AGM battery care/storage during Ohio winters

Corbinpilo

I was advised by my RV dealer to remove and store/trickle charge our T@B's battery in our house during the winter. However, I've come across information that's says that wasn't necessary for AGM batteries. If I leave it in the trailer it will be connected to "shore power" by plugging it into our house. 

Knowing how cold Ohio winters can be what would you do (besides moving to somewhere warm ? Would it cause any problems by keeping it installed in our (now winterized) T@B?

Thanks, 

Chris 

jkjenn

Your Pittsburgh neighbor left here's plugged in all winter and left the battery in the T@b with no apparent negative ramifications. @Michigan_Mikehas posted that the factory didn't recommend just leaving the T@b plugged in all of the time as a battery maintainer, but didn't state why not. Mike, did they give any reasons?

Lisa33

I'm in PA and have left my batteries out all winter for three winters.  Mine aren't AGM, though.   They are charged via solar all winter long even with the cover over the panels on the trailer.

jkjenn

Lisa33 said:

They are charged via solar all winter long even with the cover over the panels on the trailer.

I have to ask....this seems to defy logic. How were you getting any light with the panels covered?

Lisa33

The light filters through.  All I can say is that they maintained a full charge for two winters without plugging in at all.  Of course, I have 300 watts of solar panels.  

jkjenn

Lisa33 said:

The light filters through.  All I can say is that they maintained a full charge for two winters without plugging in at all.  Of course, I have 300 watts of solar panels.  

That's pretty cool!

Lisa33

I definitely consider it one of the huge benefits of installed solar!

Michigan_Mike

jkjenn said:

@Michigan_Mikehas posted that the factory didn't recommend just leaving the T@b plugged in all of the time as a battery maintainer, but didn't state why not. Mike, did they give any reasons?

In as much as the manufacturer of the electric converter says it's okay to leave it plugged in, the factory suggested that this should be done on an as needed basis ( a week or two, then unplug it) and in moderation to help preserve the unit and allow for a longer life span for the converter.  

I guess it's like anything else, if you use things sparingly and as needed the chances of of a failure "might be" diminished, as heating via use and operation do tend to wear on electrical appliances over time and can lead to premature failure. I'm sure this topic could be debated either way and the bottom line here it is up to the individual as to how they use the converter and trailer. 

bgualtieri

All of the battery issues and advice has been mostly over my head (I'm a nurse, not an electrician -- I can read your EKG but not the wiring diagrams)

but

I have to say that even in our Phoenix heat, the electrical system has maintained fine without solar tenders or in between hookups. We got our T@b the beginning of May and the longest time it sat idle between trips was from the middle of August to October 11th when we set out for California. The T@b sat unplugged to anything special, in the heat, and with no battery isolater switch. Everything was switched off every time but I presume any "vampire" draws were in effect.

After driving 3 hours or so on average to our destinations, when we hooked to shore power each time, everything worked fine. I hate to jinx myself but it seems less complicated and more reliable than others have found. Is my experience unusual?

Michigan_Mike

bgualtieri said:

After driving 3 hours or so on average to our destinations, when we hooked to shore power each time, everything worked fine. I hate to jinx myself but it seems less complicated and more reliable than others have found. Is my experience unusual?

The problem of parasitic or vampire draw as you describe it (LOL) is most prevalent or noticeable if your trailer is going to sit idle for extended periods of time, lets say a couple of weeks or even a few months without a charge or hooking it to your vehicle, etc.  Things like LED light circuits, TV/stereo circuits, USB ports, etc. do require and draw a minimal amount of voltage from the battery if they are left plugged inside the trailer.  The same thing occurs with your car or any vehicle that is not operated for an extended period of time because most vehicles today have computer components, security devices, etc. and are drawing voltage from the battery.  This is why snowbirds arrive in Florida/Arizona and suddenly realize their parked vehicle left behind has a dead battery.    

Irregardless of the above examples a battery itself will discharge voltage even when sitting idle and attached to nothing as this is the nature of the beast.  And over time all of the above scenarios will lead to a battery draining down below 50% of its capacity and this is when the battery plates can be damaged over time if a battery is not charged up and maintained properly.  And while cold weather normally brings out the worst in cars via batteries and other equipment, heat too is very hard on batteries, so being in a warmer environment is not in itself a saving grace.  

If you plug your trailer in occasionally at your home for periods of three days straight for example, this will go a long way in maintaining and ensuring longer life and usage of your trailer's battery.  And hooking it up to a battery tender is an even easier means of performing this task and allowing the battery tender to float (topping off the battery charge as needed) and maintaining the integrity of the battery.  Installing a battery shutoff switch is also very beneficial in eliminating the vampire draw and is a silver bullet in helping to minimize this demon  that lurks within your T@B.  

 

bgualtieri

Thank you for the explanation, Mike. The longest she sat idle and unplugged was 8 weeks, and I did hold my breath but all was fine. I think we were lucky. 

Paulie

I was advised by NuCamp to leave the battery in the trailer for the winter, but plug into shore power.  This isn't an option for us, as we have to store the trailer at the dealer and there is not shore power available.  Thus, my husband had to man-handle the battery to remove from the trailer.  We put it on a battery maintainer in the basement, but noticed the other day it has leaked (which I've read should not happen with the AGM).  Anyone else had this experience?  Is the battery still okay?

Sharon_is_SAM

AGM batteries that are fully charged store well without use of the converter or battery tender - even in the winter freeze.  What has it leaked and from where?  Did a seam split?  

pthomas745

Here is a battery FAQ that discusses "self discharge" of different battery types.  My trailer is sitting out back for the last two months, battery switch off, and still at about 12.5 state of charge.  The FAQ says it will discharge at about 2 percent per month.  Find the sections on "self discharge."

https://www.solar-electric.com/learning-center/batteries-and-charging/deep-cycle-battery-faq.html

ChanW

@paulie, It's my understanding that AGM batteries, under normal charging conditions don't need to vent, but that there is a vent available on them, to release pressure in case of overcharging.

Is the battery 'leaking' at this vent? Perhaps the battery maintainer is overcharging.

Can your battery maintainer be relied on to only charge at the maintainance rate that an AGM requires (AGM requirements are a little different from normal flooded batteries)? I recommend Battery Tender chargers for a reliable charger, which can charge (and maintain) both types of battery. 

Your battery might be fine, if the case was that it was only minimally seeping from the actual vent. Remove it from the charger, and check the voltage periodically (every week or so) to see if it's holding a charge. If it does hold a charge, losing minimal voltage over a month or two, you're probably good to go.

Sharon_is_SAM

Good point Chan.  

Paulie

@ChanW the battery was on a DelTran Battery Tender.  It has leaked around both terminals, but seems a bit more significant around the negative terminal.  We "unplugged" it, as I had assumed it may be due to overcharging.  I'd much rather leave the battery in our trailer, as it was a beast to get out!  But, despite being an AGM, it seems the reviews are mixed about leaving it in the trailer and not plugging it in.  To top it off, we appear to have some sort of short in our battery disconnect, so sometimes despite "disconnecting", we still have power.  The dealer cannot seem to track down the issue.

ChanW

Hmmm! 
It seems like you should contact NuCamp, that your battery is in question. It's not supposed to leak! (Unless your Battery Tender is faulty, and is overcharging)

Paulie said:

@ChanW the battery was on a DelTran Battery Tender.  It has leaked around both terminals, but seems a bit more significant around the negative terminal.  We "unplugged" ....

tabiphile

Winter storage for your trailer battery is not the same as storage of an automobile. The auto battery needs to be maintained so that you can restart it and to keep memory settings in the computer.

The trailer can sit over the winter without a battery or even with a dead battery (not suggested). Point being, a tiny voltage drop during storage is not a concern. Don't worry about it.

For a trailer all you need to do is to check the voltage level, charge it up before you store it and disconnect the negative terminal....the very small amount of voltage drop that occurs during storage is insignificant.

In the spring or whenever you get ready to use the trailer again simply recharge and reconnect. There is no need to run a trickle charger or to keep the trailer plugged in while it is in winter storage. Keeping a chrger attached constantly is more likely to cause issues than prevent them.