Windlass / Bowthruster power.

[Papawads]

What we currently have on our 22yo Jeanneau.

AFT:
3 x 110Ah leisure batteries - charged by alternator (originally one), shore power and solar via MPPT.
1 x 100Ah starter battery charged by same alternator and shore power only. This powers the starter and anchor windlass too.

Forr'd:
2 x Optima Red Top 50Ah batteries, only charged by same alternator. I'm replacing these two next week.

My victron shore power charger has outputs for only two banks, and Victron MPPT just one.

Questions:
Most basic.... thoughts about running both the windlass and bow thruster, solely from the pair of 50Ah Optima Red Tops, knowing that only the alternator charges these....

Thinking... this will protect the starter battery, and there must be much power loss to the windlass, over 10+ meters of cable.

If that approach alone is a concern, then maybe reuse the now redundant fat cables (running Aft/Frrd) and install a DC/DC charger, from the 330Ah leisure battery bank.

Thoughts very welcome. Please be gentle if I've said something dumb, in case the wife ever reads this! She doesn't need any more stones to throw.

Papawads

[tkeithlu]

Hey, Mamawads! Get off his case! He's doing really well and he's more than any wife could hope for.

That said, Let me make two recommendations. First, have a way to cross connect your batteries in various locations. As it stands now, if your starter battery dies (they do) then you are, as they say, dead in the water, and she has lots of anti-boat ammunition. Think through scenarios that could happen, and have cross connections, even if they are just jumper cables, that will give you a source of juice when something goes wrong. After painful experience in this I can not only run my panel off a battery that is not low in the boat, I can run my VHF radio off my Dewalt driver battery. Always have a plan B and C.

Second, consider having a small (suitcase) generator somewhere on the boat. Solar takes too long to charge your starter battery as you drift toward a groin at night with no power. Volatile hydrocarbons store a bunch of energy, and a 30 pound generator will convert it to electricity quicky.

Best wishes for your project.

[ranger58sb]

Originally Posted by Papawads

What we currently have on our 22yo Jeanneau.

AFT:
3 x 110Ah leisure batteries - charged by alternator (originally one), shore power and solar via MPPT.
1 x 100Ah starter battery charged by same alternator and shore power only. This powers the starter and anchor windlass too.

Forr'd:
2 x Optima Red Top 50Ah batteries, only charged by same alternator. I'm replacing these two next week.

Questions:
Most basic.... thoughts about running both the windlass and bow thruster, solely from the pair of 50Ah Optima Red Tops, knowing that only the alternator charges these....

Thinking... this will protect the starter battery, and there must be much power loss to the windlass, over 10+ meters of cable.

I'm assuming by "Forr'd" you mean the Optimas are physically up near the windlass and thruster?

Thoughts:

1) You probably don't use either the thruster or the windlass at the same time, and probably also in only short usage periods for each. Recharging either thruster bank (Optimas, yes?) or starter battery via alternator probably doesn't take much time.

2) FYI, Optima batteries don't seem to enjoy a great online reputation these days... unlike maybe when they were first introduced. If you're replacing anyway, you might want to do some comparative shopping if you haven't already.

Otherwise, I don't see much that needs fixing...

A pair of jumper cables on board might be useful, though.

-Chris

[Lee Jerry]

Originally Posted by ranger58sb

Thoughts:

1) You probably don't use either the thruster or the windlass at the same time, and probably also in only short usage periods for each. Recharging either thruster bank (Optimas, yes?) or starter battery via alternator probably doesn't take much time.

One more addition to this - both of these are usually used while the engine is already running.

[Muaddib1116]

My boat is mostly 24V, and from the factory was set up to run the bowthruster and the windlass from the house bank, situated in the aft cabin. That's some pretty long runs for high amperage equipment. At some point, the previous owner installed two red optimas in the forward cabin to run the bowthruster. Presumably this is the same owner that removed the bowthruster thermal cutoff. I suspect he tended to lean on the thing while docking in the med.

The optimas are charged by a 5amp victron dc-dc charger. This setup has been working fine for me. As Ranger said, you tend to use a bowthruster or windlass for short periods and then not for a while. A low amperage charger should be able to handle recharging in the downtime.

I'm planning to replace my windlass this summer, and I suspect that I will rewire it to run off the same battery bank as the bowthruster. I don't believe this will be a problem, but worst case, I could increase the size of the forward bank.

[Statistical]

Yeah I would use the forward bank for both the windlass and bow thruster. The bats are already up there no reason to grab power from the other end of the boat. Windlass uses a lot of power but they don't use a lot of energy. If your Windlass is 2400W that is 100A @ 24V but you run it for what 5 minutes 100 * 5/60 = 8Ah which is nothing for the forward bank.

Switching to a DC to DC charger for the forward bank can simply your alternator wiring.