Electrical Marine Mechanic

[dgetswet]

Having an issue with my Vetus bow thruster 55. When I put the boat in the water I forgot to hook up the negative on the battery. I heard the motor spin a couple of times then did nothing. When I got to the dock I hit it again and it spun then nothing. After I docked the boat (wish was a bitch in the wind without the thruster) it just clicked like a dead battery.

There is a separate battery for the bow thruster. After I put the negative cable on I figured the onboard charger on shore power would have charged the battery but after 3 days It just clicked.

I have 2 sets of 6 volt batteries hooked up in series, The 5th bow thruster battery is 12 volt. I have a 2 switch battery control and all the batteries are on the same charger.

So if anyone has ideas would appreciate it or if you have a marine electrician that doesn't hurt to much that you can recommend I will try that route.

[rebuckley]

Clarifying question - the thruster is only hooked up to the single battery, and it still spun - even without the cable attached to the negative post?

[dgetswet]

Clarifying question - the thruster is only hooked up to the single battery, and it still spun - even without the cable attached to the negative post?

The previous owner had 5 batteries. 2 sets were 6 volt batteries linked in series. The 5th battery was a 12 volt on its own. I think I found the problem. The thruster was hooked up to the single battery. The extra negative cable went to the batteries in series. That would complete the circuit for the battery to get recharged. The draw on the thruster is intense so the battery went completely dead.

I'm trying a battery charger on the battery to see if that is the problem If not I have no idea what happened.

[rebuckley]

That does make sense - and makes the negative run much longer than positive run to the thruster - I know there is an equation to calculate what that does to the power - I think in one of Nigel Calder's books - and I think maybe why it is dead is due to the wiring as well. I may be wrong, but I have always been taught that my smart charger assesses the batteries on a single circuit and evaluates how to charge them. This set up of 2 sets of 6v in series and a single 12v, all of which are being discharged at different rates - I think would add confusion to the charge scheme. I have my tow main batteries set to the charger in one "battery connection" and my generator battery as a second battery. If your charger (assuming it is "smart") is hooked up and "sees" all of the batteries as a single bank - it may not know how to charge properly. So maybe a better way (if not to wire the 6th battery directly to charger) is to bring all negs to a common BUS and then to charger?

[dgetswet]

That does make sense - and makes the negative run much longer than positive run to the thruster - I know there is an equation to calculate what that does to the power - I think in one of Nigel Calder's books - and I think maybe why it is dead is due to the wiring as well. I may be wrong, but I have always been taught that my smart charger assesses the batteries on a single circuit and evaluates how to charge them. This set up of 2 sets of 6v in series and a single 12v, all of which are being discharged at different rates - I think would add confusion to the charge scheme. I have my tow main batteries set to the charger in one "battery connection" and my generator battery as a second battery. If your charger (assuming it is "smart") is hooked up and "sees" all of the batteries as a single bank - it may not know how to charge properly. So maybe a better way (if not to wire the 6th battery directly to charger) is to bring all negs to a common BUS and then to charger?

After looking closer at the thruster it turns out the negative is a yellow wire and the positive is red. I am having a hard time following the yellow wire but I am betting it is connected to a grounding bar on the boat. After checking my photos the 5th separate batter had 3 red wires and 1 black that went to the batteries in series. This worked last year so don't understand why it would not work now.

So now the thruster just clicks. The battery was almost fully charged after this took place. Time to bring in the professional I think.

Don