House Battery System Configuration Brainstorming

boomerang said:

Oh I'm worried about the stock alternator quitting while trying to bring the batteries up from a depleted state too! That's why we carry a relatively inexpensive spare with us. It's not too bad to change but not something one enjoys doing, especially while cruising.
I looked into a better quality Balmar 70A, one where I could use the same belt & get by, but they are rather adamant about it's rotation for cooling. I was one on the "lucky" Mainship Perkins owners who got a contra-rotating 6.354. It runs like a top but in this case, I would rather have had the standard-rotation one.

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I missed this post until just now, I also have a counter rotating 6.354 in my 34', I am planning to send my coolant water pump off to TAD this fall for rebuilding and also want to have some replacement injector lines made. They have the patterns but it will be pricey.

I ended up altering my plans on the battery plan a bit and bought 4 group 31 AGM batteries from Batteries Plus Bulbs. They have a pretty good reputation and a physical location I can walk into if I have problems, that is worth a lot to me. I had been on the verge of ordering some 200 AH AGM's via Amazon or Ebay but their where some pretty bad horror stories about damage in shipment or no one standing behind their product, the manufacturer and vender just pointing fingers. The first two 31's showed up quickly and I was able to swap them straight in replacement of the shot group 27 FLA that cam with the boat. The second two 31's were back ordered until today. I'll need to assemble the new battery leads and install the fuses for these in a new location. I'm just using the same gauge, length and manufacturer cables and fuse holders as the existing batteries so they should be receiving a balanced load and charge.

I hate batteries I hate complicated electrical systems that being said that’s just me for me simple is better but like I said that’s me I understand other people want other things I have two batteries that run everything . I think they may be a group 27 but I’m not really sure to be honest with you they are fairly large batteries but still small enough that you can carry them anyways I don’t have a TV I don’t have a microwave I don’t have electric anything except for LED lighting and a couple of 12 V outlets for charging tablet and cell phone. As far as windless and bow thruster my main engine is running when I use those things if I need to bake something i.e. since I don’t have a microwave a barbecue grill works for that a two burner propane cooktop works for coffee and whatever else you need a cooktop for no A.B. switches no anything but a couple of batteries I do have a single cylinder diesel engine and a aluminum enclosure sitting on the floor of my shop one of these days I’ll put that in the boat I can hand crank that to start it anyways you might think about going simple again maybe not oh yeah I forgot my reefer I have one of those old fashion top loaders you can set it as a refrigerator or a freezer I have it set as a freezer so when I am cruising everything is frozen if I was to stay on the hook for more than a couple of days I would have to run the main engine to keep everything frozen a big ice chest with ice is always handy

I didn’t really mean to say that I don’t have anything that runs on batteries everything in the boat runs on batteries water pumps and everything what I meant to say is I don’t have anything that a couple of batteries Can’t handle anyways there I go being a big dummy again

Scooby5959 said:

I didn’t really mean to say that I don’t have anything that runs on batteries everything in the boat runs on batteries water pumps and everything what I meant to say is I don’t have anything that a couple of batteries Can’t handle anyways there I go being a big dummy again

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Nah, you're good. Simple boat, simple electric, and it works for you. I, OTOH, started my boating life (canoe and Dad's ski boat don't count) with a 42-foot Grand Banks in 1986 with all the amenities one of those beauties come with. When checking out my current boat before purchase, I was pleased to find it had as many amenities as the GB albeit in a smaller package. Different strokes....

I figured I would follow up on this thread as it closes the loop and may serve someone else.

After I upgraded to 4 group 31 agms with a nominal capacity of 420 AH (not usable), I ended up upgrading my inverter/charger to a pure sine that also has a higher DC charging capacity. I expected to do this at some point, but it happened sooner as expected when the old modified sine wave unit bit the dust. The new unit does support LiFePO but I'm certainly not going to change out batteries at this point. Thankfully, the way I wiring in the new batteries, it made the inverter/charger upgrade really straightforward.

I still have a lot of 12V nonsense where circuits intertwined and probably cross connected with the engine loom and gauge wiring, there are a string of fused switches at the lower helm panel that would be better served by a breaker panel. These circuits all ground out to the engine block through a string of old circuits, all of this will need to be rectified to be able to install a battery shunt. This will be a painstaking process to avoid messing up my instrument wiring.

The bottom line is that I now have a workable system for my modest needs and I appreciate the input, Ranger42c suggested precisely what I ended up with.

I faced a similar decision on my Hatteras LRC. Had 6 T105(6 Volt) for house and 2 GGM for Engines. Removed the house and replaced with Lithium. More power, less weight. Keeping the old inverter/charger for the engine bank (for charging and a back up emergency inverter). Added Victron inverter/charger for the lithium. If adding lithium probably need to put a DC to DC on your alternator output to be sure not to burn it up if connected to the lithium. The lithium can accept lots of charging current so the DC to DC regulates that.