Bow thruster battery

[mad_boater]

I had a Sidepower SE80 bow thruster fitted and had it wired with very thick cables back to the 3x110v (domestic side) batteries.Would I be better putting in a dedicated battery with a blocking diode for charging just to run it so not to run down the domestics when not plugged in to shore power. I would be interested to know how other people do it and would one battery be enough to power the thruster?

 

[AllanJ]

I have an F33 with a single battery for the b/t. No problem. I suspect that it is mainly about the current (hence power) that your battery can provide. Not sure how it will run down the domestics when it is not running the b/t.
I'm not an electrician though!

 

[Ripster]

I hav Prestige 32 and this too has a single dedicated batt right next to it with very short cables! The boat also has a bank of 3 domestics and dedicated starter. In my last boat, I had an electric windlass and BT fitted and these had a new shared additional battery as recommended by the marine sparky, rather than tap off the two domestics that were on there.

 

[rafiki_]

The b/t should not run the domestics down, unless there is a current drain problem. There is really no easy answer as to battery near the thruster or near the charger (engines). Except the cable can be smaller diameter for charging, if the batt is near the thruster.

 

[mad_boater]

The b/t should not run the domestics down, unless there is a current drain problem. There is really no easy answer as to battery near the thruster or near the charger (engines). Except the cable can be smaller diameter for charging, if the batt is near the thruster.

Having it connected to the domestics and was used quite a bit before moorng up thus caning the batteries, then if not plugged in to shore power and I needed as much power as possible for fridges lights pump ect for a couple of days it would not be a good idea having wired up that way.

 

[Boathook]

I had a Sidepower SE80 bow thruster fitted and had it wired with very thick cables back to the 3x110v (domestic side) batteries.Would I be better putting in a dedicated battery with a blocking diode for charging just to run it so not to run down the domestics when not plugged in to shore power. I would be interested to know how other people do it and would one battery be enough to power the thruster?

My bow thruster, a vetus 55kgf has its own 110amp battery nearby. This is charged from the domestic bank by a Adverc? 12/12 volt charger. This only allows the BT battery to charge when the domestic bank is 'fully' charged. All still seems ok 6 plus years except for the battery that I had to replace. The original one was cheap and a cell failed after a couple of years.

 

[henryf]

The reason for a battery near the thrusters is to avoid voltage drop. The lower the voltage the bigger the risk of voltage drop along a given length of cable. You could fit massive cables from the batteries, or an additional battery.

Just to compound things the thruster will be in the front tip of the boat, the batteries somewhere near the back. The thruster also draws a hefty current and so the thinner the cable the higher the resistance which will cause heat and heat increases resistance still further.

Henry

 

[rafiki_]

Having it connected to the domestics and was used quite a bit before moorng up thus caning the batteries, then if not plugged in to shore power and I needed as much power as possible for fridges lights pump ect for a couple of days it would not be a good idea having wired up that way.

I have 2 batts starting the starboard engine, and running the BT, a separate batt for the port engine, and separate domestics, so 3 banks. For me this gives good back-up when required. All are in the engine room close to the engines/charger, with a heafty cable running to the BT in the bow. Clearly this can see quite a voltage drop down the cable, but has never caused me a problem.

 

[Deleted User YDKXO]

The problem with running the b/t off the domestic batteries is not so much discharging the batteries but the power loss over the long length of battery cable and hence loss of power of the b/t. Some boat builders prefer to run the b/t off the domestic batteries because its cheaper than installing a separate battery in a housing with vent and connecting it to the charging circuit but really a separate battery is the way to go because it minimises power loss

 

[mad_boater]

I have 2 batts starting the starboard engine, and running the BT, a separate batt for the port engine, and separate domestics, so 3 banks. For me this gives good back-up when required. All are in the engine room close to the engines/charger, with a heafty cable running to the BT in the bow. Clearly this can see quite a voltage drop down the cable, but has never caused me a problem.

The cables I had to run the bt are very very thick.I don't know if there is any voltage drop. I'm begining to think I should have gone for the battery up front option but I didn't fancy having a battery in the bedroom.One way or another I think I will have to isolate the bt battery so as to preserve the domestic bank.

 

[henryf]

Do keep in mind the fact that you will be running your engine(s) whilst operating the bow thruster and so your batteries will be getting charged. There will be sufficient power from the alternator to reduce capacity drain to more or less zero. When not being used the thruster will have zero effect on the batteries. Or do your domestic batteries not get charged when engines are running?

Henry

 

[rafiki_]

The cables I had to run the bt are very very thick.I don't know if there is any voltage drop. I'm begining to think I should have gone for the battery up front option but I didn't fancy having a battery in the bedroom.One way or another I think I will have to isolate the bt battery so as to preserve the domestic bank.

There will be a voltage drop, hopefully someone will have worked out the science, and there will be a negligible drop as in my set-up. I don't think you have a problem with the physical location of the batt, but you might want to consider reconfiguring the battery banks, separating out domestics from engine/BT.

 

[AnthonyWR]

I also own a Sealine 360 and last year a local boatyard installed a Sidepower SE80 bowthruster and I installed the electrics to save cost. I installed a seperate 110ah battery with short cables to the bowthruster and directly connected the charging cables to the port engine battery bank via a charging box that only cuts in when the port engine battery bank is fully charged. This box cost around £35 from Tanners in Cardiff. I also fitted a isolation switch on the charging cable to remove charging when sleeping on board, but never noticed any fumes from the front locker, so probably not needed.

This setup works 100%, no issues to date. The thruster has loads of power even in very strong side winds/tides. I decided to fit the extra battery because of the size of cables necessary to avoid voltage drop. The cable size will need to be increased as the cable run length increases. I've used a friends boat with direct cable run to the bow thruster and the setup doesn't work well.

 

[mad_boater]

I also own a Sealine 360 and last year a local boatyard installed a Sidepower SE80 bowthruster and I installed the electrics to save cost. I installed a seperate 110ah battery with short cables to the bowthruster and directly connected the charging cables to the port engine battery bank via a charging box that only cuts in when the port engine battery bank is fully charged. This box cost around £35 from Tanners in Cardiff. I also fitted a isolation switch on the charging cable to remove charging when sleeping on board, but never noticed any fumes from the front locker, so probably not needed.

This setup works 100%, no issues to date. The thruster has loads of power even in very strong side winds/tides. I decided to fit the extra battery because of the size of cables necessary to avoid voltage drop. The cable size will need to be increased as the cable run length increases. I've used a friends boat with direct cable run to the bow thruster and the setup doesn't work well.[/QUOTE


I will have to try and make the system work I have at the moment.The'charging box' you mentioned sounds like a good idea it could be usefull if I isolate one battery for the bt.

 

[fergie_mac66]

just looked at this thread though sandymans arch enemy had posted details of his new battery

http://www.ybw.com/forums/showthread.php?t=284793

 

[Barry Jones]

Normally when I install the electrics for a BT, I put the BT battery in the bow near the thruster and connect it with comparatively thin cable to the starter battery. I put an interlock in, so the BT battery is disconnected from the supply when the BT panel is switched on.

This way, it charges when the engine is running, never gets used when the engine is off and doesn't try to draw large amounts of current down the feeder cables.

 

[mad_boater]

Normally when I install the electrics for a BT, I put the BT battery in the bow near the thruster and connect it with comparatively thin cable to the starter battery. I put an interlock in, so the BT battery is disconnected from the supply when the BT panel is switched on.

This way, it charges when the engine is running, never gets used when the engine is off and doesn't try to draw large amounts of current down the feeder cables.

Thanks I think I can do something similar to my system

 

[Mike k]

I have a battery located beneath the forward berth which serves the windlass and Bt with no problems.

 

[Csail]

Only bit i don't get is why mobos need a bow thruster.

 

[AnthonyWR]

Only bit i don't get is why mobos need a bow thruster.

Cos mobos catch the wind unlike a sail boat that is far less affected by high cross winds. I don't often actually use the bow thruster but the stress is removed when it's blowing half a gale by the fact that it is available should I need it.