Batteries

[Jamtorky]

Is it better to have one 12 volt battery or 2 six volt batteries for your TT???

Oh and is an Inverter neccassary ??

[Jamtorky]

Is it better to have one 12 volt battery or 2 six volt batteries for your TT???

Oh and is an Inverter neccassary ??

[DAN L]

jam...
2 six volts in series are generally better. they don't "cannibalize" off each other as much as 2 12 volt batteries in parallel would. 2 6v vs 1 12v would yield a higher amp hour rating.
volts add up in a series hookup, amps add up in a parallel hookup of multiple batteries.
it really depends on how much room you have and your budget.
2 six volt lifeline 300 amp agm sealed batteries recently cost me $720 from bd batteries online.
i will never have to add water and i was able to mount them on their side for clearance. you can mount them upside down if you want to.
weight is a consideration too. mine weigh 90# each.
the bigger your battery bank is, the more useful an inverter becomes to power 110 volt ac appliances from your batteries.

[LindaH]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Jamtorky:
Oh and is an Inverter neccassary ?? </div></BLOCKQUOTE>
Is it necessary? No. But, if you do camping away from electrical hookups, it sure comes in handy!

[BryanL]

There is no inherent advantage to using 6v batteries in a bank and, no, there is no battery cannibalism.

The energy capacity of your RV battery bank depends primarily on the weight if the batteries. Plan on about 10 watt hours of usable energy per pound. If your single 12v battery weighs about the same as your planned pair of 6v batteries, then the available energy will be about the same.

As for how much battery you need, you should get enough so that each use will discharge the batteries at least 10% but no more than 50%. That means, for a 12v system, that your battery voltage will read 12.2v to 12.4v after they have been sitting for an hour or so with no significant charging or discharging. That will exercise the batteries properly for longest life.

An inverter is only necessary if you need to run household electrical devices off your battery. The inverter converts the battery 12v DC to 110v AC to do this. If you plan to run a microwave or hair drier or other appliance that needs more than a couple hundred watts, the inverter needs careful installation attention.

[aa6vh]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BryanL:
There is no inherent advantage to using 6v batteries in a bank and, no, there is no battery cannibalism.
</div></BLOCKQUOTE>

I will have to disagree. Batteries wired in parallel will have the problem that if one of the batteries goes bad, or is drawn down, the other battery will attempt to "Charge" the bad battery, thus bringing both batteries down. That is what is referred to by "battery cannibalism".

Batteries wired in series do not have that problem.

BTW - You would not want to wire two 12 volt batteries in series, as then you would have 24 volts (by the same token, you would not wire six volt batteries in parallel, as then you would only have six volts. Of course, if 24 volts or six volts is what you want, then go for it. Most trailers though are 12 volt systems).

[BryanL]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Batteries wired in parallel will have the problem that if one of the batteries goes bad </div></BLOCKQUOTE>
any time you have a battery fail in a bank, the bank will suffer. The only difference between serial (6v) and parallel (12v) is how they suffer.

As many note. If you do find a battery failure in a 12v (parallel) bank, you can remove the battery and still have a usable bank. You can't do that with a series bank. There you are stuck with a bank that has reduced voltage.

But the reality is that failure modes of this sort are rare in comparison to the usual sulfation aging. That is the reality that makes the argument rather useless anyway. Cannibalism in batteries is like cannibalism in humans - not something one should have on the list of things to worry about in day to day living.

[FiverBob]

This discussion is missing one important aspect highly important. Normally, when we talk about 6v batteries, we are meaning a deep cycle battery commonly called a golf cart battery. The most common 12v battery used is the RV/Marine which is not a true deep cycle, rather a hybrid, somewhere in between a starting battery and a deep cycle. The life cycles and durability of a deep cycle far exceeds that of the RV/Marine. The typical life span of the RV/Marine is about 2 years if used in much dry camping situations. The typical life span of the deep cycle is more like 5 - 7 years. Further, the deep cycle can be discharged deeper without hurting it than that of the RV/Marine. In the parallel connected battery setup, any unbalance between the two batteries will result in the weaker battery dragging the good battery down with it. When replacing parallel connected batteries, you should always consider replacing them both at the same time - - not necesarily so with series connected.
Bob

[Jayco1]

Would it be ok for me to step in and ask a question concerting 12 Volt batteries?

I will need to replace my two 12 volt interstate RV/Marine batteries in my 5th wheel this winter.

At this time due to space limitation I would like to stay with the two 12 volt batteries but I would like to have true deep cycle batteries to replace the RV/Marine I have now.

My question what would be the best 12 volt deep cycle to purchase.

I like AGE batteries but I believe I would need to change out my factory inverter changing system.

Thank you.

Gaylord Maxwell: follow your RV dream

http://www.youtube.com/watch?v=F9B9H3-6pOU

[BryanL]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Normally, when we talk about 6v batteries, we are meaning a deep cycle battery commonly called a golf cart battery. The most common 12v battery used is the RV/Marine which is not a true deep cycle </div></BLOCKQUOTE>
another myth that seems to have severe tenacity.

The fact is that there is no "true deep cycle" battery available for general RV service. That is, unless you start to play games with the meanings of words ... ;-)

You do not want to make a habit of 'deep discharging' any battery in your RV if you want long life. That means that best life is going to be obtained by not discharging your batteries beyond 50% as a normal thing.

The best battery to purchase would be one designed for your intended service sold by a retailer who sells a lot of them to folks who use them like you do and stands behind what he sells.

see Basic battery guidelines for more on getting the most from your battery bank.

[DAN L]

bryan:
check out mr transisters post for a very good discussion on batteries.
i believe that the best (and most expensive) batteries are lifeline agm's.
i mounted mine on their sides for clearance. you can mount them upside down if you want to.
i got mine from bd batteries on the internet.
they do not charge extra for shipping.

[BryanL]

There are so many "very good discussions on batteries" -- I just wish they were more consistent with each other, had better congruence to basic concepts, and were better sourced ...

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">i believe that the best (and most expensive) batteries are lifeline agm's. </div></BLOCKQUOTE>
I agree that AGM batteries have their benefits.

The question is whether these benefits are worth the cost premium that often exceeds twice the price of an equivalent capacity wet cell. Mounting freedom usually isn't a big deal for many. The higher current handling capabilities can be useful. The sealed nature of the batteries can be nice but requires care if depended upon. After that, I see many who have expectations for an AGM decision that aren't in line with actual experience.

I don't think there is any one definitive answer for every circumstance in this area. I do think that the dissatisfaction many encounter boils down to a few basic issues and that it takes a while before folks figure out that there isn't a magic bullet to solving them. The misinformation and conflicting suggestions and single best solution proclamations tend to make things more difficult for those trying to figure out what is best for them, IMHO.

[Jamtorky]

Wow... what a can of worms ... good discussion though ... I have to thanks BryanL for the link ... plenty of reading there before the big trip... I think I'll start with 2 12v batteries in parallel and go from there .. unless someone else has another suggestion .. I will be mostly be in hook up grounds with a night here or there with out for this trip ... we'll see what happens

thanks for all the info

Jamtorky

[Jayco1]

Thanks for all the information but I would like to ask two questions?

Are there any 12 Volt "true deep cycle" batteries available for general RV service?

Like we have all admitted AGM is probably the best out there but is it not true that AGM requires a real good charging system (beater than the one that comes from the factory) to main Taine them?

Thank you,


Gaylord Maxwell: follow your RV dream

http://www.youtube.com/watch?v=F9B9H3-6pOU