Two 6 volt batteries or two 12 volt batteries ??

lawrosa wrote:

otrfun wrote:

ktmrfs wrote:
. . . if the pair of GC drops below about 75-80% SOC, you can hit the inverter shutoff limit pretty easy with loads of 800-1000 W. Some may depend on the specific inverter and what it's lower limit is.

Now if the batteriesa are above 80% or so, you in good shape. but that means keeping them near full charge when you want the inverter. So.... run the furnace at night then get up and turn on the toaster.... likely be a nope! low temps= higher internal resistance, lower capacity, coupled with partial discharge.

IMHO if your happy with your current 12V setup, don't mess with it. Or, get GC for most of the stuff and run the inverter off 1 or 2 12V AGM's or similar.

We had a situation where we had to run 35 ft. of 2/0 cable from a 1000 PSW watt inverter to two GC2 batteries. On a number of occasions we placed a 65 amp load on the batteries with the inverter (~700 watt a/c load) and regularly ran the two GC2 batteries down to 50% SOC with no inverter alarms or shutdowns. Output from the inverter was always stable at 117 vac. DC voltage drop (due to 35 ft. 2/0 cable) with the 65 amp load was approx. .35v (3%). This particular inverter was supposed to alarm at approx. 10.6v and shutdown at approx. 10.0v. It never alarmed or shutdown.

Thats what I would like real world scenarios on. The voltage drop with 6 volters. There are a lot of variables im sure. But is this a real concern?

Scenarios meaning what size cable and how many feet did others have that had issues?

Like I said I thought 6 volts were a no brainer until I read about said voltage drop.

BFL and someone else said they had issues @ 80%soc.

I guess I can test with my 3 batts all paralleled and see what I get with my new set up..

Im able to monitor voltage from in the camper now.

My last test was flawed as I had the solar hooked up..

My theory also was even if I ran a high current draw, my new set up with two panels and 40 amp mppt will offset the draw.. ( And voltage drop?)

Anyway and if I think about it more, I would only use the high draw appliances in full sun. I can easily use the RV oven and the perculator I have to make the pizza and coffee.

My next two items that are a muct is a c pap machine and a box fan in summer. Furnace in colder months.

C pap without heater and humidifier is about 6 watts. With humidifier and tube heater its only 50 watts.

Furnace 7 amps

Box fan on low is maybe 25 watts. ( I know on high its 100 watts).

Fan and c pap will run through the night and probably a TV ( 30 watts until 1-2am)

So my thinking is if I can eliminate the coffee maker and toaster oven 6 volts may be the better way to go???

IDK just talking out loud here.. As I have no experience with 6 volters.

I do 90 % boondocking. Back in the day I got by with a smaller inverters of 120 watts each x2. TV and fan only. Charged batts with 6 gauge jumper from alternator of truck to rv batts and one solar panel doing 15 amps in on sunny days.

Ditch the coffee maker and heat water on the stove and use a french press or areopress, use the oven on the generator if needed or get a pizza stone and use the gas oven if you have one.

Your other uses, and lot's of boondocking point towards GC. And with decent GC you can get 500+ charge discharge cycles even going down to 25% SOC (75%DOD) a big advantage over 12V cycle life. And how many years will it take to put that many deep discharges on the GC? I barely did it in 10 years on my last set and the batteries were still acceptable. I think age had as big effect as the cycles. They lasted our daughters in-laws another 2 years of abuse before it was time to toss them.