PSA: Change your 12 volt battery every 4 years

If you keep an eye on the battery, it can last quite a while. I'm on 8 years with mine.

Most go 5 years and change

 

Check the voltage every so often and charge it manually if it gets low. Then you will know it's always kept fairly charged up

 

One way to 'test' your battery:

With your foot off the brake get it in ACC and roll the driver window down and up.

Now with your foot on the Brake put it in ready and do the same.

Did they both take the same time? Was the first really slow compared to the second?

If just the battery was way slower than the battery charged by the inverter, you need a new battery soon.

(Many of us do not know how to test our battery, as we wait til we hear that slow starting sound in 'normal' cars UR Ur ur click. That does not work in a Prius as ithe 12 volt system never starts the engine.)

 

What did you get?

 

I have a 350mA charger on mine. Charge it for ~12-15 hours once every few months while I am charging & balancing my Hybrid battery with my Prolong Battery Charger

 

If you install a "Scangauge" in the car you can watch the battery voltage (when you get in first thing in the morning, for example, before putting it in "ready"). When it starts reading below 12V it may be time to watch more closely. The brake lights or even the headlamps are a good "load test" for it. If it drops down to or below 11V when you turn on the headlamps (car still not in "ready") it's time for a new one.
You can even use a multimeter. The underhood "jump point" is a good place to measure from. But the "Scangauge" is a better and easier solution.

 

David, I am running late for work, and had way too much coffee, hope this makes sense:

So, I replaced the original 12v battery in 2012 (?, maybe 2013), with a Toyota TrueStart. If, I test with the multmeter at the underhood jump point...

With car totally off, I hook up the multimeter, open the car door and do nothing else but turn on the headlights and go back and read the multimeter, is that what you are talking about?

kris

 

Kris,

He's offline now. I am reading it the same way you are. Just checked mine with my meter 12.6 at rest 12.0 with headlights on, I put my 4 amp charger/maintainer (Battery Tender 12248) on it. Haven't charged it in the last six months. I think I still got at least another year or two left in this one here...

Ron

EDIT: After 15 minutes or so the Battery Tender was already flashing. That means the battery is fully charged and ready to go. I am still happy with this one.

 

If anyone wants an Xmas toy, look into Solar BA5. It's a prosumer level electronic tester, around $60.

 

My original 12V lasted 50 months and I've heard over and over that they should be replaced every 48 months.

 

Did it die at 50 months, or did you simply change it out for peace of mind?

 

Oh it died. It was totally dead. I had to jumped it with a battery charger I had at home. Every time I turned off the car I had to use the jump pack to restart it. Lucky for me one of the two dealers by me had a battery in stock.

 

Thanks for the reply and the info. By chance do you let the headlights turn off by themselves (30 second delay) or do you turn them off manually? Not sure if the 2010 does this. I know the 2013 does... Also any ideas of what actually killed your 50 month old battery?

 

Very rarely do I let the car automatically turn off the lights, I manually turn them off when I turn off the car. I have an old Volvo 960 that I did jump two or three times using the Prius 12V, unknown if it hurt the battery or not. Found out the Volvo security system is a real killer of batteries and I now keep a trickle charger on the car. The replacement 12V battery I have in my Prius now has never been used to jump another vehicle. I'm just automatically planning to replace it next August (47 months) just to make sure I don't have any problems.

I've just read over the years it is a good practice to replace these twelve volts every 42 to 48 months depending on the environment the car is in. The hotter it is like in the southern U.S. you may want to change it out a few months earlier than someone that lives in the northern climate.

 

If you install a "Scangauge" in the car you can watch the battery voltage

I'm with David on this one - Besides - If you have a Scangauge - you can also watch 3 other things.............

 

Thanks for taking the time to look into our products. They actually work quite well. We have sold thousands of them to Prius, Lexus, and Honda hybrid owners all over the world. Here are a couple recent reviews from fellow PriusChat members:

HybridAutomotive.com Charger Impressions | PriusChat
and
[Review] Prolong Reconditioning Kit | PriusChat

There are dozens more reviews on our FB page and hundreds more on our eBay seller feedback. Our products work in the same manner as the well established hobby chargers cycling individuals modules, only we do it at the pack level and while the battery is still in the car. We have patents and trademarks filed around this technology because it is only going to grow as the Gen3 Prius start to age. Here is an example of the results from a 2005 Prius that had a hybrid battery "failure". After reconditioning and regular hybrid battery maintenance with our products is still running great almost three years later: