New Electrical System Questions

[SV Miss Fe]

Couple more questions. Thank you for all the great responses.

I've got Calders Electrical and Mechanical book plus Boatowners Illustrated Electrical handbook. I think both are pretty good books but I'm partial to Calder. Both books aren't exactly written from the starting from scratch/ complete rebuild perspective are their any that are?

Could anyone better explain battery box venting? Are we talking airtight with a vent tube to the outside of the boat? Or more like let air get in and out?

As for inverters I need AC power for only 1 thing, my desktop computer. It will be probably a 350 watt PSU on the computer and 2-3 24'' led monitors (this may sound excessive but its a source of income for me and therefore not optional). Would a 1000 watt inverter be about right? Any recommendations on good reasonably priced unit? My concern is that a larger inverter would be nice but would be chronically under loaded and not as efficient since its main purpose is the computer.

[David B]

Once I'm confident with my diagrams I want to do use one of the deluxe panels from paneltronics. My theoretical max load (everything on at full power) is around 150 amps. Can I use a 100 amp panel since having everything on at once will never occur?

[/QUOTE]

Have a look at Blue Seas Systems. I have used one of their panels in the past, and was most impressed by the build quality, back-lit labelling, range of labels etc.

Their web site also has a lot of useful info such as wiring diagrams, installation photos etc.

Hope the re-wire goes well. My suggestion if it is as bad as you describe is to rip all rubbish wiring out (using old wiring as draw-wires to pull the new cabling through). Decide whether hardware is mounted correctly and in the right location, then run your main power feeds, and then your branches.

Give some thought also to those battery banks. Nice to have isolation switches so that you can charge one bank while the other is doing service.

What I do at the start and end of each season is isolate the batteries into banks, and then put a smart charger (Projecta IC5000 is my choice) on each, with the charger in 'Recondition' mode. It equalises the batteries, minimises the chance of sulphation, and hopefully gives you another several years life (of course during the 'off season' they are trickle-charged).

Either arrange your wiring so that this can be done at the flick of a switch, or else have Anderson plugs at convenient places to plug in to each bank once isolated.

Hope that helps,

David

[Chuck Hawley]

I have just rewired my Alerion Express 38 Yawl, which is probably similar in complexity. I ordered a semi-custom panel from Blue Sea Systems, and it has been terrific. YOu build it online, submit the very detailed plan to BSS, and the OK it on ABYC guidelines, and build it. Mine arrived in 7 days, and it's perfect.

I specified the VSM 422 monitor, and I love it. Very clean interface, and it can do tank levels, bilge pump operation, etc. Very nice piece of kit.

My panel was about $1500, but that included AC and DC breakers, and the VSM 422.

Chuck

[gchead]

I too have been doing a partial re-wire of my 31' yacht, Halo (built in 1986) and am finding this forum very useful.

I have attached my wiring diagram so far, and would be interested in hearing any suggestions from experts out there as to improvements I should be looking at. The batteries are 2 x 130 Ah House and 1 x 780 CCA Start.

[bcfurumasu]

Hi I'm curious by your comment of panels on steel boats, (I also own one) and am interested in finding out more about what you were alluding to for wiring on a steel sailboat. Thanks...

[ramblinrod]

Originally Posted by SV Miss Fe

I've recently purchased a sailboat. The electrical system is um "home built" and quite frankly a mess to say the least. So I'm in the process of diagramming everything out for replacement and have a few questions.

Currently the house bank is 4 Trojan T105 running at 12v (1 year old). I'd like to add two more T105's but I hear its bad to mix batts of different ages. Obiviously I'm not about to junk 4 almost new batteries. Do I have any options?

Yes, Just add the new batteries. If the original batteries were treated well, the new batteries won't be affected. The rule about not mixing applies more to not mixing new with old abused batteries. You new batteries will take the brunt of the reduced capacity (if applicable) of the old batteries.

Once I'm confident with my diagrams I want to do use one of the deluxe panels from paneltronics. My theoretical max load (everything on at full power) is around 150 amps. Can I use a 100 amp panel since having everything on at once will never occur?

Follow ABYC 11.8 Load Calculations for DC Systems. Basically your system has to be rated for the sum of continuous loads + 10% of intermittent loads.

Currently there are two large 12+ switch panels one forward near the mast and one aft near the battery bank. There are also multiple 3-6 switch panels spread around the boat. In my mind its a 33' boat. I'll never be far from the main panel can I just put the vast majority of switches in one large panel?

Yes. However, a home run system (everything running to one panel) can increase wiring runs. Sometimes, it makes sense to run separate panels (e.g. main panel at nav station for cabin loads (bilge pump, pressure water, etc.) with waterproof panel at helm for external loads (nav, spreader, and spot lights, etc.)

Most panels seem to come with either digital or analog meters. The boat came with a xantrex link 20 battery monitor. Can I use this and forgo the panel meters?

Yes, for the DC panel as long as the battery monitor is set up to display battery voltage and instantaneous current. I recommend a Voltmeter and Ammeter for the 120Vac system.

Assuming I'm using high quality circuit breakers and excluding sensitive electronics do I need to use fuses anywhere?

Yes, the house bank batteries should be fused, as well as the safety items connected directly to the battery terminals, such as bilge pump, VHF, sniffer, etc. You will also need one, anywhere you branch off a main circuit with lighter gauge wire (after you assure you will not exceed the current carrying capacity of the original branch circuit.)

Thank you in advance for your help! This forum is an awesome resource.

This kinda feels like the time I had kids pull up alongside in a run-about and ask for directions to a destination out in Georgian Bay.

After considering that I could be sending them to their peril if they didn't get my instructions right, I told them how to get to the nearest marina to buy charts.

So, the best advice I can give is to read ABYC E11 (Electrical Standards) cover to cover, and if there is anything you're not sure about, ask. If you have to ask more than 3 things, you need to read it again.

While Calder's and Casey's books are pretty good about certain systems, they really don't cover good general wiring practices well enough. (It's also a, "Just because you saw it on the internet (or read it in a book), doesn't mean you can do it", kind of a thing.

Next, my best advise is don't go cheap on the products. Use Ancor wiring and connectors, Marinco shore power cables and connectors, and Blue Sea panels and breakers.

Equipped with this, please don't burn your boat to the waterline (which is all too easy, even if your think you have it all figured out.)
There are things one just can't learn from an evening of reading or an hour of YouTube video viewing.

Just because 12Vdc won't electrocute you, doesn't mean it doesn't deserve your full respect and attention.

As part of my current marine electrical seminar for boating groups, I start out asking...

"Who does their own electrical repairs and improvements?"

(About 50% of hands go up.)

Then I ask, "Of those, who believes it was done properly?"

(All the hands stay up.)

Then I ask, "Who is so sure of that, they will invite me aboard to perform an electrical inspection, free if it's safe, $200 if I find one electrical safety issue?"

(All the hands go down.)

After the seminar, when I've shown several images of tragic boat fires, and gone through many of the electrical safety issues I encounter, 2 or 3 come up and ask me to do a $200 inspection. They know (now) that they have (and I am going to find) electrical safety issues.

The reason I can do this, and stay in business, is because in my experience to date, about 90% of all boats on the water today have unsafe electrical issues, and about 50% of owner DIY work, is absolutely atrocious. If asked, nobody will say, "The wiring I performed is all wrong". They simply don't know just how unsafe it is.

I'm not saying, "Don't do your own electrical work." I'm just saying, "If you are going to do it, for everyone's sake (yourself, your crew, the next owner, and the boat), ensure you do it right, 100% right."

When you need it, a bilge pump must work, to the best of its potential performance, or a maritime tragedy could occur. When you need it a VHF must work, to the best of its potential performance, or a maritime tragedy could occur. When you need it, the engine starter must turn, to the best of its potential performance, or a maritime tragedy could occur. You get my drift.

There are few electrical / electronic devices aboard that could not become a critical piece of safety equipment some day. Even a Marguerite blender with a botched plug replacement. (A line/neutral short, with a secondary boat wiring or current limiting fault, could result in a catastrophic fire.)

Recently on this forum, I read a thread of a bunch of people (about a dozen) telling the OP that it is OK to use 18 gauge wire when adding LED fixtures to existing cabin lighting wiring. Not one of them said (or probably even knew) that in doing so, one must address current limiting in the new branch circuit, or an electrical fire could ensue before the original fuse or breaker ever trips.

Sailing gives one all kinds of freedom, to move without the sound of infernal combustion engines, to move without roads or guard rails dictating where, to move without adherence to strict schedule, and so on.

It also gives one the freedom to mess up electrical stuff if they don't know what they are doing.

Ramblin Rod
About Sheen Marine

[GrahamHO]

Originally Posted by SV Miss Fe

I've recently purchased a sailboat. The electrical system is um "home built" and quite frankly a mess to say the least. So I'm in the process of diagramming everything out for replacement and have a few questions.

Currently the house bank is 4 Trojan T105 running at 12v (1 year old). I'd like to add two more T105's but I hear its bad to mix batts of different ages. Obiviously I'm not about to junk 4 almost new batteries. Do I have any options?

Once I'm confident with my diagrams I want to do use one of the deluxe panels from paneltronics. My theoretical max load (everything on at full power) is around 150 amps. Can I use a 100 amp panel since having everything on at once will never occur?

Currently there are two large 12+ switch panels one forward near the mast and one aft near the battery bank. There are also multiple 3-6 switch panels spread around the boat. In my mind its a 33' boat. I'll never be far from the main panel can I just put the vast majority of switches in one large panel?

Most panels seem to come with either digital or or analog meters. The boat came with a xantrex link 20 battery monitor. Can I use this and forgo the panel meters?

Assuming I'm using high quality circuit breakers and excluding sensitive electronics do I need to use fuses anywhere?

Thank you in advance for your help! This forum is an awesome resource.

Firstly rip out all the old wiring if it is a "mess"
The 4 house batteries you already have should be all you need. I imagine you have a start battery as well. It is possible to have too much battery capacity for your generating capacity to cope with. Run them down after a few days at anchor and it could take a while to fully charge them again. Bad for them not to be fully charged. You will need a splitting diode about twice the amp rating of your alternator to charge separate house and start batteries circuits. Realise that any anchor winch ( should be connected to start battery) will be powered through the diode with the boat engine running, as it should be when winching.

You should consider some solar panels as well; but as those few days at anchor might be cloudy, again don't have too many batteries for your generating capacity.

Make sure you or an electrician use suitably sized marine tinned copper cables. Don't use plain copper cables which rot away in salt air.


You will need (spade) fuses on the solar controllers to batteries cable near the battery connection.
You will need fuses for voltmeters etc either at the battery or distribution bus. Imagine a cable falling off the voltmeter or controller and touching a negative.
You should have low amp fuses for your sailing instruments as well as a circuit breaker on the panel. A separate breaker and circuit for the GPS is a good idea. Your instrument instructions will advise.
Fuses on any other accessories that you don't want to switch.
You might want heavy fusible links on your +ve battery posts, as in cars.

[GrahamHO]

Originally Posted by SV Miss Fe

Couple more questions. Thank you for all the great responses

As for inverters I need AC power for only 1 thing, my desktop computer. It will be probably a 350 watt PSU on the computer and 2-3 24'' led monitors (this may sound excessive but its a source of income for me and therefore not optional). Would a 1000 watt inverter be about right? Any recommendations on good reasonably priced unit? My concern is that a larger inverter would be nice but would be chronically under loaded and not as efficient since its main purpose is the computer.

For my MacBook Pro (obviously smaller than your desktop) I use a 370 watt pure sine wave inverter with heavy 12 v cables in keeping with its terminals.
An earlier non sine wave ( square wave) inverter caused battery problems in the laptop. Likewise you might want pure sine wave although you don't have a computer battery, you do have sensitive computer electronics. My inverter is claimed to be something like 95% efficient. I feel that a 1000 w inverter sounds about right for you but you should get a computer experts opinion. While operating, your computer is presumably not always consuming 350 w. That would be its max I would think.


I think the inverter will isolate your computer from any voltage spikes in the house system ( water pump, electric toilet, electric fridge, 12 v vacuum cleaner etc) but I'd get an expert opinion about that too. It is also possible ( I think) that an inverter itself may cause an AC spike when it's switched on, so it may be an idea to turn it on before you turn on your computer. Again something to check out.


If you do need more inverter power for other uses, you could have a second inverter to maintain the efficiency you mention when a larger than 1000 w inverter might be under loaded. I have a second dedicated (square wave) inverter to drive a fridge freezer.
Rather than one huge inverter you can have 2 or even 3 smaller ones dedicated to their own tasks. Then also you don't need to run a complicated AC system. You can have a domestic extension cable and perhaps 4 point outlet box for each inverter, as I do.

[GordMay]

Greetings and welcome aboard the CF, gchead, and bcfurumasu.

Metal boats generally have an isolated/floating ground (negative), and utilize 2-Pole circuit Breakers.
➥ http://www.cruisersforum.com/forums/...ats-73621.html

[exMaggieDrum]

Originally Posted by SV Miss Fe

Could anyone better explain battery box venting? Are we talking airtight with a vent tube to the outside of the boat? Or more like let air get in and out?

What is important with battery box venting is two things: getting rid of toxic gasses, e.g. hydrogen and sulfuric acid, so they don't build up, and, heat dissipation. A tube to the outside is not something to do at all. There won't be any air flow to speak of, and you have one more hole to allow water in to the boat (less likely if you vent it at a suitable place but still no real air flow).

So - don't install the batteries touching each other or the battery box/container. You need spacers to allow at least some air insulation and flow between the batteries - on all sides. Use spacers in between. They can be wood but it will deteriorate from the fumes from wet batteries. Starboard or some other more inert material is better. And the batteries should be secured so that, even if the boat goes on its side, or goes turtle, or slams up and down with waves, the batteries will not shift.

Vent holes or a louvered vent should be used close to the batteries to ambient air. And you should put them out of the engine room if possible (but this is often not done if other space is not available). You want airflow to help dissipate heat to the extent possible. The total effective open area is what's important, and it should not just be on one side. But if it is on only one side it should be the entire length of that side to allow some air circulation. The holes should be at least on the high point of the side, but ideally top and bottom.

This is important when hard charging your batteries. They will get very warm. If they get too warm they can go in to thermal runaway and start a fire. I have had to put ice on batteries on boats to cool the batteries when they were found in that condition. It is self-promoting as the heat creates more heat and they get to where they melt the battery containment material.

Someone mentioned ripping out all the wires and use the existing wires to pull new. That is very tempting and I do that often, BUT, if the existing wire route is sub-optimal you can be creating more of the same mess you had before and can leave in nice chafe spots. I often interrupt a wire pull to reroute the wire to a better route where it will be tidier in the end, can be secured to walls, decks, whatever, and, will avoid chafe spots. You may have to install chafe material when going through panels or over things. This is not a trivial exercise and it can add hours to the job. It is also critical to do and if you cut corners now you will regret it forever and may decide you have to redo it later. The actual best practice is to label and diagram all the existing wires - from panel to power using device - and pull all the wires that go behind panels (like going in to the panel enclosure) and then pull each new wire (right gauge for each use) through the blind spots (leave a pull wire or add a new one if needed for a different route). You need to pull it either all the way to each device, or, make sure you have plenty before cutting it off and to the next.

The only way to do all this is to buy rolls of wire, in 25, 50, or 100 foot rolls and pull the wire off of the roll and only cut after you are 100% positive you have enough, with plenty of slack to secure the wire and provide for drip loops at both ends, etc. If you don't do this you will be tempted to try and put wires you cut a little too short in places you can't properly secure it and/or can't leave drip and service loops (extra so you can pull out the wire when you need to get the device out and check or replace a terminal).

I admire your pluck. You will be able to get through this. And having done some other minor wiring will help you immensely in sorting out all this. BUT don't overestimate how much you need to learn. This is far different than any of the other things you have done (from what you said originally).

Reading and understanding the ABYC manual will be helpful, but it is difficult reading, in the way it is written, and it has some stuff in there that won't apply to everything you may want to do. It does have great sample, acceptable, wiring diagrams for both AC and DC. If you will not have shorepower, a built-in inverter, a genset, or other AC producing device it really won't matter. But if you have any of that, or will have, you need to look at the AC part too. A standalone small inverter for your PC is fine. Nothing really to worry about except fusing and tidy, secured DC wiring, and none at all if using a DC plug outlet (which must be fused).

Highly recommend you pull a couple of wires and see how they need to be secured as you go (every 10" or so). I like to preinstall wire tie mounts along a wire route and put in wire ties that are uncinched and then pull all wires through those. If you don't you will underestimate the length of wire you need which you will discover when you try to secure them later. And you won't be able to get to where you need the wire tie mounts. I hate conduit as it captures heat and can make pulling wires the first time and later very difficult. Leave the wiring open (with some few special exceptions may be) and use wire ties. Do not use the "C" clamps. Much easier to cut and replace wire ties if you need to add new wires or replace wires in the future. You only want to put in the mounting screw one time!!!

I also highly recommend you use square hole screws rather than phillips, and certainly not slot, screws. You will also find an angle drill will get you into spots you can't get in to otherwise. I guarantee you will make mistakes and have to redo some things. Don't sweat it. It happens to everyone.

I think your bank account will be very surprised as to how much all the wire will cost you. Rolls of wire are very expensive but required. You'll need 10 gauge (usually not a lot), 12 gauge, 14 gauge primarily - red and black. Yellow is used as the "new" black but it is hard to find many times. And if you won't have AC you don't need to worry about mixing it up. I never did anyway since AC runs should be separate from DC and you always have white with black for circuits any way. But it doesn't hurt. Don't use red for ground - ever - even with black tape or labels to say it is not really positive, and ditto for black for red. Use the right color for every wire. And label both ends - clearly and with a good labeling system that can withstand water and oil. Masking tape will fall off quickly.

Good luck and make sure you take it slow and easy.

[ramblinrod]

I think there are a number of issues with these recommendations...

Originally Posted by GrahamHO

It is possible to have too much battery capacity for your generating capacity to cope with.

Actually, battery capacity should be sized to your energy demand. The real issue is that you can have too little charging capacity to replenish your batteries when you discharge them. One can never really have too much battery capacity.

You will need a splitting diode about twice the amp rating of your alternator to charge separate house and start batteries circuits.

This is one solution. A better solution is the battery switch, and best solution is an ACR, due to the voltage drop of the diode isolator and it's negative impact on charging systems.

Realise that any anchor winch ( should be connected to start battery) will be powered through the diode with the boat engine running, as it should be when winching. This is one solution. Many use a dedicated windlass battery. If a dedicated battery is not used, it is actually better to connect the windlass to the house bank (assuming large enough), so the starting battery can never be discharged to the point the engine can't be started. While the engine is often running when anchoring, this is not necessarily so when anchored many days in an area with a high tidal range and scope needs to be adjusted regularly. Of course you are not supposed to pull up the boat by the windlass, but many do anyway.

Running the engine (actually alternator and/or generator) when high current loads are operating is good advice.

You should consider some solar panels as well; but as those few days at anchor might be cloudy, again don't have too many batteries for your generating capacity.

Not really. Energy needs are what they are. Again it is not really possible to have too many batteries (except for weight, space, and cost considerations); the issue is too little charging capacity to replace energy used.

Make sure you or an electrician use suitably sized marine tinned copper cables. Don't use plain copper cables which rot away in salt air.

You will need (spade) fuses on the solar controllers to batteries cable near the battery connection.

Any correct rating fuse will do, doesn't have to be ATO or ATC style.

You will need fuses for voltmeters etc either at the battery or distribution bus. Imagine a cable falling off the voltmeter or controller and touching a negative.
You should have low amp fuses for your sailing instruments as well as a circuit breaker on the panel. A separate breaker and circuit for the GPS is a good idea. Your instrument instructions will advise.
Fuses on any other accessories that you don't want to switch.
You might want heavy fusible links on your +ve battery posts, as in cars.

I wouldn't recommend automotive fusible links. Too hard to change if one blows. Battery terminal mounted fuses are great.

[jeepbluetj]

There were a few questions after I posted.

Google tells me the double-pole breaker thing had it's own thread - some good explanations in there:
http://www.cruisersforum.com/forums/...ats-73621.html

For fuse types, use what fits. MRBF are really convenient if you can handle the extra height from the batteries. They can go to 300A and have an interrupt rating of 10000A. ANL's can be had in the same rating ranges, but the holders are bulky. AMI/MIDI are a good option if the current ratings fall within your needs.

[exMaggieDrum]

Personally, I don't like the idea of using the start battery for windlasses. The start battery should be reserved for starting the engine and for emergencies when you need to power radios, other electronics, and/or lights. House batteries should be fine for the relatively slow and short draw on them.

One thing that should never be done is to use diodes, of any type, in between charging sources and the batteries being charged. Diodes drop the voltage several tenths of a volt, which is major in charging regimens. Not necessary and I haven't seen them in over ten years, and only then on very old systems that have not been brought up to current levels. They will work to isolate the batteries but they are not switchable and they can fail easily, leaving you without any charging. Don't do it.

[GrahamHO]

Originally Posted by ramblinrod

I think there are a number of issues with these recommendations...

Rambling: There is no difference between - to much battery capacity for your charging capacity; or too little charging capacity for your battery capacity.
Only in the words you choose.

Using the starting battery for your winch is correct (if you don't want a dedicated battery). A start battery is the correct type of battery for a winch. Your start battery is or should be always charged whereas the house bank can be low say in a morning when you want to depart.

You will not flatten your start battery by winching because you should run your engine while you winch.

I said nothing about pulling the boat forward on the winch. Your boat motor is running so you can use that.

If your motor is running when you are winching you are getting maybe 14.5 volts instead of a nominal 12 volts at your winch. The winch will run better and faster. It is bad for a brush motor to run slowly. It can overheat or the commutator can get carbon-ed from the brushes. ( I'm sure you are familiar with the back EMF effect in a shunt wound electric motor which results in less current drain as it runs faster)

If you use a VSR (voltage sensing relay) instead of a diode, and if you connect your anchor winch to your house bank, and run your engine while you winch ( as you should) you will eventually burn out the contacts in the VSR as the full 70 amps or whatever your winch requires will be going through the VSR.

Likewise if you are using a VSR you must connect your winch to the start battery as then the VSR will not be passing the winch current through its contacts.

Your regulator can be corrected for the around .5 voltage drop from a splitting diode. That is standard practice.

If you have a dedicated winch battery and if you install it up front, you still need heavy cables connecting it to the engine alternator system. That is because the winching current will be mainly supplied by the alternator. If you decide to use light cables to charge the winch battery they risk overheating if your boat motor is running. If your boat motor is not running your dedicated winch battery might not be able to handle a 100' deep anchorage.

So if you want a dedicated winch battery you may as well simply have 2 start batteries near the motor. I just have one start battery myself, with an emergency parallel switch to connect to the house system.

[exMaggieDrum]

Originally Posted by GrahamHO

Rambling: There is no difference between - to much battery capacity for your charging capacity; or too little charging capacity for your battery capacity.
Only in the words you choose.

Using the starting battery for your winch is correct (if you don't want a dedicated battery). A start battery is the correct type of battery for a winch. Your start battery is or should be always charged whereas the house bank can be low say in a morning when you want to depart.

You will not flatten your start battery by winching because you should run your engine while you winch.

I said nothing about pulling the boat forward on the winch. Your boat motor is running so you can use that.

If your motor is running when you are winching you are getting maybe 14.5 volts instead of a nominal 12 volts at your winch. The winch will run better and faster. It is bad for a brush motor to run slowly. It can overheat or the commutator can get carbon-ed from the brushes. ( I'm sure you are familiar with the back EMF effect in a shunt wound electric motor which results in less current drain as it runs faster)

If you use a VSR (voltage sensing relay) instead of a diode, and if you connect your anchor winch to your house bank, and run your engine while you winch ( as you should) you will eventually burn out the contacts in the VSR as the full 70 amps or whatever your winch requires will be going through the VSR.

Likewise if you are using a VSR you must connect your winch to the start battery as then the VSR will not be passing the winch current through its contacts.

Your regulator can be corrected for the around .5 voltage drop from a splitting diode. That is standard practice.

If you have a dedicated winch battery and if you install it up front, you still need heavy cables connecting it to the engine alternator system. That is because the winching current will be mainly supplied by the alternator. If you decide to use light cables to charge the winch battery they risk overheating if your boat motor is running. If your boat motor is not running your dedicated winch battery might not be able to handle a 100' deep anchorage.

So if you want a dedicated winch battery you may as well simply have 2 start batteries near the motor. I just have one start battery myself, with an emergency parallel switch to connect to the house system.

So we'll just have to agree to disagree as I think several of your recommendations are controversial. To each his own. Thanks for taking the time to give yours though. You definitely have thought them out.

FWIW - most windlass installations I have seen have been connected to house banks, including my own. My new boat came that way. I have installed many that way. But I am sure connecting them to a start battery will work provided it is charged well, is a sufficient size, the motor is running when you winch, the battery cables are beefy, etc. A medium/large bank of deep cycle batteries will have no problem working a windlass just from surface charge. So either will work but sometimes start batteries are a bit undersized to start a cranky engine and work a windlass and both tend to be used at the same time so the battery starts out a bit low for one or the other. But if it is big enough, or up in the bow, no problem.