Windlass battery

[Laceynhans]

Hello
I
Am slowly sorting out the electrical nightmare of my 1980 Gulfstar 50 and trying to figure the logic of my windlass configuration.
I have a seperate bank for the windlass at the bow with. Selector switch. When the switch is on windlass draws from house bank as well as windlass battery.. Seems useful if necessary. But if switch is off only uses designated battery. This makes sense except that windlass battery is not being charged unless switch is on. The switch is not in a convenient place. So I have been leaving selector switch on, engine is always running with higher RPMs when using windlass.
Is this a common configuration?
Drawbacks of this system?
Thanks for any input, I'm learning lots from all y'alls other posts

[smac999]

no I have never seen a switch on the charging line like that.

a lot of boats simply have no swtich between batteries which I consider wrong. with a switch going to the windlass.

an ARC or echocharger would be a better choice depending on the wire size between the 2 banks.

note that wire should be fused at both ends of the charge line. and the windlass should be swtiched and fused as well from the windlass battery. this swtich should be accessible.

if the cable is fat i would consider just removing the windlass battery. gernally only need batteries in bow for bow thrusters not windlass.

[billzona]

I just completed the same installation of windlass with forward AGM battery. I included a SI-ACR near the house bank with a on -off switch forward of ACR. I USED 1/0 cable. The switch was recommended as a safety item should short in cable. I intend to leave it on to allow charging of forward bank. The ACR is a great idea. I spoke to Blue Sea tech support several times about my design and the concurred with design. Good luck.

[Scott Berg]

On larger boats a windlass battery makes sense; we install them with a wire that can handle the full house charging load (fused on both ends), a charging relay (ACR) that can handle the full charging current, AND a paralleling switch that parallels the ACR in case of failure. You need to fuse BOTH ends of the connecting wire as both batteries are power sources... For what it's worth EVERY battery should have an on off switch in my personal opinion; I know ABYC permits smaller (under 800CCA) but I see that as a false economy...

[Sandero]

I installed a Maxwell VWC 1500 on Shiva (36') and ran very heavy battery cable to the bow with 100 amp fuses. When I use the windlass the engine is running and the batts would charging from the high output alternator. The house bank are 2 - 8D AGMs. This approach has served me well and I can't see the wisdom of a dedicated battery for the windlass. Please explain.

[Scott Berg]

It's a question of boat and windlass size; as loads increase voltage drop becomes a larger issue. Small windlass models like your 1500 (drawing only about 100amps) can probably be operated without the battery voltage dropping below reasonable levels. However, even with an engine running many boats will have house batteries drop below 11v while loaded by the windlass. (A 100amp alternator can't handle a 200amp load). Larger boats use 3phase AC or Hydraulic models but in the middle a dedicated bank (often for windlass and thruster) makes good sense.

[Laceynhans]

So it sounds like this design is logical, i just need to make sure it is properly fused. I know there is one at the windlass, I'll check around for another. It should between the switch and house batteries?

[Privilege]

A good solution for you, and cheaper than changing your configuration, would be this;

Leave the battery switch turned off so that neither of the batteries can drain into each other and the windlass batteries are isolated solely for the windlass. Keep the switch for emergencies only. Connect a VSR (voltage sensitive relay) to each side of the battery switch, i.e. one end to the windlass positive and one end to the positive of the other bank. Now when the main bank is receiving a charge it will also top up the windlass battery. If neither battery is receiving a charge, it will automatically isolate the two systems.

An easy $100 peace-of-mind fix.

[Laceynhans]

Love it! Thank you