12 volt rv battery vs 6 volt gc batteries

Glad you got them working. Now you need to figure out the circuitry in your trailer.

Specifically you need to know what your kill switch (battery disconnect) is doing. It may be isolating your solar so your batteries don't receive any charge. And at the same time it might not be isolating your propane detector, which the factories commonly do for safety reasons, but which leave a parasitic drain on the batteries. Ironically you might have shot yourself in the foot by using the kill switch.

In my opinion a battery disconnect should completely isolate the battery bank from everything, including converters or solar chargers. It should be the equivalent of pulling a clamp off the battery post. But OEM they often are not done that way.

You need to understand how YOUR system is wired. Then you will know how to use it. There is no standard in the industry so we can't tell you how yours is set up.

The RV shop you just used sounds pretty sharp and fair. Maybe you should pull your trailer over there and buy an hour of their time. They can explain how it all works and teach you how to use it. Your batteries won't survive too many of these complete discharge episodes.

I went and picked up my Trojan 105 batteries today and they were fully charged. Hector said when they are so discharged it takes several days in order to fully charge them again. He showed me each cell is charged. I asked him "how much" and he said "No charge, on the house". He stood behind his product and work! You can't ask for anything more.
Gary

FWIW, I'm happy with the 2 6v GC batteries I got at Sam's 2 years ago. Still going strong and a lot more capacity than my 2 12v's.

Lyle

If it has solar, the batteries probably don't need to be isolated for storage. Especially in California.

GON2SKI wrote:
I upgraded to two T-105's and discovered discharged batteries after a couple months even though I had shut off the factory kill switch on our 27-5L AF. Some parasitic discharging occurring. I then followed the advice from fellow forum members and installed a knife switch to the battery post and bought a smart charger plus a digital tester to measure both static charge and recharging output. It did take a couple of days to restore to full charge and now everything is holding up fine!

x2 on putting a disconnect right in the battery compartment. I'd be willing to bet that the "whole coach" disconnect is either not hooked up or they missed hooking something up to the switch at the factory. (NO?! Who'd think that?)

Lyle

I upgraded to two T-105's and discovered discharged batteries after a couple months even though I had shut off the factory kill switch on our 27-5L AF. Some parasitic discharging occurring. I then followed the advice from fellow forum members and installed a knife switch to the battery post and bought a smart charger plus a digital tester to measure both static charge and recharging output. It did take a couple of days to restore to full charge and now everything is holding up fine!

I took the two Trojan 105 batteries over to the RV shop were I bought them. A previous mechanic had tested them and said they were dead but the place were I bought them from checked them and said they were completely discharged but he said Trojan batteries were the best ones out there and he thought they were still good. He connected them together to form one 12 volt battery and began charging them. I called back about 5 hours later and he said they were still charging but he said when they were so completely drained it usually takes a long time for them to be completely recharged but he still thought they were still good. I mentioned that I had thought about going with two 12 volt batteries and he said he thought I would be making a mistake. He seemed pretty convinced that they were still good but needed to be fully charged. I hope he is right but I don't know what I did wrong to fully discharge them. I'm kind of apprehensive that I may make the same mistake again if they are still good. I'm trying my best to understand the battery procedures on what to do when they are in the trailer while its in storage. My 29-5T has a battery kill switch, a Blue Sky Solar Boost 2000E, 2 120 watt solar panels and I use the stock connection on the roof. My rig came with the stock charge wizard so if any electrical whiz out there knows the best way to handle my storage problem please speak up. I have been very forgetful lately and maybe I did something wrong and I caused my own problem so what I want to do is draw up pictures on what I should do and the order they are done and have also the written procedure with it. I would like to put together a book for everything on it so I have it all organized. If I'm going to use my 5'ver I want to do it right! I'll post the final test results when I find out, maybe tomorrow!
Thanks for all your help
GaryCQ

The OP and his friend have answered their own questions.. It could be ANYTHING that killed those batteries, and blaming the batteries and thinking of replacing them with 12v batteries is nothing but a waste of money up front. A VERY large percentage of the folks reading this are running 2 or 4 series-parallel batteries and none of us have this problem (except for the poster above, but he is the exception).

If you don't have the experience, find someone that can track parasitic loads and make sure it's really not the RV. Then go find someone that can work on recovering those batteries. Just because your mechanic can't recover them doesn't mean it cannot be done. While it's possible you actually have a problem with a battery, switching to 12v won't solve that problem.

I had 4 T 105's in my class A, charged with a solar unit. Constantly had to add water, and they only lasted 1 year before going flat dead! Went to Sams club and bought 4 GC batteries, which lasted 6 years and were still going strong when I traded it! I would never spend the money on the T 105's again!

Hi Garycq,

Welcome to the forums.

How many watts of solar do you have? What charge controller is in use?