Looking for advice- dead 12v battery-

I'd say at 7 years it wouldn't take much to finish killing it. I think you are doing the right thing replacing it yourself. I just did mine, very easy! Mine was just in a weakened state and one morning when I hit the start button it wouldn't go into reverse.....and flashed a warning on the screen that the accessory battery was weak. I pressed the start button again and it stayed on and went into gear and drove ok. No parts houses nearby had one in stock so I ordered one off Amazon and installed it 2 days later.... (took about 10-15 minutes)...and everything is working perfectly again. You may notice a bit lower gas mileage the first day or 2 if the battery isn't fully charged, but the car will charge it up in short order depending on how much you drive it.
Good Luck!

 

Save your headaches for another day- have the place selling you the battery measure the battery in front of you with a volt meter and buy only if over 12.7v

 

THIS.
Another case of making something more complicated that it really IS.
Get a new battery.
Make sure it is fully charged before installing.
Drive it another good 7 years.

 

Good advice, but I didn't have that option. I had to order mine online...nobody nearby carried it . I also don't have equipment to measure the voltage so I assume that's what was happening....but all is well now...and I'm getting 3-4 MPG better than before so it must have been dragging me down for a good while.

 

If the battery is dead the charger may not work but it's worth a try.

 

Not exactly right but close enough.
The onboard charging system might NEVER get it up to a full charge and doing that once can help extend it's life.

Also, "shipped" batteries often come pretty DEAD for safety reasons and those MUST be charged before use.

 

Yeah it's a pretty easy DIY. You'll need a 10 mm box wrench, that's pretty much it. The battery's in the rear/right corner of the hatch, under the floor.

Disconnect the negative cable first (goes from right side post to car body on right side), then the positive. Tuck them out of the way. I like to isolate them by stuffing the cable ends into heavy leather gloves.

Also, if there's any chance you're going to close the hatch: don't.

Then disconnect and remove the hold-down bracket, and pull off the vent tube (at the left end).

There should be a strap on the battery, makes it fairly easy to lift out, it's a small car battery.

Install the new one in reverse order, connect positive cable first, and then negative. Don't go nuts tightening the the little bolt: snug it, then slightly more for insurance, and give it a wiggle, make sure it's secure. I like to hold the (small) wrench near the middle, to have less leverage, make's it less likely to strip it or whatever.

When reinstalling the hold bracket, if there's a slight difference in battery height, you might need a shim washer or two. The Toyota bracket design is poor in that regard, can't accomodate any amount of height variation.

Don't forget to reconnect the vent tube.

Here's a Canadian Tire link, I've set "my store" to a Toronto address, not sure if that will stick when you click on it, but that's fairly easy to fix. You can verify stock and price at store nearest to you. I'm seeing this:



The one BIG stumbling block, it's out of stock, and every other store in the area, same story. I would phone them though, see what's going on, because that's kinda nuts.

"Core charge" is basically a $20's you're charged when you buy it, and you're refunded that amount if and when you return the dead battery to them, for recycling.

2012 Toyota Prius Car & Truck Batteries | Canadian Tire

I could drone on about battery smart chargers, battery testers (just a simple digital vot meter, for starters), jump packs (and associated "memory saver cables"), but I guess leave that for another day, lol.

The aforementioned suggestion to fully charge the new battery is a good idea, I'd strongly recommend the CTEK 4.3 charger for this. It's something I always do. Still, in a pinch, if you're using the car regularly, and just install it, it should be ok, usage will charge it.

 

Battery is 7 years old, it gets the tip of the boot.

 

how much is oem?

 

i would risk it. what the warranty?

 

Some comments to go with all the other advice so far ...

If you don't want to climb inside to do the hatch release, you could power the car via the jump port in the fuse box in the engine bay, as shown in the owner's manual. Apply 12V there, either from another car's 12V battery, or from a battery charger. Then hatch release, etc. would work.

On the "F01" code, I'm guessing that's on the battery charger? If so, the trick is that modern battery chargers have safety features built into them so they figure out what they're charging before they do something wrong. So if your completely dead battery does not look like a 12V battery, the charger will not try to charge it. The workaround is to use an older charger, or apply 12V from another car battery to get the modern charger started, at which point the other car battery can be removed from the circuit (jumper cables removed) while the charger finishes its job. Then, if your 12V battery is still good, it should charge up almost as well as it did before it drained.

If you don't have your own battery charger yet, I'll point out that one can be had for less than 20% of the cost of a new battery. Similar thinking for a multimeter and clamp ammeter.

Yes, on the charging a new battery (or old) with the charger vs. letting the car's alternator (most cars) or DC-DC converter (Prius) do it, drawing energy from the fuel. In cars with alternators, it's also considered not optimal to do since the extended high current load on the alternator can wear it out quickly.

If your battery is 7 years old, and you're not completely comfortable or interested in optimizing the last ounces of life out of it, no shame in just replacing it without doing anything else. But if you want to look into things now, or in the future, or if someone else reads this and their battery is only 4 years old, this info should help.

 

How much is the Optima yellow top Prius-specific battery for y'all Canadians? For me it ended up being cheaper than the OEM or any other OEM-style aftermarket battery.


iPhone ?

 

I haven't bought the Prius specific battery, but have gotten a couple of Motomasters for Honda's, no problems. The case, apart from the decals, looked identical to Honda OEM.

When I change address to be local to me:


Only one in stock at my closest store, but more at other locations in Greater Vancouver:



MotoMaster Eliminator AGM Automotive Batteries | Canadian Tire

 

I just got emailed a 10% off code for batterymart.com

"Take 10% Off Your Next Order
Use Priority Code SAVE10. Expires 11/8/19"

I previously got adapters from them for pencil post <==> SAE post cable-post clamps.

 

The reason for lower mileage after installing a battery has nothing to do with the state of charge of the battery. It is the car re-learning the optimum settings for emissions. Also never understood why one thinks the Prius is unable to fully charge a battery.

 

It's not "one" who thinks that..............
In the case of the traction battery, it's designed that way on purpose to increase battery longevity.
In the case of the 12 V battery, it is a similar thing as OVER charging does more damage than leaving it a little bit short.