07-21-2019, 05:59 PM | #11 |
Member
Join Date: Jan 2016
Location: uk
Posts: 127
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Hi Les,
yes that's it!..just make sure the tape does not catch on the plastic pegs that stick up from inside the box. I weld my cells....you can solder them but you need a high wattage iron and don't spend more than five seconds on each joint and hive the batteries time to cool. I made a battery welder, the power source is a motorcycle battery, I used a pic micro and a logic level fet transistor. It calculates the voltage and current so each weld has the same energy input..although this is not really required as a simple timer can work well. I also prove the pack before potting and make sure you use the semi rigid compound not epoxy..it's too hard. |
07-22-2019, 03:48 AM | #12 |
Junior Member
Join Date: Jul 2019
Location: New Zealand
Posts: 15
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Hi Dorrington,
Thanks again, i was going to ask what checks you did before potting. Can't get that potting mix here but found a 3M product. Very expensive though. Cost about NZ$156. Had you thought of using adhesive like Ados F2. This seems to stick batteries to each other well but is flexible enough to move slightly. Although the original packs were expoxied together so no room for expansion here. So if removal is needed its not to hard. Last question, what size batteries have you been packing with. I bought some Xcell sub c 3600mah from Nikon after getting some for testing to see what the true capacity was. They turned out to be 3400mah if discharged to 1.0v. How many of these battery packs have you done and have they been reliable. ie. not had to replace a cell. Regards Les |
07-22-2019, 05:04 PM | #13 |
Member
Join Date: Jan 2016
Location: uk
Posts: 127
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Hi Les
whatever stops the cells rattling around is good.... as far as cell themcells....I generally use https://www.ebay.co.uk/itm/10er-Akku...72.m2749.l2649 I re-touch all the welds as they rubbish. but the cells have been good so far only one actual cell failure in six packs. I have rebuilt 10+ nimh batteries and 6 or so saphion. Hope this helps... |
07-23-2019, 03:27 AM | #14 |
Junior Member
Join Date: Jul 2019
Location: New Zealand
Posts: 15
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Hi Dorrington,
Thanks you have been a great help .Great choice of battery pack, very convenient way for rebuilding. Of the one pack where you had a single cell failure were you able to remove it? I see it looks like they epoxy the cells together.My first thought was to use epoxy to make up the 10 cell packs but should i get a cell failure it would be murder trying to replace it. I received my 120 cells today and on first check with meter had only one that read ov. Attempting to charge it to see if its ok. Regards Les |
07-26-2019, 11:29 AM | #15 |
Member
Join Date: Jan 2016
Location: uk
Posts: 127
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Hi les,
the bad cell was easily removed and a substitute welded in place. my cells were shieink wrapped but otherwise loose. hope you recovered the cell, let it sit for a few days before you build the pack and test it again..a capacity test would be better, |
07-26-2019, 04:19 PM | #16 |
Junior Member
Join Date: Jul 2019
Location: New Zealand
Posts: 15
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Thanks,
After charging the cell i let it sit for 24hrs and its had only self discharged to 2%. I am going to charge it fully then see what capacity i get. With your packs being shrink wrapped, replacement should be easy. I have started my repack, used Ados F2 and when packed as 10 cells seem to be fairly solid. Maybe if i wrap the packs with tape then further glueing will not be needed.What do you think? I am trying to avoid making the packs to permanent in case of cell replacement. Do you hot glue your packs into the case?. Regards Les |
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