How many amps can a battery bank take?

Re: No, no no but then again possibly yes

I will need 220 amps per day from a domestic bank of 360. I have a choice of generation sources of the solar (pretty crap 25 amps a day, if I'm lucky), the Duogen (180 amps, assuming I can keep the speed up) and the engine to top up any negative balance. So, yes, you're right.... I have a nett power usage of about 20 amps a day. I could make myself entirely self-sufficient and charge round the boat screaming "Turn the Light off" in Dad's Army fashion, handhelm for a few hours, sing rather than listen to the CD, stop emailing etc etc. I'll need to produce some water anyway and figured that running the engine for a couple of hours will produce enough for this and top up my likkle negative balance. Of course, it might all be a lot easier if I had access to a following monster mobo to offer some fuel and spare leccie, on some sort of ambilical lead but, then again, if I remember rightly, you tend to blow every supply you connect to!
 
Re: No, no no but then again possibly yes

well I think you have got it sussed!

seems to me the addition of an accurate measure of the state of your battery bank is the key item - from there you have the tools to manage use and delivery efficiently and, if you have overestimated your consumption you might even find you don't need the engine at all!
 
Re: No, no no but then again possibly yes

How is it this thread isn't being helped along by some former U-boat engineers. This problem is not new and there must have been considerable military funded research to sort it all out.

Do submariners not need to get the most from their batteries ?

Perhaps its all top secret. /forums/images/graemlins/confused.gif
 
Simple answer ...

..... buy a second Duogen.

Then you will double the power available for free, and if one breaks you can still use the other in line with the suggestions in the thread.

I don't know if this is a sensibile or a silly idea, in reality /forums/images/graemlins/smile.gif

Has anybody else done it?
 
Re: Simple answer ...

No it's a daft idea. I would have to call it a Quadrogen then, or perhaps the Duoduogen, which would just be very silly. But at about £2K a pop, I think I'd probably buy a few more batteries and some diesel!
 
Duogen reliability...

Just a thought, but as you're going to be relying very heavily on the Duogen, have you looked into Duogen reliability? In the 2004 ARC, 50% of the boats using Duogen had problems, according to the "Yachting World" survey. With such a high failure rate, you should perhaps investigate which Duogen spares you might need to take with you, and find out in advance how to fit them.
 
Re:Huh?

Call me a pedant, but the survey has reports from just 7 users. 1 rates it 1 out of 10 on reliability but there are no comments or indeed scores on the other factors so I'm not sure whether this is a problem or a miss-code. There are two other comments referring to a fault with the coupling between prop and rod. So if you discount the 'odd' score of one, it's 29% without probs, or 43% if you do. The faults seem almost entirely to be the coupling. I have a spare.

You're right though, we are heavily dependent on the Duogen. But if it goes on the blink, then we will have to take drastic steps to minimise consumption to at least half our (generous) budget rate and turn to the little solar and the engine to keep us going (electronically speaking!)
 
Re:Huh?

There was a report published by Duogen on some sort of repetitive bearing problem earlier this year, but it seems you've already catered for the known problems so probably have this covered.

FWIW, I've been following this thread with interest, and believe you are overly relying on the 'anticipated output' of this equipment. It seems you are expecting a constant 7.5 amps 24/7 as I read it, but from my own experience on transats I suspect you will be lucky to achieve this. I reckon your average will more likely be 4-6 amps.

Do let us know how things go, particularly the reliability. Aside from the fact that we find the Duogen very ugly and ungainly (others don't I know!) we do feel it presents an 'eggs in one basket' scenario, so that aside from only being able to generate from either air or water at any one moment instead of both, if the thing fails you lose both sources.

Seems hairy to us!! I'd second others comments, and get a couple of good solar panels as back-up, and find room somewhere for additional fuel.

Anyway, I hope it alls goes very well for you.

Cheers Jerry

The
 
8 boats...

If you want to be pedantic, the survey shows 8 boats reporting on the Duogen. There are 7 listed under "Water-powered generators" and 6 under "Wind-powered generators", although 5 of these 6 are boats which also reported under water-powered, hence a total of 8 boats reporting on the Duogen.

One boat (Wing & a Prayer) rated reliability as 1 out of 10, but gave no reasons. Three boats (Checkmate, Destination Anywhere and Vrijgezeilig) reported drive failures. Hence, 4 boats out of 8 equals 50%.
 
Re:Back of a bus

I agree it's not a pretty piece of kit (but then mechanical self-steering devices are fairly unappealling too). I'm not sure either it's actually uglier than a load of solar panels all over the place and there is something rather nice about producing leccie from just the motion of the boat.

Yep, you may well be right about the amount of power it will generate too. The paperwork says it'll produce about 5 amps at 5knots and a bit more than 10 at 7knots. Even if we assume this might be a manufactuerer's 'perfect conditions' rating, you're right, I'm going to be struggling to average 6 knots - a sub 19 day crossing would be nice, but a bit unlikely (we're talking a Bav 40 here!). But this is also my thinking on the power budget. It gives me a comfortable (but by no means luxury) passage but will need to be trimmed, if things work out differently or when the boat slows down and thus produces a big battery drain. It is as the very least a crew incentive to try and maximise speed (or at least not to fall below what will become a known minimum for leccie!)

I could squeeze more fuel into every single space in the boat I suppose but I'm not sure how much better off I'll be. With such a distance, there's no way I could motor there (or back) - about 300 miles will be my range! I have enough fuel to generate via the engine alone enough leccie for a semi restricted power budget (plus 120 odd miles motoring reserve) and, if that goes pear shaped, then I have solar to at least get the basics working, for some of the time - OK, maybe I need another solar! And I've ordered a third coupling part too! Yep, if there's no sun, no wind and the engine goes kaput (I have a diesel mechanic on board as safety back-up option number 4) then I am truly in the [--word removed--] and Christmas will be a rather subdued seaborne affair!

!
 
Touché

Yes, yes, yes - OK fair point but I'd assumed the one rating under wind section was rating it in that mode - which I'm not really interested in though I accept that most of the bits are used in both modes. Not entirely sure why someone would use it in wind mode for a trade wind route anyway, unless it was at harbour.
 
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