Sizing a battery bank. Ah VS wh?
Hi again! So, I'm trying to size out the battery bank I will need for my husband and I to live off grid in a camper. We don't have tons of time or money, so that's a bit of a factor. We plan on usi...
Forum Discussion
Sarahps33 wrote:
Hi again!
I believe we need roughly 2510 watt hours.
I calculated this by getting the watts of each appliance and multiplying it by the number of hours we'd use it each day.
Good start, but you have to factor in the losses from the inverter. I will use 25% although many only waste shot 10%, so that is about 3100 watt-hours. Wh are Wh regardless of the voltage, but when you want Amp-hours at 12V (instead of 120V) you need to multiply be 10, so about 31,000 Ah !
Lead acid batteries (6V, 12V, flooded (wet), AGM) should only be discharged to about 80% of their State of Charge (SOC). That would lead you to believe that you need 155,000 Ah at 12v! Cutting it by 4 for 48V Battery is Bank is still 38,750.
You need to re-do your load calculation. What you really need us a 30A/50A Kill-a-Watt. I have never seen one. With it you can measure your usage directly.
