Side Power SE50 thruster wiring options.

[wipe_out]

Hi all,

We are in the process of fitting a Side Power SE50 12V bow thruster and I am trying to decide on the wiring plan which I am going to do myself.. I have no issue doing the wiring but I have come up with 3 options and wanted some input from the group as perhaps a logic/sanity check..

Our domestic and starter banks (linked by VSR) are in the middle of the boat under the seats so in terms or wiring only probably 3.5-4m away from the thruster (I will accurately measure this weekend).. According to the manual at less than 7m (round trip circuit length) a 50mm2 cable is recommended and at 7-14m a 70mm2 to 95mm2 cable is suggested.. The windlass already has what I think is either a 50mm2 or 70mm2 cable in place running back to the batteries.. The windlass cable has no markings so I can't be sure of the size exactly..

Here are the plans I have come up with so far..

Option 1 (Easiest)
Replace the windlass cable with a known 70mm2 cable running back to the batteries and run both the thruster and windlass on this cable.. Obviously with appropriate fusing etc. in the correct places.. Up side is this would be the easiest option and would have the added support of the alternator and all batteries combined for the thruster load.. Down side would be some voltage drop at the thruster of about 0.8-0.9v but since the engine would be running this should still see about 12.5-13v being delivered to the thruster..

Option 2 (Probably cheapest)
Add an additional 35mm2 cable to run along side the existing windlass cable to reach the required square area of copper but not sure on the correct fusing for this arrangement.. For example do I fuse each cable individually for it's rating or join the two cables together and fuse together as it it was a single cable? This would have similar pro's and cons to Option 1..

Option 3 (Most complicated and expensive)
Get a shelf or similar glassed into the bow area next to the thruster to support an additional battery to run the bow thruster.. Install a Victron DC-DC 18A charger in the bow to charge the battery from the other battery banks with a 10mm2 cable running back to the batteries.. Pro for this would be minimal voltage drop but the down side this is a much bigger job to get the shelf made that is strong enough and would cost more with the additional battery and DC-DC charger etc..

Anyway that's the basic thought process.. What are the opinions out there?

Thanks..

 

[Robih]

Option 3 definitely. Don’t put the thruster on the domestic bank, that way lies madness for so many reasons. We’ve just fitted a dedicated bank and removed the thruster from the domestic bank. The thruster draws 600A when first energised, the voltage drop was sufficient to hard boot the navigation electronics, not clever. It’s madness and expensive to run thick heavy cables though the boat. Fit a high CCA battey(ies) close to the thruster and run relatively thin charging wires up from the charging source, it could simply be a VSR connected to the domestic bank.

edit: I made battery shelf for our twin battery thruster bank and bolted it through two bulkheads, simple easy and inexpensive.

 

[wipe_out]

and run relatively thin charging wires up from the charging source, it could simply be a VSR connected to the domestic bank

Thanks for the reply..
Can you explain this a little more?
If the VSR is closed, as it's likely to be with the engine running, that effectively means the batteries are in parallel.. So when the thruster engages it will pull current from the dedicated battery AND the domestic bank so surely the cable back to the domestic bank would still need to be fairly significant?
This is the reason I had the DC-DC charger in my option 3 so the thin cable back to the main bank is not supplying the thruster directly..

 

[Robih]

Yes, fair point, it wouldn’t work via VSR. I used a Victron Argofet which doesn’t parallel the two banks as you described.

Victron Energy - Argofet 200-3 Three batteries 200A - ARG200301020 - Batteries and Solar

 

[Tranona]

That is how my Bavaria was wired with a Cristec 3 way splitter. Bavaria must have got a super deal on heavy cable as there was masses of it with the start battery behind the engine in a cockpit locker, the house bank in the saloon and the bow battery forward. Same with batteries all 5 were Exide 95Ah AGMs which are excellent for a bow battery as they have a high CCA being designed for large stop start cars like Jaguars.

However on the GH there is already a nearly new Numax leisure battery there which will be charged from the start battery through a Sterling B2B which I bought from a forumite. Cables will be 10mm.

 

[ChromeDome]

From another thread:

Our 30' has the batteries at the stern and was built with very heavy wires going to the thruster directly, operation managed via relay as not to feed the big load over a switch. Very standard setup (Side-Power brand).

However, when using the thruster at idle it would use so much power that other devices on board cut off, then restarted when the thruster joystick was released. Annoying and not good for anything, so I added a dedicated, common 72 aH Silver Cadmium start battery, in parallel near the thruster, kept the heavy wires in place for charging, and added a heavy relay to cut the original connection the split second I touch the joystick. Hence, the thruster draws from the added battery only, when working and returns to receive charge when not.
Took a start battery because the use of a thruster is pretty similar to a starter: Short draws of high power, then left alone to recover.

You could tap into the winch wires for charge to the dedicated battery, then just feed the thruster from there.

Just my 2 ...

 

[wipe_out]

You could tap into the winch wires for charge to the dedicated battery, then just feed the thruster from there.

Just my 2 ...

Yes, I could either link the windlass to the bow thruster battery as well and use the already installed windlass cable leading back to the battery to supply the DC-DC charger or leave the windlass as is but connect the DC-DC charger to the terminals on the windlass..

 

[Robih]

Good idea to shift the windlass off domestic bank too, I did that which leaves only the electric winches as the heavy load on the domestic bank, but nothing like the thruster/windlass loads.

 

[Kinsale373]

My Thruster is wired as Roibh describes, ie a dedicated battery close to the thruster and charged via a VSR from the Domestic Bank,so its linked when the engine is running and the Domestic /Alternator voltage is high. I think its the original Bene wiring. It has worked fine this way for years with no issue on the domestic side. I think that it works because of resistance in the circuits, There is very low resistance in the cables between the Thruster Battery and thruster relative to much higher between the domestic battery and thruster (Due to Cabe Size). Therefore most of the power to the thruster comes from the thruster battery even though the link is made via the VSR.
Kinsale 373

 

[Robih]

My Thruster is wired as Roibh describes, ie a dedicated battery close to the thruster and charged via a VSR from the Domestic Bank,so its linked when the engine is running and the Domestic /Alternator voltage is high. I think its the original Bene wiring. It has worked fine this way for years with no issue on the domestic side. I think that it works because of resistance in the circuits, There is very low resistance in the cables between the Thruster Battery and thruster relative to much higher between the domestic battery and thruster (Due to Cabe Size). Therefore most of the power to the thruster comes from the thruster battery even though the link is made via the VSR.
Kinsale 373

That’s interesting. It has occurred to me since my post yesterday that a VSR may well work fine because the voltage drop when the thruster is energised would probably cause the VSR to open, thereby protecting the domestic bank from the load. But it may cause the VSR to “hunt“ because as soon as it opens the domestic side voltage (with alternator charge) will cause it to close again - starting a damaging open/close cycle maybe?

 

[wipe_out]

Install is complete and we are back in the water.. For anyone interested we went with Option 3 from the original post.. Haven't used the thruster other than a couple of squirts to test when moving from the list to the berth so looking forward to trying it out.. A couple of photos below..

 

[Martin_J]

The other good thing about using the Orion-TR smart dc-dc charger is that through Bluetooth on your phone or tablet (and the VictornConnect app) you can remotely monitor both the supply voltage and the load voltage on that charger together with the state of charge of the battery in the bow.

 

[Martin_J]

I did wonder why the 'non-isolated' version of the Orion-TR though.. I just fitted a Vetus BowPro proportional thruster with a battery in the bow but went for the 'isolated' version of the Orion-TR Smart charger thinking it was preferable to have total isolation at the battery level. Maybe I was being over cautious.

 

[wipe_out]

I did wonder why the 'non-isolated' version of the Orion-TR though.. I just fitted a Vetus BowPro proportional thruster with a battery in the bow but went for the 'isolated' version of the Orion-TR Smart charger thinking it was preferable to have total isolation at the battery level. Maybe I was being over cautious.

I got a good deal on the 30A charger which is certainly overkill.. If I had gone with the 18A it would have been isolated because they don't do a non-isolated 18A version..

There are probably pros and cons to going isolated or non-isolated but I am sure both ways work and are fine.. I guess with the isolated setup you have to depend on the small anode on the thruster as the only protection for the thruster where as with a non-isolated setup the thruster would be connected to the rest of the boat and so the other anodes as well..