B-B Charger for windlass

[Ditz]

Hi folks…

On my “new” boat the former owner mounted a windlass and a battery short time before he sold to me.

I guess he was staying a lot on the docks, because the battery is only charged with a 220 volt charger. [emoji2373]

I am going to put in a B-B charger, so we can be more independent of 220 volt.

We have a 100 ah for starter, 4x75 ah housebank and 130 watt solarcell on house bank.

The windlass draws 1500 watt.


Q:

How big a charger is big enough?
Mount on the starter or house bank?

[markcouz]

Your 1500w windlass probably draws half that in normal use, so 750w (60amps at 12.5v) for around 5min = 10Ah.

A 30amp B-B will recover that in about 20min (excluding horrible lead acid charge profile).

Connect to start bank, your engine would normally be running when raising or lowering anchor, so alt/B-B would already supply half of the 60amps required, dropping recharge time to 10min.

When installing place B-B close to windlass battery, not next to start battery - for lower volt drop and better performance.

[Bycrick]

The biggest worry is that some B-B chargers won’t completely shut off when the target battery really is fully charged. An acquaintance literally cooked, ie melted, a Group 31 AGM battery this way. He had enough solar to keep the house bank at 13.1 whenever there was any sun at all. The charger was on whenever the voltage exceeded 13.1. He didn’t catch it until it started to smell "burned."

[markcouz]

I guess that could happen in a solar charge environment.

Every time a cloud passes the primary battery voltage would drop from charging voltage to discharging voltage then back again. The B-B would "restart" every time it sees the voltage rise to its start voltage and try to bulk charge the secondary battery over and over during the day.

For the OP if he connects to start battery using alternator charging only this would not be a concern.

[Scrimshaw4]

In all likelihood your engine will be running when you use your windlass so the external charger size would really not be an issue. More significantly is not draining the windlass battery while using your house bank. This can be accomplished by using an intelligent isolator between your charge source, charger / alternator, and the windlass battery. JMHO

[YANDINA]

The Yandina Combiner 100 (Combiner 100 Sheet) connected between the house bank and the windlass battery can charge it at up to 100 amps.

[Ditz]

I lean up to markcouz idea and mount a Sterling BB1230, thus I also ensure a correct charge. [emoji2]

Thanks to everyone for your thoughts.