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Old 11-22-2015, 01:55 PM   #11 (permalink)
S Keith
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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.

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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