Bowthruster battery charger

[pvb]

Looks like a good option, thanks. That’s CCA EN, a little less than CCA SAE, but close nonetheless. I might need three but still a lot less than 100kg. I’ve AGM elsewhere so would need a clever charging regime to cope with two technologies.

They're "sealed" maintenance free batteries and you can charge them at the same voltages as AGMs.

 

[Nom de plume]

I’m struggling to provide 1300 CCA for our 8hp thruster whilst keeping the battery size practicable. The attached thruster spec might give indicative guidance.

Thanks for that, we have a 15Hp thruster but it is also Sleipner so I can extrapolate from that document.
I don't have any issue with the CCA ( 4 x 900 CCA in the forepeak) - the issue is really about recharge time i.e. Having sufficient battery capacity to permit banging in bulk amps for rapid recharge.
Having had a few years experience with the set-up I'm about ditch the long-run dc cables (about 30 feet run) from the engine bank ' alternator area (I'll leave them in for back-up but leave the isolators normally open) and replace the 240/24v charger in the forepeak with a much beefier one run from the generator.
Makes more sense to me to run a dedicated 240v rather than 24v over a long run even though I've got a 180A Leece Neville alternator on the main engine.
Cheers again.

 

[Nom de plume]

Thruster manufacturers give guidance in the installation manual.

Thruster was fitted 25 years and two owners ago and I don't have a manual other than the one onboard, in a different country, 300 Covid miles away. It was more a generic question as to be honest the 15hp thruster is if anything oversized and I had a fleeting thought that I could reduce the thruster size and hence the battery bank size - therefore I do not yet know what make I might fit, so I can't look in the manual

 

[PaulRainbow]

So I have to confess I’m not entirely sure because being a new boat everything is PCB panels and not good old fashioned battery switches / emergency parallels and that kind of things. That’s the next thing to find out but I suspect there is a VSR. Now I wired in the solar panel, via a Victron MPPT to the domestic bank, so I’d imagine the thruster just gets its charge from the alternator and shore power (unless the domestic banks or wired to the thruster?)

I'd be surprised if Hanse fitted a VSR between the domestics and the engine battery. More likely they fitted a diode or FET based split charge device for alternator charging and a 3 output mains charger. Easy to check, follow the wire from the alternator that will identify alternator charging.

So, if that's correct and you connected the solar panel to the domestics, that's all they can charge. Two easy options, fit a 10w panel directly to the thruster battery, or fit a VSR between the domestic bank and the thruster battery. I'd go for the VSR, cheap, tidy and easy to install. No need to run cables to the bow for this, you can connect the VSR between the domestic bank and bow thruster terminal of the diode/FET based devices.

If your charging differs from the above, post back with details.

 

[PaulRainbow]

Thanks for that, we have a 15Hp thruster but it is also Sleipner so I can extrapolate from that document.
I don't have any issue with the CCA ( 4 x 900 CCA in the forepeak) - the issue is really about recharge time i.e. Having sufficient battery capacity to permit banging in bulk amps for rapid recharge.
Having had a few years experience with the set-up I'm about ditch the long-run dc cables (about 30 feet run) from the engine bank ' alternator area (I'll leave them in for back-up but leave the isolators normally open) and replace the 240/24v charger in the forepeak with a much beefier one run from the generator.
Makes more sense to me to run a dedicated 240v rather than 24v over a long run even though I've got a 180A Leece Neville alternator on the main engine.
Cheers again.

Current spec for a 15hp Sleipner is 700CCA @24v

Edit: that will be 700CCA DIN, so 1170 EN

 

[Nom de plume]

Current spec for a 150hp Sleipner is 700cca @24v

 

[Robih]

Current spec for a 150hp Sleipner is 700cca @24v

Paul, should that be 15hp?

Another matter - I’m tempted to take more notice of MCA in preference to CCA (we don’t sail sub zero!) - do you think that sensible/silly?

 

[PaulRainbow]

Paul, should that be 15hp?

Well spotted, although you could do some great doughnuts with a 150hp thruster

Another matter - I’m tempted to take more notice of MCA in preference to CCA (we don’t sail sub zero!) - do you think that sensible/silly?

I wouldn't get bogged down with too much fine detail, you'll be hard pressed to better a pair of those Exide batteries PVB suggested.