Also, a couple of the batteries sustained small nicks (very small… much smaller than the one pictured above), either on the top+ corner or somewhere else, of the wrapper. I don’t have any kapton tape or heatshrink. I had read that clear packing tape could be used to repair those, and was wondering if this is true?
The white stuff is just silicone adhesive, use a dull knife and/or fingernail. Just something that won't cut the heatshrink.
Look at my pic in the first post, with the three batches of four laid out. In that position, cut between each batch with scissors. Then with each batch, grab the tab with needle nose pliers, and roll it until it pulls the spot welds loose. Then unroll/straighten the bit you just pulled loose, get a new bite at it, and roll again. No need to separate the 4 cells before removing the tabs.
Yes 4 cells out of my 24 had spots like that at the top corners. I re-wrapped them. If the spots were down on the middle I'd say tape would be fine, but that close to the positive I'd only feel safe if they were re-wrapped.
84 cents. Get some. http://www.fasttech.com/products/1616/10001953/1140200-29mm-heat-shrink-wrap-1-meter
Yes, the nicks were from when the tabs were spot welded, some of mine were on the inside of the group-of-four, no way it could have been done otherwise.
I don't know if a hairdryer is hot enough. I use a butane soldering iron with no tip screwed into the hole in the end, so it just blows hot air out the end. Endlessly useful thing to have on hand. (http://www.google.com/search?&q=ST250K)
I would tape up the damaged ones... and store them away somewhere safe until you get the heatshrink.
Yeah, it doesn't take a lot of heat, it's easy to overdo it with the torch and pop a hole in it. With the torch cranked down low it's great, quick enough that the cell never feels warm.
Funny thing about heat, whether it's soldering, or heat guns, or welding... sometimes a higher temp keeps the workpiece cooler, because you spend less time pumping heat into it. I've ruined way more stuff from using not enough heat than from too much.
BTW, I’m planning to try the discharge on one of the 12 tonight (one of the clean ones). Will post back. I want to try that setting to see if it doesn’t stop midway, anyway.
I've done a top-up/discharge/charge/discharge on a few of them so far (before I got distracted by the Fujitsu packs) and the numbers don't look too hot. But this whole hobby charger thing is completely new to me, so I need to play some more before I know how the numbers I get relate to reality.
Sorry about the “distraction” :)… but it was a good one, right, I hope :)?
So what kind of numbers did you get, so we can compare?
I’m doing a charge on one of them now, and then I’ll do a discharge to 3.0V (since I got help here… I turned the safety time off, and will be watching it “like a hawk”, esp. after this afternoon’s “adventure” (sparks, smoke, and burning odor).
I grabbed 5 at random to test but only finished 3 of them, but they did 1321, 1338, & 1340. 1A down to 3.0V. But, I haven't done discharge tests on any other brand/capacity cells to know how the numbers from the Turnigy relate to the advertised capacity.
Did you see the pic I posted in the other thread about the 'distractions'?
I haven’t dared do that yet, too, so post back, either in this thread, or, maybe another thread, if you do that? Can you also include details of your setup, etc. if you do do that?
Going off of your sig, this is a learning experience…
Here’re the final numbers for the one randomly selected (but good wrapper) battery from the pack. Again, my Accucell is set with safety time to “OFF”, for these, and both charge rate and discharge rate were set to 1.0 amps:
1st Charge: Time: 71:58, Ending Voltage: 4.20V (confirmed with separate DMM also), 597 mA
Discharge: Time: 147:39, Ending Voltage: 3.00V, 2257 mA
So, it looks like the capacity (down to 3.00V) for this battery is 2257 mA.