Voltage goes up over night ?

Thom

When I go to bed and turn off my invertor I check my dvm. It is most times 12.45 v . In the morning with no wind input it reads 12.6v . I know the batteries read more acurate after resting . Is this the reason a dvm is a poor battery monitor .

Thom

BB.

Re: Voltage goes up over night ?

Yes, as the batteries "rest" the electrolyte remixes/diffuses through the battery and stabilizes at the final level (3 hours or so of no charge/discharge).

Also, temperature of the battery bank will affect readings too (probably not in this case--usually takes a while for a battery bank to change temperatures unless somebody is pumping a lot of current through it).

And, it is why measuring voltage is not a very accurate way of estimating state of charge (chemical processes, temperature, specific gravity gradients in battery, etc.).

A Battery Monitor is much better because it measures Amps*Hours (total in and out of the battery). Still not perfect, but much more user friendly.

-Bill