by JoramsWeapon » Tue Apr 17, 2012 11:21 am
I second Kin's suggestion. I have purchased a large set of these batteries from SlyCayer, well it was at slightly lower price, but anyway most of them turned out to be great batteries for what I paid for them. They are easier to take apart than Makita packs and actually had superior discharge capacity than the Konion 18650V's despite having a slightly higher internal resistance. I'm not certain if this was because they had less cycles on them or if they're actually better batteries. I'm a happy customer and I can provide a quick review:
1. The type of LiMn cells varied far too much even though on the surface they are the same by model number. For example I had some that were 18650-15M, others were 18650-13Q, some were UR18650W2, and three rare occasions were 18650E "Made in Canada" a white-ish gray coloured cell. I have never seen a manufacturer jump around so much on the cells they use, it makes it more difficult to make parallel strings of cells.
I should rank the different cell types:
1. UR18650W2, these are the cells most likely to give the most capacity at the highest discharge rate with the lowest IR. This is my second encounter with this cell type, they provide the discharge rate of the Konion 18650VT with the capacity of the Konion 18650V's...they are the best IMO.
2. 18650-15M and 18650-13Q, they are quite similar cells but the latter version proved to be slightly better. I would say they are most similar to the Konion 18650V's we are so fond of although they did give about 100-200mah more under the same discharge rate.
3. The 18650E "Made in Canada". Every time I come across these cells they are junk junk junk. None of them put up more than 0.5C. That's the ones I bought from SlyCayer and from other sources, they just suck.
2. The BMS that decides that the battery pack is a 'failure' is not very good at what it does. I had some packs where the cells were practically brand new all cells good, then some rare others where even though their resting voltage was above 17V they just couldn't pump the amps and failed to deliver 1.5C. The "dead" cells could be random at any location in the pack. The Makita packs are much more consistent, you're virtually guaranteed to get 8 or 4 good cells out of a pack usually the same cell-group.
The most important thing to mention about these cells is that although they are LiMn they differ from the Konions is one important feature: they DO NOT self-balance. I was reading somewhere that it has something to do with the nickel-laced cathode but whatever it is they do not self-balance even when capacity and resistance matched. If planning on using any of these Milwaukee cells you will definitely need balance wires.