Magnum ME2012 best practices in storage with shore power

[Steve P]

Our 2008 Knight sits in storage on a 110V 20A outlet for several months when we aren't using it.  I leave the Charger "on" using the remote, but leave the Inverter "off".  The main purposes are to power the water bay heater if needed, to run a separate 1.5A Charger that was in the battery bay when I bought the beast for charging the chassis batteries, and to power our security system using one of the interior outlets.  The security system will notify me if there is a power loss (it uses the cellular network to alert the monitoring center that pushes the notification to their app on my phone).  Which is exactly what I want because it alerts me to contact the storage facility owner before I make a 30 min round trip there. After reading Miriam's recent post on a "Full Charge", a light came on in my head.  By leaving the Charger function on, I may be doing my AGM house batteries harm even though the remote is set correctly for them.  They stay fully charged, sometimes for 6+ months, without me exercising them (which I know I should do from Tom Cherry's helpful posts, and try to do periodically).  I don't think turning the Inverter on will help since I'm on shore power, or will it?  And should I turn the Charger on the remote off?  My remote is the older 4 button, and has no AGS, so scratch that as a fallback rescue plan.

NOTE to self: put a BIRD diagnosis on your to-do list now that you are retired.

[96 EVO]

Well, your doing the same as I have for over 10yrs.

I've seen no downside to doing this. I do cycle the batteries a few times before using the coach. Helps give me better capacity when I do use the batteries.

[jacwjames]

I've owned my coach since 2008 and it has been plugged in most of it's life, usually on a 20 amp circuit to keep the batteries up.   

In 2022 I decided to try and get by with periodic charging and used a timer to charge batteries for 4 hours once a week, it worked but was a hassle to keep up with. 

So I reverted back to just keeping it plugged in but I'm able to check on it on regular basis since it's parked at my house but crap happens.  Last week my wife went into the coach and found the inverter display beeping.  Display said charger was equalizing,   Shut it all off and let the batteries settle down, filled them with 3 gallons of water and over the last 10 days have been trouble shooting, as of now I think the inverter RC7GS display, found a used one and well see if that fixes my problem. 

[96 EVO]

Ours also sit's beside our home.

I'm in it daily, as that's where my cold beer is 😀!

[Tom Cherry]

2 hours ago, Steve P said:

Our 2008 Knight sits in storage on a 110V 20A outlet for several months when we aren't using it.  I leave the Charger "on" using the remote, but leave the Inverter "off".  The main purposes are to power the water bay heater if needed, to run a separate 1.5A Charger that was in the battery bay when I bought the beast for charging the chassis batteries, and to power our security system using one of the interior outlets.  The security system will notify me if there is a power loss (it uses the cellular network to alert the monitoring center that pushes the notification to their app on my phone).  Which is exactly what I want because it alerts me to contact the storage facility owner before I make a 30 min round trip there. After reading Miriam's recent post on a "Full Charge", a light came on in my head.  By leaving the Charger function on, I may be doing my AGM house batteries harm even though the remote is set correctly for them.  They stay fully charged, sometimes for 6+ months, without me exercising them (which I know I should do from Tom Cherry's helpful posts, and try to do periodically).  I don't think turning the Inverter on will help since I'm on shore power, or will it?  And should I turn the Charger on the remote off?  My remote is the older 4 button, and has no AGS, so scratch that as a fallback rescue plan.

NOTE to self: put a BIRD diagnosis on your to-do list now that you are retired.

I’d offer this.

First.  If you haven’t REBUILT your Heater….assuming you have the “beige/brown” cargo heater….then you have NO PROTECTION as those units, 100%, fail. There is a paper in the files that has a step by step procedure on how to do it. It was based on extensive research on the actual cause, a lawyer decided, and a “laid off” ONLY TECH person who came in for an hour and told them what to install….then LEFT….never to return nor test. The “fix” has been tested and works.  Typically the unit fails almost immediately and that is covered in the writeup.  The unit is not the wattage stamped.  It barely pulls 15 amps.  The QC inspector says they run around 14 A. So…at 12 VDC, the heater is rated at less than 1,800 watts.  FWIW, the unit pulls 14 A or 14 Amp Hours….if it runs, say 10 Hours….you have used  60% or more of you available capacity of 50%…or 225 Amp hours.  You don’t have sufficient amperage to recharge properly the next day for another night.

Also, FWIW, the heaters were OK prior to 2005 or so.  In addition, the ONLY failures they have are on the NEW heaters with the “safety” ONE SHOT module.

An alternate would be the following.

Disconnect the batteries.  Leave them in place….

NOW….lets utilize the 20 Amp source.

Purchase a simple “freeze protection” module.  They come on around 35 dF and shut off around 45 dF.  Plug in something like two 100 watt bulbs.  That’s less that 2 amps.  If its really cold, a 300 - 400 watt quartz halogen work light will more than enough heat.  The cargo heater, cycles on and off.  The unit may work fine….we don’t have much data on the original design, except it “eats up power”. SO, at say even 450 watts, you are using less than 4 amps.

Next….power your security from the 120 VAC 20 A line.

NOW….you need to have the APPROPRIATE charger….and folks often “go cheap” and have issues.  The chassis battery needs a 3 stage (Bulk, Absorb and Float modes).  BTW….it takes less than 2 A (1.75 measured) to keep a “connected” battery charged.  The parasitic load is way lower.

NOW… I recommend the PulseTech XC400 works well for Lead Acid Chassis.  Highly recommend.

NOW…your AGM House will require the XC450.  It is designed for AGM.  You can NOT mix the chargers.  They are designed for specific profiles….as well as voltages.  So…if you really WANTED to leave the batteries hooked up…I’d power OFF the Magnum.  I’d actually disconnect the batteries….let them “sit” for up to three months.  Technically they probably do NOT need a “tender”….BUT if you really want to keep them properly charged…then use the TWO. If your Chassis charger IS a high tech model…then keep it on….you can decide to disconnect the Chassis….or leave them on.

That will resolve, more reliably and efficiently, than what you are attempting to even if you bought the two XC units, your total out of pocket will be less than $200 as the halogen light is $20 and the thermal freeze protection is around $15.

I’d use my 20 amp wisely…and not even turn on the inverters.  You WILL need to exercise the House AGM’s…but that would be necessary if you continued to do what you intend to do.

My thoughts….my knowledge…my experience as well as researching and also discussing with others who know the systems..  

[Steve P]

1 hour ago, Tom Cherry said:

I’d offer this.

First.  If you haven’t REBUILT your Heater….assuming you have the “beige/brown” cargo heater….then you have NO PROTECTION as those units, 100%, fail. There is a paper in the files that has a step by step procedure on how to do it. It was based on extensive research on the actual cause, a lawyer decided, and a “laid off” ONLY TECH person who came in for an hour and told them what to install….then LEFT….never to return nor test. The “fix” has been tested and works.  Typically the unit fails almost immediately and that is covered in the writeup.  The unit is not the wattage stamped.  It barely pulls 15 amps.  The QC inspector says they run around 14 A. So…at 12 VDC, the heater is rated at less than 1,800 watts.  FWIW, the unit pulls 14 A or 14 Amp Hours….if it runs, say 10 Hours….you have used  60% or more of you available capacity of 50%…or 225 Amp hours.  You don’t have sufficient amperage to recharge properly the next day for another night.

Also, FWIW, the heaters were OK prior to 2005 or so.  In addition, the ONLY failures they have are on the NEW heaters with the “safety” ONE SHOT module.

An alternate would be the following.

Disconnect the batteries.  Leave them in place….

NOW….lets utilize the 20 Amp source.

Purchase a simple “freeze protection” module.  They come on around 35 dF and shut off around 45 dF.  Plug in something like two 100 watt bulbs.  That’s less that 2 amps.  If its really cold, a 300 - 400 watt quartz halogen work light will more than enough heat.  The cargo heater, cycles on and off.  The unit may work fine….we don’t have much data on the original design, except it “eats up power”. SO, at say even 450 watts, you are using less than 4 amps.

Next….power your security from the 120 VAC 20 A line.

NOW….you need to have the APPROPRIATE charger….and folks often “go cheap” and have issues.  The chassis battery needs a 3 stage (Bulk, Absorb and Float modes).  BTW….it takes less than 2 A (1.75 measured) to keep a “connected” battery charged.  The parasitic load is way lower.

NOW… I recommend the PulseTech XC400 works well for Lead Acid Chassis.  Highly recommend.

NOW…your AGM House will require the XC450.  It is designed for AGM.  You can NOT mix the chargers.  They are designed for specific profiles….as well as voltages.  So…if you really WANTED to leave the batteries hooked up…I’d power OFF the Magnum.  I’d actually disconnect the batteries….let them “sit” for up to three months.  Technically they probably do NOT need a “tender”….BUT if you really want to keep them properly charged…then use the TWO. If your Chassis charger IS a high tech model…then keep it on….you can decide to disconnect the Chassis….or leave them on.

That will resolve, more reliably and efficiently, than what you are attempting to even if you bought the two XC units, your total out of pocket will be less than $200 as the halogen light is $20 and the thermal freeze protection is around $15.

I’d use my 20 amp wisely…and not even turn on the inverters.  You WILL need to exercise the House AGM’s…but that would be necessary if you continued to do what you intend to do.

My thoughts….my knowledge…my experience as well as researching and also discussing with others who know the systems..  

Thanks Tom - using the Inverter (or not) was my main concern. I'm not trying to run without shore power.  It's included in my storage fee.  20A is way plenty.

As to your points: 

I didn't mention that I test my cargo heater each year, but I also have a freeze protection module like farmers use for heating water troughs in freezing weather that I hook to either a light or a small heater in the water bay as a REDUNDANT backup. Plus a temp sensor that interfaces to my security system in the water bay that triggers below 35 DF and above 85 DF (in winter only) and notifies my app.

Battery charger for chassis batteries - I've been using the built-in charger for 4 years, only in winter to keep them topped off.  I have a very expensive charger for my airplane, with a temperature sensor and de-sulfating capability.  If the XC450 can do that, I have no aversion to spending the coin. 

Exercising the house batteries is a given during my periodic visits to the storage facility.  As is running the generator.  

Thanks for the benefit of your experience, research, and discussions with others. You are a key contributor to the success of Monacoers.

[Tom Cherry]

8 hours ago, Steve P said:

Thanks Tom - using the Inverter (or not) was my main concern. I'm not trying to run without shore power.  It's included in my storage fee.  20A is way plenty.

As to your points: 

I didn't mention that I test my cargo heater each year, but I also have a freeze protection module like farmers use for heating water troughs in freezing weather that I hook to either a light or a small heater in the water bay as a REDUNDANT backup. Plus a temp sensor that interfaces to my security system in the water bay that triggers below 35 DF and above 85 DF (in winter only) and notifies my app.

Battery charger for chassis batteries - I've been using the built-in charger for 4 years, only in winter to keep them topped off.  I have a very expensive charger for my airplane, with a temperature sensor and de-sulfating capability.  If the XC450 can do that, I have no aversion to spending the coin. 

Exercising the house batteries is a given during my periodic visits to the storage facility.  As is running the generator.  

Thanks for the benefit of your experience, research, and discussions with others. You are a key contributor to the success of Monacoers.

Thanks….it is something that all the staff enjoy a d do. 
 

The cargo heater, unless it was reworked by the PO, is a “crap shoot”. You can take it apart easily and check the one shot in it.  If it is the ORIGINAL, it will fail.  The amperage that it sees a d the internal heat were not in the operating parameters of the component chosen.  I would not trust it and would have a backup system.  $35 is cheap insurance.

Many members don’t have power and pull their batteries.  They get many years out of them. I have 30 amp and actually “jumper” my batteries and disconnect my BIRD system,  it is, to me, needless to keep current flowing through the Big Boy as well as keeping the BIRD Module “pulsing”. No electronic device will last forever.

I did that for over a year….left the banks hooked up.  Only 2 cycles of exercise and 100% SOC. Our other “electronic” expert fabricated a copper tubing jumper for the Big Boy where I chose a #2 gauge jumper.  He is on the 10th year of his Trojans.

If you have a three stage tender or charger….then unhook the chassis.  The ECM will be fine. The TCM will be reset and Allison recommends that to “unteach” the bad habits. 1.75A will sustain, easily, the chassis.

The XC450 will make care of the AGM and deslfonate them.  And you will not have future issues with the Big Boy contacts….and the BIRD module will get a rest.

Your call….your sense of security….good luck…