Guest Battery Switch

[Gregory Carleu]

I have the original Guest battery switch on my '87 Pearson 31-2. I want to have a "make before break" type switch, so that I can start the motor on one battery and then switch to the other, for charging, without hurting the alternator diodes.

Does anyone know if the original Guest switches are "make before break", or will I have to install a new switch?

Thanks in advance,

Greg

[Dan Pfeiffer]

Probably.   easy test.

With engine off, turn on a light and slowly switch battery from 1 to both to 2.  if light blinks off then you don't have make-before-break.

Dan Pfeiffer

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[Guy Johnson]

The original 1973 1-2-both switch on Puffin is make before break. I also have a zap-stop zener diode to prevent voltage spikes. 

Guy

Puffin 10M #6

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From: pearso...@googlegroups.com <pearso...@googlegroups.com> on behalf of Gregory Carleu <gregc...@gmail.com>
Sent: Wednesday, April 2, 2025 10:23 AM
To: pearson-boats <pearso...@googlegroups.com>
Subject: [pearson ] Guest Battery Switch

 

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[Guy Johnson]

Apparently West Marine no longer carries the "zap stop" diode. I found this online. 

https://www.cruisersforum.com/forums/f14/zap-stop-fact-or-fiction-29442.html

Zap Stop - Fact or Fiction ? - Cruisers & Sailing Forums These are two different causes of Alternator failure: Open circuiting the Alt' output causes a very rapid voltage rise, which will dammage (instantly fry) the diode trio rectifier. The 'Zap-Stop' (Medium Current Overvoltage Transient Suppressor - Motorola #MR2535L zener diode) conducts this transient voltage to ground, protecting the alternaor. An alternator field disconnect, on your batteruy ... www.cruisersforum.com

The 'Zap-Stop' (Medium Current Overvoltage Transient Suppressor - Motorola #MR2535L zener diode) conducts this transient voltage to ground, protecting the alternaor.
An alternator field disconnect, on your batteruy selector switch, can also help prevent the most common cause of open circuiting the alternator (when Batt Sw set to 'Off', /w engine running).
Install a Zap-Stop.

Guy

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From: pearso...@googlegroups.com <pearso...@googlegroups.com> on behalf of Guy Johnson <guy...@hotmail.com>
Sent: Wednesday, April 2, 2025 11:12 AM
To: pearso...@googlegroups.com <pearso...@googlegroups.com>
Subject: Re: [pearson ] Guest Battery Switch

 

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[Last Resort]

I have the same switch and changed ALL the time, just don't go through "OFF" when doing it. Switching between 1,2 or ALL isn't an issue.