Layne explained what the R means. A group number followed by the letter “R” means the terminals are reversed* when facing the battery with poles at rear of the battery from you, the Neg pole is on right.* If there is no R following the group number the negative terminal is on the left.
I learned about batteries when I had a big boat could have flown in a lot of cold beer for what I spent on batteries. In a nut shell they have so many amp hrs in them from new . If they discharge more than 25% their life is reduced so you want to keep them above 75% for best life That’s their sweet spot .
Discharge them more and suffer accelerated battery degradation
If I get 7 years out of a battery I’m happy it’s hard on alternators running weak battery’s
I’ve load tested battery’s
Used a hydrometer
Ready to go all good
Come to use the car a month later …dead …
Batteries seem to last 3-11 years luck of the draw Ymmv
Thanks to all who offered suggestions for an E type battery… It seems a bit of a mine field. Group 26,25,35 and 58 were mentioned as being OK. On my '70 series 2 OTS the battery terminals are on the top of the battery and the battery is installed to that the terminals are on the outboard side. The positive terminal is on the right and the negative earth terminal on the left. Whether this is original for my car I don’t know . Some of the photos on this topic showed the battery installed with the terminal on the inboard side.
Same here. That’s why you need an “R” like my 26 R or other R. For ease of in and out and fitting while installed get a smaller battery with adequate CA or if using in a very cold climate pay attention to the CCA.
Lots of battery charts around that give you the size of the various groups, or call a good auto parts store and tell them you want a smaller sized battery in an R configuration with good CA. I think my mid level Interstate Grp 26R has 550CA and it’s alway been plenty. But then I’m not cranking up at Christmas in Chicago either.
Sounds like the setup on my 1970. I replaced the battery cables but kept that arrangement. I also put a red rubber booty on the positive terminal. I dropped wrench on a 12V battery once. It was very ugly.
Bill, the 26 R places the Neg Pole on the left with the terminals to the outside edge of the car when viewed from the outside looking down at the battery. If the poles are away from the outside of the car the neg is on the right.
I may be wrong but I believe it is correct for the terminals to be on the outside edge of the car rather than the eng side. The outside pole position with an R battery places the + pole next to the buss by the Regulator and the - Pole next to the wheel well with a clear line to the chassis ground on the foot well. I moved my ground to the engine for better grounding. Additional chassis grounds are added from eng to chassis.