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Old 11-22-2015, 01:55 PM   #11 (permalink)
S Keith
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Quote:
Originally Posted by elhigh View Post
Okay, the longer GC didn't work. I left it on the charge for 23.5 hours. GC voltage output topped out at 180 for a while, but then dropped back down to 175-178. Output current never started to taper off. Looks like the pack's a bad 'un. I knew it was a gamble.

I have other motors to drive while the Honda is benched, so I'm going to:

Build a discharger and sock down the original pack. For future clarity, Pack 1.

The Honda is mobile with Pack 2 but the 12v light coming on is a little unnerving. I think Sweetie is happier driving a different car rather than rolling the dice. I tell her it's not much of a roll but frankly I can't blame her.
Sorry to hear it didn't work.

That's a very high peak voltage, but low temperatures can get you there. The drop is a little surprising. Were you running the fan? Are you using a Hybrid Automotive or a home-built? If it's home-built, and you're not running the fan, be very careful. Even the typical 350mA of a grid charger can cause a battery to cook if the ambient temp is high enough.

Output current doesn't generally taper unless you hit the power supply set voltage.

Just make sure you to a good solid grid charge before you deep discharge. That will ensure that the fewest number of cells will spend the least amount of time in the reversed condition.

Quote:
Also consider that there are many uses for the battery sticks that don't work in a pack. For instance, I have an old battery-powered hedge trimmer that would run maybe a minute on its original pack. Soldered in a couple of leads, duct taped a couple of sticks to the handle (to keep it nicely balanced), and it's run all summer on one charge. Not that I use it that much, but there were 3 or 4 half-hour or so sessions...
Indeed. I have 20A charger/dischargers that can discharge 300W regeneratively. That means they drain the test battery into the battery that is powering them. I have 4 strapped together (2 sets in parallel, then in series) that I use as a regenerative sink for testing other batteries at 20A discharges.

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