Easing Through Airport Security
For my recent work trip to South Africa I thought I'd take Andy's advice in respect of getting some lithium cells through airport security safely in the guise of a USB power bank. I bought a 4-cell plastic job off ebay. A 3-cell aluminium one like Andy found would be better for sure. I was only populating this one with 3 cells, and if I filled the slot nearest the switch with a cell it would jam on!
I had hoped to fill it with some protected lithium cells already in my possession, but the extra length was too much for the holder, meaning that I had to buy some new, unprotected 18650 cells.
So, it went through Manchester airport without comment whereas a small Hobbyking pack I also took got swabbed.
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| Cheap 3-cell holder with spiral spring contacts - Avoid |
For use on the hill top I had a cheap series-wired 3-cell holder. This had worked Ok with the protected cells, which have a nipple at the positive end. But my new cells have a nearly flat end. On test at home the pack seemed Ok, but on the summit it would not behave and appeared open-circuit. Another attempt on my second summit saw some benefit from strapping tight with cable ties, but the contact was still not sufficient for providing useful power and I had to admit defeat, resorting to my back-up pack.
On my return I took some time out for a refit. By now I had two new 3-cell holders that I knew were too tight for protected cells, and proved just right for my new ones. So I wired one in 3S1P configuration with a Powerpole charge/discharge lead and a JST balance lead (from another ebay seller).
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| Powerbank, new 3-cell case and some JST leads |
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| Ready to rock |
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| A mess of wiring plus hot-melt glue |
The cells had already been charged in the powerbank, but took another 800mAh from my S60 balanced charger. This pack is now ready for my next activation.
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