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RV Wizard · 03-29-2009, 04:05 AM

My 4 interstate U2200 six volt batteries are 7+ years old and are doing quite well. I have boon docked for a week at a time twice a year but the rest of the time I have been plugged in or running down the road. The biggest thing is to use the right battery for the intended purpose and take care of it; it will take care of you.
"Batteries don't die, they're murdered" !

Minisprint · 03-30-2009, 06:19 AM

I want to thank everyone who replied .
I guess I have a few option's. so today I am going shopping and get pricing .
I like the two six volt GC idea but only have room for two batteries. but I am leaning that way.

Thanks again George

DAN L · 03-31-2009, 03:33 AM

Quote:

Originally Posted by Minisprint

I want to thank everyone who replied .
I guess I have a few option's. so today I am going shopping and get pricing .
I like the two six volt GC idea but only have room for two batteries. but I am leaning that way.

Thanks again George

gel cells are too problematic in charging and use.
agm cells are more tolerant even than flooded cells, and do not require water service. similar to gel cells in that regard.

Tom N · 04-01-2009, 08:57 AM

Quote:

Originally Posted by Forest Grump

The quality of a battery has nothing to do with it's voltage. Trojan makes excellent 12v deep cycle commercial batteries as it does 6v. It takes two 6v to equal one 12v.

Actually, it takes two 6v RV batteries to equal TWO 12v RV batteries.

After 4 years and 2 months my 2 - OEM 12 volts bit the dust. I replaced them with 2 - 6 volts Sams Club golf cart batteries for a total of $145.56.

I've installed hold downs since I took this photo.

-Tom

RVDude · 04-01-2009, 10:06 AM

All opinions aside, to answer the technical question of WHY 2 6v in series is BETTER than 2 12v in parallel:

Batteries wired in PARALLEL (+ to + and - to -) that is, 2 12v batteries, when wired in parallel they are parasitic upon each other. That is the slightly lower 12v battery (no batteries are exactly equal) will feed upon the higher charged battery. This induces an extra load on the batteries and reduces total output. Parallel wiring requires that the batteries be matched by brand/date/size.

When 2 batteries of 6 volts are wired in SERIES (+ to – which gives 12v) they are NOT parasitic. Hence, given exactly equal battery capacity between a parallel and a series setup, a series configuration will have more output. This is why multi battery rigs use the 6v setups - to minimize the parallel connections. In fact, if there are NO parallel strings in your battery bank you can replace any of the 6v batteries in the series string with any 6v battery, they do not really need to be matched BUT it is still far better if they are for charging reasons.

So, go with the 2 6v - it is simply a better way to go. If they made them, 12 1v in series would be the best!

Forest Grump · 04-01-2009, 10:29 AM

Thanks for the humor but each battery cell is in the two volt range, chemistry, and they do make 2 cell wet batteries for about $1400 each which you put in series for your desired voltage.

As for wiring parallel batteries can discharge at different rates, they can also equalize. Cells in a series can also have problems such as shorting out. Lot's of cans are possible but less probable with good maintenance, proper sizing of wiring, a high quality battery and using common sense.

It takes two 6v batteries in series to equal one 12v battery which you coach operates off. You do not need more than one 12v battery to operate the coach. You do need two 6v batteries. If you have only two 6v batteries and loose one you are done. 6 + 6 = 12. 12 = 12.

Now for Ah.

They do make large 12v deep cycle batteries to operate large equipment such as man lifts and floor cleaning machines. One of these is the J-185H size it produces 215 Ah at twelve volts. It takes two 200 Ah 6v batteries in series to equal it in voltage and Ah. There are other batteries made with higher amperages but they are also bigger and heavier which limits their use in a RV. They are a little pricey too.

In your picture you have room for 2 J-185H's which would give you 430 Ah, twice what you have with your 2 6 volt batteries.

Forest Grump · 04-01-2009, 11:38 AM

http://www.sierranevadaairstreams.or...ry-config.html

If you boondock for several days at a time then a higher capacity, i.e. heavier battery is suggested along with solar.

RayandPamT · 04-01-2009, 04:41 PM

Has anyone tryed "Optima Blue Top"

Edw · 04-01-2009, 06:49 PM

I have the Optima Blue Top for my chassis battery. Had just about 1 year and so far so good. Sam's had them with 3 year replacement. As a side note just filled my 3 year old +/- U2200 6v batteries today for first time in a year. each cell was about 1 inch low. Used distilled water to underside of inner tube wall.

tropical36 · 04-01-2009, 09:58 PM

Quote:

Originally Posted by Minisprint

I will have to replace my coach batteries this year.

I have two 12 volt Interstate Batteries in there right now.

I was wondering if there are any other type of battery I should be checking out before I replace with Interstate.

I look forward for some replies

I don't think the name brand is as important as the type of battery, so I would just opt for whatever 12V GOLF CART BATTERIES I could find for the best price possible and go with those.

Tom N · 04-02-2009, 08:42 AM

Quote:

Originally Posted by Forest Grump

In your picture you have room for 2 J-185H's which would give you 430 Ah, twice what you have with your 2 6 volt batteries.

Since I'm the only one that posted a photo in this thread I surmise you're directing this comment to me.

I can fit 4 - 6 volts in the space shown in my photo plus have enough room for the 12v starting battery.

I have no need for that capacity as we only stop for the night and leave the next morning. I only run computers, TVs, DVRs and satellite receivers off the inverter. We always eat dinner out. In the morning we run the hair dryer and I start my 8 kw Onan for that. When driving, if it's very hot, I'll run the generator and the basement AC.

Sam's 6 volt golf cart batteries are the most bang for the buck at $71.28 each, IMHO.

BTW, I've been parked here in FL since Nov. 7th plugged into 50amps.

-Tom

Forest Grump · 04-02-2009, 12:18 PM

Quote:

Originally Posted by RayandPamT

Has anyone tryed "Optima Blue Top"

They do not offer very high Ah capacities and are expensive so your cost per Ah is about as high as you can go.

If you require a high Ah capacity then you are going to end up with a lot of very expensive batteries that should perform well.

If you need just 2 then you have the most expensive 2 you can get with about the lowest Ah rating you can get and they are not serviceable.

RayandPamT · 04-03-2009, 03:47 AM

Quote:

Originally Posted by Forest Grump

They do not offer very high Ah capacities and are expensive so your cost per Ah is about as high as you can go.

If you require a high Ah capacity then you are going to end up with a lot of very expensive batteries that should perform well.

If you need just 2 then you have the most expensive 2 you can get with about the lowest Ah rating you can get and they are not serviceable.

I've recently came to be the proud owner of 12 (new in the box) optima blue top's, and have been wondering what to do with them.