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Battery isolator switch

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I just purchased a perko battery isolator switch. I tried to install and couldn't get it to work out. I either couldn't get power to the radio or couldn't start the boat. Can anyone help with step by step directions on where the positive and negative cables should go? Or at least let me know where the power for the radio comes from?

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All negatives are in parallel and without isolation.

Post one on the back of the Perko gets connected to battery one positive.

Post two gets connected to battery two positive.

The alternator feed, helm buss and all stereo equipment, whether directly or indirectly, will be connected to the perko common post.

Nothing but the Perko switch will be wired direct to the batteries. The only exception would be a float switch and bilge pump if applicable to your situation. Although you can run your source unit memory battery direct, most do not since this creates a draw during long periods in storage.


Earmark Marine

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If it's just the on/off switch, all you should have done was disconnect the red wires off the battery and connect them to the rear of the Perko (the 'C', or common post). Then you would need to have ran another wire from the other post (the '1', or Battery 1 post)on the back of the switch to the place you took the red wire(s) off your battery, effectively just interrupting the original red wire(s).

Did you buy the switch with the field disconnect option? If, so, are you using them for anythng? You should not be using them unless you ran the appropriate wires back to your alternator.

EDIT: Also, if you did hook it up properly, you must be sure you used the proper gauge wire from the switch to the battery...at least 2 gauge with proper and well done terminals on both ends. ALL the current used to start your boat will run through this wire.

Edited by RTS
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I have the Perko, 2 battery switch also.

When in the "both" mode, does that mean that twice the current essentially goes to the starter? And is the overall best position to run the boat in? Thanks again,

Steve B.

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No, twice the current will not go to your starter (spinning it twice as fast) but you have twice the current available, if that makes sense. According to Kirchhoff's circuit laws, with the switch on both, you will have the 'normal' current going from the switch to the starter, but half the current going from each battery to the switch. Theoretically. Each battery would have to be at the exact same voltage and draw down symmetrically as the key was turned and starter engaged.

And which setting to 'normally' run is largely a matter of preference, and what you do when you are 'parked' in the boat. I have the stock stereo (no crazy battery draining going on when the engine is off), so I set the switch to either 1 or 2 to start my day, then about halfway through the day I'll switch to the other.

Edited by RTS
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