Adding SO43DS Battery Capacity

[CycleSailor]

I'm a new owner of 43DS and I'm hoping other owners can share creative solutions for adding battery capacity. It currently has the standard Group 31 starter & 3 Group 31 house bank under the aft berth. I'm shooting for a minimum of 600 Ahrs but am apprehensive about adding weight aft by modifying for L16's or 6C AGM's. What's worked for others in upping capacity but maintaining trim?
Thanks!
Gene

[Zanshin]

I had 5 100Ah batteries back there in my old 43DS and the weight is low down and not too far aft; they are just behind the maximum beam so the weight need to deepen the draft there needs to be pretty significant). So adding another 2 100Ah batteries there should be OK unless you already added so much equipment and weight elsewhere. Is there enough room for that much battery capacity? In my case I would have used the port and starboard spaces outboard of the current battery boxes and moved the Cristec charger forward.
Do you have a genset in the aft liferaft compartment? If not, then that weight really shouldn't affect the trim of the boat.

[rxc]

I have a 2003 43DS, so I understand your situation. I went to 4 golf cart batteries in the space provided under the bunks, and moved the engine starting battery (Group 31) further aft on the stbd side. I have the genset starting battery (Group 24) under the bunk on the port side, just aft of the installed battery compartments, with an inverter right next to it. I do not think you will be able to fit any tall traction batteries back there unless you are willing to so some major cutting of fiberglass. Also, golf cart batteries are easy to find, relatively cheap, and not nearly as heave, compared to the tall traction batteries.

I had to do some minor Dremel work on the fiberglass pans to get the golf cart batteries to fit, but now they work quite well. I also have a Group 31 battery forward for the windlass and the bow thruster. One battery there handles both, because they are not used simultaneously.

My only regret was not spending the extra money for a charger-inverterm instead of just the inverter. I thought the existing charger was fine, but it only outputs 50 amps, while a real charger-inverter would easily put out 100, which is just right for my battery bank.

Big thing to know is to replace all the batteries in the house bank at the same time, so they age together.

I agree with Zanshin that the weight is not an issue. I have the genset aft, and a big arch and probably more stuff than I should have, aft, so I try to keep the fwd water tank full at all times. I also have a lot of chain fwd, so the boat doesn't squat too much. If you have any specific electrical questions, I can provide help. I have done this sort of electrical upgrade on 2 boats, and the system I have works well.

[CycleSailor]

Thanks to you both for the info & reassurance re weight. The boat formerly had a genset but was removed by PO; at some point I'd like to pursue a replacement, but right now it's getting the battery capacity ramped up along w/the requisite higher-output alternator, etc. Leaning toward the golf cart option w/perhaps the starter battery placed under the galley sole in front of the engine. Zanshin, your website is invaluable for a new owner.

[boltnbrew]

Have a similar setup: 600ah via golf cart batteries plus starter battery and inverter/charger under aft bunk. No generator, but not a problem. We have a small outboard on or stern rail though. You can always balance by adding chain or hook to your anchor setup!