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2014-05-29

Watts up in the house?

If you were me, and all else were equal(ized)...

Plenty of ab crunches in my future if this is the way forward.
Can't resist a good electrics pun, I'm afraid.

I've posted this query on Cruisers' Forum, but it struck me that I have a fairly experienced readership right here, so why not ask?

Let's assume I wish to make a six-battery, roughly 1100 Ah house bank. Assume I have all my charge sources sized correctly and adequately, and I have all the space I require close to the boat's CG. Assume I like Trojan products and the tall L16 form factor, although this is not a must-have if I can save a few hundred with an equivalent battery maker.

Would there be a case to favour six 2V batteries to form one big bank using this model of Trojan L16: Trojan L-16-RE-2V 2V, 1110AH (20HR) Premium Line Flooded Battery

or to go series/parallel with three pairs of 6V batteries of this model? Trojan Battery Company

The rationale for hooking together a bunch of massive two-volters is found here: http://navigatorpublishing.com/ondig...ad_edition.pdf





End result is the same, and I gather the 2Vs are more robust in terms of plate thicknesses and general construction, but if one of the 6Vs went bad, would I not have the ability to remove its partner and simply fall back to a house bank 2/3rds (two pair instead of three) the intended size?

I've got a feeling some of you could provide real-life-based guidance here. It's akin to those compartmentalized batteries Rolls sells, only via a different methodology. Thanks.

Oh, and for the curious, I would keep the separate 12 VDC start and windlass batteries (probably Group 27s) charged via echo charging from this house bank. The charge sources, mentioned here before, include four 135 W solar panels, a 400W wind generator, and one 180 amp alternator or two 75-90 amp alternators, switchable to charge either house (default) or start batteries.

UPDATE 14.06.05: Have yet to hear back from the Ceol Mor's perfectionist skipper, but collected wisdom is favouring the "three pairs of 6VDC batteries" option. Now I have to shop as concepts such as "core charge"  and the vagaries of buying in Canada versus in the States (shipping, HST, yadda yadda) strongly affect the end prices of each battery. Seriously, there are significant price differences that don't appear to be related to battery format or Ah capacity. I'm a bit off the Trojans now, as I've been persuaded that the "quality gap" has been largely closed and you're paying for the name...for which I don't care to do. So I'm pricing these U.S. Battery L16s and these Interstates. And I'm trying to find some old dead batteries to offset the prices I find if I buy here in Canada. Thanks to Jeff C. for some leads.

11 comments:

The Ceol Mors said...

Forwarding this to Capt. Perfecto...

Rhys said...

Thanks, Cidnie. He's probably already mulled this one over in terms of pluses and minus. Almost made another pun there. Almost.

Ken Goodings said...

Since you're ostensibly cruising off the beaten path get six volt flooded batteries (230Ah) and use them in pairs to get the total capacity required. If you kill one, you take it out plus it's mate, retaining your nominal 12V on the system and losong only 230Ah of house capacity. Golf cart batteries are available relatively cheaply worldwide. Our ($100Can) six 6V Crowns (totalling 690Ah) lasted 5 full years of year round cruising in tropical conditions with only solar recharging in daytime. We easily replaced them in St Lucia for $200 each. Not bad for 5 years if use I'd say. Using standard components like these batteries can help you down the line when far from home. BTW, recommend that you get more panels and sell that Airex wind genny. 400 watts from those typically noisome Airex is very very optimistic. Solar is quiet with no moving parts needing replacement.

Ken G said...

Dump the Echo-chargers, if you need to automate charge sharing go with a simple ACR (automatic charge relay instead. Our Echo charger lasted less than a year.

Rhys said...

1) Ken, I am starting to agree with the 6VDC over the 2VDC, but with three people, a bigger boat and some other goodies, I want the larger bank circa 1100 Ah. I can probably score L16 6VDC for $300 each if I shop carefully. They are around 370 Ah/12 VDC paired. Glad to hear your Crowns did so well, but frankly, I would expect no less from someone with your background. The Air-X will be installed later in the summer and I will evaluate it then. I know it's supposed to be loud, and I may go to a KISS or some more robust model. It's not really about making 400W; it's about keeping a trickle going overnight on passage. I have four 135W Kyoceras already; again, once they are hooked up to whatever house bank I determine is going to work, I'll start logging SOC and draws to see if my ballparking is valid.

2) I was quite happy with my Echo-Charger, and presumably it still works (it's stowed until I finish the battery installation). I'm not wedded to it, however, and if there's an ACR with easily variable set points and some sort of display to indicate if it's working, I'm open to hearing about it. What brand do you recommend? Thanks for contributing, by the way.

Ken Goodings said...

We trashed the EchoCharger as it failed within 6 months. We decided to make our charge distribution decisions manually. A 2 pole Blue Seas 5511E battery switch controls the 12 V start battery and 6V golf cart house battery array simultaneously.
"OFF" disconnects both 12V starting and house batteries from the boat.
"ON" turns on both the 12V starting and paired 6V house battery.
"Combine" puts the starter battery and house in parallel for manual crossover charge current sharing.
The 115A diesel alternator is connected full time to the starter battery. The so-called "Smart" Balmar external three stage alternator regulator failed in the first 200 miles of our trip. We tossed it out in Kingston Ontario as it had partially melted and boiled our starter battery dry. The alternator regulator had been bypassed by a popular battery shop in Toronto which might have contributed to the failure. The alternator, internally regulated, charges the starter battery, much like your car would, whenever the engine runs. When we want to augment the charge going into the house battery we switch to "COMBINE" and then monitor the status of our house battery amp hours on a Xantrex Link 20 dual battery monitor.
Note, when the battery switch is in "OFF" position, the house boat's electrical system still receives power from our 440 Watts of combined solar. We rotate the 6V house batteries every 6 months or so to equalize their loading as one pair is situated midships while the other four are mounted aft. This can help to age them all more equally. During rotation time, the fridge (2.7A)and VHF (1.5A) etc all remain adequately powered from the solar panels...even on a cloudy day.
Back to the wind genny, with all of that house battery capacity you'll not likely need a so-called "trickle charge" overnight.
Lynn uses a 110VAC electric heat gun to defrost the fridge. We also have a smallish AC shop vacuum. The surplus 2500W inverter happily sucks 100-odd Amps from the house battery for a few minutes at a time with no ill effects on the house battery. We also have a 700W inverter for general use and several smaller inverters to run the laptops etc. You've likely seen those cigar plug USB chargers. Beware; as we had one fail and it impressed 12.5 VDC on a USB device requiring only 4VDC with disastrous results.

Rhys said...

I am wary of those USB chargers and don't use them. I concur with the rotation plan on the 6VDC...but for the rest, I'm guessing your advice is essentially "keep it simple and keep an eye on it". By the way, all my batteries, with the exception of the windlass 12VDC forward, will be within about a meter of each other either side of a bulkhead and equally close to the engine lugs.

If I don't need the wind genny, I'm pretty sure I can trade it for more panels. I have a pilothouse roof that could easily take them, although they be shaded in part. We'll see. Estimates are great until reality intrudes.

I already have a 2000W inverter-charger. I'll have to see about the EchoCharger: Mine worked like a charm and met a need, your negative experience notwithstanding. Thanks for the "schematic", however. It's all stuff to consider.

Chester Breder said...

Thanks for the links to those 6 volt batteries. Also for the one to "core charge" I got a laugh or two there.
If you have experience managing your battery, Then the expensive 6 volt ones will be good. The suggestion that the golf cart ones are readily available is also valid advice.
My preference after experience all the ins/outs of lead acid, would be LiFePo bank.

Rhys said...

Thanks for the comment, Chester. LiFePo batteries have some big advantages in charge capacity versus weight, for instance. But I chose to go with "traditional" flooded batteries on the basis of cost per Ah, availability worldwide, my willingness to test for specific gravity, i.e. "do the proper servicing", and the rather simple fact that I have no particular need to restrict weight or size of the bank. The newer batteries indeed meet several desirable parameters, but our boat doesn't have those requirements. "Reliable", "obtainable" and "serviceable" (which includes a relatively straightforward charging regime) trump "can be laid on its side", "light" and "keeps a charge for a month on the hook".

In other words, our boat is a delivery truck: it will charge itself on a near-daily basis as we will be full-time liveaboards.

Silverheels III said...

After re-reading your 6V decision, really recommend you get four "standard" pair of 230Ah 6V batteries rather than three pair of taller more powerful (and harder to replace away from home) 6V batteries to achieve your total power requirements. If you mount one pair toward the bow you will not need a separate 12V anchor windlass battery. We always run the diesel when anchoring/re-anchoring or hauling anyway do IMHO a dedicated 12V battery for the windlass is not necessary.

Rhys said...

I'll consider it, Ken, but the L16s are not really uncommon (they are "floor-washer" models and the taller thing isn't an issue given where I wish to put them. Also, going from 370Ah to 230 Ah is a big drop per pair given our prospective energy budget (which does not rely so much on having a big bank as it does in having a narrower band of draw down given our numerous charging sources). But I can measure the 230Ah 6V batteries and make a call this winter, which is when I plan to a) build the box, and b) build a set of stairs around the box. The dedicated windlass battery idea came from a) the fact that I have way more buoyancy forward, b) there's some good reasons for me not to want to run a long length of heavy-gauge wire forward to the windlass from the diesel on a steel boat, and c) the 12 V battery itself would be kept fully charged through a lighter-gauge relay and, when needed, off a surplus charger I can relocate forward, thus giving me another (with a separately charged 12 VDC start battery in the engine bay) backup. The context of all this is that there's about 1,250 pounds of lead ingots forward at the moment just for trim. If I move those aft (or out as I put in gear), putting tools and a single 12 V in will still leave me out of trim! I don't have the same problems with weight in the ends as I do with the FG boat...but I do want to put the half-tonne of batteries and the 3/4 tonne of water tankage as close to the boat's CG and CE as I can. The fuel tanks are right where they should be, but the batteries need to be forward of the engine for "best trim", and how to deploy the water tankage. Once I do that, I can make decisions involving weight in the forepeak workshop and whether the lead ingots are staying put, moving or leaving the boat. I appreciate your thoughts on the matter, however.