Want 12 Volt Battery Specs.

It is supposed to be AGM. However in the past some owners (usually Classic or base 2G) reported their batteries contained liquid acid. What is weird is that the external battery markings were exactly the same as other batteries with AGM.

The 2G battery for Smart Entry/Smart Start-equipped Prius has a black case. Hence one way to determine if it is AGM without opening the top would be to remove the battery, hold it in your hands, shake it, and see if you hear any fluid or not.

 

Pat: It seems like most of these "Maint free Bat" have a label over the portion where you would normally service the Bat. That is so on my GS. I partially peeled back the yellow warning stickers and underneath was a opaque plastic piece running the length of the Bat. I did not take the stickers off as the Bat is in good shape and I did not want to change its seal. The plastic piece looked pryable, but for all I know it could have individual cell caps for servicing. I think it's also liquid electrolyte. Perhaps the matting material is there to slow down evaporation and act as a baffle to lessen spillage and splash.

 

Hi Andy,

Yes, the opaque plastic piece can be pried out so that you can look into each of the six cells. I did that with the original GS battery from my 2001 after I installed the Panasonic replacement battery that Toyota prescribed per a TSB.

My battery was AGM: I could see the fuzzy white mats between each plate; and there was no free liquid within.

 

Hello Pat: OK, Thanks for the information.

 

I lost my 12 volt battery last week and ordered the optima kit from E Learn aid PO BOX 921585, Los Angeles, CA 91392-1585 USA. I want everyone to know it is a very high quality part even better than the toyota part. I order an extra one for my wife's prius I live in Wheeling WV if anyone close gets in a fix you can use mine and order me a new one. E learn shipping was fast, 2 days. The only other suggestion I would make is remove the plastic handle from the optima battery before you install the battery, this make the install perfect. Others tell you to bend the fuse holder around the plastic handle, the battery only weighs 26 pounds, lets see bend something to fit or remove a stupid plastic handle on a battery I will probably never see again. good buy handle. [email protected]

 

Officially you can't "check the 12V battery for electrolyte level". So it's a "no-maintenance" item. Unofficially it IS possible to pry off the caps and add distilled water, though usually by the time the battery needs that it's old enough to be just about finished. This is because in the Prius use it doesn't see abuse (other than full discharge ). For example, it isn't in the engine compartment so doesn't see high temps.

DO check the -ve cable connection to the chassis behind the battery. Jay has found it comes loose or corrodes on his car.

You don't have to get into the hatch to charge the battery or connect the battery tender. Do that under the hood using the "boost terminal", which is under the red "flip-up" plastic cover in the fuse box.

After saying all this, so far I haven't had -ANY- trouble with Pearl's battery (I know, I'm jinxing myself!). Be aware, both the interior overhead light and the one in the hatch has a three position switch - off - door activated - on. I forget the exact orientation of the switch positions, but I suspect leaving the hatch one in the "on" position is responsible for about 1/2 of the full discharges owners have reported. The other 1/2 are probably caused by shutting off the car and sitting in it with the headlamp switch in the on position. The lamps won't go out until you open the -drivers- door. In Canadian cars, the DRLs won't go out until you open the -drivers- door as well.

 

In my Prius, it was corroded after less than 4 months. I'm in the habit now of backing off the bolt, then snugging it back up again, twice a year.

 

i, too, just installed the Optima yellow top via eLearnaid.
no plastic handle was included w/ mine so i did not experience Wheelin1's issues.
the shipping was fast, installation easy.
i'm very happy w/ the purchase

 

One thing eLearnaid could improve is the lug (chassis end) of the negative cable. It needs a bend or an offset to make the contact surface flush with the chassis when the mounting nut is tightened. The original Toyota cable has the lug offset to make the contact surface flush. As supplied, my cable had the lug nearly on-axis with the cable, which would leave a gap and tend to cause the mounting stud to pull out of the chassis when the nut is tightened. The instructions even remark on the danger of pulling out the stud. I used the visegrip to put an appropriate bend into the lug. Fortunately the relative orientations of the lug and the battery terminal clamp were such that the installed cable easily accommodated the bend. It might have been the case that the necessary lug bend would have put the clamp into an awkward position.

The hole in the lug is also much larger than needed, almost as big as the captive washer on the mounting nut (which would be bad), and it had the rough look of a modification to the original lug. If it is a mod it should leave a smaller hole.

 

Excellent assessment...
Agree w/ the all of the above. Yet, it functions just fine.