Battery upgrade, maybe solar option also

Lithium batteries provide a smaller and lighter package with a lifespan longer than wet cell batteries with more available amp hours at a good voltage. No, you can't charge them below 32F but you don't need to charge them full every day either. No water to add or check...no terminal cleaning. However, four AGM batteries should easily hold you through the night. Something in your system is bad.

Regarding solar, I haven't run my generator in 45 days of camping except to "exercise" it. Solar is wonderful...install and forget about power. You'll have it.