My 12v Battery Voltage Readings

You might be in a fairly hot climate, like I am, so your battery is getting close to the average age of failure for most lead acid batteries. It certainly won't hurt to put in a new one and see what happens.

Prime is still affected by extra load charging the battery. It just doesn't cost as much in this part of the country thanks to reasonable electricity prices. With my battery charge level being similar to yours, that could explain why I seem to get a couple tenths lower in my miles/kWh than I did a year ago in similar weather. I'm just not as motivated since I have the jumper pack and still got over 3,500 miles on the last tank and am at about 1,500 so far on this one with over 7/8 of a tank left.

I'd think that, if a new 12V would give you peace of mind, it's money well spent. If you do go that route, let us know what happens, please. We're all still learning.

 

I think the Solar BA9 can measure both Cranking Amps and Cold Cranking Amps. And I think Cranking Amp value would be higher than Cold Cranking.

Then if @Marcius was in fact measuring Cranking Amps, Cold Cranking Amps would be even lower.

Like you though I suspect it was CCA he measured. Maybe he can confirm.

 

I'll do that. I have another project on this car that takes priority right now. I have that ridiculous front-drivers side axle noise when braking at slow speed. I'm going to try greasing it as per the OBSOLETE TSB out there, and per the TIS manual's instructions on axle installation. I bought the $40+ Toyota grease, which must be magic grease! I've never heard of greasing the outside of an axle, but Toyota says it's required. However, that's for another thread. We bought this car earlier in the year with 55k, and now have 65k. The only other problem I see, is the passenger dash board area rattles. Oh yeah, not sure if I have a problem, but when I accelerate hard from a stop, I can sense, what I think, is some very, very slight slippage at first when the torque is highest (not the tires.) All topics for other threads.

 

Yes, it's CCA. (Darn, it's too late to update my original post.) I'm a newbie with this stuff -- so thanks everyone with your patience.

 

Mine is 12.3V below freezing temperature, about 15F or -10C. With IGN on, press power2x without pressing brake pedal, 11.7 V.
Headlight halogen On 11.3 V
Window defroster, blower, headlight on 10.9V.
What I remember from LuciousGarage Prius specialist, as long as it never drop below 10V when we start the car, it is still fine. The voltage dip or drop split of second when we go to READY mode, and on weak battery it can dip below 10 V and get triangle error. That's when we need a battery replacement. But if occasionally we need jump start, that is also time to get a replacment.

The 12V battery is only charged by DC to DC converter from the HV hybrid battery, never from the engine. It does not matter if the engine runs or not. It is about 14-14.5V when charging. Remember, that device is only max at 100Amps, so never jump starts regular car with hybrid, ut may destroy that expensive unit which is part of inverter.

Always get original Yuasa Battery. Optima battery warranty is not good, and it is like lottery, the internal resistance on OPTIMA hit and miss. NAPA battery offer better warranty than OPTIMA.

I still can start the car. Never have single problem starting the car. The battery is 6 years old. I still get 50 MPG or more.

 

11/13/20