My Panasonic was 5 1/2 years old and I just started to notice it cranking a little slower than it used to so decided to get a new one. Took a look through the forum and did a little research on what's out there. Hope this helps someone out.
I don't think there's any doubt this is the ultimate upgrade.
The DieHard Platinum PM-1
However at almost $300, it's a bit on the pricey side and since it's larger than the stocker, it requires at least a little modification to get it in and hook it up. It'll fit but it would put another 25 lbs on the front driver's side of the FJ which I don't need. I seriously thought about relocating the battery to the passenger side rear of the engine compartment and using this one though.
Also thought about the DieHard Platinum P-5 (Group 35)
which fits right in and has about the same CCA as the stock Group 27F. However, it's a smaller battery than the stock one and the reserve capacity is only 100 minutes. Maybe not the best choice to use with a winch.
Optima makes a Red Top in Group 35 which is probably worth considering. They also make a Yellow Top in Group 35 but the CCA is a little lower than stock. Here's the link to their battery selector
which is about the best way I can figure out to give a link to their site. These and the Platinum P-5 are right around $200 but the real turn-off for me was the lack of reserve capacity. They're probably great for a rig without a winch.
After thinking about it for a while I haven't had any problems with the Panasonic conventional wet cell so why not see what's out there for a regular old Group 27F replacement battery?
Believe it or not, as far as specs go, one of the better options may be the Duralast Gold Group 27F
from Autozone. Same CCA as stock (710) and 165 minutes of reserve put it only 40 minutes behind the DieHard PM-1 and at 1/3 the price. The fairly low CCA and high reserve capacity suggest this battery is a little more of a deep-cycle design which should be a good thing for use with a winch. I'd be trying one of these out right now if my local Autozone had one in stock. I know there are probably plenty of haters out there who will say these batteries are junk but it has a 3 year free replacement warranty - same as Optima and the price is only $95.
What I ended up with is a DieHard Gold Group 27F
. Specs on it are 750 CCA and 140 minutes of reserve so it's more of a starting battery than the Duralast. It still has a lot more reserve than the Platinum Group 35 though. This one also has a 3 year free replacement warranty so at $105 I figured it's worth a try. It's actually about 1/2" taller than the Panasonic but still fits fine with the stock holddowns.