I just bought a new-to-me travel trailer. It's a 1973 21 foot coachman travel trailer. I'm looking at the electrical system and it came with a deep cycle flooded battery. I'm wondering if I can take my deep cycle flooded battery from my previous travel trailer and wire it in parallel to the existing trailer battery to increase my available Ah? I realize everywhere tells you to only parallel the same brand batteries, bought at the same time, but my understanding is this is because your system will only be as good as your worst battery. Are there any safety concerns?The two batteries are different brands, one is about 3 years old and the other is one year old. They are both flooded however one has a higher Ah capacity. Are there any considerations or limitations I should be aware of? My thoughts are, even though it won't be as great as if the batteries were the same, I'll still be increasing my overall available Ah.I won't do it though if there are safety concerns or I could damage my charger or other components of my systemThanks!

No issues while in use.If stored (fully charged) without a float charge I would separate the batteries.I think you know if spending money to get a matched set for best results.

Not a problem if one isn't bad. I would charge each one separately before wiring in parallel. Use large jumper wire between to batts to get a better balance.

Well the fact is what have you got to loose? Run em tell they die then replace with a matched set. You will be that much ahead right? Seems it would be a waste if you didnt use both. The capacity is a non issue anyways. The truth is you could put a new set of batteries and have the same issues as pairing used batteries.

Economics wise, three useable unalike used batteries (whew)...Would find the wisest usage hooked up and working for you. No way could any other alternative render the same service per $A simple solar maintenance panel would kept them fed and minimize cannibalism when at rest.As always the objective is to minimize $ for the total number of kWh service rendered.

Using different flooded batteries in parallel | Good Sam Community

14 Replies

NinerBikes
Explorer
May 13, 2015
When the 12V's take a dirt nap, replace with a pair of GC-2's in 6V and wire in series. No longer an issue.
SirBenji
Explorer
May 13, 2015
grizzzman wrote:

Google anderson pole connector. You can get water proof caps for when disconnected.

Perfect. Thanks!
BFL13
Explorer II
May 13, 2015
Do it while camping and get those extra AHs. Separate them once home and recharge each to actual full (as measured by SG) and then:

A. if no hook ups, leave them separated and goose each once in awhile with a charger, or

B. if hooked up, leave them now individually full but separated and put one on the converter and another on a float charger, (I use this one, but wait for when it is on sale for half price every three months or whatever--it sits forever at 13.4v)

http://www.canadiantire.ca/en/pdp/motomaster-eliminator-intelligent-battery-charger-2a-0111506p.html#.VVKYdWd0xjo

or

C. if hooked up, leave them now individually full but in parallel on your converter.
Shadow_Catcher
Explorer
May 13, 2015
Batteries that are not identical, same age make etc, will default to the weaker of the batteries.
grizzzman
Explorer
May 12, 2015
SirBenji wrote:
jrnymn7 wrote:
Just remember, those loose ends will be live. Find something to cap them with.

Good point. I was thinking of using the connector from my solar panel that allows for interchangeable connectors (o-rings vs plyer grip) and then just snaping it into the panel when I bring it out. Anything you could suggest? Do they even make a plug for something like that? I'll get a pick for you tonight.

Google anderson pole connector. You can get water proof caps for when disconnected.
wa8yxm
Explorer III
May 12, 2015
Done it with no problems.
SirBenji
Explorer
May 12, 2015
jrnymn7 wrote:
Just remember, those loose ends will be live. Find something to cap them with.

Good point. I was thinking of using the connector from my solar panel that allows for interchangeable connectors (o-rings vs plyer grip) and then just snaping it into the panel when I bring it out. Anything you could suggest? Do they even make a plug for something like that? I'll get a pick for you tonight.
jrnymn7
Explorer
May 12, 2015
Just remember, those loose ends will be live. Find something to cap them with.
SirBenji
Explorer
May 12, 2015
Thanks everyone! I agree Grzz, what have I got to lose???

MEXICOWANDERER wrote:

A simple solar maintenance panel would kept them fed and minimize cannibalism when at rest.

I do have an external solar panel. It's a portable unit that I bring out whenever we set up. It has the charge controller mounted right on it. I'm thinking I'll just wire the connections right on to the batteries and run it out of the battery box so I can just snap it on to the panel once I set up. Anyone else have any ideas or would this make the most sense?
MEXICOWANDERER
Explorer
May 12, 2015
Economics wise, three useable unalike used batteries (whew)...

Would find the wisest usage hooked up and working for you. No way could any other alternative render the same service per $

A simple solar maintenance panel would kept them fed and minimize cannibalism when at rest.

As always the objective is to minimize $ for the total number of kWh service rendered.