Okay, if I understand correctly:
1. The generator doesn't charge a battery. The generator provides power to the converter and the converter charges the batery.
2. If we assume the generator provides 7.5 amps of power into the converter, then simple math says the converter will provide 10 times that (75 amps) into the battery. This is because the generator provides 120 volts and the converter converts it to 12 volts.
3. However, a converter like mine has a maximum output of 55 amps. Supposing some items are being powered, I suppose it's safe to say 40 amps of power are being used to charge the batteries. I don't know why I chose "40" amps, but I can say this is over my head. The converter output is approx. 13.6 - 14.4 Vdc, but I don't know how to make practical use of this figure. I'm missing something here.
4. Charge rate depends on the amount the battery(s) is discharged. The more volts in the battery the slower the charge.
5. If I understand this correctly, considering I have a 85ah of battery and a converter with a maximum output of 13.6 to 14.4 Vdc, if I'm not using much power when the generator is on (i.e. not using the microwave), then it doesn't matter whether I use a 1000W generator or a 2000W generator, because they both provide more power than the output of the converter.
