Battery 12 volt problem

Optima DS46B24R Optima battery $175 direct fit replacement for Prius 2004 + & Plug-in Prius with Instructions

If it is 5 years old, it is time to replace it.

 

Lot's of 12v replacement material on the site, look around, most replace with the Optima yellow top, the new model has the correct terminals to connect to the prius, the prior model needed to have some modification, it's a gel, deep cell battery, or you can buy an oem from the Toyota dealer.
Taking the Mylar(covers the holes) off the one in your car, filling it with distilled water and trickle charging it for a day, will make it last a bit but as the motor is always charging a battery that won't quite take a charge, you'll be using more gas then necessary.

 

The Optima is not a gel battery, it's a spiral wound AGM lead acid battery.

John (Btitprius)

 

You do not say in your avatar where you are from, if your not in the US the Optima is not for you. As even the OEM poor as it is, is more realisticaly priced outside the US. There are other options.

John (Britprius)

 

There may be something draining your battery and you likely need a new one.

If you have the smart key option, which I love, then it is drawing power searching for a key. This is not usually a problem unless the car is left unstarted for long periods, say a couple of weeks. In that case turning it off with the button under the steering wheel is best.

But with this age, assuming it is the original battery, and the reported voltage reading, and the fact it has needed jumping 4 times now, it is most likely weakened to the point of needing replacement. With every jump you run the risk of connecting it in reverse resulting in very expensive damage. Better to replace the battery when and where you choose instead of the alternative. In that case you might find this thread interesting. Fitting mobility 12volt AGM battery. | PriusChat

 

Duh!

 

I got my Optima Yellow from Advance Auto. It lists at about $200 but the big box auto stores often offer large promotional discounts (20% or more) on their websites. I ended up paying about $150 plus tax.

 

Correction: some replace with Optima brand. Most replace with Toyota.