Two 6 volt batteries or two 12 volt batteries ??

SoundGuy wrote:

lawrosa wrote:
Good read

http://yarchive.net/car/rv/golf_cart_batteries.html

http://yarchive.net/car/rv/battery_resistance.html

My comments are exactly the same as I posted in your own concurrent thread on this same topic, as follows.



More than a "good read", rather both are great articles from someone who understands much more than the masses here on this forum about the intricacies of deep cycle battery use for RVs, and which is summarized nicely in this statement which I've copied because most won't want to read through either of these links in their entirety. It sums up what a few of us have been trying to explain anytime this subject comes up - why 12 volt jugs in parallel are often the better choice than 6 volt jugs in series for RV use.

"Brian, if you have any large 12 volt loads such as an inverter I predict you will be disappointed with the golf cart batteries. I'll explain.

Two years ago I accepted the advice here in this group without thinking too much about it and replaced my two paralleled group 27 batteries with a pair of golf cart batteries. I immediately noticed several differences. One, anytime I operated a heavy load the voltage sagged MUCH more than it did with the old batteries. My inverter would trip off long before the batteries were discharged because of this. I'm speaking of terminal voltage and not at the other end of a length of wire. I could no longer fast charge them. The internal impedance was so high that they simply would not accept a fast charge without heating. My cordless battery charger could charge the old pair in an hour. It took several hours with the new one. Cranking the genny would drop the voltage so much that the inverter would trip. I got in the habit of hitting the interconnect switch before cranking so that the start battery could do the job.

I did some research like I should have done in the beginning. I learned that golf cart batteries are optimized for long, moderate rate discharges and are NOT designed for heavy loads. This is a mis application. In RVs that don't have heavy loads and don't need to fast charge it is not a problem."

And this has been just my point anytime this discussion comes up - adapting deep cycle 6 volt batteries that were originally designed for moderate, intermittent long term draw in golf carts is not the best choice when one of the main tasks of those batteries in an RV application is to supply power for short duration, heavy load inverter draws. These 2 articles you've linked to are the best I've seen that explains this in terms that are easy to understand, even for the "6 volt or go home crowd". :R

agree completely. I've advised many friends to NOT use a GC when they don't dry camp much and like to run microwaves, toaster etc. on the inverter. Each battery type has advantages and disadvantages. I think some people are oblivious to the disadvantage of a GC. At many RV shows, I've talked to Trojan reps about batteries. Just a "what battery should I use" and EVERY time the first question is "do you like to run a microwave, or electric tea pot etc." then followed by some other use questions. In every case they have said if high current draw is important, then use a 12V deep discharge battery NOT a GC.