I’ve got a 2018 Prius Prime Premium with the original 12v battery. Recently I’ve not been driving the car. I went to use it and the 12v battery was dead. I charged it and it started up fine. I drove it out of EV mode for about 30 minutes to have the car charge the 12v battery. I went to use it a few hrs later and it started fine and drove fine in EV mode. But as I was driving the radio turned off and it went through the initial audio start up. Is my 12v battery ready to be replaced or is there another underlying issue.
Yes definitely. And yes maybe......but you won't know until you get a new fully charged battery in it and all 4 of the main cable connection points checked. IF.....you are going to have periods of more than 2 weeks without driving, you NEED a battery tender or your new battery will soon be bad too.
Get one of these, and you'll no longer need to do an internet survey. And if practical with your parking situation, with one of these, used regularly, you'll breeze by 5 years.
If the car was plugged in for that period when it wasn't used, and it was a fairly long period of time, the battery was drawn down by the monitoring of the charge circuit. (Others are welcome to explain it better.) For a long period when the car isn't driven don't keep it plugged in. If you plan the idle period, follow the owner's manual about how much charge to leave in the traction battery, then stow the cord. Yes, installing a battery maintainer (smart trickle charger) is wise but not always necessary. CTEC chargers are very good, and I also like NOCO chargers. Their prices start at $30 for a 1 amp unit, $50 for a 2 amp, or $40 for a 2 amp direct mount maintainer that bolts to the car under the hood somewhere. You need to supply power to the battery maintainer. For the present battery allow it to get fully charged then have an auto parts store or other battery seller use their battery tester on it; they probably don't charge for the test. That will tell you if your battery is still OK or not. Batteries in hot locations have shorter lives, my 2016 battery in the 2017 Prime is still good, but I'm in a temperate location, and I maintain the electrolyte level annually.
How much, roughly? Seems like supply-and-demand is a factor: for older, common cars they're still around $150~175 (CDN). Last one I got was for a relatives Corolla, maybe 15 year old car. The more expensive option at Canadian Tire was $165~ CDN IIRC.
The 12V battery will be charged whenever the car is in 'Ready' state whether it's in EV or Hybrid mode. It's charged by the Inverter/Converter assembly which operates continuously. If the radio turned off and went through the initial start up, there may be another electrical problem. The Inverter/Converter will maintain a 12V, actually more like 14V4 output at all times. Only a loose connection or a radio fault would cause the radio problem you described. Ed
Do you have any info to support that statement specifically related to the PP? A car with an alternator depends on the battery to keep the voltage stable, so a flakey battery absolutely can create electrical havoc in that type of system. In the PP, the 'converter' part of the Inverter/Converter Assembly takes the 350V from the traction battery and steps it down to 14V4 at up to 100A. The converter is fully regulated and filtered. I would not expect a flakey battery to have nearly as much of an effect in the PP as in an alternator-equipped car but, of course, murphy rules. Ed
I’ve got a battery-related question: can I use my Noco Genius 2 charger/maintainer safely on my 2022 Prime as a maintainer? I am going away for a couple weeks with a different vehicle and would prefer to not have the Prime 12-volt drain.
There are threads here of people getting error codes, including for the traction battery, that were solved by installing a new 12V. Maybe they were with just the hybrid, but it also uses a step down converter instead of an alternator. The system monitors the 12V battery, which opens it up to negative feedback.
I can't think of any reason why not; that's what they're for. I guess what you're saying is: is there anything special about the Prime? FWIW, due to low usage (currently lucky to do 3K kms yearly) our 2010 pretty much LIVES on a charger (a CTEK 4.3), with the battery installed in the car. Never any problems.
Yes. Absolutely fine. BUT......if the battery is healthy and you don't have any "phantom drain" from added accessories, it should be fine for 2 weeks. Connecting your Noco until it says "fully charged" right before your trip and than disconnecting it for the duration of the trip would be a good test of your battery. After you see if it starts and runs OK when you get back. then another charge with the Noco would be a good idea.
While the car is actively charging, it is providing energy to the 12V battery to run charger electronics. I don't know if having a separate battery maintainer plugged in at the same time would be harmful, but any potential harm is avoided by just having the car unplugged when using the maintainer.
Thank you for your thoughts on this everyone. Yes my concern was whether using a maintainer was not good for a plug-in hybrid. But, yes, I’d use it without the traction battery being plugged-in. And, the only thing about charging the 12 volt ahead of the vacation and then not maintaining it is that I wonder if this would then allow the 12volt to discharge and reduce its life. What about charging the 12 volt ahead of the vacay, not maintaining it, and then recharging it upon our return before starting the car? Perhaps not as god as maintaining it because this might allow full 12 volt discharge?
Ours just sits on the charger, day after day, no ill effects. Current battery was installed September of 2015, an Optima Yellow Top. This voltage reading was taken recently, first thing in the morning. The day before the car was taken off the charger and driven a good distance, so minimal or no surface charge I would think:
