Falcon1

I picked up a cat 8D 12 volt battery for my RV. When connecting it to my existing battery in Parallel is there anything I need to be aware of?
Greg

dodgezilla04

they will not charge to the same capacity. it is best to match batteries by the amp hour ratings.

FiverBob

Here is some good stuff on RV's including batteries.

http://www.phrannie.org/

Click on his poop sheets and find batteries. Very well written and complete.

Bob

Falcon1

Good read. Thank you.

Greg

pronstar

Thanks for the tip. I was about to add a larger-capacity battery to my current setup...

Falcon1

I was told by several sevice departments that do RV's that installing a larger capacity battery in parallel with a smaller capacity battery will not hurt anything.

Greg

supr

For what it is worth, (2) 6 Volt golf cart batteries hooked togerher in series typically provides the best bang for the buck. They do take some space. They could be wired to your existing 12V deep cycle as a future option. These batteries go for about $55 at Sams or Wallyworld.

Falcon1

Ok I just got ahold of 4 heavy duty 6 volt batteries from a man lift. It took 8 to run it. The mechanic at work checked the electro lites in the batteries and are real good, he's putting a charge on them for a load test today if they work out I think I will use two of them in series because of a larger reserve.


Greg

supr

Yes, that is the idea. These batteries are work horses and are often built better than other deep cycle RV batteries.

Falcon1

Thanks I hope it all works out and they are good batteries if not I think I'll pick up a couple of 6 volt batteries from walley world or sams club. So when hooked in series my 12 volt charger and 12 volt converter in my 5ver will work to charge these batteries correct?

Greg

John Faughn

If some one is telling you that connecting different batteries together is not a problem , then stop talking to them about advice , this is wrong .
To build a battery bank [ more than one battery , in series or parallel ] they all need not only to be the same make , model , brand , but same age .
Most charger controllers / converters in RVs do not do a good job , they over charge [ boiling the water/acid out ] .
Some people will say thats its simple to do a battery bank , but it takes a lot of basic electrical/battery knowledge to get your moneys worth , I get a min. 10 yrs of life out of my set ups .

grantx5

I am no expert but I did read as much as I could when we bought our Sunnybrook. The link to Phred site is a good one, read all you can.

With that said, I use 12v 'cause their cheap (I'm cheap). 6v is the best and when I hit the lottery will be my battery of choice. My '99 SB came with 2 12vs. The first one to die died last summer ('06). When it did I replaced it with a new 12v from WalMart (flame suit on). The second one died about 3 months ago. The TT has a charge wizard on it but I still remove the batteries when I get home unless we are going out real soon. I've always used a good battery charger to charge them and always monitor their health on a monthly basis. They are stored indoors and usually charged on a 30-45 day cycle.

Unfortunately it's true that TT chargers tend to overcharge things and use up the water. Make sure to always check the voltage and water level and keep them in shape. I expect 7-10 years out of my batteries.

FiverBob

It is so frustrating when you go to the "experts" and they start talking about things they know nothing about just so they can sell something - - like the truck salesman that tells you his 3/4 ton will handle a 15,000# fiver with no problems. Likewise with some battery people.

A 12v RV/Marine battery is not a true deep cycle - - it is a hybred in between a starting battery (high current) and a deep cycle. Pick up a Trojan T-105 6v golf cart battery, which is a true deep cycle, and the same size RV/Marine - - you will quickly see they are not the same animal. The 6v has much thicker lead plates and will take much more abuse and still keep ticking. It can handle deeper discharges and many more charges than can the RV/Marine. Parallel batteries must be identical or the weak one will destroy the good one. A pair of golf cart batteries will long outlast a pair of RV/Marine batteries with identical care. The next thing to consider is the converter (charger). As Grant said, the cheap converter will charge at a constant voltage regardless of the charge condition of the battery. If the battery is fully charged, it just keeps on charging which will destroy the battery (s).

So, best bet (for the dollar) for lots of boondocking - - 2 or 4 golf cart 6v'ers with a smart charge converter. 10 years battery life is not unusual for this setup versus about 2 for the RV/marine with a cheap converter. Mine are now about 6 years old and still test like new. The best I ever had out of the RV/Marine setups was 2 years if I was lucky.

Bob

White OneTon

I agree with FiverBob . I have been working on battery powered equipment for almost twenty tears now . Although you can get true deep cycle 12vdc batteries they are expensive . I have had very good luck with t-105s and if you want a little more get a t-125 I believe they also have t-145s that are about the same dimensions.
Mark

Jeff in TD

FiverBob is giving good information.

I would avoid using a starting battery, even a huge one from a cat, as a deep cycle. Starting batteries were intended to do tons of cycles, but only a few percent depth of discharge.

Mismatched batteries in parallel will work, in that the lights will come on, but you won't get optimal performance or life.

Unless you have very difficult access to batteries to check water, or plan to leave them out in super-cold weather, I personally don't feel the extra expense of AGMs is warranted over a good set of flooded cell batteries.

I'm currently running Trojan T125's, which perform well. They aren't rated for as many cycles as a T105, but are higher capacity. For a floor buffer or some other machine that cycles the batteries daily it would matter, but for the typical RV the batteries will die of old age first...

This is one of my favorite pages explaining RV batteries...

http://www.wind-sun.com/Batteries/Battery_FAQ.htm