Cable size for 1500 W electrical windlass

[s/v Jedi]

Originally Posted by Sailorman97

Lots of ways to do it. But before you get totally invested in putting a battery up front with everything that might entail ( mounting off gassing etc) , perhaps you should try it out and see what kind of voltage sag your going to get when you run that windlass direct off the battery. I would think it would be significant but only a test will tell. Now get some high quality long jumper cables and connect the battery together with the house batteries. Run the windlass an check the voltage drop on that set up.

The calculators mentioned are accurate, there is no need for testing to verify it.

[Sailorman97]

Originally Posted by s/v Jedi

You have your house bank at the bow thruster? Interesting

In that case, either you need bigger cables, have high resistance in crimps/terminals or you batteries are end of life or too small.

I mean something is wrong. You can’t expect to put propulsion on a house battery that also feeds electronics that want a stable power input.

You make lots of assumptions but with zero information about really anything at all.

[smac999]

Everyone is overthinking. this. The windlass makers know you are going to have lower voltage and they are designed with this in mind. Your 1/0 cable at 7% loss will give many years of normal use. No boat has 4/0 run for anchor.

[s/v Jedi]

Originally Posted by Sailorman97

You make lots of assumptions but with zero information about really anything at all.

I just make assumptions that are correct for 99% of boats, who don’t have their house batteries at the windlass. It’s just out of luck that you are that 1% with a setup unlike any I have ever seen.
You may be flabbergasted by this but yes many boats put batteries near their windlass or bow thruster because their house bank isn’t located there, incl. The OP which has 30 feet to span.

Originally Posted by smac999

Everyone is overthinking. this. The windlass makers know you are going to have lower voltage and they are designed with this in mind. Your 1/0 cable at 7% loss will give many years of normal use. No boat has 4/0 run for anchor.

Wrong, I do. And ai have doubled up 4/0 (so 4 cables total) to the engine room.

[Sailorman97]

Originally Posted by s/v Jedi

I just make assumptions that are correct for 99% of boats, who don’t have their house batteries at the windlass. It’s just out of luck that you are that 1% with a setup unlike any I have ever seen.
You may be flabbergasted by this but yes many boats put batteries near their windlass or bow thruster because their house bank isn’t located there, incl. The OP which has 30 feet to span.

I am only flabbergasted that anyone one would argue about something they have never seen. That something being my boat

Originally Posted by s/v Jedi

Wrong, I do. And ai have doubled up 4/0 (so 4 cables total) to the engine room.

I have this also. Full power to where ever it is needed. I have 4 runs of 4/0 from the battery to various places.

[s/v Jedi]

Originally Posted by Sailorman97

I am only flabbergasted that anyone one would argue about something they have never seen. That something being my boat

You may want to start with completing your profile so that your type of boat is known and prevent this from happening. It’s how it’s done on this forum, you’re not gonna change that.

[sailingharry]

Originally Posted by smac999

Everyone is overthinking. this. The windlass makers know you are going to have lower voltage and they are designed with this in mind. Your 1/0 cable at 7% loss will give many years of normal use. No boat has 4/0 run for anchor.

Yes. My windlass, a Maxwell, specifically states that their recommended cable sizes are based on 10% voltage drop. Sure, larger cables are better, but their design drop is 10%

A bigger issue is VOLTAGE. Not drop. A 12.5V battery feeding a load with a 3% voltage drop, delivers 12.125V to the load, still above the nominal rated power of 12V. If you are running the engine while using the windlass, you likely have a battery voltage of 13.5. If you size for 10% drop, you are delivering 12.15V to the load. So, what delivered voltage is the windlass designed for? And based on what battery voltage? And how does it change with the higher normal voltage of LFP?

Oh, DC motors do NOT increase current as voltage drops (to maintain rated power). As voltage drops, current DROPS and power drops (and speed drops, like cranking an engine on a weak battery). Similar to light bulbs, where as voltage drops they dim, rather than drawing more current to maintain brightness. Unlike AC motors, where speed (and therefore power) is constant (directly related to power frequency) and voltage drop does increase current. A motor designed for 230V ( household power) will burn out on 208 (a single phase of 440 3-phase industrial power).

[Sailorman97]

Originally Posted by s/v Jedi

You may want to start with completing your profile so that your type of boat is known and prevent this from happening. It’s how it’s done on this forum, you’re not gonna change that.

2 thoughts on that.

I did not know that was the law around here and no one told me your the enforcer.

I did not think that since I did not have my profile filled out that someone would arbitrarily assign me a boat.

Who would have thunk...

[s/v Jedi]

Originally Posted by Sailorman97

2 thoughts on that.

I did not know that was the law around here and no one told me your the enforcer.

I did not think that since I did not have my profile filled out that someone would arbitrarily assign me a boat.

Who would have thunk...

You want people to understand what boat you have and how things work for you, but you keep it a secret while telling people they don’t even know what boat you have but they are wrong and it goes on and on but you still never explain what boat you have and why your house battery is at the bow. But at the same time you keep slapping me for saying that most boats do not have their house batteries at the bow and the OP has 9 meters distance.

[Goudurix]

Sailorman97,
Sorry, I don't understand exactly what you suggest?
- run the windlass directly from the house batteries with HQ jumper cables and test for voltage drop?
- or install the (extra) battery close to the windlass, and connect that battery with the jumper cables to the house batteries en test for voltage drop?

I could install the windlass battery inside the anchor box behind the windlass; to operate the windlass I have to open the anchor locker so gassing off would not be an issue. Another possibility is to install the (AGM - very limited gassing?) under the front cabin bunk, but then gassing of will be more of an issue.

Your opinions?

Jan

[Scrimshaw4]

Remember that you will also have a .5 volt drop for each mechanical connection between the battery and the windlass. The last thing you want to do is undersize the wire. Given your distance I'd recommend a booster battery located up forward for the windlass to run off. That will reduce the wire size going from the battery thru the breaker to the switch relay and then to the windlass. Intelligent isolators are reasonably cheap and can be used in the charging circuit. Remember that the vast majority of the time you'll have a lot of power available from your alternator since you'll be using the windlass while the engine is running. JMHO

[motion30]

Originally Posted by Sailorman97

2 thoughts on that.

I did not know that was the law around here and no one told me your the enforcer.

I did not think that since I did not have my profile filled out that someone would arbitrarily assign me a boat.

Who would have thunk...

What kind of boat was assigned to you? Did you do better than the one you currently have?

[sailingharry]

There are a lot of proponents for a battery forward. And it does have value. But there is also a question of the return on investment -- chargers, batteries, space concerns, 100 lb of weight where it's least desirable, maintenance related issues, etc.

My boat is a recently high quality semi custom boat. I have a 1 KW windlass, and about a 20 m round trip to the main batteries. Factory installed, it is run from the main battery Bank on 2/0 cables. It is now 25 years old with an extensive history of distance cruising and anchoring, still running that original windlass. We have continued that history in the four years that we've owned it, anchoring hundreds of times in depths to 70 ft (55lb Rocna and all 5/16 G4 chain). The performance of the windlass has never been the slightest of concerns.

One thing that is worth noting. Your 1500 watt windlass is probably over spec'd. Not a problem, bigger is certainly better. But just like the 250 horsepower engine in your car only produces 20 horsepower at highway speeds, your 1500 watt windless may rarely consume more than five or 600 watts -- it only draws what is needed at that moment in time.

[Sailorman97]

Originally Posted by s/v Jedi

You want people to understand what boat you have and how things work for you,

I have no need for this. Perhaps you do.

Originally Posted by s/v Jedi

but you keep it a secret while telling people they don’t even know what boat you have but they are wrong and it goes on and on but you still never explain what boat you have and why your house battery is at the bow.

No one is keeping anything secret but I can see it bothers you a lot. Let me put you at ease by assuring you my house battery is not at the bow but is forward of midship.

Originally Posted by s/v Jedi

But at the same time you keep slapping me for saying that most boats do not have their house batteries at the bow and the OP has 9 meters distance.

I have no idea what your going on about here since you appear to be the one attacking me.

Clearly you have some issues here but I never said you are wrong that most boats do not have batteries at the bow.

However the last thing I would do is put any battery at the bow where cresting a wave might result in a 15 foot elevation change in 1-2 seconds and relatively jarring stop. I would just buy some wire.


Going to likely come as a real shock to you but the boat you claim to have or don't have does not impress me or tell me anything about your qualifications as a sailor or as person who knows their boat, nor does it tell me that you actually work on your boat or are good at it. (not a slap just a statement of fact) I know people who have large boats who can not even change a breaker or properly trim a sail yet think they are gods of sailing and would tell you they do their own maintenance.

If I recall we were recently both on a thread where you demonstrated you have no idea what tacking angles are yet claimed 50 yrs of sailing & racing experience.

Nor should the boat I profess to have make any difference on the consideration given to my answers. If the answer is good and makes sense then that is good enough. The answer should be detailed enough that it is complete. If someone choses to go a different way that is better for them then that is okay because there are always different paths to go down. More than one way to skin the proverbial cat so to speak.

In other words, we come hear seeking help and answers to questions and we can take or leave them as we choose and who one purports to be by their signature and profile makes no difference at all.

As for what boat I have, it matters not. What is important on this thread is that I know enough not to try and run 150amp DC through 60 ft of 1/0 cable and expect no problems, and can make real world suggestions about cabling options and where to source cable. The reader is under no obligation to pay any attention to my suggestions.

You complain about being slapped. I don't recall slapping you but if you took it that way perhaps you should change your communication style.

This will be my last response to you. I am here for ideas to fix problems I have, to learn from others, to perhaps provide suggestions that might work for others. I am not here to get in a flame war. Your contributions seem overly forceful. Please bother someone else.

Cheers

[Sailorman97]

Originally Posted by Goudurix

Sailorman97,
Sorry, I don't understand exactly what you suggest?
- run the windlass directly from the house batteries with HQ jumper cables and test for voltage drop?
- or install the (extra) battery close to the windlass, and connect that battery with the jumper cables to the house batteries en test for voltage drop?

I could install the windlass battery inside the anchor box behind the windlass; to operate the windlass I have to open the anchor locker so gassing off would not be an issue. Another possibility is to install the (AGM - very limited gassing?) under the front cabin bunk, but then gassing of will be more of an issue.

Your opinions?

Jan

It looks like you prefer to go the extra battery option so it is option number 2. Install battery connect to house bank with jumper cables and test for voltage drop.

I am not sure you need a charger or that it would help much during actual windlass usage. If you keep batteries the same type you should be able to do without the charger.

I am not sure about putting a battery in the anchor well. If the drain gets plugged and your in heavy seas for a long time these things can fill up and your battery gets drowned.

My only concern is spending money you can not get back on a system that in the end does not perform correctly. Nice to be able to do a test if possible.

All my batteries have always been under bunks or settes. Off gassing only really became an issue when we were out on a cruise and when we got back the big charger would punch the voltage up. Other than that we never noticed. Maybe we just got lucky for 30 yrs

I am not a fan of AGMs and if you talk to any reputable battery salesman they will tell you the best bang for your buck is flooded. AGMs still have acid in them it is just wrapped in glass mat. If you overcharge AGMs they still off gas but now you can not replace the liquid and over time this kills the battery

I am currently rebuilding the area my batteries ( flooded) are in ( still under a bunk) and thinking about the ventilation aspect. If you use flooded and try to ventilate you must use an ignition proof fan. I think a small brushless computer fan could do this. It is not like your having to move huge volumes of air your just trying to keep hydrogen gas concentrations down in the battery box area.

Cheers