Battery Disconnect

[hydroguy]

Heres something to think about that concerns a discussion I have been having with another v driver. I told him that my boat was just about ready to go and he asked if I had installed a battery disconnect as per IHBA. I told him no but would get with the program. He informed me that his disconnect was on the negative side and when I asked him why he said there was already lots of stuff on the positive terminal and the negative would stop all voltage flow anyway. I did a little research and came to the conclusion he was correct and the IHBA 'positive side' was bogus tech. When you think about it even if you have a disconnect on the positive side any accidental short across the positive is still going to give you a big problem if you are dealing with a electrical fire or etc. If you disconnect the negative you have taken away any completion of the circuit. However YMMV :eek:

[PE 316]

Heres something to think about that concerns a discussion I have been having with another v driver. I told him that my boat was just about ready to go and he asked if I had installed a battery disconnect as per IHBA. I told him no but would get with the program. He informed me that his disconnect was on the negative side and when I asked him why he said there was already lots of stuff on the positive terminal and the negative would stop all voltage flow anyway. I did a little research and came to the conclusion he was correct and the IHBA 'positive side' was bogus tech. When you think about it even if you have a disconnect on the positive side any accidental short across the positive is still going to give you a big problem if you are dealing with a electrical fire or etc. If you disconnect the negative you have taken away any completion of the circuit. However YMMV :eek:

In preparation for the Phoenix race, we wired the disconnect switch in the 207 boat to the NEGATIVE (-) SIDE of the battery for the same reasons you mentioned. I'm going to ASSume the only test (besides a "visual" inspection) in the tech lanes will be to actuate the disconnect switch and then have the driver attempt to turn the engine over using the ignition switch...

[FC-Pilot]

One of my concerns with a disconnect switch in a boat has to do with the high vibration and bouncing that they deal with. Maybe not so much with the drag boats, but I thought about putting one in our Biese but decided against it because I have seen times when tire shake or vibrations have shut them off. You think about the bouncing of a boat in rough water and it would definitely be a concern.

Paul

[Norseman]

One of my concerns with a disconnect switch in a boat has to do with the high vibration and bouncing that they deal with. Maybe not so much with the drag boats, but I thought about putting one in our Biese but decided against it because I have seen times when tire shake or vibrations have shut them off. You think about the bouncing of a boat in rough water and it would definitely be a concern.

Paul


Paul

Another reason to run a mag!:D

Bob

[warpt71]

In preparation for the Phoenix race, we wired the disconnect switch in the 207 boat to the NEGATIVE (-) SIDE of the battery for the same reasons you mentioned. I'm going to ASSume the only test (besides a "visual" inspection) in the tech lanes will be to actuate the disconnect switch and then have the driver attempt to turn the engine over using the ignition switch...

We did it the same way for the PE114 boat and for all the same reasons. Tech is not going to pull the bottery cover (hydro, its in the sponson) to check which side of the battery it's conected to. Guess we'll find out next weekend?!?!?!?!?

[RiverRacer]

You "NEVER" put a shutoff/disconnect on the positive side, always on the negative. Without a ground you have nothing period!..

[warpt71]

Exactlly!!!! Rules were ment to be broken right? :D :D :D

[RiverRacer]

Exactlly!!!! Rules were ment to be broken right? :D :D :D

FK the rules, I've seen fires start by a spark connecting a positive with the ground connected!..:D

[AquaCraft]

For boats with alternators; if a battery disconnect on the hot side is turned "off" while the engine is running the motor will continue to run on the alternator current and the alternator diodes will "fry".

The exception is unless the battery disconnect is a special "field disconnect" type or there is an isolating diode wired-in to break the alternator connection if the battery switch is accidentally turned-off while the motor is running.

Will runnng the battery disconnect on the ground side get around this problem too and eliminate having to run a special "field disconnect" type switch or isolating diode?

[tunnelrunner]

For boats with alternators; if a battery disconnect on the hot side is turned "off" while the engine is running the motor will continue to run on the alternator current and the alternator diodes will "fry".

The exception is unless the battery disconnect is a special "field disconnect" type or there is an isolating diode wired-in to break the alternator connection if the battery switch is accidentally turned-off while the motor is running.

Will runnng the battery disconnect on the ground side get around this problem too and eliminate having to run a special "field disconnect" type switch or isolating diode?

My understanding is that it would make no difference whether the disconnect is on the positive or negative side. The nett result is still a break in the circuit.
Of course, Im happy to stand corrected....;)

[RiverRacer]

My understanding is that it would make no difference whether the disconnect is on the positive or negative side. The nett result is still a break in the circuit.
Of course, Im happy to stand corrected....;)

That is correct but there's too much chance of spark when turned back on with the ground on!.

[RiverRacer]

For boats with alternators; if a battery disconnect on the hot side is turned "off" while the engine is running the motor will continue to run on the alternator current and the alternator diodes will "fry".

The exception is unless the battery disconnect is a special "field disconnect" type or there is an isolating diode wired-in to break the alternator connection if the battery switch is accidentally turned-off while the motor is running.

Will runnng the battery disconnect on the ground side get around this problem too and eliminate having to run a special "field disconnect" type switch or isolating diode?

With an alternator you can take both cables off the battery and it will run, quick way to tell if it's charging or not!.:D

[Norseman]

That is correct but there's too much chance of spark when turned back on with the ground on!.

Art:

The spark will be the same wether you disconnect the positive or negative terminal to the battery. Current is current and you're completing the same circuit .

Bob

[hydroguy]

The spark will be the same wether you disconnect the positive or negative terminal to the battery. Current is current and you're completing the same circuit .

Not true, Energy does not like positive electricity, electricity flows from negative to positive. There is more of a voltage ramp when connecting the positive than there is connecting the negative last. and how many of you have shorted out the wrench when connecting the positive up last? not fun

[RiverRacer]

The spark will be the same wether you disconnect the positive or negative terminal to the battery. Current is current and you're completing the same circuit .

Not true, Energy does not like positive electricity, electricity flows from negative to positive. There is more of a voltage ramp when connecting the positive than there is connecting the negative last. and how many of you have shorted out the wrench when connecting the positive up last? not fun

Exactly!.....