Sharing wiring with charging cable and electric winch

[WaldPinkler]

Whoever installed my electric winch installed a pretty small gauge wire. I need to upgrade it. I've since moved all the solar controllers to that cupboard and used this winch wiring for charging instead.

The question is can I run a larger cable to this spot then also branch off to power the winch?

I did the same with the thruster and windlass but very unlikely I'll use both at the same time. It saved the double run of wires and now the windlass uses the larger gauge wiring.

All I can think of is the winch causing a temporary voltage drop which may reset the solar controller cycle. I can live with that. I wouldn't be using the electric winch much. Just for raising the mainsail.

[Jammer]

Can you? Sure, it will work fine for the most part.


Watch overcurrent protection. If you've chosen, say, an 80a breaker so that it will trip before you burn up the winch motor, but it's a bright sunny day and the solar controller is feeding 30a back into the bank, the winch motor won't trip the breaker until it draws 110a, at which point it will be toast. (I'm leaving out the effects of time for simplicity; in reality motors take time to melt and breakers allow short-duration overloads because of that but the big picture is still the same)


If it were me I would put overcurrent protection, separately, for the winch and solar, in your cabinet there, in addition to the breaker at the main panel.


It might be easier just to run another pair of wires for the solar controller, and will be less confusing later if there are problems to isolate.

[WaldPinkler]

Yes. the circuit protection is understood.

Running 2 lots of 1/0 or so would be pricey and perhaps redundant with how little the winch would be used.

[ozsailer]

Originally Posted by WaldPinkler

Whoever installed my electric winch installed a pretty small gauge wire. I need to upgrade it. I've since moved all the solar controllers to that cupboard and used this winch wiring for charging instead.

The question is can I run a larger cable to this spot then also branch off to power the winch?

I did the same with the thruster and windlass but very unlikely I'll use both at the same time. It saved the double run of wires and now the windlass uses the larger gauge wiring.

All I can think of is the winch causing a temporary voltage drop which may reset the solar controller cycle. I can live with that. I wouldn't be using the electric winch much. Just for raising the mainsail.

No, no, no, no. I'll put it this way. Lets say you have a home with with a stove circuit but you want extra lights. Would you run your lights from this circuit, NO. Its the same for a boat. Do not mix your circuits. One reason is for safety 2) is for ease of fault finding are two reasons straight away. And yes I have an electrical background. Save yourself a lot of worry and run the correct wire and circuit protection.


Ozsailer

[WaldPinkler]

Originally Posted by ozsailer

No, no, no, no. I'll put it this way. Lets say you have a home with with a stove circuit but you want extra lights. Would you run your lights from this circuit, NO. Its the same for a boat. Do not mix your circuits. One reason is for safety 2) is for ease of fault finding are two reasons straight away. And yes I have an electrical background. Save yourself a lot of worry and run the correct wire and circuit protection.

What's your reasoning?

Yes, fault finding in your stove/light example makes sense but if you had a distribution point in your kitchen then circuit breakers could be branched from there to both circuits.

The distribution panel does exactly what I'd like to do except I'd have the charging circuit coming in. The winch would be fused just as the distribution panel has a fused branch for it's circuits.

[smac999]

The winch needs to be switched. Abs the solar shoukd not be switched. So I would not use the same pos
cable. You could share the ground.

[Fishspearit]

Originally Posted by WaldPinkler

Yes. the circuit protection is understood.

I'm not sure if it's fully understood. Normally, you always want to provide overcurrent protection to protect the conductor, not the device. You set that protection at the rating of the conductor, so for your solar panels you want them protected at whatever amps that conductor can handle. Motors are different because they can suffer from 'locked rotor current'. This is more commonly a problem with bilge pumps, and the important thing here is that the overcurrent protection of a motor must always be EXACTLY what the manufacturer recommends. For example if a bilge pump should have a 4 amp fuse, but you put a 10 amp fuse in there thinking you're ok because your wire can handle 20 amps, and then the rotor locks up, the resistance goes up and (ohms law) current goes down. So that 10 amp fuse never blows, the bilge pump eventually overheats and catches fire.

In your case you need overcurrent protection for the conductor for your solar charging, and you need separate overcurrent protection for your motor. Hence separate conductors.

[stormalong]

How large is your solar array? Do you really need 1/0 for it?

[WaldPinkler]

Up to 50A on charging circuit. I believe the winch can go to 140A looking at the manual.

Currently 4 awg run on a 8m round trip.
50A = 5.4% drop (high charging)
30A = 3.3% drop (average charging)
140A = 15% drop (obviously wrong gauge for winch which was installed)

Perhaps the charging cable is near good enough. I could double it with another parallel run of 4 awg of extra cable from removing windlass wiring. Install 1/0 for the winch as suggested in the lewmar install manual.

The only benefit I can see of separate wiring would be the awkwardness of relocating the isolation switch. Appropriate circuit breakers would be installed.

[s/v Jedi]

Originally Posted by WaldPinkler

Up to 50A on charging circuit. I believe the winch can go to 140A looking at the manual.

Currently 4 awg run on a 8m round trip.
50A = 5.4% drop (high charging)
30A = 3.3% drop (average charging)
140A = 15% drop (obviously wrong gauge for winch which was installed)

Perhaps the charging cable is near good enough. I could double it with another parallel run of 4 awg of extra cable from removing windlass wiring. Install 1/0 for the winch as suggested in the lewmar install manual.

The only benefit I can see of separate wiring would be the awkwardness of relocating the isolation switch. Appropriate circuit breakers would be installed.

No, you seem to be winging it. To do as you propose is like installing a sub panel so in this case you need a set of busbars with something like 2/0 - 4/0 cabled to the primary busbars, then add fuses for each branch circuit.

What you seem to want will most probably invalidate insurance because it goes against installation standards.

[WaldPinkler]

Exactly what I was suggesting. It doesn't need a bus bar, just a heavy duty stud for 2 circuits.

I'm leaning towards just installing the extra 1/0 for the winch and doubling up the 4awg for the charging and be done with it.

[ozsailer]

Originally Posted by WaldPinkler

What's your reasoning?

Yes, fault finding in your stove/light example makes sense but if you had a distribution point in your kitchen then circuit breakers could be branched from there to both circuits.

The distribution panel does exactly what I'd like to do except I'd have the charging circuit coming in. The winch would be fused just as the distribution panel has a fused branch for it's circuits.

Without going into a full electrical dialogue with you, I think the easiest way to explain it to try and understand what you want to do. By your thoughts You wish to wire two totally different electrical systems onto one circuit. This is just a no no, The whole idea of circuits is so that each can be wired, sized, labeled and protected correctly. By your thoughts one could one one large wire down the centre of the boat and run everything off that provided the protection was adequate. Very simply It does not work that way and should not we wired that way.


Ozsailer

[Mike Banks]

No.. The smaller cable was to charge a battery which in my vessel powered the heads macerator, and the waste tank discharge pump, anchor windlass and heads lighting, as well as an fan which worked through a small inverter and expelled air from the heads and forward washroom. Pumping out stale air allows fresh air to enter the hull aft and move forwards through the vessel. I also had solar vents on small dorade boxes which kept the boat fresh while unattended, and some axial fans mounted in ducts which sucked air out of the bilges and vented it above decks. It worked in daylight hours driven by a small solar panel. I think the panel was thirty bucks and 12 volts output. The axial fans do not use much power.

But running the anchor windlass from cables aft without using a forward battery station is not very practical. The best solution is a hydraulic motor driving the windlass from the engine using an electric clutch to drive the hydraulic pump.

[Rumrace]

I wouldn’t ever piggy back anything on an electric motor power supply. I have 3 power winches all dedicated wires fused and reset. They are monsters on juice.
My anchor winch Roller and bow thruster feed off a bus bar with fuses.
No lighting or electronics have any connection to any motor on the boat save a a few stepper motors. The stepper motors are on an isolated circuit run by a raspberry pi. Cross talk from electric motors can cause issues worth avoiding.
If it’s a 4 wire I’d buy the 4 colour 4 strand. In a tight cupboard I’d be tempted to use silicone coated wires.

[WaldPinkler]

My thruster had a large fused cable running to it with an isolator switch also.

I removed my smaller windlass wiring and did the piggybacking I suggested on that larger cable with another breaker coming off there to the windlass. I can't see any issues doing this. I'm not going use both at the same time.

Yes, there's the option for a forward battery and reducing wiring but there's already a large gauge cable installed and since I don't visit marinas, that thruster isn't used regularly.

The isolator switch is too hard with the electric winch in the cupboard. I'll just run another circuit.