Gjac wrote:
BFL13 wrote:
A "700 watt charger" probably has PF of 0.7, so that is 1000 VA for the inverter to supply.
If the charger is set to 14.8v DC and is 85% efficient (typical) output watts is 595 and at 14.8v, amps would be 40.2.
Ok so I should have divided by DC volts not AC volts. So that means with my MSW 1000 watt inverter I should be able to charge my house batteries with my 40 amp B&D charger while in route to the next campsite right?
EDIT--I had to hang the inverter outside the engine compartment on its short fat wires clamped to the battery. Up on the fender the inverter got too hot and shut down using its heat protection. I don't know how you can do this driving down the road where the inverter is not in the engine compartment so that makes its DC wiring long enough to reach where the inverter is (so too long with voltage drop)--and how do you route wires through the firewall anyway?
I have run a 20 amp Vector from a MSW CanTire 400w inverter clamped to the truck battery ok. Vector rated at 320w and the inverter was too for continuous. Watts readout on the inverter said 320w.
I have done the same with a Vector 35 amper rated 600w with a CanTire MSW 1000w inverter on truck battery and had no problems.
I can't remember if I ever tried with my 40 amp 1093DBD with inverter on truck battery. It has a higher watt rating with its higher voltages than the previous Vector 40 amp 1093A model. (785w?)
I did a Kill-A-Watt test with the 35 1092A and the 40 1093DBD with Honda gen as supply on low enough SOC batts for amps acceptance. Got:
35-- 125.9a, 6.89v, 568w, 868VA, 0.65PF doing 33.2 amps
40-- 125.4a, 8.4v, 680w, 1063VA, 0.64PF, doing 40.4 amps
You can see the 40 amper made the Honda's voltage (126.8 unloaded) drop more than the 35 did.
Once the charger is doing fewer DC amps as when you reach Vabs and amps taper, the input watts requirement drops right off with the lower amps out as they taper.
