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
BFL13 wrote:
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
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Thanks. Good info. I haven't really looked at how my batts respond to loads as mine (loads and batts) are pretty small. IIRC -0.2V is all I've seen when the furnace fan comes on (not sure)?
Anyway if 100A causes a 1V drop, maybe my ~20-25A (250W) coffee grinder will cause a 0.25V drop, max? Add 0.15V max for the 10' 6ga cable drop and get 0.4V total drop? (That line loss is actually a greater proportion than I thought it would be). And if the batts are at 50% SOC, say 12.0V in the morning, that means coffee grinding will drop it to 11.6V, worst case. Add in the furnace fan ... 11.4V?
And the coffee grinding takes 15s. :)
All back-of-the-envelope B.S. but still, the inverter's alarm doesn't come on until 11.0V and it doesn't turn off until 10.6V
