John,
Part of the problem is that unlike a car a boat can have large draw items like a frig or even heaters running on shore power. Most Car (or Cheap) chargers do not have the ability to step back in there charging routine to lets say from trickle to maintenance. This means that the charger can be over taxed. Not sure which ones can or don’t but I have one of the Top of the line BRUSA chargers and it doesn’t but I charge a Propulsion bank that charges a House bank so the drop is within its set point for about 30 days. I then have to reset the Brusa to start the run time over.
Steve in Solomons MD
From:
Sent: Friday, October 26, 2012 11:20 AM
To:
Subject: Re: [Electric Boats] Re: Lead battery charging
Well, this is part of what is driving me to wire up my own charger.
The "smart" systems are probably GREAT for high tech batteries and for charging as fast as possible.
But if I'm sitting at a dock, with shore power, and have all week to charge - a small DUMB charger should get the job done.
And then it's simple enough to test with a voltmeter and see if it's putting out power (works) or not (broken).
With the smart chargers - how do you test the thing?
It won't show voltage until it senses a battery.
And even then, it's hard to tell whether the charger is putting out any current or not. I guess I should be able to put an ammeter in line with the charger and see what's going on.
John
From: Andrew Gilchrist <andrew@fastelectrics.com>
To:
Sent: Friday, October 26, 2012 3:40 AM
Subject: RE: [Electric Boats] Re: Lead battery charging
John
have a think about how much information you got with you last lead acid battery.
Now how much do makers care?
From:
Sent: Friday, 26 October 2012 2:15 PM
To:
Subject: Re: [Electric Boats] Re: Lead battery charging
Surely the manufacturers wouldn't expect those boat owners with "maint. chargers" to disconnect them every time they went out??
Or are you saying that it's ok to have it connected, just not powered?
(thinking out loud here, correct me if I go astray...) The charger is a power supply. If there's a diode and a current limit resistor, it should be protected. If the charger gets unplugged, while the battery is still attached, the diode keeps the battery from discharging into the charger. If the voltage goes up (from an alternator), the diode should still prevent back current into the charger. If the voltage of the battery / system goes down due to heavy load, the current limit resistor should keep the power supply (charger) from being able to source more current than it was designed to. IF that should be exceeded, there should be thermal limits in the regulator devices that shut down the regulator.
In the case of one of my chargers, there's also a fuse that blew. Though now I have to go back and figure out if it's because of running the charger when the motor was running (trying to drain too much power from the charger - which should have been protected as described above), or if it was from some dufous switching the leads at some point. Though one would think that if the leads had been swapped, OR EVEN if it was just overcurrent that blew the fuse, the little green LED on the charger shouldn't stay lit....
John
From: don cavers <doncavers@yahoo.ca>
To: "electricboats@yahoogroups.com" <electricboats@yahoogroups.com>
Sent: Thursday, October 25, 2012 8:26 PM
Subject: [Electric Boats] Re: Lead battery charging
A fast way to kill most chargers is to draw power while they are connected. The charger is designed to 'push' amps against the resistance of the battery. If you draw power you are bypassing that resistance and it is easy to overdraw the charger, and fry it. That is why some chargers have a "start" position whose use is supposed to be limited to seconds.
Don
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