How is wiring for bow thrusters normally done?

[Chotu]

I'm asking this question to save me a little time.

I'm getting used to a new boat. And it has bow and Stern thrusters. The batteries are dead. I have a new battery Bank getting ready to go in. Of course I would like to know why the batteries were dead to begin with. Currently trying to trace the solar array, regular charger, Etc.

However, this boat has a bow thruster and a Stern Thruster. Each Thruster seems to have its own battery located at the thrusters. How are these normally wired in? Are they connected to the house bank? Will they be dead also and pulling my house back down? Or are they their own system? How would it normally be done? This is a very professionally set up boat. So I'm wondering what the normal procedure is for wiring in these battery Banks and thrusters. Then I'm going to continue tracing it.

The wiring in this boat is buried everywhere. It is very hard to trace. So a few hints might help.

[paulajayne]

Batteries are close to the thrusters as current draw when in use is high. Shorter cable length means smaller cable size.


I calculated that if I were to connect to my house bank then 70mm cable size would be required. Battery fitted close to thruster then only 30mm.

[Chotu]

Originally Posted by paulajayne

Batteries are close to the thrusters as current draw when in use is high. Shorter cable length means smaller cable size.


I calculated that if I were to connect to my house bank then 70mm cable size would be required. Battery fitted close to thruster then only 30mm.

Yes. I get that. Sorry if my question wasn't clear enough. I'm trying to find out how that system is normally wired to the rest of the boat.

Each thruster has a pair of batteries located right next to it. How are those batteries charged? Where are they connected? At least by industry standard I am wondering. That will help me in tracing the wiring.

Are they typically put in parallel with my house bank and no battery isolator? Does that mean those batteries are also dead if my house bank is dead? I'm trying to explore how these are typically set up so that I can diagnose and understand a new electrical system.

[chowdan]

Originally Posted by Chotu

Yes. I get that. Sorry if my question wasn't clear enough. I'm trying to find out how that system is normally wired to the rest of the boat.

Each thruster has a pair of batteries located right next to it. How are those batteries charged? Where are they connected? At least by industry standard I am wondering. That will help me in tracing the wiring.

Are they typically put in parallel with my house bank and no battery isolator? Does that mean those batteries are also dead if my house bank is dead? I'm trying to explore how these are typically set up so that I can diagnose and understand a new electrical system.

I am not entirely 100% but usually the isolated batteries have a DC to DC battery charger such as sterling battery charger

[Gary Mc]

I believe it is common to install an echo charger to the thruster battery.

It will charge at maybe 10 amps so that when you wish to use your thruster the battery is fully charged and hopefully will be all you need.

The big advantage is that you can run smaller wiring to handle the 10 amps from your house bank instead of running a cable sized to supply the thruster load which would be much larger.

Good Luck

[Chotu]

Beautiful. Thank you for the knowledge. It will surely help to know the standard practice as I get started tracing all of this out.

Will hunt around the bilges for an echo/dc-dc charger in the wiring runs.

[dw1979]

My thrusters are powered by 24 volts. My house bank is 12 volts. So separate charging systems.

[apirate]

Our thruster runs off 24 volts and has its own batteries. Those are charged by a dc to dc charger which converts the power from the 12V house bank to 24V.

[captmikem]

I have a separate bank of two group 31 batteries fwd for the thruster and the windlass. I rarely use the thruster but often use the windlass. I have a 4/0 cable running back to my engine battery with a 100 amp breaker. Normally running the engine keeps the fwd batteries topped up. However last year I added a separate, 110V 30 amp dual battery charger to the fwd batteries (installed next to them), so whenever the gen set is running or plugged into shore power the fwd batteries are being charged/floated. I open the breaker except when anchoring/maneuvering. This allows me a back up engine start bank other than the house batteries. It all works well.
Hope this helps,
M

[waterman46]

Batteries for thrusters are best located very near to the thrusters due to the high current requirement. For charging, each battery should be on its own connection to a battery isolator. So your house battery will not be affected if you need to run the thruster battery down, and vice versa. Given that you probably also have a starting battery, you should have a direct connection from alternator to either the house or the starting battery. All other 3 batteries will be connected to isolated outputs of the battery isolator. If there is no isolator, your professionally installed network is junk.

For an initial check, I would measure the voltage across each battery with the engine and shore power off, and record the voltage. Then start the engine and measure the batteries again. If the voltage is somewhat higher at each battery when engine is running, your alternator and all charging system is OK. Do same with shore power charger.

Let everything charge up on shore power overnight. Disconnect or turn off shore power charger, wait a couple hours and remeasure all batteries. You should have >12.5 volts on all. If not you probably have bad battery.

[Akapeterc]

I’d say it would be a bit like how the windless is wired up. the battery is connected with the starter battery but in between that is a switch and let’s the current go one way only so when your starter battery is charging when full it charges that battery at the front then keeps it topped up

[sailah]

I'm in the process of rewiring my charging system. I spent a fair amount of time letting Maine Sails excellent schematic sink in. Down at the bottom he posted the schematic attached, I have studied it and plan to execute almost verbatim.

I swapped out my main battery switch to a Blue Sea that allows both start and house to be switched on, and if needed, to be paralleled in an emergency. But now all loads, except for the starter, are connected to house.

All my charging goes to my house bank. From this house bank, I run a Blue Seas ACR. When it senses 12.75V (or something like that) the relay closes and it parallels the banks for charging only. This way my engine start battery is isolated from all other loads and is charged when engine is running (or shore power or generator/solar which I don't have). The ACR will charge up to 120A I think.

I think if you study his diagram it will make sense and some appropriate ACRs to charge up your thruster batteries would make sense to me at least. If you want to get fancier with parallel switches etc might make sense to ask him about a paid consult to modify the diagram to your needs.

[Pelagic]

This discussion comes up often with 2 schools of opinion.
1.... Centralise your House and Start Banks and charging systems, isolate with On Off and Emergency Parallel switch then run heavy cable to large loads of Thruster and Windlass with appropriate fuses/relays and Switches.

2.. Put seperate battery at bow and stern to be charged separately.

I favor #1 so that I have:
Better battery management, Centralized weight
More reserve and charge buffering if needed in a grounding emergency.

I think Cost of properly sized large cable is a one time cost, whereas individual batteries compromised by bow installation is an unnecessary and repeated cost of replacements as the OP is finding out.

Just my opinion though

[Chotu]

Pelagic:. I tend to agree with you. That's exactly what seems like the problem is. I think these thruster/windlass batteries are dead as well as the house Bank.

I will be investigating that a bit tomorrow. And the next day.

The thing is, I'm in the manual windlass camp. I much prefer a manual windlass because of these types of situations. So I don't really have the experience in following and tracing proper installations of windlass batteries and wiring. So this is new to me.

Again, all of these posts have been very helpful. I can basically picture the types of standard installations in my head. And I will just see which one they did. Luckily, everything was professionally installed. So it's not any weird systems made up by the previous owner.

[Pelagic]

[QUOTE=Chotu;2867096]
The thing is, I'm in the manual windlass camp. I much prefer a manual windlass because of these types of situations. So I don't really have the experience in following and tracing proper installations of windlass batteries and wiring. So this is new to me.
/QUOTE]

I never noted what size and type of boat you bought but with two thrusters I am assuming quite large.

Most windlasses have a Manual function as does mine shown below.
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It has a large two handed lever that cranks up half a turn at a time.

But with heavier ground tackle you will appreciate the power function.

If you are new to using power windlass, the most conservative way of setting your anchor is to de-clutch and Gravity Feed out using a light touch on the brake, so that if anchor comes up hard, it slips a little extra chain rather than putting stress on the anchored gears and cone clutch

I only use power for bringing in the tackle with a wander lead so I can peer over the bow spirit to check for fouled chain and to rinse off the mud .