CB35 battery system diagram

[Rondo]

Working to decipher how the batteries are connected on our 2007 35 cb. No problems have surfaced, but want to understand how they are cross connected. We have a pair of 8d's, and a group 24 on the genset. One of the rotary switches is marked "house" and the other is marked "engine", the third is marked "generator". The PO kept everything set to the "all" position on all of the switches. As a quick look, nothing seems to change when I change the switch positions, but not much works if they are not all set to "all". Doesn't seem right.

An upcoming project is to connect a battery meter, like the Victron unit, to help keep an eye on charge, discharge, etc, so need to know.

Does a schematic or diagram exist for this system? There was nothing on board. I can trace it out, but will take some time. So if anyone can point to, or share a diagram it would be appreciated.
Ron Owens

[Sanatee]

Albin NEVER had diagrams or manuals for anything except OEM items installed! My 96 32+2 has 3 series 31 batteries, one starter & gen, one thruster and windlass, one house. I can use the 3 switches to select them independently or put them on ALL so that they share parallel power to everything. I also use the ALL setting so that all 3 are charged from the alternator when running.

[Rondo]

Thanks for the quick reply. Not surprised to learn that, though our Hatteras spoiled us with a diagram for most everything. Just thought I'd ask.
I have traced out several of the cables, and "think" I know where most of them go. The selector switches for the two 8D's are tied together, which makes it very easy to have them as one bank. The downside is, if you draw the house bank down too far, there is no other start battery. Only the genset is mostly isolated from the other loads.

I installed a new and really good, 50A, 3 bank charger, and it is keeping things in nice shape. Since all the batteries are AGM's, no additional programs are needed. I am seeking a belt and suspenders approach to the "what if" the 2 8D's get too low to start the Cummins? The pair run everything on the boat - fridges, freezer, thruster, windlass, lights, etc., so after a long night on the hook, this is not a wild thought. I am leaning toward swapping the genset to a group 31 AGM (overkill) and then running a positive 2/0 cable through a switch, then on to the starter on the Cummins. I am pretty comfortable that if I put the Group 31 online, it will start the main engine, if need be. The plan is to first start the generator, then switch the Group 31 on to power the starter for the short start time needed.

We are not adverse to running the generator. It needs some work, as it had only 65 hours when we adopted her. Just want to avoid that sinking feeling of waking up and having no easy way to get everything going in the morning. Especially before the coffee is ready.

Incidentally, we were in Solomons in May for a visit with friends who live there. Such a great spot.

Thanks again,
Ron Owens

[Sanatee]

Never had a problem with my 31 gel starting the Cummins. I've gone thru 3 house and 2 motor batteries in 23 years, and I can lift the 31s! I did replace the original charger with a better Charles and it has done well.

[Rondo]

You've had good life from your batteries, to be sure. Our boat only had one previous owner, who bought her new in 08. The boat was kept on a lift in St. Petersburg, and only used during winters, as the owners were from next door (Canada). Only 460 hours on the Cummins. PO took great care of her, and I inherited a stack of receipts and service records. I don't think they spent many nights aboard. I have deducted that the batteries are original to the boat. I have isolated and load tested them and they seem just fine. Nonetheless, 12 years is a long life for marine batteries. I am glad to hear that the 31 handles the Cummins, and it reinforces my decision to just swap the genset 24 for a 31, and use it as a backup for main engine start. Even a set of jumper cables would do it. We have the newer QSB 5.9 model, which I like a lot. No hesitation on going, but with the low hours, I wouldn't expect less. Ditto about being able to lift the 31's. These 8D's are man killers - at least old man killers.
Cheers, Ron Owens
2007 35CB "Journey to ---"