Batteries

[SailorSam]

A fully charged lead/acid battery will not freeze until temps get somewhere near -90F. The only issue with cold temps is possibly dropping it while cold and cracking the plastic battery case. Modern batteries do not need to be stored on a board, the idea that putting them on concrete is an issue no longer applies - it was an issue 50 years ago.

In my mind, the only reason to take batteries out of an RV is if you have serious concerns about them being stolen.
If you remove them, put them somewhere cold. As was noted, the colder they are the slower they self discharge. At +50F self discharge is a serious issue.

I suspect the common killer of batteries over winter is people putting them on any kind of charger and not monitoring the water level. Charged and disconnected you don't have to worry about this.
If you have a battery disconnect switch, make sure it disconnects EVERYTHING. A CO detector will kill your batteries faster than you would think. To be certain all loads are disconnected, take off the negative battery lead.
According to the US Army COE, a fully charged lead acid battery can be stored "virtually forever" at 0C.

[Dave Pelletier]

Originally Posted by SailorSam

A fully charged lead/acid battery will not freeze until temps get somewhere near -90F. The only issue with cold temps is possibly dropping it while cold and cracking the plastic battery case. Modern batteries do not need to be stored on a board, the idea that putting them on concrete is an issue no longer applies - it was an issue 50 years ago.

In my mind, the only reason to take batteries out of an RV is if you have serious concerns about them being stolen.
If you remove them, put them somewhere cold. As was noted, the colder they are the slower they self discharge. At +50F self discharge is a serious issue.

I suspect the common killer of batteries over winter is people putting them on any kind of charger and not monitoring the water level. Charged and disconnected you don't have to worry about this.
If you have a battery disconnect switch, make sure it disconnects EVERYTHING. A CO detector will kill your batteries faster than you would think. To be certain all loads are disconnected, take off the negative battery lead.
According to the US Army COE, a fully charged lead acid battery can be stored "virtually forever" at 0C.

Good post. A good charger mitigates water use and is strongly recommended. For examply my multi stage progressive dynamics multi-stage charger has a storage mode that "Maintains charge with minimal gassing or water loss." but yes, you should always check the water levels every so often.

I don't disconnect my batteries because to do so would cut off power from the converter charger as well as the solar charger as I mentioned in a previous post.

[Soppy]

I fully charge my batteries , then disconnect them when I put my motorhome into storage. They sit in the cold Northern Ontario winter untouched till the snow melts in May . The voltage will be 12.7 when I reconnect them. My current set (house and starting) batteries are 14 yr old AGM batteries. The cold actually prolongs the life of the battery.

[Persistent]

Originally Posted by TralrVirgin

Hello all. There’s a lot of battery questions on this forum, here’s a silly one.

With my TT plugged in I understand it trickle charges my batteries (two 6v in series). Still I feel bad for them sitting out in the cold when I’m parked for long periods of time.

Does it make sense to periodically isolate them from the trailer a fully charge with my portable smart charger, or is this a waste of time?

Opinions?

Rule #1 for storing lead acid batteries.

Always store lead acid batteries fully charged. Fully charged means 14 to 18 hours on a high quality charger like those often installed in RV's. It takes that long to clean sulfate crystals off the lead plates. Abused batteries may benefit from 24 hours charging.

Battery terminal voltage of 13.2 or higher for at least 10 hours is required.

Rule #2 for storing lead acid batteries.

Always fully recharge lead acid batteries before battery terminal voltage drops below 12.4 volts. 10 to 14 hours is required.

I have attached a PDF file documenting some good methods for storing lead acid batteries.

[TralrVirgin]

Interesting. In my case the trailer is parked but in use, so it’s not exactly ‘storage’. It needs to stay plugged in.

All the batteries run is the water tank and waste tanks level monitors when the trailer is plugged, as far as I can tell.

Definitely an updated/upgraded converter charger is in its future.

In the meantime, I like the idea of an Inexpensive clamp on monitor, for piece of mind. I have a battery kill switch wired in, I would have to use that to use a monitor when plugged in, I would think. Consequently adding a little inconvenience of having to disconnect the monitor and switch on batteries to check the tanks.

Previous owner wired the kill switch into the positive side of the battery circuit for some reason. My question is, if I were to do the above method, would it be prudent to wire a kill switch on the negative side as well, to avoid any back feed or whatever to the monitor from the trailer? I’m no electrician.

[Persistent]

Originally Posted by TralrVirgin

Interesting. In my case the trailer is parked but in use, so it’s not exactly ‘storage’. It needs to stay plugged in.

... battery kill switch wired in, ...
Previous owner wired the kill switch into the positive side of the battery circuit for some reason. My question is, if I were to do the above method, would it be prudent to wire a kill switch on the negative side as well, to avoid any back feed or whatever to the monitor from the trailer? ...

The "kill" switch is properly installed in the positive battery cable. You do not need a second "kill" switch in the negative cable.

Just turn the switch back "on" for the gauges to work.

How to store lead acid batteries.
Fully charge for 14 to 18 hours.
Check water level. (Charging consumes water.)
Disconnect using the kill switch.
Monitor battery terminal voltage periodically until you are sure voltage will stay above 12.4 volts.
Flooded cell batteries in good condition will stay above 12.4 volts for up to 6 months.
Fully charge for 14 to 18 hours before voltage drops below 12.4 volt.

You can probably get a digital voltmeter at your local hardware store for $10 to $20.

[Marine359]

Why bother with all this mind numbing madness about “managing” your batteries. For $300 OP can buy a single 100ah LiFePo4 and forever forget about caring for batteries. Unless you live in a climate with prolonged periods of sub zero temperature, you can just put a LiFePo4 to sleep at 60% SOC, and when you wake it up you’re right where you left off. Life is too short to spend time taking care of batteries. I’d rather use that time fixing things on my rv that broke.

[Dave Pelletier]

Originally Posted by Marine359

Why bother with all this mind numbing madness about “managing” your batteries. For $300 OP can buy a single 100ah LiFePo4 and forever forget about caring for batteries. Unless you live in a climate with prolonged periods of sub zero temperature, you can just put a LiFePo4 to sleep at 60% SOC, and when you wake it up you’re right where you left off. Life is too short to spend time taking care of batteries. I’d rather use that time fixing things on my rv that broke.

...but nothing has broken on my rv so I have nothing better to do!


Dave

[hamm2018]

[QUOTE=TralrVirgin;6069896]Interesting. In my case the trailer is parked but in use, so it’s not exactly ‘storage’. It needs to stay plugged in.

All the batteries run is the water tank and waste tanks level monitors when the trailer is plugged, as far as I can tell.QUOTE]

If you have a radio, AM/FM/CD player, it is also powered by the batteries when plugged in. Also include the CO2 detector as being plugged into the 12VDC circuit.

[TralrVirgin]

Originally Posted by hamm2018

Also include the CO2 detector as being plugged into the 12VDC circuit.

Seems like not. The light on my gas detector says on with batts off. I guess I could test it with some hair spray, see if it beeps with batts off.

Originally Posted by Dave Pelletier

...but nothing has broken on my rv so I have nothing better to do!

Yup pretty much . Just waiting for the next problem.

[SailorSam]

Originally Posted by Marine359

Why bother with all this mind numbing madness about “managing” your batteries. For $300 OP can buy a single 100ah LiFePo4 and forever forget about caring for batteries. Unless you live in a climate with prolonged periods of sub zero temperature, you can just put a LiFePo4 to sleep at 60% SOC, and when you wake it up you’re right where you left off. Life is too short to spend time taking care of batteries. I’d rather use that time fixing things on my rv that broke.

OP lives in Calgary AB. I suspect the trailer is stored nearby and subject to "prolonged periods of sub zero temperatures".

[mdecastra]

I have 4 boats,1 TT, and I golf cart. All of them use lead acid batteries and I check the charge level every month during the winter when any of them are not in use.

The first year, I lost 6 golf cart batteries because they went dry.

I now have a system install on top of all golf cart batteries to ensure water level is full.

See attached:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Every other month, I take 1 gallon jug of water and go around and attach my filler tube (which takes water from jug and attaches to the end of the tube on my battery top). Then squeeze the water from my jug until it's hard to pump. I am confident the water level is full.

I do take my boat batteries out because it is easier to keep charge during the 9 mo off period. They are lined up on my shop floor on a wooden blank and I connect a battery charger and just go down the line.

I do loose them eventually (especially boat battery). Someone once told my to replace them every year.....I keep mine for many years (some are 4-5 years old).

[xc-mark]

My suggestion for anyone like myself that leaves battery in there powersports toys and RV's to install a battery charger designed to Desulphated-bulk charge-absorbsion charge and storage charge all with temp compensation. I had a simple 2 amp charger on one group 31 interstate battery. AS of today, it is 11 years old and still starts the skid steer, I will admit it's not as strong as the day it was put in! The skid steer is stored in a 20' shipping container in central NH and every winter it will see -25*F a few times and regularly will be -10*f overnight.

Depending on your battery bank size you will need a bigger charger then 2 amps, The 10 amp versions are rated for around 200 amp hours. If you have more than 2 battery's I would suggest going to a Victron IP22 30A charger for maintaining your RV banks. I tried using a 8 amp on my 540 amp hour battery bank it didn't have enough output to push the voltage into absorsion stage on a flooded lead acid bank (it was only rated at 250 amp hours).

The battery minder can be installed in damp or dusty locations , the victron IP22 can not be installed in damp and dusty locations. Victron sell a IP68 charger but is NOT temp compensating by itself. Ther is two versionss of the victron a 15A and 30amp both are available with one or three outputs. the 30amp version had no problem charging my 540 amp hour bank from 50% SOC and it is fully programable for your future battery plans . Flooded , AGM , Lithium , custom voltage are not a problem with a simple smart phone APP from victron . The App shows you the current real time voltage, amps and what phase of charge it is doing.

https://www.batteryminders.com/batte...er-desulfator/


https://www.victronenergy.com/charge...t-ip22-charger