by mistake. I thought I was sending it to the forum...
Greetings and TIA for any help and guidance you can offer. Having got my SBMS0 a few months ago, problems with making and plating the buss bars delayed me and I am just now getting ready to set it all up. I am new at this, though have some basic knowledge, from camper vans, house wiring, college many years ago and more recent reading. This is on a 38 foot wood/glass catamaran. This is a distributed system with a main feed from the batteries to each hull and the cockpit, with individual fuse blocks for each cabin. I think I have a reasonable grasp of the required layout beyond the battery for the shunts, fuses etc.
The batteries I am assembling are made up of two 150A/h packs for the house bank and a smaller 75A/h pack for starting the two outboards. Each of the house packs is built with 24 Navitas 25A/h cells, configured as shown in the drawing below. 3P8S configuration? Below that is a photo of the actual pack as assembled. The starting battery will be charged by the alternators, managed with a Victron SBP. I will have provision for charging the starter battery from the house system for emergency use.
My original layout had the two groups of 12 cells in opposite directions but I believe it’s better to have the main connections at opposite ends of the pack (?). Because the Navitas posts are too short for a battery lug with the 1/8” buss bars, I made the end two longer with a bolt hole for the battery cable lugs. Not sure how to address this if the extended buss bars won't work. I can make any cables I need but the lug thickness required won't allow for more than a single connection on the Navitas posts.
First, does this configuration look ok? If so, in the top drawing I have shown in blue where I think the leads for the SBMS0 should be attached. Are these correct and if not, what am I missing?
Then there is an additional problem of having two identical house batteries. This is for for keeping the packs a manageable size and weight as well as for redundancy. Is there a way to connect the SBMS0 to both packs or will I need a separate SBMS0 for each pack? Although this would mean extra expense and complexity I will do that if need be.
(And yes, after putting these packs together I realize that I would have been much better off with a small number of bigger cells but this is what I bought so need to make it work).
This will be a 12V DC system only. The only charging source will be 900 watts of PV. With my calculations of the daily loads this will be plenty for energy independence and I am not going to install a shore power system or a generator. The outboards could be used for charging in an emergency (12A each) but I do not plan on depending on them for charging. I have a Victron 70/15 MPPT for each of the 220W panels because there will be variable shading on the four panels. The MPPT’s will be controlled by the SBMS0 with VE direct non-inverting cables. So can I join the four VE Direct cables at the SBMS0 end so they would be turned on and off as if they were a single unit? If not, how do I accomplish control of the four SCC's?
Whew. Building this boat has been a long haul. I am very close to getting it all done and ready for launching. Having scrimped, scrounged, bargained and struggled over the years to build it with a limited budget, I am now impatient to get it done and within reason will buy any additional items I may need to make this system safe and effective. I will probably have other problems come up as I finish this, but for now I think that’s it.