bow thruster battery charge question

[ozzie]

Still getting used to our (new to us) Beneteau Monte Carlo 37Ht. We have had a string of niggles that have taken an age to get sorted by the broker (she was a part ex stock boat). She has been on the Hamble since we got her, and are waiting to move her back to Torquay. We had to leave Mercury today because of dredging, and when I checked the Max Power bow thruster prior to leaving the berth nothing! I checked the usual isolators and trips, they are ok. The joystick activates and I can hear the relays clicking. I borrowed a multimeter and found the two thruster batteries were only reading 9v. It was late afternoon, so we made our way to Ocean Village. I checked the batteries again, and they were reading 10v. Question is, are the batteries charged just by the alternator or by battery charger when on shorepower? In the handbooks I have found an operation manual for a battery isolator to distribute the charge current. Would this just supply the domestic batteries or the bow thruster batteries as well? The boat is 6 years old and I assume they are the original batteries. Could they be on their way out, and if so would it be coincidence they are both reading 9v. Any advice on how to proceed with fault finding would be greatly appreciated!!

 

[admillington]

Sorry to hear you are having problems. I would strongly recommend that you speak to Mike (Mr Thruster) at Osmotech 023 8045 6450 as he has fitted some many thrusters that I am sure he will have an answer for you.

 

[A_8]

Still getting used to our (new to us) Beneteau Monte Carlo 37Ht. We have had a string of niggles that have taken an age to get sorted by the broker (she was a part ex stock boat). She has been on the Hamble since we got her, and are waiting to move her back to Torquay. We had to leave Mercury today because of dredging, and when I checked the Max Power bow thruster prior to leaving the berth nothing! I checked the usual isolators and trips, they are ok. The joystick activates and I can hear the relays clicking. I borrowed a multimeter and found the two thruster batteries were only reading 9v. It was late afternoon, so we made our way to Ocean Village. I checked the batteries again, and they were reading 10v. Question is, are the batteries charged just by the alternator or by battery charger when on shorepower? In the handbooks I have found an operation manual for a battery isolator to distribute the charge current. Would this just supply the domestic batteries or the bow thruster batteries as well? The boat is 6 years old and I assume they are the original batteries. Could they be on their way out, and if so would it be coincidence they are both reading 9v. Any advice on how to proceed with fault finding would be greatly appreciated!!

Don't know your boat specifically but I would be very surprised if they are not charged by the battery charger AND the generator. 6 yrs on a thruster battery is probably as much as you get. If they are done they should get warm when on the charger so maybe check the voltage (should be 13.5 ish up to 14.4 ish) with the engines running or the charger on.

 

[Momac]

Sounds like batteries are shot.
If there are two batteries it could be a 24v bow thruster motor ?

 

[rosssavage]

Can't answer the question without checking over the boat really.

Some factory installs unbelievably don't connect the thruster battery to the mains charger. I worked on one where the only charge was supplied by the stbd engine alternator, which is fine if you're a fisherman using your boat every day. For the rest of us, that's a terrible solution and the owner ended up always having a flat battery when they first left their berth.

Check your charger - is it a two or three output job? Had to swap out their charger from a two to a three output one to get the thruster battery charged on shore power. (There are other ways to do it though - battery to battery charger for example. See the Sterling power website for ideas)

And 9v is almost certainly knackered if they've been left in that state for any time...

 

[ozzie]

Funnily enough, I did notice that the starboard alternator was showing a higher voltage than the port on the trip to OV. Would that suggest the alternator was working harder to put charge into flat batteries? There is a digital readout in the cabin showing that the domestic batteries are being charged. The battery charger is a CRISTEC with a 10 amp output, so I assume its only a single output, although I have not looked at it yet. The thruster is a Max Power CT80 12V. The thruster was working fine 2 weeks ago, so it appears to have gone down in that time. Could I connect a charger direct to the thruster batteries to see if that makes any difference?

 

[A_8]

Funnily enough, I did notice that the starboard alternator was showing a higher voltage than the port on the trip to OV. Would that suggest the alternator was working harder to put charge into flat batteries? There is a digital readout in the cabin showing that the domestic batteries are being charged. The battery charger is a CRISTEC with a 10 amp output, so I assume its only a single output, although I have not looked at it yet. The thruster is a Max Power CT80 12V. The thruster was working fine 2 weeks ago, so it appears to have gone down in that time. Could I connect a charger direct to the thruster batteries to see if that makes any difference?

If you have the MC 37 HT there is no way the charger is only 10Ah, maybe there is another one? The amount of red cables coming out of the cristec will indicate how many battery banks its charging. I would simply measure the voltage on the batteries while charging and if its not what I wrote earlier but still above the 9-10 volts you had I would get new batteries.

 

[rosssavage]

Funnily enough, I did notice that the starboard alternator was showing a higher voltage than the port on the trip to OV. Would that suggest the alternator was working harder to put charge into flat batteries? There is a digital readout in the cabin showing that the domestic batteries are being charged. The battery charger is a CRISTEC with a 10 amp output, so I assume its only a single output, although I have not looked at it yet. The thruster is a Max Power CT80 12V. The thruster was working fine 2 weeks ago, so it appears to have gone down in that time. Could I connect a charger direct to the thruster batteries to see if that makes any difference?

Absolutely - that's what we did until the owner got the new charger. We used a basic Halfords charger, once a month. If you go for a simple car type charger, make sure the area is well vented in case of hydrogen gassing.

A single 10a output is woefully inadequate for your boat. Minimum you should have is a three output at 45a.

If you go down the upgrade route (and if you only have the 10a charger you really should) then consider a Victron / Mastervolt type combi charger / inverter. If you're going to be spending a few quid on a decent charger, the extra outlay and installation effort would be a seriously good upgrade.

 

[ozzie]

I have not looked at the charger yet, I am just going by a leaflet I found in the owners handbook pack. I have spoken to the broker and their technical guy thinks it is only charged by the alternator but he is going to check with Beneteau. If that is the case I will fit a new 3 way upgraded charger.

 

[ozzie]

Been down to the boat this weekend and have got the problem sorted. Firstly the bow thruster batteries were dead flat. I connected a donor battery to them as well as a portable charger and over the weekend got them fully charged and working. Next problem was the charging. I found 2 chargers, a 40a 3 output and a dc to dc charger. It was physically impossible to track where the wires went, so I had to make do with checking all the surface mounted fittings. It would appear that the bow thruster batteries are charged through the dc to dc charger on both the alternator and shore power (not sure how). I put a multi meter across the input on this charger, all fine, on the output I got a 12.5v reading before realizing this was the power FROM the batteries. Disconnected the output and no output. I connected my portable charger to these leads and got a charge at the batteries. I took the dc to dc charger off to source a new one and thought I would take the front off on the off chance it may be something simple and it was!! a blade fuse on the input, all ok, fuse on the output didn't look blown but didn't right. A quick check and its a dodgy fuse. Job done. If I had known about it would have been a 2 minute fix. At least I now know my electrical system intimately. I also found that to access the circuitry and batteries the whole cupboard comes out in one piece for access. I now have to put it back together again...