Re: charging while fishing
Rabbit is correct about "killing" the batteries.<br />Now for the "don't make and break connections on live circuits" sermon.<br />The "life safety" part.<br />First of all, even with outboards, the fuel tank is usually inside of the boat, and as we all know, fuel vapors are heavier than air....so they stay close to the floor/bilge. Where are our batteries ? Usually on the floor. What happens when we connect or dissconnect a large current draw....SPARK! What NOT to have around fuel vapors.....SPARK.<br />OK, Now we come to the "I don't want to damage stuff on my boat part". Electronic components (from alternator diodes to fish finders) like a nice steady voltage within their range. Voltage spikes will either kill something right away, or it may take several times to damage them.<br />Even with a good Marine battery switch (should not make any sparks) if your engine is running and charging the starting battery (it was used for 5 seconds and should not be anywhere close to dead)your charging system is just topping off the battery....then you throw the switch to the "dead" trolling battery....everything (diodes, regulator, etc.) has just went from "loafing along" to a split second later of full current draw. While this is not good, it probably won't kill anything (your ignition system will not appreciate going from a happy 13.8 volts down to....10 volts).<br />Now for the real problem :you started, switched over to the dead trolling batteries, you pull anchor and drive 10 minutes to the next spot and flip back to the starting battery. In an instant, your charging system has went from full fielding(putting out every available amp trying to get those dead batteries back to operating voltage) to...... no load at all. The diodes and voltage regulators have just went beyond their maximum voltage( if they didn't just cook) for a split second or two there could have been 18+ volts flowing out to your ignition system and accessories (might have been absorbed by the battery....might not) your fish finder just went into cardiac arrest.<br />Yes, this is extreme. Will it happen ? Most likely not....could it happen? YEP
