Dual battery isolator vs Voltage Sensitive Relay

[wingssail]

Originally Posted by Simi 60

^^^^^ and regardless of what you say, or what the manufacturers say to cover their arse, our real life daily experience differs.

Pulling the boat up with a LARGE windlass is not a new concept.

And pulling a medium sized boat is a piece of cake. When weighing if you hear the windlass straining, (lugging) stop for a second and let the catenary draw the boat up and get some momentum, then resume. Only in strong winds have we considered using the engine to move the boat toward the anchor. (20,000lb boat, Lowrance Concept One windlass, 20+ years old, through bolted in balsa core deck using windlass inside bits as the backing plate).

Power the windlass from the house side of the battery switch, running engine at normal charging RPM, it provides more than 85amp (our windlass breaker size)
and there is no drain on the battery. Usually the battery switch is still set to house, start batt is rarely used. In 20+ years we've popped this breaker exactly twice.

A battery isolator or similar system is not needed if you monitor the battery SOC. The start battery lives happily by itself, without charge or discharge, for weeks. Periodically we use it to test that it still will start the boat, and charge it occasionally, but it never takes much to keep it up.

So, take personsal responsibility, monitor and switch it yourself, and toss out one more little electronic part, save some bucks, and worry less about if it is still doing its job.

[Hartleycruiser]

I use one of these on my yacht.https://www.australiandirect.com.au/...gers/KAVSROVER

[Simi 60]

Dragging this back up as today was the first time we have had the house batts below 24v while underway and, we didn't see evidence of it working.

Looking at the pic we have the two red cables connected as per pic.
One side registering 27+ v so the starts
The other side registering 23v so the house.

The neg bat cable for house and start are on a single remote terminal inches away but in no way connected to the victron device as I was not concerned about the start assist at this stage.

I'm guessing that it needs at least the thin wire connected from that neg terminal to the spade connector on the victron to work?

[millsie]

yep, it has to see the neg to see the voltage.
It is a voltage sensitive relay

[smac999]

Originally Posted by Simi 60

Looking at the pic we have the two red cables connected as per pic.
One side registering 27+ v so the starts
The other side registering 23v so the house?

where you holding the neg of your meter in mid air when you took these readings? because that is what the victron is measuring.

yes it needs a ground to work.

[Simi 60]

Cool,
ground is connected, hopefully we'll see a result next time we move

[Simi 60]

Success.
Amps smashing in.

[Wotname]

^^