Problem: red triangle & red power light when powering on car

Good point. This is why almost any battery that physically fits will work, I keep an old RAV 4 battery on a float charger (wet cell) as my next aux bat. After being installed the cars charge system will continue to charge at something comparable to my float charge. I also keep a small gel (7.5V) for emergencys. If you want to repeat the same problems again in 3-4 years by all means get the OEM Battery. Incidently, both of my substitute batterys work fine, I installed them and tested them for a couple of weeks. :cheer2:

 

Certainly any vented 12V battery will work. The fun is in finding one that fits in the available space and in making the Toyota cables fit to its posts.

 

True, I filed down one of the post on the wet cell and drilled a small hole for the vent tube above the electrolyte line. But you are right, finding the right physical size, and approximating 30AH is the problem. I think a lot of Motorcycle batteries would work also.
:rockon: