Small AC motors and Inverters
Disappointed that my ancient Mod Sine Wave inverter (140W cont, 200W surge) shuts down with a 120W coffee grinder. Works ok with the 400W (cont) MSW inverter built-into the truck, though a little ...
Forum Discussion
I have found that whatever the voltage drop is at high SOC it stays about the same all the way down. So eg, if the inverter draws 100 amps and that makes for a 0.9v drop, then if batts were at 12.7 they will drop to 11.8 and if at 12.2 then to 11.3
So in that case to stay above 11.0 the batts would have to be 12.0 going in. EXCEPT, once that initial drop happens the voltage then slowly drops some more as the load stays running, so now you need more margin depending on how long it takes to do the job.
It is easy to test for this while at home to see what your set-up can and can't do, so you know what to expect once out there camping.
Don't forget while you are teetering on the edge with the voltage at 11.00001, and you think you are getting away with it, all of a sudden the furnace comes on and adds more load! Oops there goes the inverter alarm (if you can hear it above the furnace noise) :(
So in that case to stay above 11.0 the batts would have to be 12.0 going in. EXCEPT, once that initial drop happens the voltage then slowly drops some more as the load stays running, so now you need more margin depending on how long it takes to do the job.
It is easy to test for this while at home to see what your set-up can and can't do, so you know what to expect once out there camping.
Don't forget while you are teetering on the edge with the voltage at 11.00001, and you think you are getting away with it, all of a sudden the furnace comes on and adds more load! Oops there goes the inverter alarm (if you can hear it above the furnace noise) :(
