Throw the switch?

bridma · Posted: Wed Apr 24, 2013 12:16 pm Post subject: Throw the switch?

Can I change the battery switch between 1/both/2 while underway? Should I switch off any electronics at the helm before changing the switch?
Can I change from stbd fuel tank to port fuel tank, and vice-versa, while under way?

Martin.

Will-C · Posted: Wed Apr 24, 2013 12:22 pm Post subject: Throw the switch?

I would never move a battery switch position with the motor running. Maybe it's just me but I think I remembered a long time ago someone told me don't throw the switch with the motor running. So I don't. It won't hurt to leave your electronics off either. The fuel selector switch we switch all the time when running to try and keep the boat balanced.
D.D.

thataway · Posted: Wed Apr 24, 2013 12:38 pm Post subject:

If you have "Make before break" type of switch you can do the switching when the motor is running. Or if you have a switch which disrupts the field sensor current as you switch it is OK. But if you have just a simple switch, which will open the circuit and close it on the next contact, there is a very good chance you will damage the output diodes of the alternator.

Never go thru "off" when switching.

Many switches are make before break. Some switches will say "do not switch with engine running"

One way to check, is with the engine off, turn on a light you can see from the switch position, or use a 12 volt test lamp. As you turn the switch if the light stays on--it will be OK. If the light flickers off, then it is not OK. You can also use a Digital volt meter to check to sure if there is always current flowing as you switch.

Bill K · Posted: Wed Apr 24, 2013 2:07 pm Post subject:

Or you could do like I just did and look it up on the internet. LOL

I found mine by image and then went to the web page where it told me it was a " make before break " switch.

journey on · Posted: Wed Apr 24, 2013 2:38 pm Post subject:

As far as the tank selector switch goes, that can be switched any time. I assume that we're talking about the gauge reading selection. All that switch does is route 12 volts to the desired tank sensor and the senor output to the gauge. And those sensors are just a variable potentiometer, controlled by a float. Having the engine run or not is immaterial.

All Perko 2 battery switches are make-before-break, so the engine alternator only sees a change in load, not an open circuit. Blue Seas doesn't say. Just to be safe, check as Bob suggested. Nevertheless, I regularly switch to both batteries when the engine is running. The batteries will absorb any voltage spike, so you can keep the electronics on.

Boris

thataway · Posted: Wed Apr 24, 2013 4:19 pm Post subject:

Boris, the Perko PKO-8501DP are not break before make. Some will say "Stop engine before switching".
Here is some basic information on the Perko switches. The first two are not safe to switch with the engine running. The last 2 are, since they have field disconnect. But you have to hook that up as per the diagram.

Cat No. 8501 Series Basic Switch
Cat No. 8502 Series with Key Lock
Cat No. 8503 Series with Alternator Field Disconnect
Cat No. 8504 Series with Lock and Field Disconnect

journey on · Posted: Wed Apr 24, 2013 11:38 pm Post subject:

Well, Bob, all the Perko switches I've used have been make-before-break, thank goodness. As we both recommend, check, it's a simple thing to do.

BTW, the Perko 8501 thru 8504 are make before break, per the data sheet. It does have an alternator field disconnect as an option and a warning not to turn the switch to OFF unless the engine is off. Switching between 1-ALL-2 is OK.

I also submit that the alternator field in an outboard motor is not readily available.

Anyway, just check as you suggested.

Boris

colbysmith · Posted: Thu Apr 25, 2013 6:45 am Post subject:

I have a make before break switch. However after replacing a $100 fuse wire on my outboard, I'm a little leary now about moving that switch while the motor is running. I like the idea of testing the switch with a light. I'll have to try that to see if something else happened. (This was right after I bought the boat, that just had the batteries replaced. It's also possible that they reversed polarity accidentally while hooking them back up. Mech I bought the fused wire from said that would blow the fuse to, and the fused wire is their to protect the motors circuitry.)

NewMoon · Posted: Thu Apr 25, 2013 9:04 am Post subject:

AFIK from talking to them on the phone years ago, Blue Seas 1-both-2-all switches are make before break.

I've switched mine between 1 and 2 through both, not through off, about a zillion times in the last 15 years without a problem.

Dora~Jean · Posted: Thu Apr 25, 2013 1:09 pm Post subject:

Each of my engines (twins) are hard-wired to their respective battery, therefore switching during running isn't a problem, it is only affecting the house electrics. And...mine is a make-before-break, always have been on all my boats (just like Boris!).