Electric windlass

[mldpt]

I have decided its time to install an electric windlass. !000w I will install the battery in the bows, with all equipment up there to keep the length of heavy wire to a minimum, but what section wire do I need to use to charge the battery. My boat is 36' so I guess the length of cable run will be 20'. I have a 105 A alternator through a splitter one side goes to 330AH service batteries, other side to a 40AH starter battery, can I simply take leads from + & - from the starter battery to the windlass battery should I perhaps increase the starter battery size to 100AH
Regards Mike

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[Robin]

Others more knowledgeable will no doubt answer but IMO if you want to have a separate battery in the bows for the windlass then it MUST be completely separate, anything other than that is dangerous and a fire risk. If you connect it in parallel with the starter battery then the cabling MUST be the same as between starter battery and engine, ie the very same heavy cables you were trying to avoid running up to the bows. To charge the extra battery depends on your existing set up but you will may to fit a 3 way split charge diode (or repace an existing 2 way with a 3 way) or similar such that the alternator charges all 3 separately, the cable size will need to be able to take the full alternator output over the 20ft run (40ft there and back, this is the figure to use) and this I would expect could be the same as your existing alternator to battery cable size, one of the forum experts will no doubt comment on that.

Windlass wiring options always draw discussion, we ran very heavy cables on our previous boat back to one of the main battery banks (heavy to avoid volt drop), these were starter cable type about 12.5mmm dia ordered via a car accessory specialist not a swindlery. Our current boat came with the same arrangement of running off an existing bank which works well.

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[Talbot]

Battery in the bows is the best solution in that it avoids the power drop (even over big cables) to the 1000w windlass. I looked at two solutions to charging the battery although there are four:

Connecting forward battery to engine starter battery (after all, engine will always be running when doing this) with cable that has the ability to handle the load , but would cause unacceptable voltage loss if this was the cables to drive the windlass -i.e. minimum weight/cost, but retaining the safety, and additional boost from the engine starter battery.

Connecting forward battery to engine starter battery with cable sufficient to transfer charge (size will depend on boats charging capability) and disconnecting this link before using the windlass. I rejected this solution on the grounds of safety - sod's law states that at sometime the windlass would be run without disconnecting.

A company (adverc I think) sell a battery charger that is run from another battery bank, thus you would have relatively small cables running forward and the ability to recharge. I rejected this solution due to cost.

You could install a dedicated solar panel just for this battery. If you have a lot of anchoring, the re-charge rate might not keep up with the useage.

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[Sunnyseeker]

Surprised... we had a 1000w Lofrans on a 40' yacht working fine from domestic battery bank midships, nice and low down. In practice you never run the windlass to max load, if the anchors jammed you dont try and break it out with the winch, you always motor or sail up to the anchor or do it slowly. The time when it works hard is anchoring in 100' of water off a steep shore and pulling the lot up vertically.
The current consumption/voltage drop only really happens when an electric motor comes under a lot of load, when its nearly stopped, as that should never happen why the problem with the cable run?
Ours lifted 30 metres of 12mm and a 30Kg anchor vertically when off a steep shore easily.

Yours confused...

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[snowleopard]

you are generally advised to have the engine running when using the windlass. this means that a high proportion of the current will come from the alternator. this means that you need cables from alternator to battery capable of carrying the full amperage of the alternator and those from battery to windlass must be fit to carry the amperage that trips the circuit breaker. in your case the figures will be approximately:

alternator: 105
windlass: 80
circuit breaker: 100

so go for cable rated to give 10% voltage drop at 100A at the full length of the circuit from alternator to windlass and back. 50-60 sq mm according to my table.

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[cliff]

<A target="_blank" HREF=http://www.adverc.co.uk/products/osca/oscar.asp> Adverk </A>

<A target="_blank" HREF=http://www.sterling-power.com/> Sterling Power </A> Click on products, battery to battery chargers

Both of the above appear to do a similar job, I.E. charge the remote battery but don't appear to allow you to draw power from the alternator / main batteries while operating the winch.

Perhaps you could ask both suppliers what happens if you operate the winch when the engine is running I.E. charging.

Plan "b" is to run heavy cable from the main battery box / engine compartment to the winch battery to allow power to be drawn from the alternator / domestic battery bank.

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[Birdseye]

I installed a 1000w Lofrans in my boat using electric welding cable (good cable, available cheap from ind equipment suppliers) to run from the domestic battery bank forward to the windlass. Works fine.

You will be taking something like a max of 100 amps and then only on brief occasions. So even without your engine running, your domestic bank would work the windlass at max load for about 90 mins. How likely is that ? So I wouldnt bother with an extra battery at either end of the boat - they are only extra cost and batteries dont last that long.

As for the power loss, with your engine running the system voltage is likely to be in the mid 13's . I havent measured my windlass voltage under load at the windlass itself but certainly the cable doesnt even get the slightest bit warm. But make sure you do the terminals well, and waterproof them to avoid corrosion and resistance.


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[pvb]

Your easiest solution...

What you’re proposing, Mike, isn’t really the easiest (or indeed the cheapest) solution. By far the easiest way is simply to run heavy cables from your domestic or starter batteries. You’ll probably need 35 sq mm cables. And you’ll need a circuit breaker as close to the battery end of the circuit as possible (ideally a thermal/magnetic type; E-T-A breakers are worth considering). That’s all you need.

In contrast, if you go for a bow battery, you can’t just use thin wire to charge it. The windlass will usually be used when the engine's running, and the windlass will draw current both from the bow battery and down the charging cables. To prevent overheating in the charging cables, they must be heavy enough to carry a significant current - say 10 sq mm. You’ll also need to protect the charging cables against overload with fuses or breakers. But, remember that, as there's a battery at each end of the charging cables, you’ll need a fuse or breaker at both ends. And you’ll need some way of isolating the bow battery - perhaps by having a VSR to feed it. The other thing to bear in mind is that a bow battery will get shaken about a bit more than the main batteries, so it needs to be very securely fitted, which probably involves a purpose-built glassed-in box with a metal tie-down facility (and it will also need some means of ventilation). Add up the cost of that little lot and, all things considered, it's probably easier not to have a dedicated bow battery.


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[jerryat]

Hi!

Suggest you read Nigel Calder's 'Boatowners Electrical and Mechanical Manual'. As I recall, he definitely advises against a separate battery in the bows, and quite correctly too IMHO.

As several others say in their replies, you do NOT save anything on cable size, since these must be capable of carrying the full load from your alternator which will, with the engine running as it should be, be pumping out near maximum amps. Good quality battery (or welding) cable will be necessary, as will a properly sized circuit breaker, in your case circa 90amps. You can take the cables from one of your domestic batteries with no problems.
I have a Lofrans 1000w windlass with exactly this set-up that has been successfully used for the last seven years cruising and literally hundreds of anchoring situations in the Med and Caribbean.

Finally, surely the last thing most owners want is a damn great weight right up in the bow!! Take my and others advice, and don't do it!

Hope this helps

Good sailing!

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[mldpt]

Re: Your easiest solution...

Thanks for that, I can see that what I was planning makes little sence, where will the control switchs be situated in your layout at the battery end . I have ordered a remote and control box which I assume is a solenoid which is controled by the remote low current, and the control box handles the heavy current & I guess this is situated near the battery is this correct.
Mike

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[jerryat]

Re: Your easiest solution...

Hi mldpt!

If I may 'but in' on your post to pvb, you ideally should site the control box (the solenoid) right up front as near as is reasonable to the windlass motor. Try and site it where it will not be subject to a thrashing anchor chain or get wet. For example I fitted mine on the cabin side of the chain locker bulkhead and cased it in with matched lining. The low current supply to the solenoid can be taken from the main main windlass cable terminals, with the positive line, of course, going via your remote control/deck switch. In short, there's no need to run the low current cables right back to the batteries.

The 90/100 amp circuit breaker should be fitted in the windlass positive line, as near to the battery take-off as possible.

Hope this helps

Good sailing!

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[mldpt]

Re: Your easiest solution...

HI
I see you have a fulmar I have a Corsair, both great boats, IMHO and thats all tha really counts. I am fed up with hauling my anchor up by hand and the Manual Vetus I have had for the past 12 years is far too slow, so I am going electric, This heavy cable what section wire have you got on your Fulmar. I have upgraded the connection from Alternator to splitting diode and from there to service battery and starter battery, but they are both short runs, I used 10mm cable for that. What do I need for a 20' run.
Mike

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[pvb]

Cable size...

I'd suggest you use 35 sq mm cable. Try to get cable with lots of fine strands, so it will be more flexible and easier to thread through the boat. Vetus supply this sort of cable.

Ideally, take the positive feed from your main switch - this will ensure that your windlass power is disconnected when you leave the boat. Make sure that the wire from the battery to the main switch is heavy enough for the added current when the windlass is operating. Put the windlass breaker as close as possible to the main switch. A 100A breaker should be fine. Index Marine supply a good one (E3410/100).

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[cliff]

<A target="_blank" HREF=http://www.stealth316.com/2-wire-resistance.htm> All you want to know about voltage drops in cables </A>

Example 30' drawing 100A =>0.48V drop using 33.361mm² copper cable so 35mm² is not out of the way in theory... read on.......

Now if your input voltage is 13.8V (engine running) you could go down to 10mm², live with ~ 1.8V drop, and still leave 12V at the windlass. /forums/images/icons/crazy.gif This would save a lot of your pennies coz Cu cable is not cheap - even welding cable!

Do not use starter motor cable - it is not really flexible enough to route neatly and use soldered ends rather than crimped (or crimp them first then solder them)

I used 30' as the length as you will want to thread the cable around a bit to get to the windlass so you will use an extra few feet. I also used 100A as the max amperage allowable (to suit a 100A breaker)

Try to get tin plated multistrand if possible also neoprene covered rather than rubber.

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[Robin]

That is a really useful link Cliff, but I still favour bigger being better.

The length of cable to use in the calculation is the up AND back length though, so double the 30ft figure you used which will produce double the voltage drop you quoted. Also as I understand it if the voltage at the motor drops then the amps used increase to compensate to provide the same power requirement (watts) so the motor can overheat and many windlasses have thermal cutouts built in which might trip earlier and at an awkward moment. 12v is very much a nominal figure anyway, a 100% charged 12v battery for example is 12.8v. IMHO saving a few pennies to use a smaller cable is false economy and running the larger size is no more difficult with a little care in route planning. Also to consider is the possible later addition of a bow thruster which could plumb into the same circuit if correctly sized, since a windlass and thruster are unlikely to be in use simultaneously.


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[pvb]

Oh, no it isn\'t!!

As Robin says, the length of cable used in the calculation is the complete circuit (ie all the way there and all the way back).

So, if you reckon it's a 30 ft run, you'd actually use 60 ft as the length in the calculation. Therefore the voltage drops would be double the figures you've quoted.

This means you certainly couldn't use 10 sq mm cable. Using too small a cable has serious risks involving overheating, too.

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[cliff]

Re: Oh, no it isn\'t!!

Ooops - I stand corrected - again - I am so used to not bothering about the return which one needs in a plastic boat

60' @ 100A =>33.631mm² at 0.95v so 13.8 (engine running, alternator working) voltage across windlass 12.85 - no problem on 35mm² cable - good job someone else is checking my sums - bottom of the class /forums/images/icons/blush.gif/forums/images/icons/frown.gif - I'd better go back and check what I did at work today as well - got a horrible feeling........ /forums/images/icons/blush.gif

Still need the 100A breaker/fuse to prevent burning the motor!

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[Birdseye]

Re: Oh, no it isn\'t!!

In a 10m boat I used 35mm sq multi strand welding cable and it cost me just over 4 years ago about £1 per meter from the local engineers supply place.

<hr width=100% size=1>this post is a personal opinion, and you should not base your actions on it.

 

[cliff]

Re: Oh, no it isn\'t!!

Cash in hand?, end of roll?, boss not about? VAT receipt?

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