Selector/Relay wiring?

[BravoVita]

Hello, I am trying to rewire my boat and found the battery wiring very different than what I would have expected it to be. Also, I cant find direct diagrams for my current hardware due to an older style (3 stud) Perko selector switch being part of my configuration. Firstly, I am trying to figure out why someone would have wired the configuration the way it is. There once was a battery charger as part of the diagram however I do not know where it was located (I have a feeling someone ran the previous charger to the relay in stead of the batteries themselves). Right now, the starter is running off of the A terminal of the BlueSea 7610 ACR where I would expect to see it on the lower terminal of the battery selector. Also the alternator is running to the A terminal of the BlueSea relay where I would expect it to run directly to the Starting battery. I believe all of this is because a PO was trying to take shortcuts but I am not sure. I also included a diagram of how I believe I should be wired short of a new battery charger that has output for a few chargers that I plan to run directly to the battery terminals and not to the relay as the PO is believed to have run it. I have a few wiring books but I have gotten a bit overwhelmed and was hoping for some outside perspective. Thanks

[msponer]

Hi,
My preference is for the master switch to turn absolutely everything off. Including the starter and alternator.

This helps with maintenance: to easily de-energise the engine while you are working on it. For example, the four cylinder Yanmar's have the starter connections right where your hand wants to be when changing the raw water impeller. On another engine I've had, the dipstick had a tendency to short out on the back of the alternator.

But most important, a boat has burned to the waterline because a wire to the engine shorted out. The folks on board were not able to quickly cut power to it, so even though they extinguished the fire, it kept flaring back up. So, I feel it's important, if you smell smoke, for one switch to turn everything off. Which is why I believe in having a large fuse, either between the batteries and the switch, the switch and the starter and alternator, or both.

However, your configuration has the advantage of never being able to blow the alternator by selecting 'off' while the engine is running.

Connecting the starter and alternator through the master switch also allows you to only use the house bank to start the engine. I prefer that flexibility. If for some reason the starter bank is super low, I dislike the only option being 'combine', which will have the house bank charging the starter bank while you are trying to crank the engine.

I am probably in the minority, but for many of the same reasons I don't like automatic combiner switches. I think one loses flexibility for the small convenience gained. If there is a problem with the house bank, I prefer being able to run the VHF, GPS, depth, and etc from the engine bank, and be able to charge it without the combiner kicking in.

[BravoVita]

Can you provide a simple diagram of the idea you are trying to describe? I am having difficulty imagining what you are describing because it sounds almost exactly what my second "planned route" diagram is aside from the alternator (something I was guessing about anyway)

[DeepFrz]

Scroll down to post #28.
http://www.cruisersforum.com/forums/...re-174865.html

Also, do search for electrical 101.

[msponer]

Originally Posted by BravoVita

Can you provide a simple diagram of the idea you are trying to describe? I am having difficulty imagining what you are describing because it sounds almost exactly what my second "planned route" diagram is aside from the alternator (something I was guessing about anyway)

Yes: I would just move the alternator to the switch. And consider big fuses if you want more safety.

[BravoVita]

Originally Posted by msponer

Yes: I would just move the alternator to the switch. And consider big fuses if you want more safety.

Great thanks

[BravoVita]

Originally Posted by DeepFrz

Scroll down to post #28.
http://www.cruisersforum.com/forums/...re-174865.html

Also, do search for electrical 101.

Thanks, I have a few books but I was just looking for opinions on my theory.. you have a great setup but I'm not going that nuts with this boat.

[DeepFrz]

That diagram was posted by Maine Sail (Compass Marine). I just thought the power switch section would be of interest.

[smac999]

having the house and engine off the same switch is how they did it 20 years ago. and no longer done. you don't have a house and engine battery. you simply have 2 batteries but either one is doing everything. there is no separation.

alt goes to house bank.

buy a 2nd switch so you have separate house and engine switches.

you can connect the acr to the batteries at the battery switch to save cable.