camperdave wrote:
Step 1 is to get a good battery monitor. I don't know what the latest one to get is, ...
Step ZERO is knowledge ! Read everything you can about the subject.
I agree with Step 1.
Step 2 was already mentioned. KNOW YOUR LOADS ! If you are going to use an inverter, don't expect to be able to use the coffee maker and the toaster at the same time.
Related to Step 2, is what can you run directly on 12VDC. It is always more efficient to run as much as you can off of 12VDC.
Last, for $500, you are not going to get much. Maybe ONE 12V non-deep cycle battery, a 100W solar panel and a 1000W modified sine wave inverter. Realistically, you want a PAIR of 6V golf cart batteries, at least 300W of solar, and a GOOD 1000W inverter charger like a
Samlex EVO-1212F. With all of that, you are likely pushing $2000 !
Bonus ! With a GOOD invert/charger you can
dump what is likely the weakest leg of your current DC power system, the converter !