A new house/cranking battery bank!

So...until now my house batteries have lasted the night while anchoring out. *Lately though they have gone downhill....like I drop a hook for a couple of hours for an afternoon swim and they don't want to crank the engine back up! *I never paid much attention to the batteries as I wasn't concerned about it but lo and behold, previous owner, in his foresight, installed 4 group 24 automotive cranking batteries for a house bank, NOT deep cycle marine batteries. *

I swamped them all out tonight with 4 group 24 deep cycle marine batteries but soon I am installing an inverter and probably moving the house batteries to a better location. *What do you think is the "ideal" set up for a house battery bank for a boat (and why) that will have a small inverter and a big ol' 8 KW northern lights generator (kinda wish it was just a 4KW!!), no solar or wind power yet. *What say ye?

Well, I'm*probably the least qualified to answer as I don't know how your boat is set up.

On my boat, there are three hatches in the pilothouse floor*for accessing the engine room which contains the batteries, etc.* The middle one is directly over the engine.* The port-side hatch provides access to the inverter and a battery box (the boat has two battery boxes, one*containing two batteries for the "house" and the second box for the engine's battery, but I forget which side either is on), and the starboard-side hatch where there is another battery box.* The battery boxes are a highly-convenient step down as well as a seat while fiddling in the engine room.

Starboard side, showing battery box, water heater, air compressor, and air tank:



(I don't have a port-side photo readily available at this time.)

The wire circuitry includes a house-battery switch, an engine-battery switch, and a third switch placing them in parallel:

Mark,
Your pictures and engine room are completely not applicable to my situation- you have NO grease, NO oil, NO diesel stains, wiring is all in order, everything is tidy, etc.

yes, I know my comment above is only engine room envy but...... :cowboy:

Woody, do you have separate house and start battery banks or one combined bank?

There's the battery capacity issues, storage volume needs, the power consumption issues, battery monitoring requirements and the shore and alternator charging issues that need to be addressed.

You could have an inverter bank separate from the house bank. Those G24s might serve that purpose well for occasional 110 use of a coffee pot or microwave. I agree that GCs are a good buy, especially the Costco interstate ones. I put in a bank of 6 for 660AH at $75 a piece...less than $500 for a capable bank. Storage space might dictate how large you can go with your bank. Some batteries are just too tall for my storage area and others don't make good use of the space like my GCs do.

But a large bank comes with other requirements in the charging area. I am upgrading one alternator to a 125A Balmar with a smart regulator to better charge my house bank. I should probably upgrade my shore charger, too, but that will have to wait. A rule of thumb is 4:1 battery bank capacity to charge rate is considered adequate. (i.e. 100 A alternator for a 400AH bank) I'm less than that, but it's not a perfect world. Also, alternators above 100A require a larger belt than my 1/2" belt, so I'll regulate mine to 100A. (not installed yet!!)

House batteries need charging and TLC. For TLC, I have a Xantrex LinkPro battery monitor to keep tabs on battery health. (also not installed yet!!)

It's like that children's book, "When You Give A Mouse A Cookie"

Tony, David M. is right on.* On Moonstruck there are two 8d AGM house batteries for a total capacity of 510 amp hrs.* Also there is an 1800W inverter. We cook with electric.* Hanging on the hook 4 days we run the generator about 2 hrs a day.* That is about an hour in the morning, and an hour in the evening----enough for cooking, hot water, and charging.* We have LED lighting, refrigeration, and TV running off the inverter. When on the hook, we turn off the dedicated icemaker.* That worked in the Bahamas with 4 teenagers on the boat for 3 nights at anchor.* The state of charge with that regimen never got below 75%.* I think s 400 amp hr bank would be the minimum you would want.*

Woodsong: My Krogen Manatee is about ready for a new house bank as well. I've got about two years before we hit the cruising road, probably the loop. I'm thinking that I'd probably spring for some big gel batteries once we go, but until then I wonder if replacing my two 8D monsters with the same thing is worth the trouble. They're a heck of a thing to pull out of there, and with 800 watts of solar charger, a 100 amp alternator, and an 8K Northern Lights gennie, I'm thinking that the group 24 bank may be all we need till then. The fridge is also propane/12V/110V, and the biggest loads I would have on it would be the momentary bow thruster, windlass, and occasional microwave. If your cruising habits are going to be pretty much the same for the next 2 to 3 years, maybe 440 AH is good enough. It's hard to beat a standard, deep cycle wet cell battery in cost per AH. As far as maintenance, I'm looking at the new snake watering system on Trojan batteries which pretty much resolve the visual check problems in low clearance areas. The local golf cart dealer here uses them, and says the systems are working well, and cut the time for water maintenance to less than a minute on each cart.


-- Edited by healhustler on Wednesday 6th of July 2011 09:46:07 PM