Battery Switch

BMsuper

Cadet
Joined
Jul 3, 2008
Messages
15
I recently purchased a 88 Starcraft Islander with a single battery setup. I want to add a second battery with a "perko" type battery switch.

I have read somewhere that you cannot switch batteries with the engine running without damaging the alternator, unless, you have a "make before break" type switch. Is this true?

What type of switch (brand name) can I use that is a "make before break" switch so I can switch batteries while the engine is running if I want to? Where can I get one?

Any other information on battery switch use or installation would be helpful. I am new to boating.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: Battery Switch

Most of the new style switches are make before break so it is not much of a concern. Check the manufacturers web site before you buy. The specs will tell you if it is or isn't.
 

BMsuper

Cadet
Joined
Jul 3, 2008
Messages
15
Re: Battery Switch

I've read many, many threads regarding the two battery setup.

I've decided to install a Deep Cycle Marine battery to run the GPS, Fish Finder and Radio and use the start battery for starting only. I will charge the deep cycle when I get home, (I keep the boat on the trailer at home).

I carry jumper cables and a boost box in case the start battery does not do it's job.

Do I need to disconnect the start battery or deep cycle battery when the boat is home, not being used?

Any other ideas or suggestions, this is all new to me. This forum is a life saver.

Thanks, Bob F.
 

fishmen111

Chief Petty Officer
Joined
Feb 1, 2008
Messages
637
Re: Battery Switch

The Perkos are a "make before break" design. You'll be fine, just read the instructions well.
 

BMsuper

Cadet
Joined
Jul 3, 2008
Messages
15
Re: Battery Switch

Fishmen,

Which perko should I get? They make one that disconnects the field from the alternator or just a standard one. Will the standard work if both are "make before break"?

Thanks, Bob F.
 

fdmsiv

Petty Officer 1st Class
Joined
Mar 2, 2008
Messages
283
Re: Battery Switch

Unfortunately Perko is still selling the older non-making before breaking switches. Make sure you get the right one, if I recall the non making model number is 8501, the making is 8503 or something along those lines. If you are at a store and they have two switches appear identical but one cost more, be sure to read the package carefully. I recently purchases one and was about to go with the cheaper one, but I decided to take a closer look.
 

fishmen111

Chief Petty Officer
Joined
Feb 1, 2008
Messages
637
Re: Battery Switch

8501 is non-locking, 8502 is locking, 8503 is non-locking alternator interupt in "OFF" mode and 8504DP is the locking version of 8503. I could be wrong, but I believe that all four Perko two battery switches are a make before break design. My understanding is that the 8503/4 only offers some protection to the diodes/rectifiers if accidentally turned to the "OFF" position while the engine is running. Keep in mind we are talking about switching batteries while running...not turning the switch to off which should never be done regardless of switch make or model until the motor is turned off.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: Battery Switch

If your boat is an outboard, you don't need the field disconnect feature. Thats for inboards and I/Os. Actually, unless you also have a trolling motor, you really don't need a second battery if you are carrying a jump box. The locator, lights, and other stuff doesn't really draw that much current. What it does require is that you should have the biggest capacity Marine Starting/Deep Cycle battery you have room for. Your engine will keep that battery charged provided you make some reasonably long runs or if you charge it back at the dock. No sense adding weight where it really isn't needed.
 
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