I am getting old. When I bought my 311 five years ago I put new batteries in it and have pretty much done nothing with them except unhook them in the fall and charge them in the spring. I can get a good deal on some batteries through a group discount some friends are working out but I can't remember what size I need. I think they are Group 24? Is it possible to go bigger without a lot of modifications in the mounting?

As long as your battery bracket can fit (in inches) 10-1/4 long X 6-13/16 wide X 8-7/8 high (group 24), should be no problem. Attached are the dimension specs for the BCI group numbers.

http://www.rtpnet.org/~teaa/bcigroup.html

Hey Wantsa311,

It is funny you are bringing this up. I just had this question and debate on what to do.
It comes with 24 series batteries.
I had just recently ugraded my stereo and use my fridge regularly. I had found with draw from the stereo I was killing my batteries to quick.
I just ordered 31 series batteries. I also called Bill @ Diamond Performance (302)521-0123 and ordered a pair of battery trays for the 31 series for approx. $80.00 each.

They are the same width just a little longer so they will fit along the sides where yours are mounted now.
Assuming your 311 is the same as mine.

Good Luck !!!

Jeff