Can I charge the 12 v with a conventional battery charger?

It's just like any other small 12 volt lead/acid battery. A charger will work fine on it, although you have to kind of dig down in the trunk to get at it. Be careful not to get the terminals connected backwards, you'll break things if you do.

Roughly the same age/miles where I replaced mine.

I got that one, was a pain to install but works good so far.

If he's refering to the smart key system, there's a small button on the dash under the steering wheel that will turn off the SKS.

 

Give yourself plenty of time if you put in one of the yellow top batteries.

 

You don't have to dig in the trunk to charge the battery. There are jump points under the hood for that purpose.

Tom

 

Do you have a key less entry option? - If yes it helps if you disable it by pressing the left button that is located bellow the steering wheel,.

(There are two buttons there, the right one is for resetting the Tire Pressure sensors and the left controls the key less entry)

Once you do that the system will not add drain to the 12 v trying every few seconds to locate a nearby fob.

 

Do you have a voltmeter? With the car OFF measure the voltage at the jump points. It should be 12.6V to 12.8V. If it's less than 12.0 V it's definitely time for a replacement. If you don't have a voltmeter use the self-test procedure given in this thread:
PriusOnline.com • View topic - how to put 12V battery in sleeping mode?

If you install the Optima using the eLearnaid kit note that it is very helpful to use pliers to put a bend into the lug on the negative cable so that it will fit flush against the mounting surface in the car. Otherwise it will try to pull the mounting stud out of the car wall as you tighten the nut (all this will become clear when you have the kit in your hands).

 

Note that TSB PG007-03 specifically recommends against using a regular 12V battery charger, so this is at your risk. Also note that the TSB sugggests charging the battery when it is disconnected and out of the car. I think the reasoning for this is two-fold: in case the battery explodes while being charged, it will not damage the car, and the charging current has no opportunity to damage the vehicle's electronics.

I see no problem using a regular charger, as long as you set the current switch to the low current position, such as 2A. Note the warning label on the battery top that says 4A is the maximum charging current.

You've got a reasonable maintenance routine, with the car being made READY for 30 min. every two weeks. However it doesn't surprise me that your battery died after four years, since it is not being used much.

Note that if you move to the Optima you'll have to install a new positive battery terminal connector on the fuse block, and use a new negative battery cable, since the Prius original equipment battery uses smaller than normal terminals.

I see that the Optima price is $180 incl shipping; depending upon how much parts are marked up at your local Toyota dealer's parts counter, you may find that you can buy the replacement for less there, perhaps $130 - $160 or so.

 

Hi Chris,

I don't think that anyone has owned the Optima long enough to say for sure that it is really better than the original equipment GS battery. In theory it has better specs, but who knows.

It sounds like your normal schedule would have you return to CA only during the summer. If true, then my suggestion is that you leave the car alone for now with its dead 12V battery, and worry about replacing it when you come back in June or whenever. Your mother-in-law will be happy that she doesn't have to start the car periodically, in the interim.

The only problem will be that the traction battery may lose some charge over the next four months. However, if the last time that the car was run the SOC gauge was in the blue region, then I think it should be OK.

If you will continue to live in El Salvador indefinitely, then I suggest you consider one of the following alternatives:

1. Sell the Prius so you and your MIL don't have to worry about it.
2. Charge up the traction battery to green bars by using the force-charge method, and make sure the 12V battery is also fully charged. Then disconnect the 12V battery and leave the car alone until you return the following summer.
3. If you are storing the car in covered parking and have access to a 120VAC outlet, then invest in a battery tender to keep a trickle charge on the 12V battery, and have your MIL start the car once a month, leaving the car READY for an hour or so, for the sake of keeping the traction battery charged up.

The force-charge method is to shift into D, hold the car stationary by pressing the brake pedal with your left foot, then floor the accelerator pedal with your right foot. Since the car cannot move, the ICE will spin MG1 and the energy from MG1 will be directed into the traction battery. Use of this technique is at your risk as the transaxle is stressed during this process. You'll note that the engine RPM will decrease as the traction battery SOC increases.

On a different subject, I hope that you are changing the engine oil and oil filter annually even if you are not driving the car much, to avoid engine sludge buildup.

 

I would prefer to see it driven every couple of weeks.

Tom

 

The Prius 12 vdc battery isn't known for outstanding long life or durability. Remember that unless special modifications are made to the Prius, you cannot use one of those chargers that plug into the "cigarette lighter" plug under the dash

I'm frequently away on business, and also had trouble the first winter with my Prius. You can blame -40 temps, constant use of electric rear defrost, and headlights always on in our dark winters, for that

I finally put in a VDC Battery Minder, and that solved all my battery problems. I use the Battery Minder on all my equipment now

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

I didn't catch where the car is parked, or if it's parked inside a garage. If it's a moderate climate, no extremely cold temps, especially parked outside, I really wouldn't worry about the car not being run.

There are plenty of classic and collectible cars that stay parked 5-8 months of the year, with no motor damage. Of course, heated dry indoor parking helps there.

The nice thing about the Prius gas tank bladder system, is that you shouldn't have moisture condensing inside the tank

 

It would be a lot cheaper to rent a car for six weeks each year than to buy one, no? The Prius environmental benefit is going to waste sitting in a garage 48 weeks of the year.