T-Pain Is On A Boat: Re: [Electric Boats] battery charging question...

Monday, August 19, 2013

Re: [Electric Boats] battery charging question...

BINGO!

I checked on the batteries tonight, afer leaving them on the charger overnight. The voltage was up, but died as soon as I unplugged the charger.

I checked the water level as you suggested. Though the batteries were relatively new, they were bone dry. I topped them off, and they are now (hopefully) *really* charging now. Will check on them again tomorrow...

From: matt elder <mattelderca@yahoo.ca>
To: "electricboats@yahoogroups.com" <electricboats@yahoogroups.com>
Sent: Monday, August 19, 2013 11:40 AM
Subject: Re: [Electric Boats] battery charging question...

What is the electrolyte level in the batteries?If they are extremely low you can get readings like this.

mattelderca

From: oak <oak_box@yahoo.com>
To: "electricboats@yahoogroups.com" <electricboats@yahoogroups.com>
Sent: Monday, August 19, 2013 12:25:23 PM
Subject: [Electric Boats] battery charging question...

Curious issue....

I went out to the boat Friday evening. Checked the battery bank voltage for the 48V Torqeedo - the display read 56V (fully charged, maybe a tad high). Note that the charger was still plugged in. I left the Torqeedo "on", but unplugged, cast off, and motored out using the GAS engine.

When I checked a few minutes later, the motor indicated an error: Dead batteries.

Back at the dock, the battery voltage for the batteries read almost zero. Very strange. To go from what I thought was fully charged to completely dead without running the motor? I could understand a short - but that would generally also give lots of smoke... I went ahead and unplugged the charger from the battery bank and went home for the night.

The bank is made up of 4 x 12V deep cycle lead/acid marine batteries. They are relatively new (9 months old?). Not used much. The charger is a Soneil 48V, 2A charger from Thunderstruck.

Since I suspect the charger, and hope the batteries are still good, I bought 4 cheap 12V chargers locally, and took them out the next day.

By now, the battery voltage on all 4 batteries "floated up / recovered" to 9V. This was borderline too low for a trickle charger to work - they tend to read that voltage and shut down, rather than try to charge. I had also brought along an "old school" charger (probably a transformer and diode inside) that I put on each of the batteries for about 15 min to bring it up enough that the 4 trickle chargers would work....

Once I had all 4 trickle chargers going, I was able to turn the Torqeedo on, and run the Torqeedo (at VERY LOW POWER) for a minute or two, just to ensure that the motor and wiring was good. All seems to be ok.

SOOOOO>>>>>

Is it possible to have a battery bank that is essentially DEAD, but still reads enough voltage (at no load) to trick the charger into thinking it's fully charged??

How does one get a "smart charger" to fully charge a battery?

We've had a couple of weeks of temps over 100 degrees (which would be VERY hot inside the locker in the boat). Would this likely be the problem?

I'm still tempted to build a batch of "old school" chargers that just dump a regulated voltage at low current... But I haven't found a good schematic for anything that I can easily put together to put out up to 2 amps.