Docan Power 12v Lithium Batteries

[pwhittle]

I replaced 4xLifeline GPL-6CT’s (600AH) with 2xDocan Power 12V 230AH prebuilt batteries a few months ago and have been very pleased with their performance.

I installed the batteries in the same bay as the Inverter and I think this made a huge difference and I only have 5-6 ft cables rather than the approx 25 ft Ground and 35 ft 12V from the original install on our 2005 Signature.

They just got those batteries back in US stock at the same $380 each I paid, and now also have 12V 300AH for $410 that are about the same size. If I had it to do over, I would have bought the 300AH models.

https://www.docanpower.com/index.php?route=product/product&product_id=494

https://www.docanpower.com/index.php?route=product/product&path=241_293&product_id=556

Paul

[vito.a]

Wow, that new 300ah battery looks like the way to go! 

If you follow the not more than 50% discharge for the Lifelines, a pair of the new Docan batteries would be twice the available power. 

[pwhittle]

And less than half the price too.

Paul

[Tom Cherry]

Curiosity….from trying to learn and understand the pros and cons of the Lithium conversions.

Thought that 80/90% SOC Discharge level was one of primary reasons for conversion…so one could boondock for entended periods?.?

Next, how does one, with a simple “setup” like the plain vanilla Magnum know the correct state of charge?  With the 80/90% SOC discharge, one could, I thought, use a “rough” voltage number?

Does any Lithium Conversion “REALLY” need a shunt type “Battery Monitor Kit”?  So one can set an alarm, and like the Magnum, and there are, as posted” many other equivalent brands and models, then have realtime monitoring….thus preventing damage?

”ASKING FOR A FRIEND”….as this topic “might” be covered at the Gathering….in a presentation.

Seriously….just trying to learn and understand….and maybe shed the false depiction as  Mr. LITHIUM Hater…

Thanks….feel free to expound and post…..

[folivier]

From my experience first building a 1000 amphour system and another system with 3 Battleborns I'd highly suggest the Victron BMV-700 series shunt/battery monitor. Due to the sudden dropoff when you hit the low voltage stage of LiFePO4's you want to avoid damage due to that low voltage.  The BMV calculates SOC rather than voltage and helps you avoid this.  It also has a signal you can set to trigger a relay either for an alarm or to shut down the BMS.

Higher/deeper SOC is one benefit, quicker charging avoiding the absorb stage, lighter weight. These IMO are the real benefits.

[cbr046]

Sam's Club GC2 $120 x2 = $240 for 12V @ 215Ah . . . . or Docan $380 for 12V @ 230Ah.  Seems like a pretty good deal (and for an extra $30 I'd get the 300Ah anyway . . . x2).

But it's always "everything else" holding me back.  Whether legacy Magnum or Xantrex, they aren't made for charging / maintaining LiFePO batteries so I'd be looking at a new LiFePO capable inverter anyway . . . and might as well get PSW . . . . with a 3000W upgrade. 

Same for alternator charging.  While some trust the engine alternator to not overheat, or send overvoltage to the battery, I'd still go with a DC-DC charger. 

And a monitoring system, with Bluetooth of course.

So $820 for LiFePO sounds like a "deal" (and it is), it's the other $2000 I'm concerned about.  And haven't even thought about solar yet. 

But still very tempting . . . .

- bob

[saflyer]

11 hours ago, Tom Cherry said:

Curiosity….from trying to learn and understand the pros and cons of the Lithium conversions.

Thought that 80/90% SOC Discharge level was one of primary reasons for conversion…so one could boondock for entended periods?.?

Next, how does one, with a simple “setup” like the plain vanilla Magnum know the correct state of charge?  With the 80/90% SOC discharge, one could, I thought, use a “rough” voltage number?

Does any Lithium Conversion “REALLY” need a shunt type “Battery Monitor Kit”?  So one can set an alarm, and like the Magnum, and there are, as posted” many other equivalent brands and models, then have realtime monitoring….thus preventing damage?

”ASKING FOR A FRIEND”….as this topic “might” be covered at the Gathering….in a presentation.

Seriously….just trying to learn and understand….and maybe shed the false depiction as  Mr. LITHIUM Hater…

Thanks….feel free to expound and post…..

I don’t know if the “80-90%” rule is gospel for LiFePO4 batteries. Some say 100% or near is doable.

Battery voltage is not a reliable determinant of SOC as the charge curve is so flat for lithium. I still have the battery monitoring kit I installed from when I had AGMs and it’s somewhat accurate. Magnum now has a lithium specific one which should be more accurate. If I was doing it again I would go with Victron instead of upgrading my Magnum inverter to PSW. Can still install the Victron BMK. Just might do that. That brings up a question. Can you install two BMKs with two shunts in the same line?

Ed                
‘05 HR Ambassador 

[Tom Cherry]

The “GOSPEL” is like the “goodbook” and each religion has their own….  The discharge level should come from the Specific Manufacturer.  The discussion or 50% versus the previously printed “Gospel” of being able to drain, without damage, to 80/90% WAS THE POINT.

One needs to know….HOW LOW CAN YOU GO? One needs to fully understand the charging profile and test or ascertain that their Charger meets or will accomlish.

These fundamentals are not often “emphasized” and the “god like virtues” of Lithiums often overshadow the real world.  We NOW have more good and solid advice and experiences….that is great.

BUT the road to success has been littered  with failures and expensive wasted $$ outlays and unacceptable performance.  Many had spent big bucks….and got less than 3 years were disappointed.  They usually went back to Flooded.  Same happens to AGM. Folks think   NO MORE MESSING WITH BATTERIES..but fail to realize….AGM’s require just as much care and exercise as flooded.  The only benefit is no Distilled water adding…which takes maybe 5 minutes of the “lets drain and recharge” cycle….

THAT is what we want folks to understand.  You have to know WAY more than what you read in a quick overview and you also have to know your system.

Thanks for the input.

[pwhittle]

I had already updated to a Magnum MS2812 and am using the Custom settings.

When traveling, I set Absorb to 14.4v and Float to 13.6V. Batteries stay at 99-100% when plugged in or on the generator. 

I will also combine the battery banks with my ML-ACR while driving without the generator running and see between 50A and 20A depending on the SOC of the batteries.

When parked or in storage, I adjust the MS2812 to Absorb 13.1, Float 13.1 and the batteries maintain about 50-60% SOC.

I already had a Magnum BMK but I really don’t pay much attention to it.

I just review the batteries as a bank using the BMS bluetooth and the LIONTRON Multi app on iOS which lets you connect to multiple batteries and monitor them as a single battery bank.

if I want to drill down to individual cells or change individual setting (I have not changed any settings), I use the Overkill Solar iOS app

If I was in the position of upgrading my inverter, I would go Victron and 48 Volts.

i would still move the batteries to near the inverter.

Paul

[wamcneil]

On 9/23/2024 at 11:36 AM, Tom Cherry said:

The “GOSPEL” is like the “goodbook” and each religion has their own….  The discharge level should come from the Specific Manufacturer.  The discussion or 50% versus the previously printed “Gospel” of being able to drain, without damage, to 80/90% WAS THE POINT.

One needs to know….HOW LOW CAN YOU GO? One needs to fully understand the charging profile and test or ascertain that their Charger meets or will accomlish.

These fundamentals are not often “emphasized” and the “god like virtues” of Lithiums often overshadow the real world.  We NOW have more good and solid advice and experiences….that is great.

BUT the road to success has been littered  with failures and expensive wasted $$ outlays and unacceptable performance.  Many had spent big bucks….and got less than 3 years were disappointed.  They usually went back to Flooded.  Same happens to AGM. Folks think   NO MORE MESSING WITH BATTERIES..but fail to realize….AGM’s require just as much care and exercise as flooded.  The only benefit is no Distilled water adding…which takes maybe 5 minutes of the “lets drain and recharge” cycle….

THAT is what we want folks to understand.  You have to know WAY more than what you read in a quick overview and you also have to know your system.

Thanks for the input.

Lithium CELLS must never be discharged lower than a specific minimum voltage or permanent irreversible cell damage will occur. Likewise for over-voltage and some other bad conditions. 
But you don’t need to worry about those voltages because every lithium BATTERY will have a built in battery management system. The BMS will disconnect the battery if any one cell goes out of range and shut it down before the voltage reaches a critical point. This prevents conditions that will quickly destroy the battery. 
It’s fine to run all the way from 100% to 0, but lithium cells prefer to live in the middle of their voltage range and will last longer if not regularly driven to <10% or >90%.  They’ll still last a long time if driven hard, but pretty much forever if not driven to the voltage extremes. 
Having 4 golf cart batteries is like having a 5 gallon gas tank in your car. When you only have 5 gallons of fuel, you stop at every gas station and spend a lot of time worrying about going lower than 50% and running out of fuel before you finish running your errands.
But a big lithium battery is like having a 20gal fuel tank. You can drive around between 3/4-1/4 tank and not worry about having to stop at every gas station and keep the tank full because you know you’ve always got enough gas to get through the day. 
When I moved to lithium, I set my shore power charging parameters more conservatively because I don’t “need” the battery to sit at 100%. When I’m relying on solar, I let it charge more aggressively, but if the battery doesn’t charge to 100% I’m ok with that. 

Edited Tuesday at 07:26 PM by wamcneil

[Tom Cherry]

29 minutes ago, wamcneil said:

Lithium CELLS must never be discharged lower than a specific minimum voltage or permanent irreversible cell damage will occur. Likewise for over-voltage and some other bad conditions. 
But you don’t need to worry about those voltages because every lithium BATTERY will have a built in battery management system. The BMS will disconnect the battery if any one cell goes out of range and shut it down before the voltage reaches a critical point. This prevents conditions that will quickly destroy the battery. 
It’s fine to run all the way from 100% to 0, but lithium cells prefer to live in the middle of their voltage range and will last longer if not regularly driven to <10% or >90%.  They’ll still last a long time if driven hard, but pretty much forever if not driven to the voltage extremes. 
Having 4 golf cart batteries is like having a 5 gallon gas tank in your car. When you only have 5 gallons of fuel, you stop at every gas station and spend a lot of time worrying about going lower than 50% and running out of fuel before you finish running your errands.
But a big lithium battery is like having a 20gal fuel tank. You can drive around between 3/4-1/4 tank and not worry about having to stop at every gas station and keep the tank full because you know you’ve always got enough gas to get through the day. 
When I moved to lithium, I set my shore power charging parameters more conservatively because I don’t “need” the battery to sit at 100%. When I’m relying on solar, I let it charge more aggressively, but if the battery doesn’t charge to 100% I’m ok with that. 

Fascinating reading.  Keep posting.  Read (few hours) some of the major manufacturers’ specs and data and such.  Trojan has yet to come out with a 12 VDC unit. Have a great 48 VDC GC model.  As usual, their “Owner Manual” is first class….so, assuming that one, as most manufacturers say, can “series string” FOUR”…so one has a 48 VDC bank, learning about BMS and DoD (DOD). All so far have the specs written for 80% DoD ….as they all say….BEST LIFE EXPECTANCY.

Some say.  99% DoD is OK….asterisk of course….others say 90% DoD is recommended max.  Each has a fascinating write up on optimum charging temp ranges…..very narrow…..and then the disclaimer…..capacity is reduced significantly if DoD is outside of “charging” range.

One “Off Shore” guidelines or “holy grail” of how to protect oneself from being “electrically” BLACKED OUT has some interesting and “snide” comments about using RV “grade” electronics and purchasing “RV Grade” Lithiums.

More reading and the comments here as well as the past “how to do it RIGHT” are wonderful resources….as this site is inclined to have.

WOW….BMS with BT that will give you data on your phone….Leaps and Bounds jumps in technology….

[folivier]

IME what I've found is the manufacturers who "allow" 100% DOD are under rating their batteries, IOW a 100 amp battery may actually be 110 amps in order to provide 100% DOD, at 100 amp. When I built my first system there was not much information on LiFePO4's. There is more empirical info available now. Float or not to float? that was one issue that has changed over the years. In fact when I built my first 1000 amp system I used the existing 1998 model Xantrex inverter/charger. What I did to get the charge volts up high enough was to set a battery temperature to trick the charger into charging at a higher voltage. It worked. But I'd have to turn off the charger once done since the float voltage was higher than I'd like.

Also a Victron BMV-700 series battery monitor or their smart shunt will give you accurate state of charge over bluetooth. 

The devil is in the details. Don't get too wrapped up in the details. LiFePO4's work great, last a long time, if you plan to keep your coach that long.

[wamcneil]

3 hours ago, Tom Cherry said:

Fascinating reading.  Keep posting.  Read (few hours) some of the major manufacturers’ specs and data and such.  Trojan has yet to come out with a 12 VDC unit. Have a great 48 VDC GC model.  As usual, their “Owner Manual” is first class….so, assuming that one, as most manufacturers say, can “series string” FOUR”…so one has a 48 VDC bank, learning about BMS and DoD (DOD). All so far have the specs written for 80% DoD ….as they all say….BEST LIFE EXPECTANCY.

Some say.  99% DoD is OK….asterisk of course….others say 90% DoD is recommended max.  Each has a fascinating write up on optimum charging temp ranges…..very narrow…..and then the disclaimer…..capacity is reduced significantly if DoD is outside of “charging” range.

One “Off Shore” guidelines or “holy grail” of how to protect oneself from being “electrically” BLACKED OUT has some interesting and “snide” comments about using RV “grade” electronics and purchasing “RV Grade” Lithiums.

More reading and the comments here as well as the past “how to do it RIGHT” are wonderful resources….as this site is inclined to have.

WOW….BMS with BT that will give you data on your phone….Leaps and Bounds jumps in technology….

It might be more educational to read spec sheets on the bare cells.  EVE recommends 10-90%. But they say 6000 cycles running all the way down to 2.5v cutoff voltage before capacity is reduced to 80% of new. Even if run hard, these batteries can last a long time.

It’s a different paradigm. FLA batteries NEED to be kept at 100%. Lithium do not.  FLA batteries MUST NOT be deeply discharged. Lithium don’t care.

Float charging isn’t applicable to lithium. When the battery voltage rises to that of the charger, current flow STOPS. As far as the lithium cells are concerned, there is no such thing as float charge because there is no residual trickle current that continues to flow through the battery like with FLA. So, the charger doesn’t necessarily need to “stop” at the end of the cycle because, to the battery, there’s nothing special about the charger’s “float” voltage. Float voltage just needs to be set at some arbitrary voltage that is lower than the charger’s Absorption voltage. (There’s really not much of an absorption phase either, but that’s of little importance).
Once the charger completes its absorption phase, it reduces the voltage and the current STOPS  

Here’s an example spec sheet : EVE Spec Sheet

 

Edited Tuesday at 11:53 PM by wamcneil

[wamcneil]

1 hour ago, folivier said:

IME what I've found is the manufacturers who "allow" 100% DOD are under rating their batteries, IOW a 100 amp battery may actually be 110 amps in order to provide 100% DOD, at 100 amp. When I built my first system there was not much information on LiFePO4's. There is more empirical info available now. Float or not to float? that was one issue that has changed over the years. In fact when I built my first 1000 amp system I used the existing 1998 model Xantrex inverter/charger. What I did to get the charge volts up high enough was to set a battery temperature to trick the charger into charging at a higher voltage. It worked. But I'd have to turn off the charger once done since the float voltage was higher than I'd like.

Also a Victron BMV-700 series battery monitor or their smart shunt will give you accurate state of charge over bluetooth. 

The devil is in the details. Don't get too wrapped up in the details. LiFePO4's work great, last a long time, if you plan to keep your coach that long.

Yep. I suspect cell capacity variation and balance is a big factor in how the batteries are rated. If the cells are carefully matched in capacity and exactly balanced, then the battery can be used from 0-100 just fine. But if any one cell has significantly lower capacity, or otherwise out of balance, it’ll trigger the BMS to shut down the battery when the one cell hits it’s upper or lower limit. 
Especially at the lower price points, there’s not gonna be a lot of quality control and deliberate cell balancing going on. 
It’s probably more cost effective to use bigger cells and de-rate the battery than to match and balance. 

[CAT Stephen]

On 9/22/2024 at 9:11 PM, Tom Cherry said:

Curiosity….from trying to learn and understand the pros and cons of the Lithium conversions.

Thought that 80/90% SOC Discharge level was one of primary reasons for conversion…so one could boondock for entended periods?.?

Next, how does one, with a simple “setup” like the plain vanilla Magnum know the correct state of charge?  With the 80/90% SOC discharge, one could, I thought, use a “rough” voltage number?

Does any Lithium Conversion “REALLY” need a shunt type “Battery Monitor Kit”?  So one can set an alarm, and like the Magnum, and there are, as posted” many other equivalent brands and models, then have realtime monitoring….thus preventing damage?

”ASKING FOR A FRIEND”….as this topic “might” be covered at the Gathering….in a presentation.

Seriously….just trying to learn and understand….and maybe shed the false depiction as  Mr. LITHIUM Hater…

Thanks….feel free to expound and post…..

@Tom Cherry,

Here are the LiPO4 battery facts:

• To maximize the Cycle life of any LiPO4 battery to yield 6000-8000+ discharge cycles, the battery should not be discharged below 20% on a regular basis. 
  • Discharging below 20% on a regular basis shortens the cycle life by ~15-30%, regardless of false claims by shady LiPO4 battery manufacturers.  Its just a truth of LiPO4 battery chemistry.
• To maximize the Cycle life of any LiPO4 battery to yield 6000-8000+ discharge cycles, each LiPO4 battery model requires the use of custom charging parameters. 
  • Unlike lead acid / AGM batteries, each LiPO4 battery manufacturer specify precise charging parameters that must be utilized to obtain 6000-8000+ discharge cycles.
  • Using a lead acid charger with an LiPO4 battery bank will result in charger faults and potential damage to other electrical system components.  Any manufacturer that claims otherwise is providing deceptive marketing information as the truth is driven by LiPO4 battery chemistry.:
    • https://www.relionbattery.com/knowledge/can-i-use-my-existing-lead-acid-charger-to-charge-lithium-batteries
    • https://www.offroadliving.com.au/blog/our-blog/can-i-charge-my-lithium-battery-with-a-lead-acid-c/?srsltid=AfmBOopl9BWDABteNdAWOzTz_g1elRTpCMwguA_YjDwRUlaTPxEhnCWV
  • LiPO4 battery banks absorb very high current resulting in rapid charging. 
    • This very high current absorption during charging can damage lead acid chargers and will destroy alternators that are designed for lead acid battery systems.
• LiPO4 Batteries have a very flat and narrow voltage operating band, thus a negative shunt is required to count electrons to determine the true state of charge if integration with other systems is desired.  Additionally, each shunt must be programmed with the parameters specified by each battery manufacturer to provide an accurate state of charge
  • Some LiPO4 batteries have a bluetooth enabled BMS which permits the use of an android or IOS proprietary application that provides the LiPO4 state of charge without a negative shunt, but these standalone proprietary bluetooth solutions integrate with nothing in an RV or a marine application and are generally only useful in stand-alone use cases such as an electric trolling motor where there are no other systems present to integrate with. 
    • Some users elect to utilize the built-in LiPO4 BMS cutoff, but the BMS cutoff is always below 20% depth of discharge which results in shortened cycle life of by ~15-30%

LiPO4 Cons:

• A lithium conversion requires the  existing lead acid inverter charger be replaced with a modern LiPO4 capable inverter/charger which is a significant investment.
• The LiPO4 battery market is currently flooded with very poor quality products made by chinese manufacturers that sell substandard products which have severe reliability issues.  These manufacturers are also infamous for publishing false marketing claims.  To avoid these issues, only purchase LiPO4 batteries from the following manufacturers that offer seven (7) year+ warranties with top build quality:
  • SOK (High value)
  • Chins (Best value)
  • Lithionics (Expensive) 
  • Battleborne (Expensive) 
  • BigBattery (High value)
  • EG4 (High value)
  • Epoch
  • Midnight Solar
  • Victron Energy
  • Sol-Ark
  • Others per testing by Will Prowse:
    • For LiPO4 battery reliability and build quality tests, Will Prowse provides independent best in the industry LiPO4 battery reviews:
      • https://www.youtube.com/results?search_query=will+prowse
• LiPO4 batteries are very bad for the environment as they can not be recycled and can / do leak toxic chemicals in landfills
  • Although Lead Acid and AGM use lead, lead is fully recyclable

LiPO4 Pros:

• Extreme cycle life (6000-8000 cycles) versus Lead Acid / AGM (~200 Cycles)
  • Extreme value versus Lead Acid / AGM due to extreme cycle life (3000% to 4000% higher cycle life)
    • For RV and Marine applicaitons, the result can be a tremendous long term cost savings for boon-dockers versus lead-acid/AGM
• High to ultra high discharge rates providing tremendous performance for inverter applications
  • Discharge rates are measured in "C" as a function of Amp-Hours regardless of nominal LiPO4 battery voltage
    • Example:
      • A "mystery" 100Ah LiPO4 battery rated at 5C discharge for 2 seconds (500 Amps Output) 2C discharge for 1 minute (200 Amps Output) and 1.5C continuous discharge (150 Amps Output)
• High to ultra high charge rates providing tremendous speed for recharging
  • Many LiPO4 batteries offer charde rates up to 1C
    • Example:
      • A "mystery" 100Ah LiPO4 battery rated at 1C continuous charge (100 Amps Input)
• Unlike lead-acid/AGM, LiPO4 does not need to be recharged after discharge from 99% to 30% SOC.
  • LiPO4 should not be left below 30% SOC (State of Charge) for an extended period of time (measured in days) as the long term result is 10-15% reduction in cycle life.  This is a truth of LiPO4 battery chemistry.
• Unlike lead-acid/AGM, LiPO4 can be discharged to 20% without impacting the cycle life of 6000-8000 cycles

 

[CAT Stephen]

On 9/23/2024 at 8:10 AM, cbr046 said:

Sam's Club GC2 $120 x2 = $240 for 12V @ 215Ah . . . . or Docan $380 for 12V @ 230Ah.  Seems like a pretty good deal (and for an extra $30 I'd get the 300Ah anyway . . . x2).

But it's always "everything else" holding me back.  Whether legacy Magnum or Xantrex, they aren't made for charging / maintaining LiFePO batteries so I'd be looking at a new LiFePO capable inverter anyway . . . and might as well get PSW . . . . with a 3000W upgrade. 

Same for alternator charging.  While some trust the engine alternator to not overheat, or send overvoltage to the battery, I'd still go with a DC-DC charger. 

And a monitoring system, with Bluetooth of course.

So $820 for LiFePO sounds like a "deal" (and it is), it's the other $2000 I'm concerned about.  And haven't even thought about solar yet. 

But still very tempting . . . .

- bob

Hello @cbr046,

 

If you go the Vicrton Energy route like I did, you will drop ~$2K for the Victron Energy Multiplus II 3KVA Inverter Charger and needed accessories (shunt, battery disconnect, ect.) and get a 6 year bumper to bumper warranty (available only from https://currentconnected.com) with premium white glove support.But, if you are seeking high value and are willing to forgo a long term warranty and associated premium support, I recommend that you consider this all-in-one combination inverter/charger/solar controller.  This controller brand (MPP Solar) has been extensively tested by Will Prowse and IS THE VALUE LEADER in the industry:

• https://watts247.com/product/pip-3048lv-mk/
  • Keep in mind that this unit runs on a 48VDC battery bank, so you would also need to buy a 48V-12V step down buck transformer for your current 12V house system.  I recommend the following buck transformer in this application:

    • https://www.amazon.com/Cllena-Converter-Regulator-Waterproof-Transformer/dp/B07RGLDX61/ref=sr_1_4?crid=GU59COJ6RA6G&dib=eyJ2IjoiMSJ9.WG-g9zxI5BZkGUbgva7vNAA6JugL_8SBWHSuMP4nUIm7R1geYlDgZph2_VRkzTSLCJa9YMt8hXwlv-SFjvPgDBshJAJx7XloRNbzm_7j97WxZ3aitoteMO4HGcFis0zoHydQI96AwJYN-zgJu_EaeEWs3WStteKodfW-p1sm29hTwnzD-seWYrDmuhTKi97Q3JjDYafFIT8hPlMp30gqnOva-I9T5odKg7IXcq6EsRE.oWcpJlmzPhViN5e_23vREQcoIMkmUD9OFv8UkyahhTY&dib_tag=se&keywords=48v%2Bto%2B12v%2Bconverter%2B100a&qid=1727228384&sprefix=48v%2Bto%2B12v%2Bconverter%2Caps%2C189&sr=8-4&th=1

 

 

[pwhittle]

@CAT Stephen I have read and considered all that you posted above many times before but thought I would try these Docan Power Batteries. They were less than half the price of replacing the Lifeline AGM’s that were in there, and so far have out performed them.

My Magnum MS2812 is configurable enough to use but it is admittedly an upgrade from the 2005 MSW inverter that was original equipment. I was already using the custom settings with my AGM batteries to compensate for the long battery leads that Monaco installed. Also the ML-ACR replacement of the Big Boy adds to the simplicity and flexibility of the system.

if I still had the original inverter and the Big Boy, I would likely have made a different decision, but based on my personal observations, I would buy these batteries again for whatever solution I decided on.

It has only been a few months, but so far my experience is very positive. I will report back again, positive or negative.

[Tom Cherry]

12 hours ago, CAT Stephen said:

@Tom Cherry,

Here are the LiPO4 battery facts:

• To maximize the Cycle life of any LiPO4 battery to yield 6000-8000+ discharge cycles, the battery should not be discharged below 20% on a regular basis. 
  • Discharging below 20% on a regular basis shortens the cycle life by ~15-30%, regardless of false claims by shady LiPO4 battery manufacturers.  Its just a truth of LiPO4 battery chemistry.
• To maximize the Cycle life of any LiPO4 battery to yield 6000-8000+ discharge cycles, each LiPO4 battery model requires the use of custom charging parameters. 
  • Unlike lead acid / AGM batteries, each LiPO4 battery manufacturer specify precise charging parameters that must be utilized to obtain 6000-8000+ discharge cycles.
  • Using a lead acid charger with an LiPO4 battery bank will result in charger faults and potential damage to other electrical system components.  Any manufacturer that claims otherwise is providing deceptive marketing information as the truth is driven by LiPO4 battery chemistry.:
    • https://www.relionbattery.com/knowledge/can-i-use-my-existing-lead-acid-charger-to-charge-lithium-batteries
    • https://www.offroadliving.com.au/blog/our-blog/can-i-charge-my-lithium-battery-with-a-lead-acid-c/?srsltid=AfmBOopl9BWDABteNdAWOzTz_g1elRTpCMwguA_YjDwRUlaTPxEhnCWV
  • LiPO4 battery banks absorb very high current resulting in rapid charging. 
    • This very high current absorption during charging can damage lead acid chargers and will destroy alternators that are designed for lead acid battery systems.
• LiPO4 Batteries have a very flat and narrow voltage operating band, thus a negative shunt is required to count electrons to determine the true state of charge if integration with other systems is desired.  Additionally, each shunt must be programmed with the parameters specified by each battery manufacturer to provide an accurate state of charge
  • Some LiPO4 batteries have a bluetooth enabled BMS which permits the use of an android or IOS proprietary application that provides the LiPO4 state of charge without a negative shunt, but these standalone proprietary bluetooth solutions integrate with nothing in an RV or a marine application and are generally only useful in stand-alone use cases such as an electric trolling motor where there are no other systems present to integrate with. 
    • Some users elect to utilize the built-in LiPO4 BMS cutoff, but the BMS cutoff is always below 20% depth of discharge which results in shortened cycle life of by ~15-30%

LiPO4 Cons:

• A lithium conversion requires the  existing lead acid inverter charger be replaced with a modern LiPO4 capable inverter/charger which is a significant investment.
• The LiPO4 battery market is currently flooded with very poor quality products made by chinese manufacturers that sell substandard products which have severe reliability issues.  These manufacturers are also infamous for publishing false marketing claims.  To avoid these issues, only purchase LiPO4 batteries from the following manufacturers that offer seven (7) year+ warranties with top build quality:
  • SOK (High value)
  • Chins (Best value)
  • Lithionics (Expensive) 
  • Battleborne (Expensive) 
  • BigBattery (High value)
  • EG4 (High value)
  • Epoch
  • Midnight Solar
  • Victron Energy
  • Sol-Ark
  • Others per testing by Will Prowse:
    • For LiPO4 battery reliability and build quality tests, Will Prowse provides independent best in the industry LiPO4 battery reviews:
      • https://www.youtube.com/results?search_query=will+prowse
• LiPO4 batteries are very bad for the environment as they can not be recycled and can / do leak toxic chemicals in landfills
  • Although Lead Acid and AGM use lead, lead is fully recyclable

LiPO4 Pros:

• Extreme cycle life (6000-8000 cycles) versus Lead Acid / AGM (~200 Cycles)
  • Extreme value versus Lead Acid / AGM due to extreme cycle life (3000% to 4000% higher cycle life)
    • For RV and Marine applicaitons, the result can be a tremendous long term cost savings for boon-dockers versus lead-acid/AGM
• High to ultra high discharge rates providing tremendous performance for inverter applications
  • Discharge rates are measured in "C" as a function of Amp-Hours regardless of nominal LiPO4 battery voltage
    • Example:
      • A "mystery" 100Ah LiPO4 battery rated at 5C discharge for 2 seconds (500 Amps Output) 2C discharge for 1 minute (200 Amps Output) and 1.5C continuous discharge (150 Amps Output)
• High to ultra high charge rates providing tremendous speed for recharging
  • Many LiPO4 batteries offer charde rates up to 1C
    • Example:
      • A "mystery" 100Ah LiPO4 battery rated at 1C continuous charge (100 Amps Input)
• Unlike lead-acid/AGM, LiPO4 does not need to be recharged after discharge from 99% to 30% SOC.
  • LiPO4 should not be left below 30% SOC (State of Charge) for an extended period of time (measured in days) as the long term result is 10-15% reduction in cycle life.  This is a truth of LiPO4 battery chemistry.
• Unlike lead-acid/AGM, LiPO4 can be discharged to 20% without impacting the cycle life of 6000-8000 cycles

 

Ya KNOW….this just MIGHT appear in a “session” at the Gathering.  Thanks as usual for the concise and informative format….

You KNOW why I am “GATHERING” info…. 
 

THANKS….

[wamcneil]

11 hours ago, pwhittle said:

@CAT Stephen I have read and considered all that you posted above many times before but thought I would try these Docan Power Batteries. They were less than half the price of replacing the Lifeline AGM’s that were in there, and so far have out performed them.

My Magnum MS2812 is configurable enough to use but it is admittedly an upgrade from the 2005 MSW inverter that was original equipment. I was already using the custom settings with my AGM batteries to compensate for the long battery leads that Monaco installed. Also the ML-ACR replacement of the Big Boy adds to the simplicity and flexibility of the system.

if I still had the original inverter and the Big Boy, I would likely have made a different decision, but based on my personal observations, I would buy these batteries again for whatever solution I decided on.

It has only been a few months, but so far my experience is very positive. I will report back again, positive or negative.

It's a slippery slope... If you rip out the entire system, extensive rewiring, complete re-engineering of the system, there are some awesome advantages to be gained. 

But you can also gain a lot of advantages by simply upgrading within the stock configuration. Like you said, that ms2812 is configurable enough to take advantage of the new battery technology. Just upgrading the batteries sounds to me like a great cost/benefit ratio in your case.

[pwhittle]

Right Walter.

My batteries only upgrades worked for me in my situation.

i really started this thread to share my personal experience with the Docan batteries more than my upgrade.

Their price point is as low as I found, and I think it may be lower than if I built the packs myself.

Paul 

[Tom Cherry]

TO MAKE IT CLEAR….this is a GREAT  DISCUSSION.  We have had many such.  Paul’s background and expertise is a resource. I am “making comments” for knowledge as well as to sort of provoke some meaningful discourse. The Topic and the others will be one of the critical components that will be blended into the BATTERY 101 discussion.  So.  Keep it civil and going….. It sort of, to me, takes a different approach.  Some previous ones were great.  Some had the “MUST DO THIS….ONLY LOGICAL THING TO DO”….as in, Lithiums are the salvation of RV Battery issues.  

Thanks for understanding….and feel free to comment, as long as it is “factual” and practical and obeys the underlying professional discussion parameters of the site.

 

 

[cbr046]

Victron (and maybe a few others) seem to be the gold standard for battery / solar / inverter integration.  But that excellence comes at a cost . . . . monetarily!

@CAT Stephen mentioned MPP Solar with a solution for their 48V 3000W inverter.  They also make a 2500W inverter that outputs 24V, perfect for 2 LiFePO batteries in series . . . . but does a user still need a DC-DC transformer for 12V coach systems or is 12V duty light enough to just draw off one battery? 

Then there's the solar side . . . 600W @ 24V = 25A.  Without a separate solar controller those would be some pretty hefty cables coming off the roof!

Not questions to be answered here but would make good round table discussion at the Gathering, including other "non-Victron" solutions.  Docan vs Battleborn is a good example . . .

Just thinking out loud . . .

- bob

[wamcneil]

1 hour ago, cbr046 said:

. . . . but does a user still need a DC-DC transformer for 12V coach systems or is 12V duty light enough to just draw off one battery? ...

- bob

Do you mean tap 12v from one of the 24v series batteries? Absolutely not. Must not do that with lithium batteries.

No round-table discussion needed... That would throw the two batteries out of balance very badly. 

But... I think higher voltages would be a great subject for the discussions. In my opinion it's just dumb to build high current systems around 12v. It would be great to have consensus on the best approaches to implement 24v or 48v inverter systems. 

Edited Thursday at 03:35 PM by wamcneil

[Jeff H]

On 9/24/2024 at 9:42 PM, CAT Stephen said:

Hello @cbr046,

 

If you go the Vicrton Energy route like I did, you will drop ~$2K for the Victron Energy Multiplus II 3KVA Inverter Charger and needed accessories (shunt, battery disconnect, ect.) and get a 6 year bumper to bumper warranty (available only from https://currentconnected.com) with premium white glove support.But, if you are seeking high value and are willing to forgo a long term warranty and associated premium support, I recommend that you consider this all-in-one combination inverter/charger/solar controller.  This controller brand (MPP Solar) has been extensively tested by Will Prowse and IS THE VALUE LEADER in the industry:

• https://watts247.com/product/pip-3048lv-mk/
  • Keep in mind that this unit runs on a 48VDC battery bank, so you would also need to buy a 48V-12V step down buck transformer for your current 12V house system.  I recommend the following buck transformer in this application:

    • https://www.amazon.com/Cllena-Converter-Regulator-Waterproof-Transformer/dp/B07RGLDX61/ref=sr_1_4?crid=GU59COJ6RA6G&dib=eyJ2IjoiMSJ9.WG-g9zxI5BZkGUbgva7vNAA6JugL_8SBWHSuMP4nUIm7R1geYlDgZph2_VRkzTSLCJa9YMt8hXwlv-SFjvPgDBshJAJx7XloRNbzm_7j97WxZ3aitoteMO4HGcFis0zoHydQI96AwJYN-zgJu_EaeEWs3WStteKodfW-p1sm29hTwnzD-seWYrDmuhTKi97Q3JjDYafFIT8hPlMp30gqnOva-I9T5odKg7IXcq6EsRE.oWcpJlmzPhViN5e_23vREQcoIMkmUD9OFv8UkyahhTY&dib_tag=se&keywords=48v%2Bto%2B12v%2Bconverter%2B100a&qid=1727228384&sprefix=48v%2Bto%2B12v%2Bconverter%2Caps%2C189&sr=8-4&th=1

 

 

So I could remove my inverter and put this plus a step down transformer and be done???

Sounds too easy.

[Benjamin]

It's never that easy. Close if you remove all connections the the old batteries, and wire the new ones directly to the all in one.  You still would want to figure out alternator charging, I'd have to look into if that will work with the PV input, probably not very well, but enough for some.  Cummins is coming with 48v alternators soon (engine emissions use only, but that could be changed), so that could change the house setup for class A's, THEORETICALLY. I'm not holding my breath waiting for an electrical system integration like the Winnebago ERV demo. 

I agree the all in one, and at 24 or 48v makes way more sense than a jumble of blue boxes and large wires for a victron system.  Problem is, victron has the reputation we'd all like to sleep soundly in a plastic an kindling box, and I just can't go for adds that are heavy on stars, close out/overstock, and limited time only.  I hereby decree consensus that all NEW systems over 2kw inverter or solar be 24v, and over 3kw be 48v, how's that*.  Yes, absolutely do not draw 12v from one battery wired in series at higher voltage, it was very bad for lead acid when it was done, and it's much worse for Li.

edit: check out Will Prowse's EG4 all in one system and review, that "looks" like a more reputable model, and the brand of server rack batteries I see more often, so trust by familiarity.  When I get there, the EG4 seems like the top contender. 

Edited 1 hour ago by Benjamin