Another stupid electrical question: Batt switch to off :o

[toddster]

I'm afraid that I'm going to have to make another 200 mile round trip just to check on this one. I managed to kick the battery switch with my foot and rotate it to the "off" position while the motor was running. The motor immediately died. Somehow, I never got around to checking the alternator output to see if I had damaged it. The batteries have been topped off because an automatic charger runs when at the dock, and the boat hasn't been away from the dock for more than a few hours since then.

But... why did the motor die? Shouldn't the ignition circuit continue to receive power from the alternator? Does this mean that it is already damaged? (It was bench tested last spring.) Wiring is as per the Moyer diagram, with only the main battery lead, and the main lead from the house panel, going to the common terminal on the switch.

I had been planning to start out on a three-day trip on the next visit to the boat, but now my paranoia is growing. I could do it in two days, but that will mean running in the dark with all of the electrical toys going...

(Yes, it continues to suck, being 100 miles away from the boat. However, said three-day trip is to move it to a closer marina I was planning to take the bus, since I won't be going back, so no car to run errands.)

[hanleyclifford]

Sounds like the alternator is dead. When a battery is switched off the sensor immediately thinks the system is calling for max output which the alternator will try to do - usually only lasts a few seconds.

[Ajax]

Aw that sucks, Todd.

It does sound like the alt. is dead. Better build a cover for that battery switch, or relocate it.

[toddster]

I dunno... I've heard it both ways. And I remember my Dad having me "here-hold-this" the hot lead while he switched out batteries from a running car.
But, this time, the engine shut down instantly, as if the ignition switch were flipped off.

Meanwhile, I figure this is as good a time as any to upgrade to a high-output alternator. Ordered one this morning that might just squeak in before my weather window closes. If the old one is OK, or repairable, I'll have a spare.

A new "mains" panel is in the works before spring. I might even look around for a new battery switch that doesn't protrude so much, or use a different battery combining strategy altogether.

Anyhow, after this trip, the boat will be five minutes away instead of 100 miles. Tinkering will get much, much easier. Finally got up to the top of the waiting list.

[toddster]

Oh, and jeez, I'd better make sure I have a heavy cable to bypass that little orange ammeter wire.

[dvd]

Battery Switch

During my cruise to the bay last month my wife decided to turn the battery switch off while the engine was running. The engine didn't die and I ordered her, (no just kidding) gently asked her to turn it back on. The engine did not die and I continued on motoring as if nothing had happened. I've since motored probably 10 hours over a 2 day period with no problem . I have not checked the output but the gage seems to be behaving normally. (showing a charge for a while after a night at the dock with the lights on)

I guess it can be done without hurting anything.

dvd

[ILikeRust]

Depends on the battery switch, dunnit? Mine has a leetle switch in the back that's supposed to make the field coils "make before break", to be a safety mechanism to prevent damage to the alternator in the event someone rotates the switch with the engine running.

This is one area of the engine I don't know as much about...

[hanleyclifford]

Wherever a fear or possibility exists of battery switch mischief ( wives, brothers-in-law, etc) it is prudent to install a battery switch with a field disconnect built in.

[edwardc]

I just had a good thought!

Todd, is it possible that your battery switch has a field-disconnect switch in it? If so, this might explain why your engine quit instantly when the battery switch was turned off. It was doing it's job, disconnecting the field winding so the diodes & regulator don't get fried.

If this thought is true, it's good news, as it means your alt is probably OK!

[toddster]

Hm. I doubt it. It's a very old, very cheap-looking switch. No extra terminals on the back. Well at least the forecast is changing so I might have favorable, or at least not unfavorable winds. I just hope that the bridge operators are on duty Thanksgiving. If I can clear my desk by noon, I'll take one final "prep" trip to the boat.

[toddster]

Well that was a lot of wasted paranoia. The old alternator charges just fine, once it gets some RPMs going.

At least I'll be set for building up the battery banks next year.

[edwardc]

That's great news!

Have a safe trip.