.  

I have more to add to this later but in regards to the over heating issue. I assume you verified the fans were running at full speed? I know a little about the heat sink compound as I have used it when I built PC's. I would be more inclined to think the heat sink fins are clogged with debris. This is a very common thing depending on the design of the heat sink itself.

Edited August 14 by Grey Goose

[Mocephus]

On 8/6/2024 at 11:14 PM, cbr046 said:

I'm curious how many amps a TYPICAL stock coach alternator puts out with a fresh start, lights on, AC fan on max and, of course, all the engine and transmission circuits . . . . basically everything the alternator MIGHT put out before charging the coach batteries. 

Every model & chassis will be different, but it might give a WAG as to how big of a DC-DC charger (for coach side) might be possible.

Or if someone has taken actual measurements . . . .

- bob

I’ve ordered an amp clamp so I’ll be doing some testing of the alternator. I’ll post my findings!

[RoadTripper2084]

1 hour ago, Mocephus said:

I’ve ordered an amp clamp so I’ll be doing some testing of the alternator. I’ll post my findings!

Doesn't the alternator need higher than idle RPMs to output it's full capacity?  If you're only measuring its output at idle, it may not be accurate of what's happening as you're driving down the highway.

[Mocephus]

9 minutes ago, RoadTripper2084 said:

Doesn't the alternator need higher than idle RPMs to output it's full capacity?  If you're only measuring its output at idle, it may not be accurate of what's happening as you're driving down the highway.

You may be right but I’m not sure. During my initial tests I had it at high idle (1250 rpm) and I’ll do that again once I get the amp clamp. I’m not really interested in adding an amp meter to monitor it going down the road though.

I did see a test done on an alternator that was putting out its full load at idle. They were showing how hot it got because the fins weren’t moving fast enough to cool the alternator. 

[Grey Goose]

On 7/26/2024 at 8:05 PM, vito.a said:

I know of several Monaco Signature and Country Coach Magnum/Affinity owners that have installed lithium battery banks with the OEM Leece Neville 270-amp alternator connected.  So far there are no issues.  These big alternators are very different than standard automobile alternators.    

You need the recommended charging profile from your battery manufacturer.  Then talk to the inverter technicians.  You will need someone that understands batteries and is not just quoting from a cheat sheet.  I used to speak to Glenn at Magnum, but he has since retired.  

Good luck!

My opinion is from the perspective of an electrical engineer with some long-term experience with large commercial DC systems as well as some personal history with automotive systems.

The Leece Neville are built bigger and better than some standard automotive alternators. One rebuilder suggested they commonly put out less current at idle and this is a good thing since it helps prevent overheating since there is less airflow at idle. But the Leece Neville units are not bulletproof and subject to the same limitations of any other alternator and heat is a problem regardless. The bigger the amp rating the more heat that can be generated and there really is not intelligence built into the design to prevent overheating. A bigger heat sink and case is all relative to the total amps produced. In this regard, the Leece Neville is just like any other alternator. People will say it works just fine but they may not really have enough long-term data to confirm that. Add in environmental factors like high ambient temperature and engine heat and the risk increases. To me it is risk vs reward. In my younger days I used to push my car alternator hard due to the sound systems I installed. I knew some people that put in bigger alternators, bigger batteries, etc but I foolishly said mine works just fine. And it did work just fine, until it didn’t. Battery and alternator failures occurred at a higher than normal rate. This was not a big deal because I was usually close to a parts store and or dealer and the parts were never hard to find. Now I can imagine that finding a replacement Leece Neville alternator in the middle of nowhere would be a different story. Add in the visual of my wife and dogs sitting broke down on the side of the road and the risk is something I don’t want to take at this point in my life. I have ways to avoid this situation but again not without at least some pain involved. If this was a risk related to some issue on the house side and would not impact highway travel I would be much more risk tolerant.

For the record my Leece Neville alternator failed about 6 months/4000 miles after I switched to Lithium. That is a coincidence and not because I had converted to Lithium. During that time period I either had the house bank disconnected from the alternator or I had a DC/DC charger in place. When I removed the failed unit I could see evidence that it had been rebuilt/serviced at some point before I owned the coach. Keep in mind this second failure happened on a coach that had just a little over 50K miles. After speaking with a qualified rebuilder I moved over to a newer design 28SI alternator that bolted in with no wiring or hardware changes and is something I could likely carry into an automotive parts store and get replaced relatively easily in any part of the USA.

[vito.a]

Fortunately, losing an alternator on a motorhome is not a catastrophic incident.  

You run the generator/inverter to charge the house batteries and place a jumper cable from the house battery positive to chassis battery positive terminal.  

[Grey Goose]

1 hour ago, vito.a said:

Fortunately, losing an alternator on a motorhome is not a catastrophic incident.  

You run the generator/inverter to charge the house batteries and place a jumper cable from the house battery positive to chassis battery positive terminal.  

This is true and I have done that. For most it is relatively easy, for others who have relocated their lithium battery bank it might not be as easy.  The other solution could be to plug in a 110/12v charger and run it off the generator. But I have also seen numerous posts from people on FB and other forums explaining how they were stranded or compromised by an alternator failure. Obviously, they were not thinking out of the box and how to work around this problem. Likely the same people that wont run their generator to cool the unit or complain their aquahot cant heat their coach going down the highway. I dont get it...

Edited August 15 by Grey Goose

[96 EVO]

OR..... Their alt seized up and the pulley won't spin.

[Grey Goose]

4 minutes ago, 96 EVO said:

OR..... Their alt seized up and the pulley won't spin.

That does happen but usually they give you some warning...but again you need to know what you are hearing when it starts crying for help.

[96 EVO]

9 minutes ago, Grey Goose said:

That does happen but usually they give you some warning...but again you need to know what you are hearing when it starts crying for help.

Ha ha, 'crying for help', or Squealing in pain 😁!

[96 EVO]

I did the last 1000 mi migration south last winter with my gen running to keep my chassis batteries charged, when my alternator stopped making power, but didn't seize up.

BIRD and Big Boy solenoid, so I didn't need any other cables between battery banks!

 

[Mocephus]

Hello friends, I tested the alternator output (as well as generator, shore power, and solar) and took readings. Here is the alternator test. I can provide the data on the other charging sources if needed.

 

Throughout these tests, the 300 AH lithium house battery was at approximately 40% SOC. This battery has a maximum charge rating of 200A. Chassis batteries with no charging source were at 12.5v. The base House current (refrigerator, microwave display, inverter, light panels, etc.) with no charging source is -17A. Ambient temperature was 80F.

 

Here's what I found:

 

Alternator Test (270A Leece-Neville)

Low Idle (595 RPM) No Load (House switched off, chassis system load still present)

Chassis Batteries Volts = 14v

Chassis Batteries Amps = 2A

House Battery Volts = 13.2v

House Battery Amps = 0A

Current at Alternator = 16.5A

Alternator Temp = 131F (after 10 min)

 

Low Idle w Load - Chassis (headlights, dash AC high, radio on, House switched off)

Chassis Batteries Volts = 14v

Chassis Batteries Amps = 2.3A

Current at Alternator = 35A

Alternator Temp = 141F

 

Low Idle w Load - House (with convection oven on at 400F and chassis load off)

House Battery Volts = 12.8v

House Battery Amps = -74A

Current at Alternator = 96A

Alternator Temp = 155F

 

Low Idle w House and Chassis Load (headlights, dash AC high, radio on, convection oven on at 400F)

Chassis Batteries Volts = 13.9v

Chassis Batteries Amps = 9A

House Battery Volts = 12.6v

House Battery Amps = 10A

Current at Alternator = 99A

Alternator Temp = 171F

 

High Idle (1150 RPM) No Load (House switched off, chassis system load still present)

Chassis Batteries Volts = 13.9v

Chassis Batteries Amps = 6.5A

House Battery Volts = 13.9v

House Battery Amps = 0A

 

Current at Alternator = 16A

Alternator Temp = 151F

 

High Idle w Load - Chassis (headlights, dash AC high, radio on, House switched off)

Chassis Batteries Volts = 13.9v

Chassis Batteries Amps = 2A

Current at Alternator = 35A

Alternator Temp = 145F

 

High Idle w Load - House (with convection oven on at 400F and chassis load off)

House Battery Volts = 13v

House Battery Amps = -27A

Current at Alternator =  142A

Alternator Temp = 156F

 

 

High Idle w Load - Chassis and House (headlights, dash AC high, radio on, convection oven on at 400F)

Chassis Batteries Volts = 13.1

Chassis Batteries Amps = 0A

House Battery Volts = 13.1v

House Battery Amps = -25A

Current at Alternator =  170A

Alternator Temp = 177F

 

Conclusions:

1. Overheating the alternator is unlikely under any of these scenarios.

2. A DC to DC charger is not needed. Damage to the alternator's diodes from runaway voltage is unlikely under these scenarios.

What I don't understand is why in each of the House Load tests, the alternator did not supply enough current to cover the demand. In each of those tests, the House battery had to pick up a fair amount of the load.

I also don't understand why the convection oven is causing such a high current draw. It is rated at 850W. If my conversion is correct, with a pure sine inverter, the oven should only be drawing about 7A. I have a modified sine inverter which could require as much as 20% more current than a pure sine inverter, but even then, it shouldn't be drawing more than 8A.

Please let me know if you have any thoughts about the House Load tests or if you have any different conclusions!

Edited August 18 by Mocephus
Additional information

[cbr046]

Great real world testing!

The alternator was spec'd when FLA batteries were king, and FLA battery voltage drops significantly with load where LiFPO voltage maintains it's voltage until the very end (20% SOC).  So turning on all those house devices would have dropped house voltage (FLA batts) below 12.5V or 12.0V easily with the alternator making up more of the difference trying to recharge the house.  Still, another 25A shouldn't be a problem. 

Thinking out loud . . . . If an engine needs 960 CCA for 6 sec those amps need replacing.  Replacing those amps in a minute would still draw 96A!  Recharging in ten minutes (probably more accurate) only 9.6A but recharge current wouldn't be linear.  If hard starting that cranking time could extend to 12 or 18 sec.  If the chassis battery is already 50% SOC it would need more recharging amps. 

None of the tests were with depleted chassis or house batteries.  How much current would be needed to recharge AGM chassis batteries . . . . . or you've spent a good weekend boondocking and discharged your LiFPO's to 20%.  Those are capable of 200A charge current!  I'd want some protection from that . . . .  

Chassis and House battery recharging is still an unknown variable. 

- bob

 

 

[Biljol]

850 watts at 120v is 8 amps at 12v that’s 80 amps. 
 

hope that answers your question on the convection oven power draw

 

[Benjamin]

I agree with cbr046, house charging is still an unknown variable.  I don't claim to be an expert on Li, but I have a decent understanding of what I don't know about them, and what to be cautious of from reading other's experience.  I don't feel either conclusion is proven from the facts presented.  Specifically 1. amps is the issue that will cause alternator overheating, and also cause the BMS to disconnect possibly leading to an alternator voltage spike (2.).

The 13 and 13.1V system voltage is a concern. " Low Idle w Load - House" and voltage at 12.8. The potential problem I see is that you are expecting the Li batteries charge current to be predictable and linear like lead acid. While the warnings I see are mostly focused on the high potential amp output and input of Li, so I don't trust the amp capacity of Li to be linear or predictable.  I don't know if that info is out of date, based on former chemistry, or if the current BMS control current better than the previous "on/off" versions. 

This is coming from someone who does not have Li, but will not be buying any more LA storage batteries, so I'm following along. 

[Tom Cherry]

12 hours ago, Mocephus said:

Hello friends, I tested the alternator output (as well as generator, shore power, and solar) and took readings. Here is the alternator test. I can provide the data on the other charging sources if needed.

 

Throughout these tests, the 300 AH lithium house battery was at approximately 40% SOC. This battery has a maximum charge rating of 200A. Chassis batteries with no charging source were at 12.5v. The base House current (refrigerator, microwave display, inverter, light panels, etc.) with no charging source is -17A. Ambient temperature was 80F.

 

Here's what I found:

 

Alternator Test (270A Leece-Neville)

Low Idle (595 RPM) No Load (House switched off, chassis system load still present)

Chassis Batteries Volts = 14v

Chassis Batteries Amps = 2A

House Battery Volts = 13.2v

House Battery Amps = 0A

Current at Alternator = 16.5A

Alternator Temp = 131F (after 10 min)

 

Low Idle w Load - Chassis (headlights, dash AC high, radio on, House switched off)

Chassis Batteries Volts = 14v

Chassis Batteries Amps = 2.3A

Current at Alternator = 35A

Alternator Temp = 141F

 

Low Idle w Load - House (with convection oven on at 400F and chassis load off)

House Battery Volts = 12.8v

House Battery Amps = -74A

Current at Alternator = 96A

Alternator Temp = 155F

 

Low Idle w House and Chassis Load (headlights, dash AC high, radio on, convection oven on at 400F)

Chassis Batteries Volts = 13.9v

Chassis Batteries Amps = 9A

House Battery Volts = 12.6v

House Battery Amps = 10A

Current at Alternator = 99A

Alternator Temp = 171F

 

High Idle (1150 RPM) No Load (House switched off, chassis system load still present)

Chassis Batteries Volts = 13.9v

Chassis Batteries Amps = 6.5A

House Battery Volts = 13.9v

House Battery Amps = 0A

 

Current at Alternator = 16A

Alternator Temp = 151F

 

High Idle w Load - Chassis (headlights, dash AC high, radio on, House switched off)

Chassis Batteries Volts = 13.9v

Chassis Batteries Amps = 2A

Current at Alternator = 35A

Alternator Temp = 145F

 

High Idle w Load - House (with convection oven on at 400F and chassis load off)

House Battery Volts = 13v

House Battery Amps = -27A

Current at Alternator =  142A

Alternator Temp = 156F

 

 

High Idle w Load - Chassis and House (headlights, dash AC high, radio on, convection oven on at 400F)

Chassis Batteries Volts = 13.1

Chassis Batteries Amps = 0A

House Battery Volts = 13.1v

House Battery Amps = -25A

Current at Alternator =  170A

Alternator Temp = 177F

 

Conclusions:

1. Overheating the alternator is unlikely under any of these scenarios.

2. A DC to DC charger is not needed. Damage to the alternator's diodes from runaway voltage is unlikely under these scenarios.

What I don't understand is why in each of the House Load tests, the alternator did not supply enough current to cover the demand. In each of those tests, the House battery had to pick up a fair amount of the load.

I also don't understand why the convection oven is causing such a high current draw. It is rated at 850W. If my conversion is correct, with a pure sine inverter, the oven should only be drawing about 7A. I have a modified sine inverter which could require as much as 20% more current than a pure sine inverter, but even then, it shouldn't be drawing more than 8A.

Please let me know if you have any thoughts about the House Load tests or if you have any different conclusions!

This is REALLY NOT a question that most have asked.  IF you had a high wattage…say 1000 or 12000 watt inverter like folks use for tailgating or having a “high tech picnic” overlooking the Grand Canyon or building a log cabin with AC tools powered off their F-150 like in the hype of the car commercials….I’ll bet you would see the same thing.

The real place to get the correct answer…call LN Tech support.  They are great.  My feelings are that since the LN sees a HIGH voltage, as in the Chassis is almost fully charged, the voltage regulator is not pumping out amps.

SO…you have measured the amps from the Alternator…call LN and give them the details.  The LN VR is old school.  It is NOT like the variable charging “regulafors” used on most cars (for eeking 0.1 MPG better EPA fuel number). The Variable Rate chargers circa the mid 2000’s or maybe later…My wife’s ATS has one.  The voltage is all over the map….same for my Yukon.  It is just like the multistage inverter/chargers…it kicks up the voltage when needed..thus, also the amps….sort of a Bulk-Absorb-Float system…but rather that displaying screens….it just “moves” seamlessly from one phase or state to the other.

The charger has the “CAPACITY” to deliver X watts.  And when the VR says…LOW battery, it pumps out max amps.  Your House and Chassis, being in parallel and charged, is not calling for any higher voltage…so the VR is working off the system voltage.

The actual LOAD within the Chassis system doesn’t matter.  You have BATTERIES…so if the load is greater then the batteries will make up the difference…..thus….start to RUN DOWN….and then the VR says….pump up the juice….and replenishes.

There is NO current sensing of the Chassis load….and the LN is working off the Battery voltage.  BUT that is my conclusion….LN will tell you.

BTW, maybe I misread a comment.  When the engine starts….the VR shut OFF charging.  WHY? The air intake heaters are sucking up massive amounts of amps.  There is a sensor and relay to control that. It was explained to me that if the heaters were on…they might BLOW UP the Alternator….  This, Cummins has the Lock out relay.  Once the heaters shut down…or are off, then the voltage jumps up to normal charging.  My VM reads 12.7 or so until the heaters go off…then the the charging or recharging begins and the VM reads 13.9 or so.

If you drive and turn the headlights….you see, typically, a 0.1/0.2 VDC drop…as the system voltage is under a higher load…..you added maybe 30A to the system…so the Batteries are carrying the load.  When the VR then pumps more current….or is charging……the system usually stabilizes. That is 30 DC amps.  The Microwave is puling 1200 Watts (10 X 120).  That is basically a 100 AMP load…or maybe THREE Times the Headlight load.

NOW….you have both banks to absorb it.  BUT, my question is….why does Cummins NOT want the high air intake heater amps being pulled?  Maybe the theory is that the starting battery, which had to deliver up to 1500 A….you have two 950/960 CCA batteries in Parallel….so a potential of 1,900 AMPS.

BTW….each of the intake air heaters is rated at 95 A, DC.  THAT is why the relays and temp sensors keep the Alternator from “being overpowered”.  When you kick on the Microwave….you are “hitting” the electrical system with as much power as one heater….

So, I would be careful….might ask LN about such….

 

[Grey Goose]

13 hours ago, Mocephus said:

Hello friends, I tested the alternator output (as well as generator, shore power, and solar) and took readings. Here is the alternator test. I can provide the data on the other charging sources if needed.

 

Throughout these tests, the 300 AH lithium house battery was at approximately 40% SOC. This battery has a maximum charge rating of 200A. Chassis batteries with no charging source were at 12.5v. The base House current (refrigerator, microwave display, inverter, light panels, etc.) with no charging source is -17A. Ambient temperature was 80F.

 

Here's what I found:

 

Alternator Test (270A Leece-Neville)

Low Idle (595 RPM) No Load (House switched off, chassis system load still present)

Chassis Batteries Volts = 14v

Chassis Batteries Amps = 2A

House Battery Volts = 13.2v

House Battery Amps = 0A

Current at Alternator = 16.5A

Alternator Temp = 131F (after 10 min)

 

Low Idle w Load - Chassis (headlights, dash AC high, radio on, House switched off)

Chassis Batteries Volts = 14v

Chassis Batteries Amps = 2.3A

Current at Alternator = 35A

Alternator Temp = 141F

 

Low Idle w Load - House (with convection oven on at 400F and chassis load off)

House Battery Volts = 12.8v

House Battery Amps = -74A

Current at Alternator = 96A

Alternator Temp = 155F

 

Low Idle w House and Chassis Load (headlights, dash AC high, radio on, convection oven on at 400F)

Chassis Batteries Volts = 13.9v

Chassis Batteries Amps = 9A

House Battery Volts = 12.6v

House Battery Amps = 10A

Current at Alternator = 99A

Alternator Temp = 171F

 

High Idle (1150 RPM) No Load (House switched off, chassis system load still present)

Chassis Batteries Volts = 13.9v

Chassis Batteries Amps = 6.5A

House Battery Volts = 13.9v

House Battery Amps = 0A

 

Current at Alternator = 16A

Alternator Temp = 151F

 

High Idle w Load - Chassis (headlights, dash AC high, radio on, House switched off)

Chassis Batteries Volts = 13.9v

Chassis Batteries Amps = 2A

Current at Alternator = 35A

Alternator Temp = 145F

 

High Idle w Load - House (with convection oven on at 400F and chassis load off)

House Battery Volts = 13v

House Battery Amps = -27A

Current at Alternator =  142A

Alternator Temp = 156F

 

 

High Idle w Load - Chassis and House (headlights, dash AC high, radio on, convection oven on at 400F)

Chassis Batteries Volts = 13.1

Chassis Batteries Amps = 0A

House Battery Volts = 13.1v

House Battery Amps = -25A

Current at Alternator =  170A

Alternator Temp = 177F

 

Conclusions:

1. Overheating the alternator is unlikely under any of these scenarios.

2. A DC to DC charger is not needed. Damage to the alternator's diodes from runaway voltage is unlikely under these scenarios.

What I don't understand is why in each of the House Load tests, the alternator did not supply enough current to cover the demand. In each of those tests, the House battery had to pick up a fair amount of the load.

I also don't understand why the convection oven is causing such a high current draw. It is rated at 850W. If my conversion is correct, with a pure sine inverter, the oven should only be drawing about 7A. I have a modified sine inverter which could require as much as 20% more current than a pure sine inverter, but even then, it shouldn't be drawing more than 8A.

Please let me know if you have any thoughts about the House Load tests or if you have any different conclusions!

You could rerun the house load test with shore or gen power to see if the battery BMS behaves differently. Obviously you would need to come up with a way to load the house battery since you would not be on the inverter for the AC devices. This would tell you if the alternator in influencing the charge rate or the battery BMS.

I know you talked about rated charge rate but what have you observed when using your Xantrex charger?

Edited August 18 by Grey Goose

[Mocephus]

4 hours ago, cbr046 said:

Great real world testing!

The alternator was spec'd when FLA batteries were king, and FLA battery voltage drops significantly with load where LiFPO voltage maintains it's voltage until the very end (20% SOC).  So turning on all those house devices would have dropped house voltage (FLA batts) below 12.5V or 12.0V easily with the alternator making up more of the difference trying to recharge the house.  Still, another 25A shouldn't be a problem. 

Thinking out loud . . . . If an engine needs 960 CCA for 6 sec those amps need replacing.  Replacing those amps in a minute would still draw 96A!  Recharging in ten minutes (probably more accurate) only 9.6A but recharge current wouldn't be linear.  If hard starting that cranking time could extend to 12 or 18 sec.  If the chassis battery is already 50% SOC it would need more recharging amps. 

None of the tests were with depleted chassis or house batteries.  How much current would be needed to recharge AGM chassis batteries . . . . . or you've spent a good weekend boondocking and discharged your LiFPO's to 20%.  Those are capable of 200A charge current!  I'd want some protection from that . . . .  

Chassis and House battery recharging is still an unknown variable. 

- bob

 

 

Thanks Bob! Good insight and setup for more tests. I’ll try to do that in the next day or so and post my findings!

1 hour ago, Biljol said:

850 watts at 120v is 8 amps at 12v that’s 80 amps. 
 

hope that answers your question on the convection oven power draw

 

Burke thanks for the correction! It still doesn’t explain why the alternator isn’t covering that load. It’s a head scratcher!

[Mocephus]

5 hours ago, Tom Cherry said:

This is REALLY NOT a question that most have asked.  IF you had a high wattage…say 1000 or 12000 watt inverter like folks use for tailgating or having a “high tech picnic” overlooking the Grand Canyon or building a log cabin with AC tools powered off their F-150 like in the hype of the car commercials….I’ll bet you would see the same thing.

The real place to get the correct answer…call LN Tech support.  They are great.  My feelings are that since the LN sees a HIGH voltage, as in the Chassis is almost fully charged, the voltage regulator is not pumping out amps.

SO…you have measured the amps from the Alternator…call LN and give them the details.  The LN VR is old school.  It is NOT like the variable charging “regulafors” used on most cars (for eeking 0.1 MPG better EPA fuel number). The Variable Rate chargers circa the mid 2000’s or maybe later…My wife’s ATS has one.  The voltage is all over the map….same for my Yukon.  It is just like the multistage inverter/chargers…it kicks up the voltage when needed..thus, also the amps….sort of a Bulk-Absorb-Float system…but rather that displaying screens….it just “moves” seamlessly from one phase or state to the other.

The charger has the “CAPACITY” to deliver X watts.  And when the VR says…LOW battery, it pumps out max amps.  Your House and Chassis, being in parallel and charged, is not calling for any higher voltage…so the VR is working off the system voltage.

The actual LOAD within the Chassis system doesn’t matter.  You have BATTERIES…so if the load is greater then the batteries will make up the difference…..thus….start to RUN DOWN….and then the VR says….pump up the juice….and replenishes.

There is NO current sensing of the Chassis load….and the LN is working off the Battery voltage.  BUT that is my conclusion….LN will tell you.

BTW, maybe I misread a comment.  When the engine starts….the VR shut OFF charging.  WHY? The air intake heaters are sucking up massive amounts of amps.  There is a sensor and relay to control that. It was explained to me that if the heaters were on…they might BLOW UP the Alternator….  This, Cummins has the Lock out relay.  Once the heaters shut down…or are off, then the voltage jumps up to normal charging.  My VM reads 12.7 or so until the heaters go off…then the the charging or recharging begins and the VM reads 13.9 or so.

If you drive and turn the headlights….you see, typically, a 0.1/0.2 VDC drop…as the system voltage is under a higher load…..you added maybe 30A to the system…so the Batteries are carrying the load.  When the VR then pumps more current….or is charging……the system usually stabilizes. That is 30 DC amps.  The Microwave is puling 1200 Watts (10 X 120).  That is basically a 100 AMP load…or maybe THREE Times the Headlight load.

NOW….you have both banks to absorb it.  BUT, my question is….why does Cummins NOT want the high air intake heater amps being pulled?  Maybe the theory is that the starting battery, which had to deliver up to 1500 A….you have two 950/960 CCA batteries in Parallel….so a potential of 1,900 AMPS.

BTW….each of the intake air heaters is rated at 95 A, DC.  THAT is why the relays and temp sensors keep the Alternator from “being overpowered”.  When you kick on the Microwave….you are “hitting” the electrical system with as much power as one heater….

So, I would be careful….might ask LN about such….

 

Thanks Tom. Good thoughts and I’ll definitely reach out to LN.