Use Start or House Battery to run Windlass?

[BozSail]

Is it generally best to use the house bank or start battery to run the anchor windlass? My boat has one 100 amp start battery and three 105 amp each deep cycle house bank. My inclination is to wire windlass to start battery, in order to preserve house bank. What do the electrical experts think?

[mickt243]

Windlass is a very high current device, operating for relatively short period.... good match for a starting battery. Minimal risk of running your start battery down, as you should never be pulling your anchor before engine start.

OTOH, windlass is not *that* high current.... not more than a big inverter at full load... so no problem running it from your house batteries (like I do)

[Island Time O25]

Im no expert but was advised to have a dedicated extra battery just for the windlass. And run the engine when using it. Put it under the v-birth to keep the cable run short using 00 cable and dedicated kill switch instead of a breaker or solenoid. Windlass an old but still excellent shape Nilsen H700. So far no issues.

[sailorboy1]

I normally do it off my house batteries unless it is windy. Then I run on both because there’s aa extra voltage drop involved on running it from the house batteries.

I don’t think there’s a “ best or better” unless you don’t plan to have the engine running before hand.

[a64pilot]

Issue is voltage drop.
So that means run it off of the biggest bank, ideally with the engine running to help boost voltage, and keep the wire run as short as possible, and or very large gauge wiring.
Instead of having a separate Windlass battery, I just ran rather large cables, and I keep my house and start bank ganged together with the selector switch.
That is apparently a little controversial, I don’t understand why though, most of us are OK with one engine and one fuel tank, why not one battery bank?

[Privilege]

There are a couple of extra considerations that you might want to take into account. How long is the run from your battery to the windlass? If it's a long run then you have to consider the price (and weight) of running two long, thick and expensive cables. If you have a dedicated battery up front, apart from the connections to the windlass, you only need a cable running to the battery that will handle the load of your charging system. A voltage sensitive relay will provide automatic charging. As others have said, there is no right or wrong.

[LoudMusic]

I've always heard that you should have your motor running when setting and picking up the anchor, so to me running it from the starter battery makes the most sense because you're basically using your alternator to lift that hunk of metal.

But every boat is unique and every operator is too. I'd say you want the windlass on the most abundant power supply you have available at a moment's notice.

[Mithril Bham]

House battery. Engine running.
Always an exception to the rule.
I have two start batteries I keep isolated.

[iGrf]

On my boat (1 start 2 parallel house batteries) the windlass is wired across all 3 of those.
I don't like it that much but it was like that when we bought her and it's on my list to improve once I upgrade the electrical system.
but so far it has worked (always have the engine running though)

[ebs001]

Windlasses should always be run from a deep cycle battery and not a start battery. While a start battery can deliver good cranking amps, they were never intended to be putting out those kinds of amps for the period of time it takes to retrieve an anchor.

[witzgall]

As mentioned, there are exceptions to every rule, but voltage drop is the #1 issue with higher current devices such as windlasses and thrusters. In extreme (but not unusual) cases, the voltage drops can cause premature wear and failure of solenoid devices on these systems. Depending on the installation, they should either be drawn from their own dedicated battery, or from the battery installation with the highest AH capacity.

Chris

Chris

[MJH]

Originally Posted by BozSail

Is it generally best to use the house bank or start battery to run the anchor windlass? My boat has one 100 amp start battery and three 105 amp each deep cycle house bank. My inclination is to wire windlass to start battery, in order to preserve house bank. What do the electrical experts think?

When I installed an electric Maxwell HWC 1500 windlass I chose to power it from the house bank of 2 x 8D Gel batteries. I used appropriate sized cables for the distance going forward thinking it was a one time cost and never having to replace them as apposed to another battery. After nine years no problems.

If you choose to add a dedicated forward Flooded battery for the windlass you will have to provide ongoing maintenance at that forward location...my advice, keep it simple.

~ ~ _/) ~ ~ MJH

[sailcrazy]

House Bank. Our 6 T-105s have (nominally) 675 amphrs vs the single small start batt. The time it takes to bring up 125', give-or-take, of chain would run the start batt to nothing. Plus, our eng alternator feeds the house bank directly, and we recharge the start batt via a Duo-Charge off the house bank.

[yachtgemini]

I started with the anchor winch on the house bank and had 2 problems. First was that I fried a rather expensive inverter that did not have adequate protection against low voltage. Then I fried a battery combiner. It was the old problem of organic growth of boat systems without having gone back to basics. Sensitive electronics don't respond well to the voltage drops caused by an anchor winch.

I should mention that our windlass will draw a full 300amps under load hence the problems.

Two years ago I installed a bow thruster with 2 big batteries in the bow and also attached the anchor winch to them and ran cables to the starter battery via a 'smart' combiner. The engine alternator is attached to the starter battery. Bottom line is that it works brilliantly but is unlikely to be appropriate for many others.

I would suggest starting with a blank sheet of paper and design the system you want. For example, will you want to add a bow thruster later? Do you want to give alternator charging priority to the house or engine bank? How will you combine banks? What is the ratio of anchor winch amps to house bank delivery capacity? What cables going forward do you have / could you install.

There is no 'right' answer but your right to be doing some serious thinking on how to do this.

[mvmojo]

Originally Posted by a64pilot

Issue is voltage drop.
So that means run it off of the biggest bank, ideally with the engine running to help boost voltage, and keep the wire run as short as possible, and or very large gauge wiring.

I absolutely agree that you want to keep wire runs short and use large gauge wiring - size it for <3% voltage drop over twice the distance of the run. But, help me understand your logic regarding running off the biggest bank... seems to me that voltage is constant and independent of the battery bank size. Only the total amp-hrs available is dependent on bank size. What am I missing?