New house batteries

pianotuna wrote:
And my 566 amp-hours of surplus acid AGM's with a load of 276 amps exhibit voltage drop to 11.7. If I cook a scrambled egg (1 minute, in the microwave), and make toast (6 minutes), I have to drive for one hour at highway speed to replenish the battery bank.

Don .... fancy seeing you here in the Class A forum!!

Boy, one hour of driving seems a bit much just for 1 egg and 1 piece of toast. Are you sure of how well your engine's alternator and rooftop solar recharging systems are working while driving down the road? :h

12.5 is good especially if there is a load on new batts. There are variables but sounds ok to me.

How many volts should we see... (I wish I saw 12.5) Depends on where you measure (I'm using the voltmeter inside the inverter).

IF measuring at the battery 12.5 is fantastic 12.6 is resting voltage full charge and with the kind of amps an inverter pulls 0.1 volt drop is amazing (on the good side).

If measuring at the inverter... Put inverter in standby (no load or minimal load) and note voltage... Then enable inverter and note voltage.. The difference is your "line loss" consisting of internal resistance in teh batteriesm, Wire loss, and connection loss.. this is your "Loaded" full charge voltage. Mine can go down rather far (I show 0.02 ohms resistance.. If I'm sucking say 1,000 watts (roughly 100 amps) that is 2 full volts drop. I'm still working to lower that resistance.

And my 566 amp-hours of surplus acid AGM's with a load of 276 amps exhibit voltage drop to 11.7. If I cook a scrambled egg (1 minute, in the microwave), and make toast (6 minutes), I have to drive for one hour at highway speed to replenish the battery bank.

It depends on the load.
If my fully charged batteries have no load and nothing putting in amps, they read 12.6.
If my fully charged batteries have a 5-10 amp load and nothing putting in amps, they read 12.5
If my fully charged batteries have a 90 amp load (coffee pot) and nothing putting in amps, they read 12.2. They go back to 12.5 or 12.6 when the pot stops brewing.

All of this is normal.

12.5 is a fill charged battery. The inverter will draw that down depending on what you are powering with the inverter.