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Old 03-04-2021, 11:55   #16
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Re: Wire size

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Originally Posted by Cheechako View Post
Yeah, especially today, it gets real expensive. The only way around it is a dedicated battery up forward, and that has to be used correctly to work safely. Not a fan of it though.
I am not a fan of a forward battery either.

Wire, being expensive needs some discussion.

The wire is a one time expense, batteries have to be replaced periodically.

Wire for a windlass - heavy wire does not need to be tinned if installed properly, neither does in need to be fine stranded. Both if these points work together. I use 2/0 copper wire where each strand is 12 ga. It is not tinned. The ends are crimped and then soldered to keep out moisture. I did this in 1991 and it is still good. When it was purchased it was $.90 per foot. Anchor tinned marine wire was about $5 a foot then. I don't know the prices today.

Many people try to use welding wire which is very thin stranded so that it can be dragged to the welding work. Historically the wire had a soft rubber insulation that deteriorated in time. I understand from other discussions on this forum that welding wire is available today with better insulation. Still, the downside of very thin strands that any water intrusion will quickly corrode it. Thicker strands are more resistant to corrosion so even with water intrusion it will last a lot longer.

So, the downside of using untinned heavy gauge strand wire. It is very hard to bend to pull through the tight spots in the boat. IIRC it took me two days to wire my 44 footer. That is the only downside my experience says to me.


Now the reasons I don't like batteries forward.

The dedicated battery forward is just that - dedicated. The power in the battery is usually isolated and not available for other uses. By using light wire to charge it it cannot draw much power from your running engine.

The bow of your boat is not a place for a heavy battery. It is the part of your boat with the most motion so the battery must be well secured. There is already a lot of weight forward - anchors, chain and the windlass itself. You don't want more weight up there.

If you need to re-anchor a few times the battery will get run down and will take a long time to recharge while an alternator assisted house bank won't get much discharge at all. It has been argued that the windlass, like the engine start battery isn't discharged much. An engine start battery draws a few hundred amps for a second or two. A windlass pulling up an all chain rode draws a hundred amps for a few minutes. Re-anchor a few times and it can put quite a dent in the state of charge. Just when you may need it most this setup would be at it's worst.
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Old 03-04-2021, 12:25   #17
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Re: Wire size

If you are using the metric system there is a simple (not scientific) way to calculate the wires area.

Measure the distance, one way, between the battery and the windlass In meter.

Take this distance times the current that the windlass use. Measure in amper.

Divide that value by 10 and you have the area in square millimetre mm².

One example:
Your boat is 35 feet.
The distance (one way) between the battery and the windlass is 30 feet.
That’s the same as 9.0 meter.

The windlass takes 60 amperes.

The cable you should have is 9 times 60 divided by 10 = 54 mm²

Observe this is not scientific correct, but for a 12 V system and 3% voltage drop, it works.
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Old 03-04-2021, 13:03   #18
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Re: Wire size

I was just notified by my wire supplier that the cost of copper has increased to the point that they will have to start passing the increase on to the customer. This as of 4/1 and it was not an April Fool's joke!
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Old 03-04-2021, 13:50   #19
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Re: Wire size

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Originally Posted by stormalong View Post
I am not a fan of a forward battery either.

Wire, being expensive needs some discussion.

The wire is a one time expense, batteries have to be replaced periodically.

Wire for a windlass - heavy wire does not need to be tinned if installed properly, neither does in need to be fine stranded. Both if these points work together. I use 2/0 copper wire where each strand is 12 ga. It is not tinned. The ends are crimped and then soldered to keep out moisture. I did this in 1991 and it is still good. When it was purchased it was $.90 per foot. Anchor tinned marine wire was about $5 a foot then. I don't know the prices today.

Many people try to use welding wire which is very thin stranded so that it can be dragged to the welding work. Historically the wire had a soft rubber insulation that deteriorated in time. I understand from other discussions on this forum that welding wire is available today with better insulation. Still, the downside of very thin strands that any water intrusion will quickly corrode it. Thicker strands are more resistant to corrosion so even with water intrusion it will last a lot longer.

So, the downside of using untinned heavy gauge strand wire. It is very hard to bend to pull through the tight spots in the boat. IIRC it took me two days to wire my 44 footer. That is the only downside my experience says to me.


Now the reasons I don't like batteries forward.

The dedicated battery forward is just that - dedicated. The power in the battery is usually isolated and not available for other uses. By using light wire to charge it it cannot draw much power from your running engine.

The bow of your boat is not a place for a heavy battery. It is the part of your boat with the most motion so the battery must be well secured. There is already a lot of weight forward - anchors, chain and the windlass itself. You don't want more weight up there.

If you need to re-anchor a few times the battery will get run down and will take a long time to recharge while an alternator assisted house bank won't get much discharge at all. It has been argued that the windlass, like the engine start battery isn't discharged much. An engine start battery draws a few hundred amps for a second or two. A windlass pulling up an all chain rode draws a hundred amps for a few minutes. Re-anchor a few times and it can put quite a dent in the state of charge. Just when you may need it most this setup would be at it's worst.
"Many people try to use welding wire which is very thin stranded so that it can be dragged to the welding work. Historically the wire had a soft rubber insulation that deteriorated in time. " I think that's true in some cases, but I have an old Forney stick welder out there with cables that are fine, it must be 40 years old. I really wonder if today's welding cables are any cheaper than battery cable though...? Copper has been going up dramatically for over 10 years IIRC.

"I use 2/0 copper wire where each strand is 12 ga. "
Not a bad thought using standard construction wire at least for a long buss to make most of the distance. One wonders if there is some with a bit thinner strands for easier bending on installation. How about aluminum round bar maybe 1/2" diameter for the straight runs!
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Old 03-04-2021, 14:05   #20
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Re: Wire size

Two thoughts:
1. However the windlass is powered it is important that voltage drop at motor not be excessive. If it is two things occur: a) Motor heats up and b) torque drops off.
2) I am a fan of a dedicated battery close to the windlass (same true for a thruster if equipped). It provides good voltage and does not deplete house or starting batteries. It can be charged using a Balmar Duocharge or similar device.
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Old 03-04-2021, 17:36   #21
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Re: Wire size

Quote:
Originally Posted by cr180 View Post
Two thoughts:
1. However the windlass is powered it is important that voltage drop at motor not be excessive. If it is two things occur: a) Motor heats up and b) torque drops off.
2) I am a fan of a dedicated battery close to the windlass (same true for a thruster if equipped). It provides good voltage and does not deplete house or starting batteries. It can be charged using a Balmar Duocharge or similar device.
I have two alternators on my engine. A 65 amp and a 115 amp. The 115 amp is belted to produce full power at idle.

My Maxwell VWC1500 has a 1200 watt (100 amp) motor. So, How much power do you think I am drawing from the house bank? How fast do you think that battery draw is replaced?

How much have I paid for a battery combiner or for dedicated battery replacements since 1991, when I first installed an electric windlass? NONE.

The wiring cost about what a decent size battery costs today.
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Old 03-04-2021, 17:37   #22
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Re: Wire size

Lofrans shows smaller wire size which is confusing
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Old 03-04-2021, 17:46   #23
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Re: Wire size

For a 1500w windlass, 2 AWG seems a bit on the small side for a 35 foot run. My 1000w windlass spec-ed 2 AWG for up to a 25 foot run each way (and I'm at about 22 feet each way). Personally, I'd want at least 1 AWG for your install, if not 1/0. 2 is safe from an ampacity / not melting the wires perspective.


Keep in mind, a little higher voltage drop than some would suggest is fine here, as the windlass is pretty oversized for any gear a 37 foot boat is likely to have, so losing a little bit of capability on a max-effort pull with the windlass isn't an issue, as it should never be loaded that heavily anyway in this application.
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Old 03-04-2021, 20:19   #24
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Re: Wire size

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Originally Posted by AmzngGrace View Post
Lofrans shows smaller wire size which is confusing
That AWG2 value seems off (chart error, I believe, since the comparable metric value (50mm2) corresponds to AWG0). And the ABYC spec for 100A over 25 ft with 3% max drop is AWG1. (AWG0 for 30 ft)

In this case, if the wire run is 70 ft (there and back) and the actual windlass draw is 100A, the ABYC spec for 3% max drop is, um, 4/0.

A dedicated battery closer to the bow is beginning to look better...
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Old 03-04-2021, 20:57   #25
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Re: Wire size

This is why many new boats are being wired for 24 volt systems.
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Old 03-04-2021, 21:33   #26
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Re: Wire size

As this thread has evolved I will add one more branch on the bush. Fifteen years back I decided to try a split house bank. 4 ea GC2 in the middle and 2 ea GC2 in the bow (now feeding bow thruster and anchor windlass). They normally are all connected in series/ parallel and the fwd pair is tapped directly for the fwd loads. Does this discharge things unequally, probably. Does this charge things unequally, probably. Does all this have any detrimental effect on the batteries, not that I can tell. It does put the power where it is needed and makes for a simple minded set up (no starting battery either). A little out of the box 15 years back, wouldn't have it any other way now, YMMV. Bow thrusters draw serious current and cost serious $$. Keeping the power source close by gives maximum thrust and saved cutting down a few copper trees.


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Old 04-04-2021, 09:02   #27
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Re: Wire size

I have seen remarkably small wire on some boats, charter boats etc that appears to work fine. I suppose when you size wire for minimum voltage drop and for "lock rotor" amps, you end up huge. And maybe that's the conundrum. Do most users put the apparatus in a lock rotor situation ever for more than a second or two?

A 1500 watt motor is about 2 HP. How many HP is normally used to pull up the weight of say 45 ft of G4 chain (1.1# per foot) + 50# anchor when you are anchored in 50 ft of water?
1/5th of a HP to lift 100# a foot per second. And that's if the motor is lifting at a 1:1 ratio, ungeared.
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Old 04-04-2021, 10:09   #28
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Re: Wire size

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Originally Posted by Cheechako View Post
I have seen remarkably small wire on some boats, charter boats etc that appears to work fine. I suppose when you size wire for minimum voltage drop and for "lock rotor" amps, you end up huge. And maybe that's the conundrum. Do most users put the apparatus in a lock rotor situation ever for more than a second or two?

A 1500 watt motor is about 2 HP. How many HP is normally used to pull up the weight of say 45 ft of G4 chain (1.1# per foot) + 50# anchor when you are anchored in 50 ft of water?
1/5th of a HP to lift 100# a foot per second. And that's if the motor is lifting at a 1:1 ratio, ungeared.

Good points. Another approach to choosing wire size- a user could mount the windlass, hook it up to a temporary battery with short heavy cable, and measure the current when raising the actual anchor (a DC/AC loop current ammeter is safest and easiest for this), then pick your wire, or decide whether a dedicated battery would be better.
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Old 04-04-2021, 19:09   #29
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Re: Wire size

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Originally Posted by AmzngGrace View Post
Wire size
So the mystery continues…
When I was reading about the size wire for my windlass and the length of my boat somebody says oh no you double it because the size of the wire is based on the total length which includes up and back for a red and black which doubles the length of my boat from 35 feet to 70 feet. Does that make sense or is it just the singular length from battery to windlass which is about 35 feet?

As posted upthread, it depends on the calculator or table you are using. Most require you to provide the one-way distance, 35 feet in your situation. I like the calculator here, which works that way.



In your situation I would think in terms of 1 AWG or 1/0 AWG as a good balance of cost vs. performance.
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Old 04-04-2021, 19:49   #30
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Re: Wire size

Arrgh.... So much noise and bother, over such a simple question.

If you are calculating the voltage drop for yourself from wire resistance per foot and such, then the total length is what you need to use. Of course if you are doing that, it is very unlikely you are posting here asking random strangers for help.

If you are using a chart or table, you follow WHAT THE CHART SAYS! Some are based on round trip distance, some are on the one way trip. IT DEPENDS! There is no "right answer" without knowing exactly what you are using for your source of data.
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