Windlass Power Source

[Lee Hadjiosif]

My windlass is wired to the starting battery. I'm wondering if it makes more sense to wire it to the house bank which is made up of three times the power and depleting the house bank is not as problematic as depleting the starting. Any thoughts on this?? Thanks.

 

[MikeHoncho]

Does to me and mine is also. I’ll add I also only use the windless with the engine running and my high output alt is wired to my house bank.

 

[dlochner]

Depends on where the alternator is connected and how the battery switch is wired and used.

A pretty standard wiring connection is Alternator to Starter to 1-2-B Battery Switch to House or Start Batteries (depending on switch position). If your boat is wired this way and when you run the engine with the battery switch in the Both position, then it doesn't matter much to which battery the windlass is connected. If you do not do this, then it matters quite a bit.

To state this in another way, the windlass should be connected to the same battery as the alternator output is connected. To avoid voltage drop the engine and therefore the alternator should be running. If either battery is not fully charged (unlikely for a house battery in the morning) when the windlass motor is engaged there can be a significant voltage drop which is not good for the windlass motor, not to mention it will slow down the anchor retrieval. The alternator output prevents this voltage drop.

Edit: See the strike through. Proof reading is not my strong suit.

 

[Lee Hadjiosif]

Depends on where the alternator is connected and how the battery switch is wired and used.

A pretty standard wiring connection is Alternator to Starter to 1-2-B Battery Switch to House or Start Batteries (depending on switch position). If your boat is wired this way and when you run the engine with the battery switch in the Both position, then it doesn't matter much to which battery the windlass is connected. If you do not do this, then it matters quite a bit.

To state this in another way, the windlass should be connected to the same battery as the alternator output is connected. To avoid voltage drop the engine and therefore the alternator should be running. If either battery is not fully charged (unlikely for a house battery in the morning) when the windlass motor is engaged there can be a significant voltage drop which is not good for the windlass motor, not to mention it will slow down the anchor retrieval. The alternator output prevents this voltage drop.

Thank you Dave, The alternator output is wired to a battery isolator box which is feeding power to the three banks evenly. There is no Both switch on my boat!

 

[dlochner]

Thank you Dave, The alternator output is wired to a battery isolator box which is feeding power to the three banks evenly. There is no Both switch on my boat!

You may want to rethink the battery isolator if it is a diode based isolator. The diodes induce a voltage drop and depending on where the regulator is measuring voltage it is chronically under charging the batteries. There is more detail on this on MaineSail's website, www.marinehowto.com. Well worth the time spent on the website.

 

[jssailem]

Lee. you say you are sailing in the Med. Based on how you state your system is wired, makes me wonder if you got your boat in Europe.

They have some different thinking about wiring boats then say we here in the US or MaineSail's excellent electrical info.
As Dave has shared, the diode isolators can create voltage issues. This will be evident in slower retrieval of your anchor and rode.

I encorage thinking about your electrical issues as systems not individual bits and pieces. The system designs of MaineSail are robust. They may help you should your present infrastructure be giving you problems.

 

[Lee Hadjiosif]

Lee. you say you are sailing in the Med. Based on how you state your system is wired, makes me wonder if you got your boat in Europe.

They have some different thinking about wiring boats then say we here in the US or MaineSail's excellent electrical info.
As Dave has shared, the diode isolators can create voltage issues. This will be evident in slower retrieval of your anchor and rode.

I encorage thinking about your electrical issues as systems not individual bits and pieces. The system designs of MaineSail are robust. They may help you should your present infrastructure be giving you problems.

Thank you John for responding. The issue was as to which battery bank to get the power for the windlass. The factory has wired it to the starting battery but is very easy for me to switch it to the house bank. As for the isolator, how else would I get the alternator output to three different banks without a both or all switch...which I do not want to have. The small voltage drop by the isolator only affects the charging by the alternator. The windlass, thruster, etc are wired directly to the motors and not going through the battery isolator.

 

[jssailem]

Good question. As suggested by Mainesail, the BlueSeas ACR is a system structure link to charge the start battery. Your House batteries are primary charged in parallel and balanced through the DC Positive busbar. No need for separate circuits. Full charge from alternator of other sources.

"What is an ACR?​

An ACR is nothing more than a fully automatic, voltage triggered, BOTH/PARALLEL switch that closes when charging voltage is present and opens when charge voltage is no longer present. by Mainesail"​

Your start battery is isolated behind the ACR and is saved/used for it's primary purpose the starting of your engine. Limited or no voltage drop.

Making Sense of Automatic Charging Relays - Marine How To

Making Sense of the ACR WARNING: ACR's are not for use with LiFePO4 Batteries! What is an ACR? An ACR is nothing more than a fully automatic, voltage triggered, BOTH/PARALLEL switch that closes when charging voltage is present and opens

marinehowto.com

 

[Davidasailor26]

As for the isolator, how else would I get the alternator output to three different banks without a both or all switch...which I do not want to have. The small voltage drop by the isolator only affects the charging by the alternator. The windlass, thruster, etc are wired directly to the motors and not going through the battery isolator.

Some isolators are diode based as dlochner was referring to. Those introduce a voltage drop that’s hard on the batteries. Newer isolators are not diode based and don’t introduce a voltage drop.

It’s very possible your isolator is the voltage-drop free type. Our Beneteau of roughly the same era uses that kind and we’re happy with it.

Back on topic - The windlass doesn’t run for very long, so it’s probably not a huge drain on whatever battery it’s connected to. Start battery is probably a better choice since it’s usually pretty close to fully charged, whereas the house bank (which Beneteau used for ours) could be already run down from sitting on anchor. As long as the battery used is getting the alternator current at the same time I probably wouldn’t change it.

 

[Lee Hadjiosif]

This is my battery isolator. It takes power from the alternator(when is running) and distributes to the three banks evenly. It says "voltage drop free"

 

[dlochner]

This is my battery isolator. It takes power from the alternator(when is running) and distributes to the three banks evenly. It says "voltage drop free"

Thanks for the photo. While the box says "voltage drop free" that is not exactly accurate according to their website. The website says the voltage drop is less than .4v at 100amps. Better than diode based isolators.

Battery splitters, MBI series 12-24V

Discover our 12 / 24 V lead battery charge distributors. International sales & delivery. Guaranteed 2 years. Plug and forget.

www.studer-innotec.com

 

[JamesG161]

On my boat, the Start Battery is used for...

1) Windlass
2) Electric hoist
3) Bilge pump

1 & 2 use High Amp surge and demand, or Same as Engine Start Battery.

Bilge pump reason = Solar Panel that maintains Start Battery when no Engine Alternator for Charging.

Jim...

 

[Scott T-Bird]

I think to a greater extent it depends on your start battery. I don't think you have described it except to say it has less capacity than your house bank. I asked this same question when I purchased a new auxiliary battery and was chastised for not wiring the windlass to the larger house bank (400 ah). I was told under no circumstance to wire it to a smaller start battery (or auxiliary in my case). I was told it doesn't make any sense to deplete the start battery by using the windlass. But then I found a few caveats in Maine Sail's writings.
1. It is acceptable if you have a higher capacity TPPL battery (I purchased a 100 ah AGM TPPL for my auxiliary).
2. Just about any battery will serve a windlass if you are regularly anchoring in 10' of water. (check)

So I went ahead and wired it to my aux battery for several reasons despite the common advise.
1. I always start my engine on the house bank no matter how depleted it is after anchoring ... I've yet to have any difficulty.
2. I always start the engine before using the windlass anyway. I don't know anybody who normally doesn't.
3. My aux battery is now a new AGM TPPL battery fully charged at all times via ACR.
4. My aux battery is mid-ships and the shortest possible run to the windlass.
5. My aux battery has only this single purpose other than being the back-up to my house bank. When I eventually change my selector switch, the aux battery will be a dedicated start and windlass battery.

So, a long story short, I think it depends most significantly on your typical anchoring practice and the capacity of your battery in determining if it is a good idea or not to use your start battery with the windlass.

 

[jssailem]

The Studer MBI 100/3 is using a diode/capacitor technology. This is different from the BlueSea ACR which is a switch technology.

Perhaps a better understanding of the similarities and differences will help guide your choice of the systems.

Battery Isolators and Automatic Charging Relays (ACRs): A Comparison

Battery Isolators vs. Automatic Charging Relays both safeguard battery power, but how are they different? Why choose one over the other? We examine this.

info.waytekwire.com

I thought the exclusions from warranty coverage interesting.

does not cover damages arising from improper use like:​

•  Reverse of battery polarity.​
•  Inadequate connection of the Inverter and/or of its
  accessories.​
•  Mechanical shock or deformation.​
•  Contact with liquid or oxydation by condensation.​
•  Use in inappropriate environment (dust, corrosive
  vapour, humidity, high temperature).​
•  Intrusion of insects, animals or any living organism.​
•  Breakage or damage due to lightning or overvoltage
  due to external cause.​
•  Connection terminals and screws destroyed or other
  damages, like overheat, due to unsufficient tighte-
  ning.​
•  The state of the internal control diode and of the
  inputs/output X and Y capacitors determine the warranty.​

Giving equal time, here is the Blue Sea warranty statement.
Our Product Guarantee
Blue Sea Systems stands behind its products for as long as you own them. Blue Sea Systems will replace or issue a credit for any of its products found to be defective in materials or manufacture. P12 Battery Chargers, P12 Remote Displays, BatteryLink Chargers, Sure Eject AC Disconnects, M2 OLED Digital Meters and Mini OLED Digital Meters are warranted for a period of five years from the date of first purchase. All other Digital Meters are warranted for a period of three years from the date of first purchase. No compensation will be allowed for products not returned to Blue Sea Systems for analysis, nor will compensation be made for labor required to replace any defective product.

 

[dlochner]

Second Star's windlass is wired to a Positive Bus Bar before the battery switch. All of the charging sources are also connected there. Typically only the house battery is connected to the bus bar. By turning a few switches the bus bar can be powered solely from the start/auxillary battery, with the house bank disconnected from the bus bar.

We have had a couple of occasions when we were unable to start the engine and had to raise the anchor (and all chain rode) by battery power alone, in those cases the solar panels helped out some with maintaining adequate voltage to the windlass. It was also possible to add the start battery to the circuit if more power was needed.

 

[Tedd]

The windlass doesn’t run for very long, so it’s probably not a huge drain on whatever battery it’s connected to.

I just got my first boat with an electric windlass and I've been worrying about that very thing, so I did and estimate and you're right, it's much less drain than I expected. For a 5/16 G4 chain lifting a 10 kg anchor from 100 m at 80 percent efficiency it's less than 3 A.h for a 12 V battery. I expected something at least in the double digits.

 

[dlochner]

I just got my first boat with an electric windlass and I've been worrying about that very thing, so I did and estimate and you're right, it's much less drain than I expected. For a 5/16 G4 chain lifting a 10 kg anchor from 100 m at 80 percent efficiency it's less than 3 A.h for a 12 V battery. I expected something at least in the double digits.

The motor on our windlass (Maxwell VWC 1500) will draw up to 200 amps at normal working loads. The chain retrieval rate is 56' per minute. With 112 feet of chain out, it will run for 2 minutes, which (if I did the math correctly) works out to 6.7 ah.

The battery issue is delivering that much current in a short time period. Unassisted house banks may not be able to provide that amount of current without a significant voltage drop.

 

[Hayden Watson]

Thank you John for responding. The issue was as to which battery bank to get the power for the windlass. The factory has wired it to the starting battery but is very easy for me to switch it to the house bank. As for the isolator, how else would I get the alternator output to three different banks without a both or all switch...which I do not want to have. The small voltage drop by the isolator only affects the charging by the alternator. The windlass, thruster, etc are wired directly to the motors and not going through the battery isolator.

The voltage drop is caused by the diodes that do the splitting/isolation. These diodes will cause a drop of between 0.4v to 1.3v depending on the type and current being pushed. I have had one on my boat for the past 24-years and it does not affect my charging because I also have an external regulated alternator. The regulator voltage sense is connected directly to the house battery, so it adjusts the voltage at the alternator to be higher by the amount of the drop in the diodes. I set the regulator at 14.2v at the battery but if I check it at the alternator, it will be over 15v.
I will soon be replacing the diode isolator with a 0-drop isolator such as the ArgoFET 200/3

 

[Davidasailor26]

Another data point - Retrieving my anchor yesterday took my house bank from 58.7% SOC to 57.7%. On my house bank that’s basically 2 AH used. I was running the engine at idle. The peak net current I saw on the house bank was -78A, including about 8 A or other house loads. Idling before running the windlass the alternator was pushing 15A into the bank, so the windlass was probably pulling just under 100A at maximum pull. Most of the other readings below max pull were around 50A out.

Windlass is a Quick Antares AT1012D rated for 1000 Watts. Anchor is 35 pounds, plus 40’ of chain. I had about 30’ of line in addition to the chain, in about 8’ of depth.

 

[Davidasailor26]

The voltage drop is caused by the diodes that do the splitting/isolation. These diodes will cause a drop of between 0.4v to 1.3v depending on the type and current being pushed. I have had one on my boat for the past 24-years and it does not affect my charging because I also have an external regulated alternator. The regulator voltage sense is connected directly to the house battery, so it adjusts the voltage at the alternator to be higher by the amount of the drop in the diodes. I set the regulator at 14.2v at the battery but if I check it at the alternator, it will be over 15v.
I will soon be replacing the diode isolator with a 0-drop isolator such as the ArgoFET 200/3

The OP’s isolator, like mine, is FET based rather than diode based. Diodes introduce a relatively high constant drop (around 0.7 V). FETs introduce a lower drop that is variable with current flow. As battery charge increases and current flow decreases the drop becomes negligible.