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Discussion Starter · #1 ·
my apologies to Leonard for taking so long to post this, the last 3 months have been pretty crazy :)

Standard format and declaration - Leonard had the US distributor send me 2x 4 cell silicone case batteries, 1x 6 cell shrinkwrapped battery and a 1A 8.4V wall charger to test. I get to keep the batteries and received no financial compensation or direction from Xeccon to do this test. In fact, I've already given away 1 of the batteries (rewired 1S4P for a friend) and the other 2 will go towards making power packs for my hand tools, so other than materials, there's not much in it for me :)

Background - I've been building bike lights since 2000 and LED lights and li-ion batteries for the last 3-4 years. I have a hobby charger which can give a rough, non-calibrated battery capacity but I am far from being an expert in things electrical (I'm a biologist, FWIW).

Capacity testing. Each pack was hooked up to a ThunderAC6 hobby charger using a Magicshine plus spliced onto a couple of banana plugs (this is how I charge my own packs). Each pack was charged at 1A or 1/2C. I also charged each pack with the supplied charger (1A). Each discharge was set at 1A (the max my charger can do).

average and SD at the end
4 cell 1 4291 4267 4390 4228 4294 69.0651866
4 cell 2 4362 4349 4438 4428 4394.25 45.24286316
6 cell 6426 6390 6386 6440 6410.5 26.65207934

Capacities are about what you'd expect, given cell variability and the (in)accuracy of my charger. Stated capacities are 4400mAh and 6600mAh, so my results are pretty close to that. The charger had a slightly odd behaviour in that it wouldn't hit a full 1A discharge (between 0.6-0.8A) for any battery, even though these batteries can clearly provide more current than that. I'd chalk that up to an artificial interaction between the charger and the pack PCB.

I also checked the PCBs for short protection and each tripped as they should. Each also reset on the charger as expected. I can't test overcurrent (I don't have anything that can draw lots of current from an 8.4V pack) or overdischarge (my charger won't discharge below 3V and my lights turn off at 3V), but I'd imagine those would work as stated as the parts are pretty standard.

When I did a teardown, I also wired up 3 of the cells from the 6 cell pack in a 3S1P configuration to run my bar light (2 XM-L @3A driven by a h6flex, so ~1.8-2A from the battery)), without PCB. When I did a run down test it lasted almost exactly 10% less time than my 3S1P 2500mAh Panasonic battery, so the cells seem to work as expected in relatively high drain situations (a bit less than 1C).

Now onto the teardowns:

4 cell pack

Things I liked:
- the silicon case was awesome. Looked like it would do a great job sealing the battery and providing some protection from drops

Things I wasn't sure about:
- how on earth are you supposed to use that strap? I spent a good while trying to figure it out, then sent it to my friend instead.

Things I didn't like:
- bad spot welds. The metal strips connecting the cells came off far too easily and didn't leave any metal behind, which indicates that the weld wasn't complete. I've pulled apart ~60 laptop packs to harvest cells and they're all a complete b!tch to get a part - these ones I could pull off with my fingers. There were also several missed "hits" where the weld only partially hit the strip or missed it entirely. Although these welds shouldn't fail, considering how tightly the cells are strapped in with shrink wrap and silicone cover, it's a something Xeccon should look into for durability reasons, especially given the high vibration environment bike lights are used in.

6 cell pack

Fewer pictures this time, although more details on the spot welding.

Things I liked:
- I could understand how the straps worked

Things I wasn't sure about:
- how waterproof the pack would be. I know people have had problems with similar style packs and riding in the rain, but I imagine this has been dealt with by the new hard case pack

Things I didn't like:
- those spot welds again. Super easy to pull off, lots of missed hits with some missing the +ve terminal entirely and hitting the top of the cell itself. This should be something Xeccon takes up with it's supplier.

I think that these are decent packs with capacity around their rated specs - the cells certainly seem fine, with nothing to raise any suspicions during my testing (coped fine with high drain, didn't self discharge). I liked the silicon cases and some of the external cases (although one of the 4 cell cases still has me scratching my head). The charger seems to do its job and terminates within battery spec. Build quality isn't great and raises some long term durability questions (although I can't comment on the long term durability of the cells themselves), which hopefully Xeccon will be able to address.
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