Battery Switch Location

[c130king]

Are you still thinking that you have multiple circuits coming from your battery to the motor? There should only be a red and black set of power leads. There will be instrimentation circuits like tach and temp and the start/run key switch. There will be tilt switches with wiring to them. The alternator circuits are not provided on my engine. But to the batteries you should only have a 12v red/black circuit. When these two wires get to the battery(s), then there is the switch and charging load protection circuits that maybe between the actual batteries and those red and black wires. It is how you choose to connect your batteries to these 2 engine power leads that is a matter of preference.

Ron,

Here is where I am not quite sure...especially since I don't have access to my boat.

In the configuration that I am thinking of going with, based on recommendations from this website, is that all power leads (red wires I think) will be wired to the "common" terminal on the switch.

I am assuming that there is a positive and a negative lead coming from the engine to the battery compartment. And that there are two leads coming from the DC Control Panel. Not sure about cockpit instrumentation, motor tilt, ignition, etc... are these wired directly to the battery in my configuration or are they somehow tapped off of the wire running to/from the motor...rhetorical question I think...I will have to look at it and figure it out.

But either way, in the configuration I plan to implement, where do the negatives go. If all the positives are placed on the "common" terminal then what are the negatives connected to.

If I connect the negative lead from the engine to..say...battery #1...then will I be able to start the motor from battery #2? I don't quite understand that part of this problem.

If you look at this diagram (at the bottom of page 2) it shows the positives from motor and DC Control panel going to the "common" terminal...but it doesn't show the where the negatives go.

Still doing my research. I appreciate all the advice and comments from my fellow Mac owners. Someday I may actually understand all of this...nahhhh...why ruin all my fun with "understanding".

Jim

[c130king]

Tang is correct. You can only do clever things like AFD with an inboard engine where the alternator circuitry is directly accessible (much like a car). An OB is a "black box", you just have one big pair of wires that suck current from the battery to start it, and pump current back to charge it. There's an alternator in there generating the charge current, but it's not practical to start tweaking with it.

Rick,

Copy all. Thanks for the info. That is sort of what I thought but was not sure. My "diode protection" will be not turning the switch off while the motor is running. I will probably build a warning label for down there.

No AFD necessary.

Thanks,
Jim

[atzserv]

I just finished putting in an extra battery and had some of the same questions. Tangentair helped me alot , and I mean alot !! He was very patient.

The negative connections go to the negative side of the battery. If you use bus bar configurations or whatever the ending point of the negative wires end at the negative post on the battery. If you use 2 batteries you use a heavy guage wire to connect between both batteries, (battery guage cable) this marries the 2 batteries together on the negative side , so either battery neg post is ok to connect the negative wires to.

Hope this helps because I was really confused.

The boat store guy had me so messed up, he said the neg went to the common on the switch, I knew something was fishy. If you do that you make a direct short and I can only imagine one or 2 high amp batteries frying or explodeing.

Gary

[c130king]

Gary,

Excellent! That is exactly the kind of information I was looking for. I just wasn't sure if I was supposed to tie the negatives of the two batteries together...the instructions for the switch didn't say.

So I will tie the two batteries together via their negative terminals and then tie the negative leads for the motor and the DC Control Panel (and the negative leads for the tilt, cockpit instruments...if their leads are in the battery compartment) to one of the two batteries. It doesn't matter which one.

I can tell that Ron is trying to advise me as well. But I keep getting things confused and my rambling posts probably don't help.

Thanks,
Jim

[Boblee]

Tangentair
My motor Etec is as Rickj says hooked up direct to the start battery by the two leads which are start and charge, the changeover switch in my case only switches the two systems (house and start) separately or together to the output going to the main distribution panel the bilge pump comes from the house system via the solar regulator and the fridge/freezer is supplied direct from the house system at the port side rear of the vee berth near the second house battery.
Have scanned the article from the magazine but now have to work out how to link (seven pages) it here or send it direct, have just got back from two days away at our annual Fox hunt so am pretty tired, will see how we go later.
Pokerrick1

Too hot for sailing?? - - - no comprende??

Probably put that wrong but because we don't have any local water suitable within 200 odd k's our trips tend to be longer and during the summer months with temperatures regularly in the 95-104+ range it is a bit hard to live on the boat long term so our trips tend to be in the cooler late Autumn/Winter/early Spring seasons if we lived near good water we would use the boat all year round however it is possible we will do more this summer out of the holiday periods.