Leverage New Bow Thruster Batteries for Windlass & Washdown Pump

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AvalonGB

Veteran Member
Joined
Nov 11, 2014
Messages
59
Location
USA
Vessel Name
Avalon
Vessel Make
Grand Banks 46 Classic
Since we will be installing a 24v bow thruster I’m hoping to make two additional improvement to Avalon’s systems using the new 24v battery bank.

We’ve occasionally had the windlass draw down the 12v house system to a level low enough to cause our Furuno TZT MFD screens to shut down – a potentially very bad situation as can damage displays memory. Now this only happens when operating the windlass for extended run times, don’t have exact time, but needs to be addressed. The house bank is 750AH and in good condition. As the windlass uses significant power, Lofrans Tigres, leveraging the 24v bow thruster bank would isolate the system from the house and seems to be a good idea.

We also have the washdown pump located in the lazerette and don’t get the best water pressure, 50’+ run to the bow, so I’m going to install a Groco C-80 24v pump in the bow and utilize the 24v thruster bank. Should give us much improved performance.

The washdown pump install is straight forward and should be relatively easy to configure and install. The windlass conversion to 24v is looking like its going to be significantly more complicated. The photo I’ve attached shows the main breaker and lower helm control for the current windlass, breaks the 12v line from house bank and includes up and down controls.

My question / challenge I’m trying to figure out.

Appears that I need to convert the current 12v controls at both helms to 24v, making the upgrade to 24v windlass much more complicated than I originally envisioned. Anyone have any thoughts on the conversion or is it possible to leave the controls 12v with windlass being 24v. Also does not seem to make sense to run 24v line to breaker at lower helm as significantly increases wire run and voltage drop vs going from thruster bank directly up to windlass. Wondering if there is the possibility to operate a solenoid or switch for 24v line remotely from lower helm.

Any thoughts or suggestions on my project are much appreciated.

Thanks,
Tim
 

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Typically one's engine is running when using the windlass, thus charging the the bank feeding the windlass. (By the way, how will your thruster bank be charged?).
If all you are trying to accomplish is not having the electronics shut down, a less expensive option is something like a NewMar NavPak: https://www.defender.com/product.jsp?id=1475041

Given all that, it seems odd that a windlass would cause that sort of voltage drop. Have you had all the connections checked out.. do they get warm when operating? How old is the windlass... perhaps the motor needs refurbing?

I did one of the things you contemplate, I added a raw water washdown pump and used the thruster bank. Worked great as the two items were never operated simultaneously.
But I should also note that the PO had the electronics powered by the thruster bank as well, which initially concerned me a little, but using the thruster never shut down or affected the electronics (2 Furuno VX2 systems and 6kw radar).
 
Service 12v System

caltexflanc - Servicing the current 12v system, motor, makes sense but I'm attracted to removing the significant power draw of windlass from the 12v house system. I've been through all the connections and all are tight and free of corrosion.

The windlass is 28 years old but functions very well and we don't notice any fluctuations in its performance during retrieval or payout of our anchor and rode.
 
I could argue to just shut down the electronics prior to anchoring, as you'll unlikely need them once anchored. If you need them, for route planning, etc., just turn them back on.

I have the house run the thrusters, too, and going to get into the habit of turning off unnecessary electronics prior to anchoring. Only minor one that could be nice would be a depth finder, but could argue to figure out the depth prior to making a commitment to anchor.

The Newmar NAV-PAC DC Power Conditioner seems like a simple and good solution if one wanted to keep the electronics on.
 
Shut Down Electronics

SeeVee, I agree with shutting down electronics prior to anchoring, its our current practice as I don't want to risk damaging MFD memory. However, it's a hassle with two stations and sometimes we're anchoring in areas where I really want access to the chart while we set anchor.
 
12v-24v truck starting solenoids are available that allow you to switch a pair of batteries from a 12v parallel configuration to a 24v series configuration. In the normal state the battery pair can power the 12v windlass and be charged from the house bank using the original windlass cable. When switched to 24v the pair is isolated from the 12v system and can power the thruster. You can't use both at once but usually not an issue.
Google "series-parallel solenoids."
 
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Or just use a 24-12v DC-DC converter, much simpler and not expensive for low amp loads.

Victron Orion series, MasterVolt, Samlex is also good
 
Consider that a dc motor can demand seven times its rated load of current until it reaches normal operating speed. Every time you start the windlass it will pull that amperage. Starting and stopping, besides causing arcing at solenoid points and motor brushes, can pull down a battery rapidly. Ideal windlasses are old starter motors off a 56 Dodge or similar. Replacing or cleaning the brushes and commutator will add years (“while you’re in there” lubricate bearings too) and replace the solenoids as they are old, right? Keep them for spares. Your instruments should be run off another source; when stepping on the windlass button, voltage can drop to 10 or so.
 
If really 10V I would address that, bigger/better bank, combine with House or others to take advantage of Peukert.

Is that with alt current going into the bank?
 
I could argue to just shut down the electronics prior to anchoring, as you'll unlikely need them once anchored. If you need them, for route planning, etc., just turn them back on.

The time when the windlass is most heavily loaded is when you are weighing anchor and getting underway.
 
caltexflanc - Servicing the current 12v system, motor, makes sense but I'm attracted to removing the significant power draw of windlass from the 12v house system. I've been through all the connections and all are tight and free of corrosion.

The windlass is 28 years old but functions very well and we don't notice any fluctuations in its performance during retrieval or payout of our anchor and rode.

Another trick is to rev the engine that charges the house when in neutral and pulling up the anchor. A little tricky, remember to cut the throttle when you are moving forward to the anchor.....

hmmmm.... could your heavy loading be due to using the windlass to pull the boat to the anchor?
 
Pulling boat with windlass

Another trick is to rev the engine that charges the house when in neutral and pulling up the anchor. A little tricky, remember to cut the throttle when you are moving forward to the anchor.....

hmmmm.... could your heavy loading be due to using the windlass to pull the boat to the anchor?

No...would never pull the boat with windlass. Actually the only time windlass is loaded with more than just chain at depth is when breaking our anchor free.

Tim
 
No...would never pull the boat with windlass. Actually the only time windlass is loaded with more than just chain at depth is when breaking our anchor free.

Tim

So, using the windlass to break the anchor? I'm not being snarky, just trying to diagnose the root cause.
 
Consider that a dc motor can demand seven times its rated load of current until it reaches normal operating speed. Every time you start the windlass it will pull that amperage. Starting and stopping, besides causing arcing at solenoid points and motor brushes, can pull down a battery rapidly. Ideal windlasses are old starter motors off a 56 Dodge or similar. Replacing or cleaning the brushes and commutator will add years (“while you’re in there” lubricate bearings too) and replace the solenoids as they are old, right? Keep them for spares. Your instruments should be run off another source; when stepping on the windlass button, voltage can drop to 10 or so.

Not wanting to hijack the thread, but I must disagree with saving the old parts for spares.
Those old parts have been used and abused for however long, heated and cooled repeatedly and exposed to the marine environment, and should not be considered “get home insurance” when they are in fact in an “unknown condition”.
Even if they did get you out of a jam, you’d still want to replace with new, so you’d be doing the changeout job all over again.
Always remember that Murphy rides on every voyage, to make sure that the worst things happen at the worst time, and it’s not luck that we should be counting on when we’re out there faced with a problem.
 
you can use relays to activate the windlass, keeps all hi amp hi draw strictly between the batteries and windlass, low amp light wire can then be ran to the switch and switch can be left original as it is, most relays only need a few milli amps running between the relay and switch to activate
 
A couple of clarifications here, the first is that the heaviest load is when you are weighing anchor - no, the heaviest load is any time you start the windlass motor and until it reaches normal operating speed, at which time the current load drops. That is why very poor operating procedure is to start and stop the windlass - there is no ability to "soft start."

The second is the relay thing - the coil, or activating part of the solenoid does only take a small load to activate but the contactors it operates, which have to handle the entire inrush of current when you solenoid/relay activates the windlass motor can get pitted and become damaged in one of two different ways: the contacts get so corroded by arcing they will not make contact and the windlass fails or the contacts fuse together when you try to run the windlass and it runs away, can only be stopped by turning off the windlass power by that panel shown in the first post.

A solenoid/relay rarely, if ever, fails on the coil side, at a guess I would say that 98% of all relay failures are the high current contacts.

As for spares, a known working solenoid is a good spare to replace a broken/malfunctioning solenoid. It will get you home. Also, almost all solenoids can be taken apart and the contacts cleaned to make them virtually new. If the solenoid is in bad shape, it would be a good idea to buy higher-spec, bigger solenoids that can handle the current better and will therefore give you more years between failures.

Another point, if you have a windlass that will also power out, in the event of a solenoid failure it will likely be the power up solenoid. You could substitute the power down solenoid for the damaged power up solenoid and free-fall down - the swap will get you home.

If you are still with me, do not ever use the windlass to set the anchor or allow the boat to swing at anchor only on the windlass. Build or buy an "anchor snubber" of the design that fits your boat, to transfer the entire weight off the windlass and on to the bollards/cleats otherwise you can bend the windlass shaft or damage the bearings.
 
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It is very common on a battery bank that if you place a large load on it the voltage will drop. Strictly Ohm's Law. If you have a voltage meter in the wheelhouse that is attached to your start system, watch what happens to the voltage when you engage the starter. Or another example, while plugged into dock power with your water heater and a cabin heater, maybe some lights on and a battery charger running, look at what happens to your voltage when you start the toaster or turn on the coffee pot - look for voltages around 100V.

You are best to connect your electronics to your house bank, probably the only battery bank on board not subject to sudden heavy loads.
 
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