Storage charging House batteries

[Bruce B]

Hello Everyone,

I just replaced the eight house batteries in my coach and I am looking for advice on keeping the batteries charged when it is in storage.  I park my coach in a garage for 7 months when not in use, I could plug into 30 amps but I worry that the water would go low while plugged in.  I use a trickle charger for the two starting batteries that works fine as they are sealed.  Is there a charger that would keep the 6 volt batteries charged without boiling them over time?  I use a charger on a car at home that sits a lot that will 'maintain' the battery and desulphate it if necessary, is there such a thing for eight 6 volts?  I cannot always get to the coach to connect and disconnect it. Good advice appreciated.

 

Thank you!

[Duffer51]

I use battery tender for mine.  It's not a charger.  It comes on only when the charge drops.  Been using this type for 14 years with no problem.  

[WayneC]

I use a solar panel for my starting batteries, I keep the coach plugged in to the 50 amp plug ,I also have Tom cat mouse deterent plugged into every receptacle in the basement and one in the coach.use wet batteries,it will be in storage for 7 months.when I do go to check the water it will not be down that much,gives me a reason to open the trays and do an inspection.

Wayne 

1999 signature ceaser 

[Rikadoo]

Multipul bank tenders

[Tom Cherry]

https://www.pulsetech.net/pro-12-redipulse-12-station-battery-maintenance-unit-gsa-dod.html
 

This is another one that will work.  The issue that is important is that, for example, you will need about 2 amps going to a pair of Chassis Batteries to actually maintain them due to the potential parasitic draw.  From discussions over the years, some tried smaller maintainers but they did not have sufficient power.  

Now you can split up a bank and use a maintainer on each battery.  Since they are in parallel, then the amperage will eventually even out.  PulsePower was one of the leading US companies that pioneered desulfurization.  Many of us are still using their desulfurization modules.  But the batteries should be charging for these stand alone units to work.

The Maintainer must be regulated to prevent overcharging.  In addition, on the house bank, periodic or maybe quarterly maintenance of the electrolyte is needed.

Also be aware that using a maintainer, which is the equivalent of using the Magnum to float charge will NOT keep the batteries at PEAK 100% State of Charge.  There is no free lunch. Per Trojan, as well as the experiences of many of us here is that if you don’t use, as in drain down to say, 50%, your house batteries every few months, even with a Magmum….or a supplemental maintainer, the Specific Gravity and the “robustness” or strength of the cells will deteriorate.

The recommended practice, to get maximum life, is to exercise or drain down the bank every 4 - 6 months using something like a 300 - 400 watt quartz halogen light.  More wattage is bad as that is not what we MH folks use in real life and smaller takes an eternity….especially if you have 8 house.

So….yes, a maintainer will be your backup.  But even a maintained battery, without being used, will eventually become weaker and weaker and when it shows fully charged, that is actually only say 70% or less.

Hope this helps clarify and also explain why using the batteries….as in starting and driving and using the Chassis keeps them more “well toned and condition”.  And I don’t use my house bank that way….so I drain and recharge….maybe 3 cycles …..every 6 months or so.  We have one member with an almost 10 year old bank of .Trojans that will recharge and be at a full 100% based on both voltage and specific gravity measurements. But he is anal about exercising.

The OTHER recommendation is to purchase the Battery Water Miser caps and replace the OEM ones, assuming you don’t have an automatic system.  Many of us, in king the member’s 10 year old set have them.  They don’t vent off water like the regular caps do.  They are miniature distillation caps and the water collect and runs back down.  We rarely add an ounce to per cell.  That makes maintenance easier and also gives you protection in case one cell is “flexing” more and giving up more electrolyte.  Just getting one more year out of a bank more than pays for them.

Good luck.

[Tom Wallis]

My coach came with this Inteli-Power charge wizard which plugs into the converter/charger. I assumed it was from the factory that way but I don't know that. I leave the motorhome plugged in to 50 amps at all times when not in use. I rarely have to add water to the batteries and they are 5 years old. All of the trailers that I owned previous to the motorhome had smart converter/chargers built in that worked the same way. I left them plugged in all the time also. I had assumed that all or most modern RVs were equipped this way but perhaps not. If they are you can pretty much plug them in and not be concerned about overcharging your batteries.

Inteli-Power_20221007_0001.pdf

[Ivan K]

I also leave the rig always plugged in when under the carport or inside the shop, regular extension cord is fine for that. Mostly see zero amps reported by the EMS so it should consume less AC amperage than it can read, with inverter off, salesman bypassed. I let the Xantrex do its job. At float, 13.3V right now, the battery monitor shows 0.2-0.5 Amps DC charge. Some of it will be the PowerPulse unit and various temp and safety sensors that I leave on. That never caused the water level to drop by any noticeable amount over couple of months it might sit in place eventhough that hardly ever happens. 

[cbr046]

21 hours ago, Rikadoo said:

Multipul bank tenders

I had a NOCO 2 that died a premature death.  It may have been lightning related.  I replaced it with a Schumacher maintainer.  I don't know if they have multiple bank chargers but there's nothing wrong with buying multiple units. 

Many of these will maintainer 6, 12, 24V batteries.  Why not connect your batts in series?

- bob

 

 

[Tom Cherry]

3 hours ago, cbr046 said:

I had a NOCO 2 that died a premature death.  It may have been lightning related.  I replaced it with a Schumacher maintainer.  I don't know if they have multiple bank chargers but there's nothing wrong with buying multiple units. 

Many of these will maintainer 6, 12, 24V batteries.  Why not connect your batts in series?

- bob

 

 

Sorry about the NOCO 's untimely demise.  The Multiple Bank units are specifically designed for certain applications.  The PulseTech variation have changed over time.  First there was a 4 Battery (12 VDC) that was designed for a car buff that had units in storage....as well as boaters that had a starting motor for the engine and then multiple trolling or deep cycle batteries.  I set up a neighbor with that one and he actually uses it for his boat (3 batteries) and his truck, which tows the boat.  So it was ideal for him and he is quite happy.  Pulse has migrated to 12 battery banks for multiple storage locations....maybe solar or RV.  However, if you have 8 Coach and 2 Starting batteries, that is 10.  If I had this setup, I would actually double up.  I would put 8 of the outputs on the House and then double up and put two each on the Chassis or starting....as they need more amperage.

They have dropped the 4, which had higher amperage....as in maybe 1.75 - 2 .0 amps....per line out.  So, the current 12 Station, set up as suggested would take care of the OP's issues.

The reason that a high voltage unit would not be my choice is that you would have to removed and then custom jumper the batteries.  With the Pulse, then you leave them set up.  IF you lose your power or your Magnum goes south, then the auxiliary charger would take care of maintenance.  The Pulse units are also the equivalent of the 3 phase (steps) charging cycle that Magnum uses.  So, if you have the Magnum ON, then it will go to float.  With the Pulse also on, it SHOULD cut back charging as the batteries are giving feedback to the charging circuitry.  The added advantage of the Pulse is the Desulfonization....

That's my take on it....I am sure that other brands make multiple charging maintainers....but BE SURE THEY ARE A MAINTAINER....and not a "household charger", otherwise you will fry the batteries....if they are overcharged for long periods of time....as you boil off the water in the electrolyte. 

[Rikadoo]

Mornin, ya know working in the automotive field for an eternity has givin me a solid insite as to the how an why things work, that said before i ever consider a chosen direction i try to get as many facts as i can. Like this issue, first thing i would do is to use a DVOM to assess what is going on, is there a draw? How much, how often. Perform seperate battery voltage loss checks, all of this is simple and easy to do. Then there is matching the equipment with your needs, which when looking at the manufactures of maintainers its a small list comparitvly.  I have purchased several different brands. I could have paid more for more complex bigger units however my needs usually derive from simplicity an functional. Over the years I Learned you never set it an forget it, thats a recipe for “I told you so”.

When it comes to lead acid or AGM batteries once you understand the concept what there tring to do the rest is simple, the maintainer is ONLY there for the battery period! That if you have ANY kind of draw you have just hamstrung its operation, that if you have a draw now you need a charger to overcome that amount all the while keeping your batterys from percolating…

Even if you seperate the battery from the load you can have a draw on the batteries that can defeat the current keeping them “up” (im reminded of a customer that with a class A turned off his battery switches, cause he had a solar bank on the roof figured it was good to go for a year of storage… he didnt account for the racoon that often got into his battery bank and used it for his toilet… several times, that was the most disgusting smell) my point is that just the dirt an corrosion on top of the battery case can cause a significant parasitic draw, let alone the connection from the terminal to battery can affect the charging. I guess where im leading with all of this is, setting it a forgetting it just doesnt work. So many well intended folks Believe all they need to do is buy it, install it an done! Plus so many try applying car an truck daily driver mentality to a coach that is going to be ignored for months on end thinking it will be just fine, it wont! It takes a shift within ourselves to understand though driving them is slightly different but the same, that is where the similarity stops, that your maintance schedule should be if nothing else the same as doting over a child. Just the mere day to day life of automotive electronics change significantly when the humidity changes during a simple rain storm, or parked in a garage where its cold an damp. 
FYI in my daily driver i have come to love a AGM rather than a lead acid battery, in the ten years my jeep had one AGM i cleaned the battery terminils ONCE, an that was only because i thought i should, the Reality was they were just fine, yet had that been a lead acid my maintance program would have been alot different!!!

I honestly believe a maintainer can work just fine on “A” battery however if your gonna use it to maintain Multiple batteries that are interconnected with cables then i believe your maintenance program will need to be spot on. That anything less than that is a recipe for less than stellar performance.

My publisher said perhaps next time concider a book form😂 sorry for it being so long, seems once i see a chance to preach i cant help myself😂

 Not only do i love my coach, i really enjoy talking with like minded folks an the sharing that goes on between us😎

[jacwjames]

This is an older thread but need some advise on keeping my batteries charged.

In the past my rig was parked outside, so my solar panels (326 watt) did a pretty good job of keeping my batteries up, I had it plugged in but I think the solar did a bulk of the work. 

I now have a garage to keep the rig parked and plugged in, don't have the benefit of solar.  I keep a spreadsheet power billing ( and just about everything else).  I've noticed my over all bill up and started to question what was going on and finally pretty much it was keeping the coach plugged in without the benefit of solar.  So last month I decided to turn off both my disconnects and turn the 50 amp breaker off.  I monitored the batteries state via the Victron BVM712 and all was good.  I have confirmed with the billing that my total KW consumption has dropped back down to what it was prior to parking my rig in my garage. 

NOW THE PROBLEM OR QUESTION

I replaced the slides on my battery tray on Wednesday and put the batteries back in, at that point I put a volt meter on the batteries and the read 12.7 volts.  On Thursday I turned the 50 amp breaker on and was surprised that the inverter/charger went into Bulk charging immediately (~14.5 volts) with the inverter display showing 77% state of charge while the Victron showing ~95%.  The batteries were bubbling quite a bit, more then I'd seen in the past.  Waited to see if the charger would drop the charge rate I let the charger run for ~4 hours and it didn't change so I decided to shut it down. 

This AM I checked the Victron monitor and the batteries were at 100%.  Still not sure why the inverter was doing bulk mode, only thought was that the batteries were cold and maybe the temperature sensor compensation resulted in higher charge voltage. 

So now I am questioning the rational of shutting everything down/off and charging the batteries maybe when they get down to ~75% or less.  Does anyone have any thoughts on this??? 

 

[birdshill123]

When we were stuck in Canada due to the pandemic, I put the Dynasty in cold storage. I had all the batteries in my workshop and bought a  battery maintainer with connections for 4 batteries. I have  2 chassis and the 8 6 volts. Would leave the maintainer on the 6 volts for a week and then switch to the 12 volts for a week. Then 2 weeks with nothing. Worked great. Hardly used any water. My workshop is heated to 50 degrees. We keep our Bluebird in Mexico and have a battery maintainer that does the same thing. The young man that looks after the house would connect the batteries for 2 days a week.   Both units have inverter chargers but they consume a lot of electricity.

[jacwjames]

With the solar charging I never really paid attention to the amp draw.  But being parked in the garage it adds up.  My recent experiment shows ~$50/month if I leave it plugged in all the time. 

So is it an option to just monitor battery charge via the Victron and just charge the batteries once they discharge to a certain level???  What would be a good target level?

[Steven P]

My coach has a Magnum inverter/charger.  By default,  when it first powers up, it goes to bulk charging.  The manual talks about the 3 stages of charging and what it takes to satisfy each before it changes stages.   I have a couple of thoughts here, but am not as experienced as a lot of people here.  

When I first bought my coach, the PO kept it stored outside and turned off the battery switches with no charger going to them and it worked for them.  So, that's what I did for probably 6 to 12 months without issue.  Then I figured out I could use 110V, 20A and run my fridge and charger and keep the batteries charged in storage.  I only have a 110v receptacle there, so I plug in and dial my Magnum down to 5A max draw and press the selector to put on 20A.  I have no idea what the power bill is as the storage pays for it (and no complaints from me).  I could see this going bad if I lose power at the storage unit and didn't know.  

Second, check your Magnum inverter settings and make sure they are correct for your batteries.  The inverter charges at different strengths dependent on the batteries you tell it that you have.  The PO had 2 12V marine batteries and when they went bad, I replaced w 4 6V AGM batteries and had to adjust the settings.  Previously I'd hear those batteries Bubbling at times and felt they were being charged too high.  Hope this helps. 

Steven

[jacwjames]

1 hour ago, Steven P said:

My coach has a Magnum inverter/charger.  By default,  when it first powers up, it goes to bulk charging.  The manual talks about the 3 stages of charging and what it takes to satisfy each before it changes stages.   I have a couple of thoughts here, but am not as experienced as a lot of people here.  

When I first bought my coach, the PO kept it stored outside and turned off the battery switches with no charger going to them and it worked for them.  So, that's what I did for probably 6 to 12 months without issue.  Then I figured out I could use 110V, 20A and run my fridge and charger and keep the batteries charged in storage.  I only have a 110v receptacle there, so I plug in and dial my Magnum down to 5A max draw and press the selector to put on 20A.  I have no idea what the power bill is as the storage pays for it (and no complaints from me).  I could see this going bad if I lose power at the storage unit and didn't know.  

Second, check your Magnum inverter settings and make sure they are correct for your batteries.  The inverter charges at different strengths dependent on the batteries you tell it that you have.  The PO had 2 12V marine batteries and when they went bad, I replaced w 4 6V AGM batteries and had to adjust the settings.  Previously I'd hear those batteries Bubbling at times and felt they were being charged too high.  Hope this helps. 

Steven

I pulled my manual for my RV2012 Trace inverter yesterday.  Mine is similar, 3 charging rates.  Since I had had it plugged in all the time is was on float charge showing ~13.4 volts.  It caught me off guard when I saw the display showing the bulk charge and 77% of charge but my Victron was showing ~95%.  I kept watching it and finally just shut everything down.  Then the next day the batteries showed 100%. 

I live in E TN and we have had pretty low $/KW rates,  In Oct 2019 the rate (including the misc fees) was $0.113/kw.  Last month it was $0.137, a 20% increase which compelled me to look at ways to save!!  Some of the increase was a service fee increase and some was an energy charge increase mostly from natural gas.

When we built our new house (4300 sq ft) I used 6" exterior stud walls to increase R value, lots of ceiling insulation plus did a foam flash to completely seal exterior walls.  I even installed 1" styrofoam with the radiant foil on the back side for walls exposed to the attic space.  In Oct 2020 prior to the garage we used 752 KW,  in 2021 we used ~1300, in 2022 we used 960 .  Some of the difference may be temp driven but definitely higher.  Enough for me to look at options on how to keep the batteries charged/maintained without destroying them.

[Ivan K]

My Xantrex also always starts in bulk mode but goes to absorption in a minute if batteries were previously fully charged. I have the AC hookup on a timer while in the shop and all it needs to do is maintaining the batteries but if I need shop space and move it under carport, it is on permanent hookup in case the heater kicked ON. The Wyze wifi timer can monitor consumption but I haven't paid attention to it, until now that it got mentioned.

[jacwjames]

I really never did pay too much attention before when I first plugged in anywhere, just made sure power was on and inverter display was working.  But with the Victron you can actually see charging voltage real time.  I saw it go high and waited to for it to drop but it never did.   Normally it would go to 13.4 volts at some point but I never paid attention as to when.  I didn't see anything in may manual with a specific time.

What cycle do you have the time on, how many hours per day? 

This might be my solution if I choose to leave it plugged in all the time

Still wondering what would be wrong with just shutting the power off and waiting until batteries deplete and then recharge.  Do different then if you are using. 

[Ivan K]

I have the timer ON for 6 hours during daytime but I don't have any reasoning for if, just the way I initially set it. I see nothing wrong with cycling the batteries as you propose if you watch them. I also have the AGS on just in case.  My absorption voltage shows 14.6V and that takes some time, maybe that's what you were seeing? Then drops to 13.4 for float and Progressive EMS shows zero amps, so less that 1 amp AC in reality. I'll pay more attention to when it goes to float and maybe adjust the timer accordingly. I suppose it could be set to only run certain days.

[jacwjames]

Thanks Ivan

You may be right on the absorption mode. 

Since I make almost daily visits to the garage I can easily track the battery SOC, that's what I did last month and the charge went from 100& to ~97% after a month.  I think I'll do the same thing this month and see how it goes. 

Maybe I'm just overthinking this🤬

My work background resulted in me having to pour over spreadsheets.  Does the term Paralysis from Analysis come to mind!!!  And  I was very good at my job!!

Edited November 20, 2022 by jacwjames