12v Yacht Bow Thruster does not work with Victron BatteryProtect 220A

[AjaxGary]

At the weekend I installed a new bow thruster, 2 new batteries and a BatteryProtect 220A.

The bow thruster does not work, I just get a clunk from the solenoid, no alerts or alarms ffrom the BT. If I bypass the BatteryProtect, the thruster works fine.

What causes the clunk?

I was expecting the BP 220 to work OK, it has a peak current (30 seconds) 600A, and the 6HP bow thruster has peak current 530A, fuse 400A, and would only be operated for 5-10 seconds at a time.

I could swap the BP for a contactor, but all contactors seem to require a momentary switch, and my fuse panel has on/off switches for each of the 3 battery banks, which I'm reluctant to change.

What are my options:

1) Is there an easy fix?
2) Parallel another BO 220
3) Installing a pre-charge unit?

TIA, Gary

 

[Julie.]

Basic question, but is it the correct way around?

What is the voltage at the thruster when it's energised via the BP?

It sounds like there isn't sufficient voltage at the thruster to start up.

 

[AjaxGary]

Yep, I did try that, iand when I swapped it round I thought i had found the problem, but then I found that having it the wrong way round means that you cannot disconnect, and the thruster is permanently live.

Yes, low voltage was my guess, I connected a battery direct to the thruster, and it worked, I then went back through the system until I came to the BP.

I can't test the voltage at the thruster when it is energised, the solenoid disconnects it as soon as it is switched on.

 

[Lucien Nunes]

First of all note Julie's comment; even if the BatteryProtect is reversed, you might get enough momentarily to just pick up the motor power solenoid, and the same if the BP is faulty or tripped. Assuming it's working and correctly oriented, as also mentioned by Julie it's important to discover what voltage is at the bow thruster input both in standby and after pressing the button.

My hunch is that the instantaneous inrush stall current of the bow thruster is higher than 530A. That might be the highest current the motor can draw when it is running, but I would not be surprised if at the moment the solenoid closes with the motor stationary, the surge is high enough for the BatteryProtect to cut out as though it had been short-circuited. It is quite possible that Victron did not foresee it being used for a 6hp motor i.e. one single large load equal to its short term rating. Obviously it's much more likely to exceed any instantaneous limit than a distributed cabin load where perhaps the highest single motor load might be 100A of windlass with 2-300A inrush.

The easy fix, IMO, is not to switch the whole thruster motor current with the BP. There's no need. All that has to be disconnected on low battery volts is the control circuit of a few amps to the solenoids to prevent the motor operating. That might or might not mean breaking into the control loom to the helm panel. What thruster is it?

 

[AjaxGary]

First of all note Julie's comment; even if the BatteryProtect is reversed, you might get enough momentarily to just pick up the motor power solenoid, and the same if the BP is faulty or tripped. Assuming it's working and correctly oriented, as also mentioned by Julie it's important to discover what voltage is at the bow thruster input both in standby and after pressing the button.

My hunch is that the instantaneous inrush stall current of the bow thruster is higher than 530A. That might be the highest current the motor can draw when it is running, but I would not be surprised if at the moment the solenoid closes with the motor stationary, the surge is high enough for the BatteryProtect to cut out as though it had been short-circuited. It is quite possible that Victron did not foresee it being used for a 6hp motor i.e. one single large load equal to its short term rating. Obviously it's much more likely to exceed any instantaneous limit than a distributed cabin load where perhaps the highest single motor load might be 100A of windlass with 2-300A inrush.

The easy fix, IMO, is not to switch the whole thruster motor current with the BP. There's no need. All that has to be disconnected on low battery volts is the control circuit of a few amps to the solenoids to prevent the motor operating. That might or might not mean breaking into the control loom to the helm panel. What thruster is it?

Thank you and Julie for trying to help me, much appreciated!

The thruster is a Sleipner Side-Power SE 80.

At the moment the BP is working as a remote battery isolation switch. Not only does it switch on/off the power to the windlass, it also does the same for the windlass, and their remote control.

I have found an EV200 contactor that I think can be switched on and off by applying 12+ & 12v-, and I could do this with the existing cabling to the BP and switch at the fuse panel.

Do you think that would be a workable, if expensive solution? It would certainly be easy for me

 

[Lucien Nunes]

Don't use a big contactor unless you absolutely need its function as a battery isolator. So long as you have a manual battery switch as a safety provision, then it's only performing a control function and the thruster's internal solenoids can do that. The problem with a conventional contactor is that even with its power-saving mode to reduce coil consumption when energised, it's still a couple of watts being drawn from the battery 24/7. The only way to avoid that would be to run an enable switch separately back to the helm so that the contactor is only switched on when use of the thruster is anticipated. Obviously there are latching on/off remote battery isolators but they can't be controlled directly from the output of the BP.

I think all that is needed is to connect the thruster main power input to the battery or battery side of the BP, but then take a 5 amp fused feed from the protected side and feed that into the thruster's control box in place of the existing connection from the main positive terminal. It's a long time since I looked at one of these so I can't recall if that is possible without pulling it apart.

Alternatively, you can use a tiny relay with a normally open contact. Connect its coil to the protected output of the BP, and use its contact to break the circuit of the red positive lead in the harness from the thruster multiplug to the helm panel, which will disable the controls. A suitable relay need only use a fraction of a watt, i.e. a few tens of milliamps. And obviously again the thruster main power feed would be taken from the battery side of the BP

Also, thinking again about the thruster load, 530A is the running current and with short, heavy, low resistance cables and good large batteries, the starting current is likely to be in the 1000-2000A range.

 

[Julie.]

As above.

Don't forget, at those sort of currents even seemingly low resistances add up to give a significant voltage drop.

Even 0.05 ohm - which we would all agree is pretty small gives a 10V drop at 200A.

That's why I asked about the voltage at the thruster, when energised the voltage would be enough to pull the solenoid in, but once the solenoid connects to the thruster motor, I expect the voltage drops significantly.

Any resistance such as contactors etc adds to this.

Permanent connection to the thruster, and merely switching the solenoid would be more effective than a contactor.

I understand the desire for the BP though.

 

[pirate]

I find that if you take off the bow warp, keep the spring line on, reverse with helm hard over, then bring in the stern line, the bow will swing out without using a thruster...however a working thruster is extremely useful for close maneouvering once you have left the pontoon, particularly in a vessel with only one engine...

Oh...sorry...wrong forum!

 

[AjaxGary]

Don't use a big contactor unless you absolutely need its function as a battery isolator. So long as you have a manual battery switch as a safety provision, then it's only performing a control function and the thruster's internal solenoids can do that. The problem with a conventional contactor is that even with its power-saving mode to reduce coil consumption when energised, it's still a couple of watts being drawn from the battery 24/7. The only way to avoid that would be to run an enable switch separately back to the helm so that the contactor is only switched on when use of the thruster is anticipated. Obviously there are latching on/off remote battery isolators but they can't be controlled directly from the output of the BP.

I think all that is needed is to connect the thruster main power input to the battery or battery side of the BP, but then take a 5 amp fused feed from the protected side and feed that into the thruster's control box in place of the existing connection from the main positive terminal. It's a long time since I looked at one of these so I can't recall if that is possible without pulling it apart.

Alternatively, you can use a tiny relay with a normally open contact. Connect its coil to the protected output of the BP, and use its contact to break the circuit of the red positive lead in the harness from the thruster multiplug to the helm panel, which will disable the controls. A suitable relay need only use a fraction of a watt, i.e. a few tens of milliamps. And obviously again the thruster main power feed would be taken from the battery side of the BP

Also, thinking again about the thruster load, 530A is the running current and with short, heavy, low resistance cables and good large batteries, the starting current is likely to be in the 1000-2000A range.

Thank you Lucien for all the info, it is really helpful. What you say makes a lot of sense. At the moment I do not have a separate isolation switch (that was the BP) and space is tight, but I will have a look this weekend, to see if I can find space.

The thruster/windlass battery bank is midships, it serves not just the thruster, but also the windlass, a 70mm cable runs to the forepeak where the is a distribution stud, 75mm continues to the thruster, and 35mm to the windlass. So I would need to use another NO relay to disable the windlass, plus run another cable from the controlled side of the BP to power the remotes.

I wish I had realised the problem with the BP before I had run the cables :-(

I have attached the installation guide, any chance you could have a look and see which wire I need to insert the NO relay? I have looked but I am not sure.

Thanks again Lucien

 

[Lucien Nunes]

Use the control relay to break the red lead of the thruster control harness, pin 4 on the multiplug.

However, if the circuit diagram is to be believed, pin 4 is simply a permanent battery positive feed protected by a 1A self-resetting PTC 'fuse' in the thruster control box. It might therefore be best to avoid the relay entirely by disconnecting the panel loom red wire from pin 4 and energising it via your own 1A fuse from the BP output. Then there would be no standing load on the battery at all. Perhaps just check with Sleipner technical first, whether that's OK?

 

[James]

I would take out the battery protector and if possible put a manual isolator inline from the batteries.
if there are fuses to protect against short circuit or stalled motor then safety is not a problem?
the control panel seems to "isolate" the unit from inadvertent operation anyway.
battery protection units i presume are more suited to smaller continuous loads so you don't leave the lights and other things on that slowly drain the battery below its minimum charge level and therefore damage it.
a bow thruster or windlass will be obvious in is usage if the battery is running low as it will Simpley not work as the big motors will stall and they will be under your control at the time.

 

[AjaxGary]

Thanks for all the help and advice it's really appreciated. What a great forum, same post same time on the Victron forum has yet to receive a reply.

Lucien, thanks for taking the time to read the thruster install guide and interpreting the wiring diagram, above and beyond!

I think this is the plan:

• Remove The Victron BatteryProtect
• Install new manual isolation switch after battery fuse
• Use 12v+ feed from fuse panel to power/enable/disable the following:
  • Thruster - Pin 4 (1A fuse) of loom (Confirm with Sleipner support)
  • Windlass (4A fuse)
  • Remote control box (5A fuse)