Last summer I get a call from the YC manager saying a transient was towed in the night before and needs electrical
Boat had motored all morning then sailed up from MA somewhere and it was getting late and the wind had died. Owner attempted to start the motor
and could not even get a click, click... When he shut the motor off he forgot to switch off BOTH... Dead batts, as in 3V when I got there. Batts were probably dead before he forgot to switch off BOTH because the alt was toast and he never knew it.. There was not enough wind to battle the tide, they tried for four hours, before ponying up for a tow.
Get to boat.
#1 Owner had been "charging" on BOTH only alt was dead.
#2 Owner had nothing but an analog volt meter that was grossly misrepresenting and not very visible
had died, blown diodes, and they never knew it until it was too late.
#4 Batteries were AGM
and by the time I tested them they were toast.
After a barrage of questions to the owner is was decided the alt had apparently died four days prior when he asked his son to switch to BOTH..
Consequences of these errors:
Tow = $$$$$ (did not ask what it cost, considering..)
Batteries = $$$$$$$$
three days of a Maine Cruise vacation
Pissed off Wife & Scared Son = Not Good!
While no one today uses Betamax no one today really installs diode isolators. Diode isolators are akin to Dinosaur saddles they have been replaced by better products. Still...
*Even a diode isolator would have left him with one good battery
*An Echo Charger
would have left him with one good battery
*A Combiner or ACR would have left him with one good battery
* The BOTH position & HEF left him dead in the water
HEF = Human Error Factor
Installed Echo Charger
Installed new batteries (he still insisted on AGM)
Added Voltmeter In Cockpit
Diirect Wired alt to house bank because the diodes were blown, which is usually a switch error...
Made a few other minor wiring tweaks to better help the AGM's charge better and hopefully last a bit longer..
Moral? BOTH Works fine, humans make mistakes
. Isolators, Echo/Duo Chargers and combiners/ACR's do not "forget"....
BTW it is only August and I am on my fifth blown alt repair from battery switch position blunders.......