Replace OEM 12V battery with Group 25 AGM

I'm pretty sure that having an AGM battery is extremely important for both safety and reliability. That means the YBX9027 would be preferred, if you can get it to fit.

 

I'm really liking the larger group 25AGM.

I know there is no 2011 12v OEM battery running today that can hold off the ICE at the entire stop light while the heater blower is going.
That 2011, old whippy battery requires the ICE to continually run to charge it if the fan blower is going.

This battery almost never allows the ICE to run at all stops, during my travels. NICE.

I'm enjoying more quiet time when I come to a stop.
my2cents.

 

The ICE does not charge the 12 volt battery. It charges the 201 volt battery via the Motor/Generators. The Inverter charges the 12 volt battery and powers the 12 volt electricals when in READY.

roughly 15:10 to 18:00

 

Mine would hold off the ICE before I replaced it at over 6 years old. I have a very long stop light when my side road meets the US highway and the ICE would never come on with the fan going, even when we had the below freezing temps for more than a week straight here. The only thing I do at that stoplight is click the headlights to parking lights.

Replaced it with the BOSCH direct fit AGM battery made just for the Prius and the ICE still does not start at that long stop light.

 

So glad I installed a Group 25 battery in my Prius.

Thought I’d add a few things I remember about doing the job which might be helpful to someone concerned this may be too difficult.

I purchased the Bosch Platinum Series AGM Group 25 MMJ25 Battery at Pep Boys.

While at the store I noticed some of the batteries didn’t have the little black plastic elbow shaped vent tube connector. I made sure to get one with my battery.

The original Prius vent tube fit on to that new connector. I didn’t need to purchase new tubing. The vent hole on the opposite side of the battery had a plug in it. So I’m venting one side of the battery.

The Group 25 battery has larger terminals.

I purchased the 90982-05054 positive terminal from Toyota. (A dealer near me had a 15% discount.)

I purchased the Everstart LF15-4-77 4-Gauge 15” Top Post ground cable from Walmart.

There are three bolts that hold the battery tray in. One of them is really hard to get at with a standard crescent wrench. I borrowed a ratcheting wrench (10mm I think). A socket wrench would also work.

I didn’t drill the hole the instructions suggested. (I didn’t have a drill.) The Group 25 battery fits snugly. I felt the battery hold down bar held the battery securely enough even with one of the bolts missing.

I didn’t have a battery charger to keep the electronics alive while I changed the battery. My settings were long gone ...

A big shout out to cproaudio for shining a light on the path. I never would have found my way without you.

 

FYI - Check stock at Rural King online before you go to the store. The group 25 battery appears to be out-of-stock nearly everywhere. I'll probably go and pick-up the Bosch from Pep boys instead.

EDIT: It appears that the group 25 AGM isn't available anywhere right now.

 

Can some of the folks with bigger battery comment on your experiences?
No one has really confirmed my observations of more ICE down time during stops and go's. thx.

FYI - a better detail comparison of Group 25 bigger battery from the two sites.

Bosch Platinum Series AGM Battery Group, Size 25
BCI #25
Cold Cranking Amps (CCA) @ 0F650
Reserve Capacity (minutes) 110
Weight (lbs) 37.0
Length (in.) 9.06
Width (in.) 6.93
Height (in.) 8.87
Cranking Amps @ 32F780
Battery TypeAGM
Right Or Left Hand PositiveLeft
Terminal TypeT
$142.00 2/25/18 Pep Boys Available

Rural King Automotive AGM Group 25 Battery RK-AGM25
Group Size 25
Part Number RK-AGM25
Cold Cranking (CCA) at 0°F 650
Reserve Capacity (MINUTES) @ 25A 110
Weight (lbs) 41 lb
Lenth (in.) 9 1/16"
Width (in.) 6 5/8"
Height (in.) 8 5/8"
Ah Cap. @ 20hr 53
Battery Terminal Type A
$125.00 2/25/18 sold out now Rural King Automotive

 

For some reason, I can't get either Rural King nor Pep Boys to allow me to order for shipment or store pickup. I have spot-checked different areas of the country with no luck. I can't find stock under the Exide brand either. It leads me to believe Exide is either back-ordered nationally on the Group 25 or has discontinued it.

If that is the case, it looks like we are left with Optima or Odyssey on the Group 25 size. Alternatively, we go with the stock but lower ah battery. In quickly looking at other battery sizes, as you found, there aren't really any other alternatives to Group 25 which fit and give a good ah boost over stock.

 

What did you end up going with?

 

• I haven't done anything yet. My original battery is still functioning although I suspect it is weakening (lower MPG) and I'm looking to preemptively replace before it goes bad. I like the idea of the group 25 replacement and I'm have been hoping something would show back up from Exide. However, it looks like I need to go a different route.

 

I don't fully understand: they won't sell you a battery, or you just can't order it online? Is there any problem just walking into one of their stores?

 

To clarify, it is not in store (checked by walking in) or available to order online. For all I can tell, it has been discontinued by Exide.

 

i would eventually like to do something similar in my prime. i use the bluetooth to netflix and chill while at work at lunch, sometimes make calls or listen to hypnosis before or after work (stress management [and no im not driving]) Too bad it has the battery under the hood now. i wanted to install a small\medium (less than 500w) sound system and firewalls are a bitch to get wire though.

 

Pep Boys -
Bosch Platinum Series AGM Battery Group, Size 25, Part #: 25-650BAGM|, SKU: 844466 $142 after 25% discount

 

I wish that would work and tried to get it. The battery shows as "not in available" online and you are not able to place an order. I also went into my local store and there wasn't any stock nor a shelf location for the battery. All signs are pointing to Exide discontinuing the battery.

 

So far, this is the best I've found. It looks like group 25 AGM batteries are no more.

SLI75DTAGM - Duracell Ultra Platinum AGM BCI Group 75/86 Car and Truck Battery (Dual Terminals) at Batteries Plus Bulbs
$190 after 10% online pay, instore pickup discount.

 

I saw this was posted in the Gen 3 forums, but it sounds like it's possible to do it in other Prii. Has anyone done this for the Gen 2 that can verify?