help me understand shore power inverter ATS current

[x00a0x0]

hey folks,

i'm looking at this inverter: https://www.aimscorp.net/2000-Watt-Pure-Sine-Inverter-Charger.html

i'm basically trying to understand, if the 12v charger/ATS is rated 70a, how many amps is this drawing on the 120v ac side? 7? i don't fully understand the mechanism which is used to step down the voltage and how that differs from an inverter stepping a voltage up, and i'm trying to plan for shore power capacity.

ideally i'd like to be able to simply plug in a regular 15a NEMA 5-15p to any outlet anywhere, ie: friend's garage outlet or something. if this inverter charger is pulling 7 amps like i'm hoping it does, that will make life easy.

i appreciate any insights y'all might be able to share!

 

[krby]

Watts is Watts is Watts. So do you solve the problem this way:

12V charger is really going to put out a max of about 14.7V when charging.
14.7V x 70A = 1029W.

So your charger needs at least 1029 watts from the input side, not counting any losses for efficiency. Let's say 80%-90% efficient. That's 1143W-1286W needed from the input. How many amps is 1143-1286W from the 120V AC side?
1143W / 120V = 9.53A
1286W / 120V = 10.71A

You'll need somewhere around 9.5-10.7 amps from the 120V AC input. There's one more complication, having to do with volt-amps vs watts, power factor, etc. The end result is that you may actually need slightly more amps from the 120V AC input, depending on the power factor of your charger. It also could be that the 80% efficiency number has enough slop in it to cover this.

 

[x00a0x0]

looks like this will work like i wanted it to, then. thank you for the clear and concise breakdown, and for the useful mnemonic.