Battery recommendations for 1500W inverter

BFL13 wrote:
Looks like not enough inverter for that microwave.

A typical "1000w" microwave wants 1500 watts input, and that 1500w will pull about 150 DC amps from the battery bank, needing say a set of #1 AWG wires between inverter and battery bank with the two wires being under ten feet long each.

You could run the MW for a few minutes on the two 6s if they are over 75% full, but you will want to double that to four 6s if you want to run the microwave with the batts as low as 50% SOC.

The battery voltage gets dragged down by the inverter running the microwave which is normal. the inverter will alarm and shut down at some low battery voltage. 11v for the alarm is common. So the idea is to get your MW job done before the alarm goes off. If the MW job is two minutes, you don't need as much battery as when the MW job is 10 minutes.

12s instead of 6s will help a little, but not change the story.

For all those who claim GC-2 is the Best or only choice for RV use, the OP has clearly pointed out a signficant tradeoff with a GC-2. They are NOT designed for high current draw.
a pair of 6v as mentioned is marginal at best and will let you down when you may need it the most with a microwave draw. a pair of 12V will do much better, lower internal resistance and each battery only supplies 1/2 the load.

A couple of things can help.

Toss the microwave, and replace it with a panasonic true inverter microwave. when you drop the power level instead of cycling the power between 100% and 0% it lowers the continous power. In our case running at 50% works great, draw is about 70A on the inverter, takes about 25% longer to heat water, warm veggies etc.

But even 70A is a signficant load on a GC-2. By contrast a pair of 12V would each be supplying only 35A, and have lower internal resistance. Hence a better solution for this application.

Now if the microwave is an occasional use need and the dominant need is long term boondocking, it may be tolerable with a pair of 6V and the true inverter microwave running on low power. But this only for short term use when batteries are above 75% or so charge.

The next step if you want to say with GC-2 is to go to four 6V, you will be in hog heaven for the microwave. And run it off a 1000VA inverter all the time at 60% or lower power and have plenty of boondocking power.