J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment Battery up-size

I am not yet a J-30 owner but hope to be soon. I am wondering if anyone has experience in mounting a pair of Group 31 (13"x7"x10") batteries in place of the standard group 24s (11"x7"x10")? I know the compartment in the port quarter berth has a molded fiberglass tray sized for the 24s, but how hard would that be to modify to accommodate a couple more inches. Anyone done this? Any other suggestions to increase the total Amp hours of the battery bank?

I installed two of these:



They're Mastervolt Slimline AGM batteries, and come in 150Ah or 200Ah capacities. They lay over nicely under the quarterberths, and I epoxied wood stops to the hull to hold them in place and mount the straps:



I have a house battery on starboard and an engine battery on port. Battery switches allow me to either split house/engine like that, to use either battery to run the whole boat individually, or to combine them if needed.

Alx, looks like a good way to double the AHs. Can the port battery fit where the two Grp 24s were at? The slimline 200 AH batteries are 119# each and it would be nice to have that wt positioned as fore & center as the originals. Do you think you would need to reinforce the fiberglass where the batteries do sit?
Mark

I chose the Slimline because it could lie on its side as I couldn't figure a way to put the capacity I wanted in or around the original battery box. I wanted to slide them under the aft part of the quarterberths, into the short space back there that's not good for much else. It's not very ideal but my Beta engine weighs significantly less than the J/30's original Yanmar, so the extra weight isn't too concerning to me.

If you wanted to put both on the same side you could (removing the original battery box), but that'd be a lot of weight off center.

I haven't done any fiberglass reinforcing, but I do have redundant straps holding the batteries in place - one across the top and another on U brackets through-bolted to the engine compartment walls.

Another option is to put the new batteries behind the engine and shaft packing - there's plenty of room in the engine compartment aft. Weight-wise it's probably not the best option, but you can certainly fit some serious capacity into that volume.

I don't know if you intend to race your J/30 one-design, but the class rules probably have something to say about all this. I don't race my boat, so I haven't really worried about that.