Battery Charging

[jhguth]

charging gets slower as the battery gets more full, so i'd at least double the estimation

 

[mr.walleye]

.....

 

[jhguth]

another thought that might be helpful:

before I had my solar panel, my 45min-1hr each way commute was enough to keep the battery recharged from the fridge running while parked from ~6pm to ~8am. after i moved, my 20 min each way commute was not enough to keep the battery charged and after about 4 or 5 days i would hit the low voltage shutoff at the highest setting on my dometic fridge if i didn't maintenance charge.

(i now have 100W solar and also have an onboard charger i use when parked for extended period of time, so haven't hit low voltage shutoff since before solar)

 

[Bumbo]

Thanks for this. So assuming 40A on average with say 35 A on idle being conservative, this should mean that a 90 Ah battery should be able to get through 50% SOC to that 85%+ stage in about 45 minutes or so. Do you think that is a good ballpark to assume in case solar is of no use?

This is an over simplification, but lead batteries have a charge profile where the time to fill is not linear with the available input current.

The ability to accept a bulk charge quickly tapers off and you will end up in an absorption phase with takes a good while to really top off.