Reconditioning the 12v aux battery

Sometimes a deep cycle battery can be revived, but forget about "reconditioning" it to near new condition. Since this is apparently a lead-acid battery (it needs a vent) you should replace it with one that fits exactly and is the same type. I seem to remember reading here that Optima batteries makes one that fits exactly.

 

Not to sound harsh or cynical, there are lots of threads about the 12 volt batteries in the gen 2 cars, yes it's a deep cycle but it happens to have an extremely short life. Optima does make a battery that physically fits, doesn't need venting (gell battery) but needs a conversion kit for the electrical connection, all very available.
When you have a strong battery the car doesn't have to run the ICE to charge it as often as a battery that's constantly in a state of discharge so your electric car is actually electric...

 

I had problems the very first winter with my Prius. A combination of a 15 minute commute, winter so headlights on, -40 temps so Max Heat and constant electric defrost, all managed to drag the 12 vdc battery down.

It got to the point when I would power up in the morning, the auto headlights would turn on to a sickly yellow glow, and almost go out before the main relay closed the the Traction battery supplied the circuit.

If you catch this problem in time, you won't damage the battery. I had to go away for a month on business, and at the time I owned a condo with heated underground parking. I pulled the battery, put it in my suite, and hooked it up to a VDC Battery Minder

BatteryMINDer® Plus 12 Volt 1.33 Amp Charger-Maintainer-Conditioner (Desulfator) | All | Battery Chargers by BatteryMINDers.com

That cured the problem. When I powered up the first time, the auto headlights barely flickered. So I wired in the charge harness and got into the habit of leaving the Battery Minder plugged in overnight.

As I rarely have to drive now, I also leave my FJ plugged into a Battery Minder 24x7.

I would suggest just getting a new battery. Make sure to properly charge the new battery before installing. The Prius isn't very well suited to properly charging a 12 vdc battery at 50% charge, and the new battery won't last very long

 

What they wrote. If you use a "reconditioned" battery you're just setting yourself up to get stranded somewhere.

 

Did you notice the Battery Minder reference in an earlier response? It is a $60 device that will recondition a 12v battery as long as it is not too far gone. There is no need for a service given an inexpensive solution already exists.

JeffD

 

Hi sclieu, you should measure the voltage of your battery in the morning after it's been sitting overnight (before you turn on the car). If it's fairly high like about 12.6 to 12.8 volts then you know you've got a good one. If it's fairly low like about 12.0 to 12.2 volts then you probably got ripped off.

Follow the instructions in the first post here : Entering Maintenance Mode (aka 12V Battery Check) without Switching Headlights ON/OFF | PriusChat but with the corrections made below.

- Do this test after you have driven the car for at least 30 minutes. This will give the battery a chance to be fully charged.
- Do this test after the car has been off for at least several hours, preferably in the morning before starting the car for the day. Yes it's a good idea for the car to have been driven a lot in the days before the test, so as to give the battery a better chance of being charged, but the test better weeds out weak batteries if it's been left off for at least several hours before the test.

-Push in the power button. (if not already on)
- With your foot off the brake pedal push the power button. Don't go to ready mode.