Windlass Charging

[Helimech]

75 amp alternator
6 - 6vdc Trojan 105 House Bank
1 - 12vdc Start Battery
1 - 12vdc Windlass Battery

Windlass battery is in the bow by the windlass. I would not have done it that way but it is what it is and I'm not going to change it. I don't know how the previous owner charged this battery since there are no charge wires. I assume he had some small portable charger for it. I want to wire it so I can charge it from the engine alternator. I'm looking at a Bluesea Automatic Charging Relay (ACR, model 7610) to disconnect the windlass battery from the alternator when in use and reconnect to it to charge when not in use. Am I right in my thinking that I don't want the alternator to be connected to the windlass battery when I'm using the windlass? I'm planing on running #4 charging wires to charge this windlass battery. JC

[transmitterdan]

The ACR will probably work for you but isn't really necessary. Connect the windlass battery to the engine start battery via a circuit breaker such as Blue Sea 7148. Leave this breaker closed unless raising anchor with engine off. Both batteries should be of the same type (but not necessarily same size). I think AWG 4 wire is adequate. Since the run is long the breaker should be close to the engine battery and another fuse should be placed at the windlass end of the positive charging wire.

There should already be a fuse and switch or a breaker between the windlass battery and the windlass. If not consider using another breaker or at least a fuse and switch.

I believe that if one has a working engine it should always be running and supplying power to the windlass when raising the anchor. No harm can come to the alternator from doing so. If you decide not to run the engine then disconnect the windlass battery from the start battery via the charging breaker.

You need the double fuse/switch or breaker anyway so the ACR doesn't really buy you much in my view.

[Helimech]

My concern was with the engine running that putting a sudden load of 75-100 amps on the alternator by using the windlass would damage the alternator. My original thought was to disconnect the windlass from the alternator via a CB or switch during windlass use then reconnect it to charge but I'll forget one time and maybe blow the alternator so thought of the ACR.

[bobofthenorth]

I don't know what you've got for a windlass but it would have to be huge to pull even 70 amps, let alone 100. Not to mention that most of that is going to come from the very wisely located battery next to the windlass. Don't make it complicated. Set up a charge wire off the engine batteries.

[Horror Hotel]

If your gonna run a charging wire to the bow, just throw in the towel and run 0 gauge wires to the windlass to run it from the house bank. That would seem to really be the simplest way. Then take the weight from the bow by removing the battery. I know if I tried to run my windlass off just one battery without a charge coming in it would not last long at all and get slower and slower. It's rare to use the windlass without the engine running anyway. Just cause it's set up that way is no reason to live with it. Your PO must not have anchored much. He cut corners and then lived with a terrible system of moving a charger around. Just run 2 big wires and be done with it.

[thinwater]

Originally Posted by Helimech

My concern was with the engine running that putting a sudden load of 75-100 amps on the alternator by using the windlass would damage the alternator. My original thought was to disconnect the windlass from the alternator via a CB or switch during windlass use then reconnect it to charge but I'll forget one time and maybe blow the alternator so thought of the ACR.

No, doesn't work that way. Not different than charging low batteries.

Really, a windlass it not many amp-hours, since it's only a few minutes. I don't see all the fuss, other than the need for big wires. It's not going to run the house bank down.

[transmitterdan]

Originally Posted by Helimech

My concern was with the engine running that putting a sudden load of 75-100 amps on the alternator by using the windlass would damage the alternator.

Alternators will not be damaged due to high current because they have a natural current limiting feature. The main thing that damages alternators are:

1) Running the alternator with no battery connected (breaks diodes).
2) Running the alternator at max current for long periods without sufficient cooling.

The time required to raise an anchor will not be long enough to overheat an alternator. Good alternator setups have temperature monitoring so they reduce current output if they get too hot.

I think running the engine when raising the anchor is a good idea. It means you won't raise the anchor only to find out the engine will not start. I know some like to sail off a mooring and there's nothing wrong with that but I just feel it's safer to have the engine warmed and ready in case anything goes awry.

[djmarchand]

Go to yandina.com and you will find an article on how to do this.

David

[jseas]

Bow solar!

[d design]

Originally Posted by jseas

Bow solar!

Hahaha

[smac999]

how long is this boat? if it's not that big I would just remove the forward battery and run large cables forward. less things to go wrong down the road. one fuse near house battery.

otherwise the acr will work. fuse at both battery sides for the size of the cable. blue sea MRBF's work nice for this. (then windless should have own fuse from windlass battery)

something like an echo charger would also work and require much smaller wire run forward as it's limited to smaller current.

[sailinglegend]

Originally Posted by Helimech

.... I would not have done it that way but it is what it is and I'm not going to change it....

So many times you see comments like this on here and other forums!!!

"That's how the manufacturer installed it...."
"That's what my electrical engineer said was best...."
"I don't think it's fundamentally wrong, but simply needing tweaking in a few areas ..."

On a boat one small change to something can mean a major re-working of other systems. You have to make the choice between following best practice, or living with a bad installation. The cost and the effort of correcting the problems will always be worth it in the long run.

I would suggest moving the windlass battery and connecting it to the house bank - assuming the same type and age - size doesn't matter. You can always find some space somewhere - it doesn't have to be next to the bank, but try and equalize the cable length or put in very large ones - 2/0. Run all charging sources to the house bank first so the alternator will then be supplying amps directly to the windlass. Use at least 2/0 for the connection to the windlass.

There are four very good reasons for having a larger house bank - see my post #137 on this thread:

http://www.cruisersforum.com/forums/...-109293-4.html

[bobofthenorth]

Locating the windlass battery next to the windlass IS A BEST PRACTICE. Keeping it charged is a trivial problem.

[djmarchand]

I agree, placing a battery at the bow and charging it from your main charging source is best practice, but hardly trivial. Some considerations:

Fuse both ends of the wire unless you are connected to an isolated output of the shore charger.

Then you have to decide what size wire to use. Depends on where it is connected. A nearly dead windlass battery in the bow can draw more current than the windlass does if it is connected to the house battery. So that defeats the purpose if you still have to run 2/0 wire to handle that current. And how do you isolate the two battery banks if you connect directly to the house bank?

The Yandina website at How to add a remote battery bank on a boat. shows one approach. It uses their 50 amp combiner to isolate the house and has thermal auto reset circuit breakers if for some reason the bow battery is run down and it draws more than 50 amps to charge. With this scheme you can use 10 gauge wire from the house to the bow battery.

Another way and probably a lot cheaper is if your shore power charger has a spare output terminal use that to recharge the bow battery. This will work if you plug into shore power every 5 days or so or if you run a generator during that period.

In this case you can still use 10 gauge wire (if the charger is less than 50 amps and you only have to put a fuse near the bow battery. But beware of the shore power limitation above- the engine alternator will not recharge the battery.

David

[Cheechako]

Leaving the windlass battery being charged is a good idea while you are hauling anchor if your wire is good size. The battery is a good buffer. Or you can switch it out of the loop for hauling and once your charge regulator backs off from the high charge rate into the main batteries, switch it in to charge the windlass battery while motoring. Yes, in theory your average 1000watt windlass motor can draw a lot of amps.... 80-90 amps. I believe the breaker that came with my Maxwell windlass was 150 amp.