Hey Now,
I just purchased a 12V, 400W/800W peak power inverter to charge my SLA's at Festy shows during the summer months while camping
. My question is for those who have run these P-inverters via their car or deep cycle battery......how long can you run the inverter to charge your SLA without having to start the car to charge your battery?
In the instructions it says to start your car or RV every 60~90min. to avoid draining your battery and run the car to charge the battery for 10min. However I think this is a general rule of thumb only if you are pulling some serious power (over 150W??).
For example: my older style Eco-charger SC-61 pulls about 20W, 120V @ .18A (180mA). The specs on the inverter say it has an “idle current draw” of .4A (400mA) - meaning it draws this current without any devices attached.
Is it correct to assume that when I hook my SC-61 to this inverter it will draw the .18A (20W) plus the load rated at idle current of .4A for a total of .580A or 580mA? That would be a total power of 70W or so (120Vx .580A = 70W). Is this right?? If indeed this is about what the inverter will pull in terms of power how long will the inverter run @ 70W off a standard automotive battery?
If you consider a standard 12V 12AHr SLA and applied around a 580mA current draw the SLA would only last about 21hrs or so run time wise (roughly). Most of the time my 7.2AHr SLA’s only take about 5hrs or so to charge so wouldn’t an automotive battery which has a much bigger amp hr rating pretty much last all night long??
Does anyone know roughly how much a standard automotive battery is in terms of amp hr ratings?? I don’t want to have to wake up every 2hrs during the night to run my rig for 10min. at a time to recharge my auto battery if its just not needed.
Thanks for any info folks!
LoS