Hi fellow BLF'ers,
Like many cautious of the risks inherent with Li-Ion cells, I am a supporter of Protected cells, especially when introducing our favourite high powered flashlights to beginners. We do recognise there is a time and place for unprotected cells, such as when dealing with high-current requirements, IMR, or some newer hybrid chemistries INR, NCR, etc.
(I think the rule is a little like sex :- always practice safe and use protection unless you want to produce some specific results!)
My personal preference is for protected batteries purchased from reputable resellers such as NiteCore, KeepPower, AW, XTAR, EagleTac, AWT, EnerPower+, and EFEST, amongst others.
These suppliers may add protection circuits, either of proprietary design (such as AW does), or provided by reputable suppliers (SEIKO is used by NiteCore). They might also modify the ends to provide a button-top or metal base plate under the protection PCB. The actual cell manufacturers (Panasonic/Sanyo, LG, Samsung, Sony, etc) do not afaik make protected cells themselves. Most don't even produce button-tops.
However, we frequently see coloured cells sold by the usual Chinese stores (GB,FT,BG,etc) listed only by the original cell manufacturer, but with protection included. I believe it is likely that the protection IC was added by a third-party and minimally re-wrapped to remain as similar in appearance to the original manufacturers colour wrapper as possible.
This opinion is based on the information provided by HKJ who states here https://budgetlightforum.com/t/-/15278 regarding the ’Panasonic NCR18650B Protected’:
“This battery is not made by Panasonic. The cell inside the battery is from Panasonic, the protection cirucit and the assembly work is done by somebody else.”
The sellers do not mention this fact and sometimes even use terms like "Authentic"; language which would further give the false-impression that the entire protected battery was made by the stated manufacturer. (My own opinion is that this is intentionally misleading).
These appear on nearly every seller’s site as a stock 18650 cell with the manufacturer’s original coloured wrapping, text and markings. Except they now have the addition of Button top (optional), Black 2-3mm plastic base (containing the IC), visible metal strip running down the side, with orange insulation tape over the metal strip. This style protection is identical regardless of the original cell manufacturer, lending further evidence to it being added by a common third-party.
There are some questions that seem to remain unknown:
- Who is adding the protection circuits to these cells?
- Do we know where the IC is made (Japan, China, Korea, etc), and by whom?
- Is there any evidence of the effectiveness or longevity of these protection boards?
- Are they always protecting against the critical three: overcharge, over discharge and short-circuiting?
Without knowing this information I would rather have quality and trusted protection IC added by the likes of NiteCore, Keeppower or EFEST, (preferably made in Japan), than an unknown IC added as an aftermarket mod to something that just appears to be from the manufacturer.
Hope this provides a useful discussion point and can possibly resolve some questions in which others may be interested.
Keep shining,
Hirsh