Carver Owners Forum

If you run a smaller gauge 12v wire to a forward battery and put circuit protection in place, say 20amps, every time you run your windless you are most likely going to trip that breaker. The windless doesn't know to only draw off the one battery. The connected battery becomes part of the bank and will try to share the load over all batteries in the bank.

What we need to remember here is that a circuit breaker isn't the be all end all in circuit safety. Even in a properly protected circuit, you can still tax the circuit and melt the wiring without tripping the breaker. Happens all the time, just look at 90 percent of the shore power cords in the marina; most are rated for 30 amps, on a 30 amp breaker, but usually over taxed for one reason or another be it load or a poor connection, but ends start melting and sometimes catch fire and breakers don't trip. They are not foolproof nor do they react in all the electrical hazard conditions as one thinks they would/should, and this has to be taken into consideration during circuit design.

I understand what the article is saying about the size of the charge wire from the alternator to the windlass battery. In a perfect world, the charge wire IS only supplemental but it's not always perfect right? Under certain conditions, and not as rare as you'd think, the windlass or any other high load for that matter can draw it's full rated load through the alternator charge wire, especially where an undersized battery is used or one that is on it's last legs and can't fully charge anymore. The alternator is just another battery in the same bank if you will, you wouldn't connect two batteries in a bank with large cables then smaller cables to a third battery in the same bank. The current in all areas of that circuit is the same, and it would try to draw the same through the alternator's charge wire. The current doesn't know that the alternator isn't a battery, it's just another part of the source/bank. It's not of a common concern because of the conditions needed however it is a consideration in safe circuit design none the less.

All this info reinforces my decision to avoid going with a dedicated windlass battery up front.
But life is never simple: Currently I have 2 Grp 31 wet cell batteries in the aft cabin under the steps, and no evidence of ventilation. The operating theory is to simply alternate between battery 1 and battery 2 via the Perko battery switch. This seems sort of primitive to me, and potentially dangerous as the aft cabin is where we sleep.
Best solution, aside from cost considerations, might be to replace the existing batteries with a sealed type deep cell battery (like a Firefly?) and install a conventional start battery more forward in the engine room - then run the windlass off the start battery which now has a somewhat shorter run. But does separating the batteries like that unduly complicate having all batteries connected to the alternator - even with an ACR? I am driven to DYI solutions because all the new Covid-inspired boaters have vacuumed up all the technicians who are now charging much more than last year.

I agree, that is exactly what will happen. The motor will pull from anywhere it is connected....that is why there needs to be the appropriate sized wire/cable when installing these types of high draw loads and that includes the charging side especially in multiple connection situations. Remember that any motor has an initial draw that will be higher than the run draw, and to add, consider a heavy anchor coming up loaded with clay and weeds....

Edit ....after seeing your post, it is a good idea to run the windlass off a start type battery, you could consider having two start batteries in parallel to provide lots of power reserve for the windlass and engine starts.

It is also easy enough to vent a battery box....hydrogen is lighter than air so it rises.....attach a vent hose to the top of the box and run it to the bilge vents if possible.....just an idea, I have done it that way and works fine.

bud37 wrote:Qr Bbpostattach a vent hose to the top of the box and run it to the bilge vents if possible.....just an idea, I have done it that way and works fine.

A large tank - I think the black water tank - runs across the engine room right behind the aft cabin bulkhead, possibly blocking access from the battery box. \i will try to confirm that later today.

Here are pictures of the installed Lewmar 1000 on my Riviera;)

Thanks, Mike. What battery setup do you have, and where are they located?
Do you know what gauge wire was used from the windlass to the battery?
TIA

SunsetSteve wrote:Qr Bbpost
A large tank - I think the black water tank - runs across the engine room right behind the aft cabin bulkhead, possibly blocking access from the battery box. \i will try to confirm that later today.

If you're running a vent for the potential hydrogen build-up in the battery compartment, it needs to have a continuous 'rise' from where it starts (near the top of the battery compartment) to where it exits the boat. Any dip in it will act the same as a trap below a sink and block the flow of hydrogen. You could run a powered blower, but I'm not sure of any real small ones that are 'ignition-protected'.
"Sealed" batteries offer a bit of protection but they will also vent if they're overcharged. They just have a little valve that allows them to contain some pressure so they don't vent all the time.

SunsetSteve wrote:Qr Bbpost Thanks, Mike. What battery setup do you have, and where are they located?
Do you know what gauge wire was used from the windlass to the battery?
TIA

I only have two batteries in my Carver, way back under the one stair to go in the aft cabin, sorry I don't have the gage if the wire going back to the battery and I'm back home;)