Retrofitting larger capacity battery in HHR
 

I did some searching on this site but couldn't find any threads on this subject. Has anyone ever successfully retrofitted a larger capacity battery in an HHR? If yes, can you point me to where I can find out how it was done?

I saw some discussion on installing a second battery but that's not really what I want to do. If possible, I would just like to find a way of replacing the tiny stock battery with something with a more charge capacity. My '08 SS gets parked outside all winter and doesn't have a block heater installed. It can get cold here in Canada during the winter and I find the car will never start when it gets down below -17 C (O F). I have installed an electric battery blanket to keep the battery warm and that helps somewhat but it doesn't help me on mornings where I didn't have it plugged in overnight because it wasn't that cold the day before and the temperature dropped a whole bunch overnight. I think it would help some if I could just get a bigger battery with a bit more charge capacity in the car. At least then the battery might have enough charge to turn the engine over a couple times when it's cold. The little batteries these cars come with don't seem to have enough to do even that when cold...

Another thing that's driving this is that I have the opportunity to get a free brand new battery for my 4Runner but I don't need it in the 4Runner so I'd like to use it in the HHR if possible. It's a little over an inch taller than the HHR battery so I'd like to find a way to make it work in the HHR if I can. Ideas? Suggestions?

Here is a chart of battery dimensions
https://www.jegs.com/Sizecharts/bcigroup.html

I put a group 47 AGM battery in mine, direct bolt-in.
https://www.chevyhhr.net/forums/comm...e2/#post769761

What group is the 4runner battery?

Does your car have a block heater?
How old is your battery ?
What is the CCA of the battery you have ?
0*F is not arctic temps.
Do you use synthetic oil ?

After you get one that fits you need to make sure it has a vent, or risk you life like we did with air cooled VWs.

Nah, when the battery came loose in a Vdub and slid into the rear seat brace then the fun began. :thumb:

As stated in original post, no block heater, just a battery blanket.

600 CCA, battery is about 3 years old. Should be under warranty but I can't find receipt. Yes, I use synthetic.

4Runner can accept a range of batteries, Group 24F, Group 34R or 35. I just put a brand new 34R Absorbed Glass Mat battery into it and then subsequently found the receipt for the one I took out which is likely Group 35 which I can get replaced free under full replacement 42 month warranty. The AGM group 34R is the shortest of the two so I'd like to try and shoehorn that one into the HHR if possible. It's dimensions are (L x w x H) 10.75 x 6.875 x 8 inches. About an inch longer, same width and 1.125 inches taller. The battery posts are a little bigger too so I'd have to change the battery posts.

From what I can tell, 34r has the posts in the wrong position. It's also 1/2"+ longer than 90 or 47, so that may be a challenge also, you may end up losing the hold down clamp. All that, plus having to change the terminals...

Just dropped the 34R AGM battery in the HHR and it fits no problem. I lost the hold down clamp on the end but tightening down the side one tight seems to do the trick. It seems to be held in quite snuggly - don't think it will move. Even if the battery does slide laterally, it can only slide about 1/4" before it hits the raised part of the metal battery platform and can move no further so I'm not too worried about it.

I was wrong about the posts. The HHR post connectors fit perfectly. Cargo compartment floor also fits on without any issues. It seems like a perfect solution. :dancingalien:

This is the battery I've put in.

MotoMaster Eliminator Ultra AGM Automotive Batteries | Canadian Tire

Now I have 775 CCA vs 600, 890 CA and 120 minutes reserve capacity. Much better! :pickle:

What about post position? Did you have to install it backwards, and then the cables were long enough?

The posts originally were to the rear of the vehicle.

Post position is exactly the same. Look at the picture of the battery on the web page I provided. Rotate it around 180 degrees in your head and you'll see that when the posts are on the back side of the battery, the positive is on the left and negative on the right. I should mention that the 4Runner I have is a 2002 (Gen 3). The newer ones may take a different battery.

The 34R battery literally dropped right in and fit perfectly without any adjustments or modifications having to be made. The only thing is I can no longer use the battery stop at the end because this battery is a bit longer than the stock battery but it's no big deal. I just tightened down the side stop really snug and the battery won't budge at all even if I really try to move it. No way it's gonna move just driving around. Even if it did somehow manage to move, it can only move laterally about 1/4" at most before it hits a stop. I can post a pic of how it fits if requested.

So, to end the story I took the 4Runner's old battery back to the store for warranty and had it tested. The test showed the battery was strong and didn't require replacing so I just cleaned up the posts and put it back in the 4Runner. As it turns out, I didn't have to buy a new battery for it but I was really lucky that I traded in a different old battery for core and kept the old 4Runner battery. I was also extremely lucky that I opted for the 34R AGM battery because it's just short enough in height and length to fit into the HHR almost perfectly. I'm really happy the way that worked out. :thumb: