New Visitor Need technical help and advice on 12v battery

welcome!

1) the display is for the hybrid (traction) battery, not the 12 volt.

2) sounds like your new 12 volt is fine

3) your hybrid battery is on the way out. this often happens to old batteries right after a service because of the way they are treated, but was inevitable anyway.

4) you can try a battery conditioner, cell replacement with balancing, or a new hybrid battery

5) all the best!

 

the 12v is charged by the hybrid battery. so a weak 12v requires more charging, and the engine runs more to charge the hybrid battery. it is too subtle too notice, except in lower mpg.

sometimes a service tech leaves the car on in neutral, which doesn't allow the engine to run, but the hybrid battery is charging the 12v, and not getting recharged itself. same thing can happen in a car wash where you have to be in neutral to pull the car through, because prius has to be in ready to be put in neutral.

if the hybrid battery is weak, this can put the weak module(s) out of balance.

a conditioner, see @jeff652 for prolong model, can rebalance if the module isn't too far gone, or if it is replaced. usually, tech stream software is used to determine the bad modules. i can't say whether it would work or not.
@Raytheeagle has some experience. all the best!

 

There was another story here, in the last year I think, someone getting a Walmart oil change and ending up with a dead battery. They had messed up in some way. Maybe someone with better memory can find it? I googled without success.

 

Welcome to Prius Chat .

@Mavi is in your area and is working on his pack reconditioning. He’s local and might be equipped to answer tor questions .

I have used the Prolong equipment successfully and share with 2 other members here.

Good luck and keep us posted .

 

So, how much luck have you had with reconditioning?

My 2008 is at 190K, low HV to full green on a downhill ride into town. I have both Prolong bits, discharge and charger. I have yet to discharge down to the lowest setting. I am hesitant to do it, some of the comments weren't positive it was a good move. Past that, it does seem to settle it down a bit.

I am planning on replacing the HV battery next year, just saving up for the replacement from here (not OEM).

 

Had really good lick.

If you discharge down to the lowest setting, you’ll definitely disturb any undesirables in the modules and remove any cell “memory”. The 84 volt setting isn’t low enough to do this.

I have not taken it down to the lowest setting before, but that doesn’t mean I wouldn’t. Our 2010’s hv battery is performing well and haven’t had a need to. But if the circumstances were different, I wouldn’t hesitate.

Hope that helps.

 

there are a lot of hybrid battery rebuilding threads here with great detail. i'll give you an overview:

1) new oems battery $2-3,000. last 10 years or so, no problems.

2) new aftermarket around $1,600. not much long term data, but lots of factory testing and good reputation

3) reconditioned battery: prices all over the place, warranties all over the place, mostly bad reputations.
only as good as the company standing behind the warranty, and you have to be prepared for downtime every time they need to replace it under warranty, which may be often

4) diy rebuild: this is the cheapest avenue and can be as good as your willingness to read and learn, investment in some tools, and the time you are willing to put into it. the longer and more patient you are, the longer the rebuild will last. but it's not new, and the older cells will still fail now and then, and you have to keep taking the battery out and repeating the process.

 

I successfully did rehab my pack.. but then I was given 2 newer 2013 battery packs.. so I sold my working 2007 pack, with just one cell changed out, with the 2013 packs. To cut my story short, I couldn't ever get them to work for long. I purchased the $1600 batteries shipped from Toaster here, installed them, and been good since. So in short.. if changing out a cell and balancing out doesn't fix your issue.. or if all your cells look fine. Don't waste you time and swap the batteries for Toaster's new ones.

Note I did manage to sell the cells over time on ebay for around 700-800 a pack.. so thanks to god.. it all worked out. Life is good

 

I too did the "full recondition" about Aug of 2017, Sept of '18 I was back in replacing another module. I and other PC members spotted the 3rd affected module in '17, but having only two on hand at the time, I did not replace the 3rd (it was well within spec, but at the bottom of average).