Four Six Volts with 300w of Solar?

Cool. Always amazed how a topic like Solar and Batteries get the crowd going! Well, I can guarantee everyone, the Cat. Heater aint happening. For me a Generator is for emergencies only. Since the Heater is the only real draw, I will figure out a way to make batteries work. I really need to weigh the rig and make sure we aren't getting on the porky side. Seems to me like it's 4400 pounds dry and has a GVWR of 6200 pounds. It has a 66 gallon(yes I did say 66 gallon) and eats up a lot of GVWR, but that is good for week long trips to the desert. I could always just keep a couple of real HOT 6v batteries in the back of the truck if things get a little weak during the week. And, we don't use the TV either. Just the radio.

2oldman wrote:

SCVJeff wrote:
There are HUNDREDS on this forum running parallel battery banks and not one single report of a failure, ever.

And thousands of trucks with dual 12v batteries.

including the CAT start batteries. That's doubly bad. Guess I'm doomed

Love my four GC-2 bank. Unlike you however, I do run a lot of A/C equipment.

Go with 4 six volts and enjoy the even temps and peace of mind with your furnace. We hardly hear our furnace and like the consistent temps with a digital thermostat. Ventless causes moisture issues and plenty of window area needs to be open. If I was that worried about propane I wouldn't be running all over the country with 22,000 pounds. If you have overcast days or need more amps use your generator in the morning to do some of the heavy work.

SCVJeff wrote:
There are HUNDREDS on this forum running parallel battery banks and not one single report of a failure, ever.

And thousands of trucks with dual 12v batteries.

mlts22 wrote:
I've yet to read about someone on rv.net having a parallel connected battery bank go boom on them, and I've read almost any horror story under the sun, be it dead shorts, and so on.

If worried about a dead short causing a fire, slap a 200 ampere catastrophic fuse on the positive terminal of each of the four batteries, and go about your business.

x2 !
There are HUNDREDS on this forum running parallel battery banks and not one single report of a failure, ever.

Guess I'll stop flying... There's a 1 in 36,000,000 chance I might be in an incident

a post in another thread, don't know the accuracy however.

Deep Cycle batteries are not all the same. Having owned a Large Marina and RV park over 25 years, and selling and installing solar and Batteries, I only used high quality AGM batteries, like "Lifeline" and others. The typical RV convertor is normally locked at 13.1 volts DC. Some newer ones are converters and chargers. A Deep Cycle Battery will only be fully charged at 14.4 volts. No more or less. This is the voltage that creates the chemical change on the plates. If you do not reach this voltage, you will not fully charge the Battery. I always use a meter to double check this important issue. Sometimes the voltage will rise a lot higher when charging. This means the battery is done and it has a dead cell. Avoid 6 volt series wired battery banks. Use 12 volt banks for the best performance. We find most 6 volt batteries have different resistance with the same brand batteries. Poor charging and short battery life. For example, our AGM batteries will last 10-15 years if properly charged and used. Never drain a battery completely. If you do, plan on replacing it soon. Any electrical-battery-solar questions, please ask!
bumpy

I understand four in parallel is a practical maximum to avoid catastrophe.
Any more and you should be increasing voltage.

Two in parallel as described by the OP is a non-issue.

smkettner wrote:
4x GC2 will work fine with 300 watts solar.

I'd agree only if stipulating that the depth of discharge was no more than 30 to 35%, and one was not boondocking for weeks on end relying only on Solar to recharge.

In such conditions as daily cycling to the 50% range for extended times, then a higher wattage to capacity ratio needs to be utilized to keep the batteries happier.

I got a better cycle per dollar ratio on 198 watts feeding 130Ah of capacity than I did 230AH, but there were some other factors involved such as holding absorption voltage for the required time to reach at least near 100%.

A high solar to capacity ratio makes this time at absorption voltage much more likely to occur, and make for happier longer lasting worry free batteries.

Right no I have 198 watts feeding 90AH of AGM, but I need to give it the high amp recharge every so many cycles from its most depleted state, or it will pack up all its toys and go home, making it not great as a solar only battery.

Charge rate is important and arguably more so when the clock is ticking and the sun is dropping.

I've yet to read about someone on rv.net having a parallel connected battery bank go boom on them, and I've read almost any horror story under the sun, be it dead shorts, and so on.

If worried about a dead short causing a fire, slap a 200 ampere catastrophic fuse on the positive terminal of each of the four batteries, and go about your business.