Prime 12V battery upgrade. Increase size, reserve, Ah, etc.

Sorry for the very late reply.

I am just finishing up the tread life of the 205/70 soon, and have already bought 205/65 again to replace them, though I cheaped out this time and got cheaper tires to experiment with. I got a pair of Continental VikingContact7 and a pair of General Altimax Arctic to play with, the first time in a long time I didn't get a matched set of 4. But I paid an average of $90 per tire on Amazon and eBay (new, mfr stickered tires) by grabbing or two as available cheaply.

The 205/70 were a successful experiment to see what is the largest tire the 17-22 Prime can use without a lift kit. But I did buy my set of them cheap and used only one winter, from a CR-V owner moving from Maine to San Diego. So they already had their diameter reduced by maybe 1/8 inch, and they did rub the wheel well one time when I pulled g's in a road dip. For that reason, I just can't recommend them to the general public, though I can verify that they did work for me.

I got them because I take my Prime into some surprisingly serious off-roading situations, believe it or not. Two of my travel interests are visiting sites of remote airplane crashes and alleged UFO incidents, mostly out in the 4-corners states.

But the handling is noticeably more twitchy and less stable than the 205/65, which are superior to the stock size in my experience. The 205/65 Michelins are just an incredible tire, and in summer will make you forget they're a snow tire. Note that I run them at 50psi myself, and love the stiffer handling that causes, plus the additiional ground clearance.

 

Sorry for the very late reply.

I am just finishing up the tread life of the 205/70 soon, and have already bought 205/65 again to replace them, though I cheaped out this time and got cheaper tires to experiment with. I got a pair of Continental VikingContact7 and a pair of General Altimax Arctic to play with, the first time in a long time I didn't get a matched set of 4. But I paid an average of $90 per tire on Amazon and eBay (new, mfr stickered tires) by grabbing or two as available cheaply.

The 205/70 were a successful experiment to see what is the largest tire the 17-22 Prime can use without a lift kit. But I did buy my set of them cheap and used only one winter, from a CR-V owner moving from Maine to San Diego. So they already had their diameter reduced by maybe 1/8 inch, and they did rub the wheel well one time when I pulled g's in a road dip. For that reason, I just can't recommend them to the general public, though I can verify that they did work for me.

I got them because I take my Prime into some surprisingly serious off-roading situations, believe it or not. Two of my travel interests are visiting sites of remote airplane crashes and alleged UFO incidents, mostly out in the 4-corners states.

But the handling is noticeably more twitchy and less stable than the 205/65, which are superior to the stock size in my experience. The 205/65 Michelins are just an incredible tire, and in summer will make you forget they're a snow tire. Note that I run them at 50psi myself, and love the stiffer handling that causes, plus the additional ground clearance.

My current plan is to do a modest 30mm lift to help the 205/65. But I may sneak in one last trip out west on the 205/70, which should get the tread down to the replacement bars at 2/32 of tread. Whether I'll do the lift before or after that, I'm not sure.

 

In 2021, two local O'Reilly's stores couldn't get the ACDelco battery into stock, so I just bought a Golabs R300 LiFePO4 power station and left my car battery alone.

But right now I'm looking at this winter being the 7th winter for my original battery, so I'm thinking it might be time to finally do the mod. Sorry you had to cut the battery tray to fit the Group 47, but I did characterize that battery length to be between ambitious and aggressive. Do you have an exact measurement of how long your new battery is (and is it the same top and bottom, or does it have protrusions) and could you tell me what make/model of battery it is?

I'm going to take another look at what types/sizes are currently available, and also check whether O'Reilly's or anywhere else cheap, can get the particular ACDelco I was planning to get.

 

I finally did the same in November 2024, after having bought the battery probably over a year earlier. I got an ACDelco Group 47 AGM with 115 minutes reserve time, from Summit Racing online. Nice battery with great specs, and pretty inexpensive compared to what many places charge even for lousy batteries now.

I also cut both ends from the plastic battery tray with a cordless oscillating tool. Plus, I cut the flanges on those ends of the battery itself off, being extremely careful to only cut it flush and not into the battery. Actually was pretty easy with the blade held flush against the battery. As you said, it was still pretty close to the sheet metal at the front, after moving the back up against the curved sheet metal there. Maybe I should have dimpled where the back right corner (as viewed from in front of the car) met the curved sheet metal, to gain another 1/8 or 1/4 inch of ability to move the battery toward the windshield. There was also the ability to do some surgery on the sheet metal closest to the front of the battery, with that being a sort of bracket shape that could have been slit and bent 90 degrees to both give more room, and to make it a flat surface rather than a sheet metal edge that the battery would hit in a frontal collision. Not that even the stock battery wouldn't hit in a collision, plastic tray or not. I ditched the foam battery surround also.

Very easy job, other than the cutting which had to be done carefully. Wires under the front of the battery tray were pretty close, so you'll feel like a brain surgeon by not slipping and cutting them if using a power tool like I used.