6v battery fail

A rule of thumb for using circuit protection with batteries is that the primary circuit breaker or fuse should be within 18" of the batteries. That rule is sometimes stretched to accomodate RV construction details. I have one bank of 6V batteries and the primary 150 A breaker is attached to one of the battery's positive terminals, the same terminal that leads the (+) wire to the distribution panel.

A user of 6V batteries and circuit breakers can weatherproof the circuit breaker by covering the breaker and terminations with a material that is waterproof like silicone, Dicor sealant, Plastidip, etc.

You haven't posted any voltage measurements of the charge current, either during charge or when in use, now that the batteries have been recovered. I would hope that you use even a cheap hand-held meter to suss out what is actually happening with charge current to the batteries. I'd also suggest to buy a glass tube battery hydrometer to measure the specific gravity of the battery cells. That is the final arbiter of battery health and will eliminate worry, speculation, or the inevitable tail-chasing that is typical when dealing with compromised RV batteries.

FWIW, at one time I was responsible for the upkeep and maintenance of a fleet of 300 6V batteries (golf course fleet). My learning curve was short and steep. It became apparent, quickly, that 6V batteries like higher charge voltages (14.8V and higher) when being charged and that float charge introduced immediately after use promoted battery longevity.

It seems you've developed a plan to insure charging, even in bad weather by relocating the circuit breaker. I think the cold weather, when you tried to use the batteries on your trip, may have been the defining factor. Using a 700W microwave and an inverter would draw approx. 60A-70A through the circuit breaker and cable. In most cases that is enough heat in the cable to melt any ice or snow on the cable. A 40A charger would return the same results.

Good luck with your 6V batteries. They are a good solution for most RV power siuations and are very durable. If you were to add solar charging, you could be assured that your batteries would be charged to 100%, eventually.

Hey Guys. Well I kept the batteries on a keeper all winter and they checked out good. I have installed them in my trailer and left them for a week checking the voltage (12.8v) at the start with a meter and hydrometer and left them for a week with the master turned off. They held a charge no problem. I then ran the furnace with it being 32f at night for 3 days and the batteries are still strong. I plugged in shore power and they topped up full. I have another theory about why they may have depleted. When I installed my inverter I mounted a 150 amp breaker on the back of the battery box. The terminals are exposed to weather. The breaker is waterproof so I didn't worry too much about it. But on the way home we hit extreme winter weather in Montana. (The batteries did not show signs of weakness until this point.) The entire trailer was encased in 2 inches of brown, salty ice. Including the terminals on the breaker. I am now thinking that this may have caused a ground to the chassy as I can't find anything else wrong. I am going to relocate the breaker inside the storage compartment to keep it dry even though the install instructions say it should be installed with in 12 inches of the battery terminal. Its unlikely I will ever use it to its full capacity of 1500 watts so I am thinking it should be fine. Most it will probably draw under normal conditions is 700 watts on the microwave.

Likely nothing wrong with the batteries other than they are not charged.

Go to Progressive Dynamics website the instructions for your converter are there. They explain in detail how your converter charger works. Testing the battery with a hydrometer is the easiest way to see the state of charge.

This article may help:

12 volt side of life

badger6724 wrote:
I have a 1500 watt inverter installed. I tested it with a 1400 watt heater when I first installed it. After 5 mins or so the heater was still working ..

I'm amazed you got 5 minutes out of two batteries. That's a big load.

badger6724 wrote:

I think around 12.3 or there about. It was a while ago. Last year.

No..what I was asking was what the voltage after you turned off you inverter running that heater. You only ran it for 5 minutes. so you only pulled around 10AH. Assuming you have 200AH batteries, you only discharged them 5%. They should be at 12.5.

A better test is to fully charge the battery and then run the inverter with the heater for 15 minutes and see where the battery voltage ends up at after the inverter is off for a couple minutes at the end of the test.

Now if I can just figure out why they were depleted in the first place.

Maybe I missed it but have you checked for continuity through the battery main wire's circuit breaker/fuse?

Most trailers will have a circuit breaker or fuse within a few feet of the battery. If that is a manual reset breaker, a failed automatic reset breaker, or a blown fuse, your converter may be outputting charge current but it won't be reaching the batteries.

Thanks for everyone's help and advice. I will let them rest for a few days and check voltage. Hopefully they will hold. Now if I can just figure out why they were depleted in the first place.

babock wrote:
What was the voltage at your battery after you removed the 1400W load from the inverter?

I think around 12.3 or there about. It was a while ago. Last year.

No need to torture them. If they hold voltage a few days just put them back in service.
Verify with a hydrometer if concerned.

What was the voltage at your battery after you removed the 1400W load from the inverter?