I am sure this is dumb!

[jimisbell]

I removed the battery switch to repair it and found the problem to be that the two balls that provide the detent were broken out of their sockets. So I removed them and now it works perfectly, but without a detent. Ok by me, the pointer works fine.

BUT while it was off the wall I discovered that there are two smaller terminals on the back labeled F1 and F2 in addition to the three large battery Terminals. I checked continuity with an ohm meter and cannot find that they connect anything to anything. Anyone know what they are for????

[Pblais]

You probably have destroyed the make / break part of the switch. You can't repair a broken switch. You toss them in the dumpster and start with a new one. What you have now is dangerous.

The switch was probably a 1, 2, both, off switch. They allow current to flow to one, or the other or both or none. They have an in and two outs. You may only really need an on, off switch. They cost less so there isn't a good reason not to replace it.

Here is another good rule of thumb. If you have to ask "Is this really Dumb?" - it is.

Another good test for these rotary switches is if you can see any sparks as you turn the switch - it's toast. Toss it out and start over. These switches carry large loads that could start a fire with great ease!

[jimisbell]

Actually, I didnt ask if this was dumb. I stated that I was sure it was dumb. But what ever was in there on those two contacts was NOT there when I opened it and there is no sign of any arcing in the switch...but then, it would only be switched without a load ANYWAY so there shouldnt be any arcing.

[Greg S]

Jim,

Paul is absolutely right. Don't screw around with it. No matter how much a new one costs, it's far less than a new boat! However, you say there was nothing connected to two of the terminals?? If so, I'm not sure what it's purpose would be?

The diagram should make it clear as to how it's supposed to work.

Greg

[jimisbell]

I was just wondering what the F1 and F2 terminals had been intended for?

Thanks for the advice and its probably good advice for most people, but If I threw out every thing I had that didnt work I would soon be a poor man. I am perfectly capable of repairing almost anything till its usually better than when it was new. Actually I usually find that most items have been poorly designed in the first place, usually to save a few pennies for the manufactuer. Most designers are NOT engineers. Its easy to upgrade them while repairing them. Electrical and electronics are the simplest and I didnt go to The University for 7 years to throw out perfectly good switches just because the detent no longer worked. Its going to work just fine now that I have repaired it and greased it with contact grease. It just wont have a detent.

[Rick]

The two terminals that you describe are provided to disconnect the field current to an alternator whose output current may be interrupted (to a battery) by your turning of the selector switch.

I advise against using such a method as it is no guarantee that you will prevent damage (to various electrical or electronic devices powered from the alternator output) from what is called "load dump". If you never wire your alternator output and its regulator voltage sense line through a switch then you will not have this potential problem and you do not need that "field disconnect" feature to pay extra for in a battery selector switch.

I agree with the others that you should not use your "broken" switch. Not only should you buy another one, buy a good brand like a Cole Hersey.

[hellosailor]

Jim, it wasn't dumb, sorry to disagree with you on that.<G>

The "F" positions are for the alternator Field coil. Some alternators break out the field coil winding (automobile alternators don't) and when they do, you can switch it along with the batteries that way. Since you're not using it...you can either ignore it, or do some other tricky things like switch the alternator battery sense lead with it, if you have one of those.

That the detent ball sockets broke, speaks to the question that either the switch was impacted or hit to break it, or the plastic was breaking down, or something else was wrong. At that point, I wouldn't question what or why, I'd replace the whole thing. If I couldn't replace it...sure, I'd rebuild them with epoxy and then install new detent balls maybe stolen from some car track on the deck, but I don't think you're that desperate. New switches aren't all that expensive. Even with the "F" terminals. <G>

If you check the reviews online...IIRC one of the companies with a generally good name also had some switches melting a while ago. This is one of the places where you want a MUCH higher rating than you ever plan to use, as cheap insurance.

[jimisbell]

This switch is used ONLY for paralleling the house and engine batterys for starting so a field interupt is not needed. It is switched only while no load is applied, the engine is started and then it is switched back to separate the house battery.

The diagram the was offered by the last poster is not as good as it could be and mine is wired differently. I would NEVER put both the house load and the engine starter on the same buss. My engine starter is on its own battey buss that is NOT shared with the house battery.

The #1 terminal on the switch is connected to the house battery, the #2 terminal is connected to the engine battery and the output is connected to the house load.

Under normal opperation placing the switch in #1 puts the house battery on the house load and isolates the Engine battery which is connected directly to the engine starting solenoid.

When the switch is in #2 position it isolates the house battery and connects BOTH house and engine loads on the engine battery. IT WILL NEVER be used in this position.

When the switch is in BOTH it parallels both batteries so that both the house load and the engine load are supplied by BOTH batteries. This position is used for starting the diesel only in an emergency when the engine battery hasnt got the ability to do it on its own (hopefully never) while the main house panel is switched OFF so it is NOT a load during starting.

Once started the switch is placed back in the #! position once again issolating the engine and house batteries from one another and the hous panel is then switched back on.

When charging there is a battery combiner (electronic circuit to make sure the engine battery is first at full charge before connecting the house battery and isolating the engine battery if the house battery develops a fault)

All the above is designed to preserve the ability to start the engine in all possible fault scenarios......of course, if both batteries are dead then the only solution is to break out the crank and hope you dont break your arm in the process...#8-)

[Pblais]

I guess I would want to back up to the original post. You wanted to know if it was a dumb idea. Well it appears the consensus is that it was and you knew it before you posted. I'm not sure anyone wants to argue about it. My original reply sounds about right.

Actually the very switch you are talking about is the exact same switch I removed and replaced because it was arcing when it was switched. I spent about $60. Probably a waste of money - unless I was right.

Sorry I didn't save the switch. For the price of postage I would have mailed it to you. It was in better shape than yours.

[jimisbell]

Nowhere in the original post or ANYWHERE did I ask if something was a dumb idea!

I asked what the terminals were for, and that is all.

Go back and read the original post, I did, and I did not ask anywhere if something was dumb. I only commented that my question about what the terminals were for might be a dumb question because it might be general knowledge.

What are you talking about???? Did you read it????

[GordMay]

jimisbell:
Goto: https://resources.myeporia.com/company_57/6992.pdf
and see the diagram at the bottom of the page.
As previously noted, F1-F2 open when either 1-C or 2-C open

[Lynx]

jimisbell - I was supprised myself on the responses. The switch is a bit outdated as most new Alternators do not require this. It is a good thing that you are replacing it. I also suggest that you go through everything else carefully as there may be other problems.

If you want some good night reading, get a good marine electrical book. And if you want something very funny, get one about 30 years old and compare it. (and you thought your question was dumb, wait till you do this)

[never monday]

Look at this
West Marine: E-Series Dual Circuit Plus Battery Switch Product Display

[jimisbell]

Hey, thats it. Just what the doctor ordered and Half the price for the standard 2 battery switch. Now I wont feel like I have to keep the old one as this is designed to do exactly waht I had in mind and at a reasonable price.

[hellosailor]

Jim, I'm not sure about "half the price" since West also advertises a very similar Blue Seas 350A switch (vs this one at 300) for literally one buck more.

I think "half the price" reflects these being the "light duty" version compared to their larger higher-rated switches. For the extra buck...I'd buy the conventional switch and have the option of using it either way.