Ways to lower 12v power draw when car is sitting?

Dont bother measuring it at the battery itself measure it at the jump points. At the battery measurement is meaningless really I want to know what voltage looks like at the fuse box because thats where the car draws it from after going through it main fuse assy and a long #2 gauge cable and then some more fuses. Thats the true working voltage of the battery.

Best place you can measure is it at the jump points. With car off measure at the jump points and write it down. Then with car OFF turn on the headlights and measure again. See what the voltage drop is. Write it down. Put the high beams on and measure that voltage.

Based on what Im seeing here and its bad for the battery life and never maintenance charged a 12.3 resting at the battery it will probably drop quite a bit into 11.7 I bet with the high beams on.

Post your test back here.

Unloaded.
Lights on.
Hi beams on.

 

Pep Boys test shows CCA higher than spec., which is good, indicates a battery in good shape. I would get it on a smart charger during protracted idle times, multiple days. In your case it's a pain, but I think the best solution.

 

Pretty low numbers.

 

you're now testing it after driving, instead of after it has been off overnight?

 

Overnight it's likely to drop even lower? Maybe it's time?

 

exactly. still trying to figure out that pep boys printout though.

 

Yeah that bothers me too: good CCA. Run it through another complete charging session, with the 200 foot extension cord, if that's what it takes.

 

Hmm, Deltran Junior is only 750 miillamps. Needs more, decent 3~4 amp smart charger is needed.

 

I wouldn't fret about those voltages. That is what I see as well. Mendel may have an optimistic voltmeter. The voltage that you see at the boost point is -slightly- lower as it is at the OBDII port (what the Scangauge sees). Going by what some on this forum say, my Scangauge readout would have me changing my 12V battery every other week.

 

mine reads within a tenth of a volt tween the battery and boost point.

 

Alright, I left my 2012 Prius on battery minder for 3 weeks. It measured 13.7V when I disconnected the cables.

 

In the pink, plus surface charge.