12 V Battery drained

Maybe you forgot to turn your car off with the Power Switch? Do you remember?

 

That would not have reduced the charge of the 12v battery as the traction battery would have continued to try to charge the 12v battery if the car was in "Ready".

It is more likely that a door was not closed tight leaving a courtesy light on all night. Even that should not have run down the 12v battery so quickly unless it was already down. Perhaps someone along the delivery path or during the "prep" was listening to the radio. It happens. It may, also, be a faulty 12v battery.

 

Batteries do self discharge, and it's best for lead acids to be stored at full charge. Which means a lead acid in storage should be charged every six months for longest life. If it was drawn down before going into the car, it won't take much to kill the battery. The smaller 12volt of the Prius also has less run time than a traditional car's.

Most modern cars have a protection circuit to keep the battery from discharging until damaging itself. It isn't starter battery which don't fare well from deep discharges. So I don't think you'll see any long term affects from this.

 

36 hrs with an interior light on will drain the battery.
it is most likely the 12v battery was never fully charged before delivery, or an interior light was left on. Which is difficult to identify once the 12v battery is dead.
Anyway, its fully charged now so see what happens over the next few days and check again for any interior/vanity lights on.

 

Talk about frustrating. I questioned the other day, just how is the 12 Volt battery charged in the PIP. Does the ICE have to run to charge it, or does it get charged when the traction battery is plugged in? I use almost pure EV all the time also.

 

The 12V battery gets charged from the inverter when the traction battery comes on-line, i.e. when you hit the Start button and goes to Ready mode. It is possible the battery got discharged when they shipped it, perhaps they never turned off the Smart key after initial test driving it onto the ship. Anyways it is something the dealer probably should check.

 

Not so, for the notoriously under powered teeny Prius battery. Read back over the years & years of dead battery experiences. You drain the aux battery is a Toyota hsd system, and it really kills the battery's health. That's why so many here on PC have switched over the little OEM aux battery to the Yellow top Optima. THOSE suckers can handle the abuse, and not end up becoming mortally wounded like the OEM's.

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Since this is the only place I could find this in my search, I wanted to make sure I'm understanding this completely before I do what I'm planning on doing

I'm starting out in astronomy and have the option of using 12v cig. lighter outlets to power the scope and camera. Buying portable power tanks is at least $50, and goes way up to over $150 depending on what you get. Ideally I'd like to build a LiFePO4 power unit, but prices on those cells are still very high. So, I was wondering if I could use the 12v on the Prius (Gen III) to power my equipment..? Seems as long as I leave the car in Ready mode, using the plugs should be fine, and the power should be coming mostly from the traction battery (6.5 amp-hours, if I read that right.. way more than I need at present for just the scope and camera for a few hours). When that gets low, the car should start the ICE and recharge the traction battery some, correct?

Not that I want to use the ICE as a generator long term, but until I get a better portable power supply, will my Prius work just fine as a power tank?

 

Yes, that will work fine. I've even slept in a Gen II in Ready w/ the heater turned. Automatic climate control kept the temperature perfect even though there was snow outside.

 

Keep your Prius in Park and Ready and all will be good. The Prius can't charge the HV battery in Neutral.

Tom

 

To the OP: Agree totally with the above. AND to any new Prius owners, Pip or otherwise. Once the 12V battery is dead, it is very unlikely that it will keep a charge properly. Monitor the 12V SOC very closely especially in the first year when the dealership may (used advisedly) may replace it. The unfortunate ongoing problems with those batteries is that the dealers do not have the right equipment to test the battery, the ability to determine a problem nor the desire to replace the battery considering the battery as non-warranteed. Under no circumstances leave a door or hatch ajar!