Running fan off battery

lkc001

Hello all-- @ how long can you run the fan off the battery before needing to charge the battery?  I have the stock fan & acid battery that came with the trailer-- battery is in good shape

pthomas745

According to @jkjenn and the spreadsheet she worked up, the power in the Tab looks about like this.  According to this sheet, fan in on Lvl 2 will use "about" 1.75 amps.  I have a stock 70 amp hour battery, so 50 percent of those amps would be 35 amp hours.  At 1.75 amps, I could run the fan for about 20 hours.  (The actual number would be less, due to parasitic drain, etc.)  But still, not bad.

@jkjenn If you read this entry, it appears the spreadsheet I copied before no longer matches the spreadsheet on your web site on "Guilty As Charged."

 

lkc001

Thank you @pthomas745-- math not my strong suit but I understand now where you got that figure from 😁

lkc001

I'm going to print this chart & put it with all my paperwork-- I've printed off a fair amount of instructions etc from the great people on this site-- love it!

pthomas745

Me, too!  Took me forever to get it all in my head.  Take these "amps" divide by two, take the watts and divide  by 12 volts, divide that by the number of minutes to compute the amp hours..or something.

There are a couple of other spreadsheets floating around.  Once I found this example, so much about my battery use became clear to me, like the "12v bolt out of the blue."

jkjenn

@pthomas745 - thanks for letting me know. It is always a risk when you put a worksheet out there with public access. I do have a backup but I do not monitor the main document all of the time. I have changed it back to 1.75.

Glad to see that it is still useful after all of this time!