replacing 12v battery myself

You may want to attach a backup battery while you swap the new one in. If you don't, then the radio and backup buzzer settings will revert to default. Not the end of the world, but you might want to write down the radio presets before they're lost. And where is that chicken dance to shut up the backup warning...

 

1) In my opinion, probably not. They have had some quality problems over recent years and aren't really much better to start with.
2) You need a name brand AGM type that will fit in the mounting space and has the right kind of posts. There probably are several different ones that will work just fine.

Others who have done this should be able to give you more specifics.

Disconnect the main negative cable first and re-connect it last.

 

welcome!
there is no consensus on best battery. some want cheapest, some want oem, some want another alternative. it's really up to you to look at cost, warranty and reputation.

i think 'unboxed' just means they don't come in a box. pretty much how 12v's are typically handled, but could it mean someone bought it and returned it? not sure. either way, i would thing it would have to be boxed up if they are shipping it to you.
someone else just put in an optima and so far so good. before you install any battery, you should check the voltage and trickle charge it if necessary. new is around 13 volts.

there are two different models for the gen 2 prius. SKS and non sks. if you can unlock the driver door and start the car with the fob in your pocket, you have SKS and need the larger, more costly battery. if you don't, you can use the smaller version, but some opt to change the battery tray and install the larger for more life and reliability.
all the best!

 

I just replaced my Optima Yellow top S46b24r, which was 3 1/2 years old (and still good) when I changed it. I only changed it because it's nearing the end of it's lifetime, and I didn't want it to fail on my wife this winter, who is using the car right now.

I replaced it with a 48 month Bosch Premium 51-440BAGM.

Although I was happy with the yellow top Optima in my Prius, several other Optimas (red tops) that I have purchased since for other cars have failed before their life expectancy - only one out of three made it to its full warranty period. I have always had good luck with Bosch Batteries (other's experience may vary).

My Prius has a key fob (SKS). I did not need to modify the battery tray for the above two battery models.

I'm not a battery expert, but I think the Optima yellow top is a deep cycle battery - meaning you can significantly discharge it and it will recover without degradation. A normal battery (such as the Bosch, or Optima red top) will be degraded (lifetime will be severely decreased) if it is fully discharged.

 

The actual physical work is not hard at all. You need to remove the vent duct from the hybrid battery and some modules on the positive terminal. First time will take 45 minutes, second time a fraction of that.

When I shopped around for a replacement, internet deals with shipping were running about $185. My local dealer's price was $215 including local tax, so I just went there. A couple of my volunteer projects are funded with local sales tax so I like to buy locally.

 

I agree with andrewclaus - a car battery is one thing you should buy locally. Makes it easier to return if the battery fails before it's warranty period is expired. My Optima yellow top was only available online though.

 

Best keep it as simple as possible. Maintaining the car's memories while the battery is disconnected is a nice convenience, but not imperative: it's gonna complicate your mission, and is a step you could skip. You just need to reenter radio presets, reset the clock, and maybe reteach auto-up on one or more power window.

The Toyota battery can be bought at a dealership parts department. One positive: it's the simplest way to to ensure getting the correct fit battery. Can you post the costs through the dealership, the battery itself, and the install?

Another step you can probably skip, but is nice: is to hook up the new battery to a smart charger, before install, bring it it right up, a good first step. But if the battery's in good condition, you'll be ok without this step.

The actual swap is dead simple:

1. Remove negative cable clamp from battery. 10mm wrench is your best bet. Isolate cable end by pushing into a heavy work glove and tucking out of the way. (That'll be the non-red post, with short cable going directly to car body. With a good light you should see an embossed negative (-) symbol adjacent to post)

2. Remove positive cable clamp from battery, similarly.

3. Disconnect vent tube and hold-down bracket, move out of the way.

4. Lift out old battery. It'll be suprisingly heavy, hopefully has a strap.

5. With some fine sandpaper or steelwool, clean the inside of the two cable clamps. Do the same gently to the posts of the new battery. Be cognizant: the posts are lead, try to contain the dust, and dispose of the sandpaper or steelwool in sealed bags.

6. Lift in new battery, install-down clamp and vent tube.

7. Install positive battery cable clamp. Cinch down the clamp firmly but don't overdo it. Verify with a tug that it's solid.

8 Repeat with negative cable clamp.

 

For a small 12 V battery ?? YIKES.
I think I've seen prices recently for considerably less than that.

 

Wait a sec........
This is a NEW battery; it had better be "in good condition".

BUT.....one should NOT skip that step.
It is very important for new batteries to be fully charged before being used.
Many come from the factory/distributor at 50% or less.

 

You also forgot the step to remove (and later reinstall) the HV cooling duct which goes over the left rear corner of the battery. And the caution to not loose the self tapper screw down behind the battery on the reinstall.

I second Sam Spade's advice not to skip ensuring the new battery is charged to full before installation.

 

And for Gen3 owners who don't know how good they've got it...

The Gen2 forgets the backup buzzer setting when 12V power is removed. It's a chicken dance to turn it off again.

I had both the backup buzzer and the passenger seat belt warning turned off. After replacing my 12V, both came back on. The backup buzzer was irritating enough that I looked up how to set if off again. The seat belt warning is still ON, and the thing goes off when my dog sits in the seat or I put heavy groceries there. The dog/groceries don't happen often enough to force me to look up how to turn it off, but it would have been nice to simply not have to worry about it.

 

Backup beep and seat belt is the same chicken dance, just the seat belt setting is engaged by buckling and unbuckling.

The reverse beep is engaged by going into reverse and park.

//cloud.tapatalk.com/s/58673d9a21f23/Reminder%20Light%20Reset.pdf

 

As I recall, you have to power cycle while buckling the passenger seat belt. One person stepping on the brake while sitting in the passenger seat and buckling the seat belt is quite a contortion. Hope that's wrong, but it's what I remember.

 

If you are not buying the OEM, make sure your replacement is an AGM deep cycle battery. These are the two most important qualities to pursue. Then of course it must have the correct physical attributes–JIS posts, positive post on the left (as you look at it with the posts nearest to you) and of course the correct width, depth and height.

 

AGM is important; "deep cycle" is not really.
Those extra dollars would be better spent getting a small automatic charger for about $30......IF the car tends to sit unused for long periods.
One which is driven regularly should NEVER have a "deep cycle" need.

 

I agree, in theory, you are correct. In practice it says otherwise. If you have a charger and you use it regularly, it is not the end of the world if it is not a deep cycle.

 

I went with the OEM since it had a good warranty. I wanted the car to be as reliable as possible and weird things are reported to happen when these start going out on a Prius. I used a small 12v alarm battery connect to the jump starting post under the hood to keep power to the system. Any 12v battery should work.

It is frustrating how expensive these batteries are, but I am not sure it's a good place to save money. The original battery went six years and I replaced it before it could fail