michaelwatkins
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 p.1 #13 · From which eBay'er to buy NEX-5N replacement batteries? | |
I am less sanguine about no-name sellers of no-name batteries, which make up the bulk of eBay sellers. I've got even less time for sellers of no-name chargers.
Lithium ion technology is not intrinsically safe. This is why you do not see lithium ion rechargeable bare cells for sale at your grocery store but you will find at various retailers intrinsically safe rechargeable cell technologies like Nickel Metal Hydride.
Li-ion cells can be used safely if used within an overall system (cell / pack, consuming device, charging device) where each component is designed with safety in mind and is sized properly for the task at hand.
In another part of my life I've unfortunately had to become something of an expert on lithium ion and lithium polymer rechargeable power solutions and chargers for same. While the cells and battery packs are physically different than the cylindrical mostly lithium cobalt based lithium ion cells found in laptops, the underlying chemistry and charger requirements are exactly the same. LiCo are the least stable formulation of li-ion cells, but also the most common as they offer more storage capacity for volume than some of the safer varieties. If managed correctly (by the device consuming power from them - check, we assume companies like Sony and Ricoh do this; and by the charger) they are more than safe enough.
I started writing my standard li-ion lecture but am going to ditch all that detail and cut to the chase a little faster than I ordinarily would, which still won't be a bullet point or two.
Cells / power packs: budget makers often skimp on quality, or the truth, and certainly on product support; I'm aware of factories that purchase cast off materials from the established quality makers. There are a handful of terrific makers in China whose production is sought after and spoken for by multi national OEMS. There are a whole bunch more makers of questionable or variable quality. Unfortunately it is very difficult to trace who made what unless one is willing to open up and often destroy a pack in doing so, and even that is no guarantee you'll be successful in IDing the less reputable makers, although the quality makers generally are not ashamed to mark their products properly.
Further complicating matters, often the cell producer is not the same outfit as the pack maker.
As buyers of budget power packs you can't know if the innards are coming from one of these lesser cell producers. Some pack makers change suppliers as often as they change their underwear, whatever is cheapest today, please. This is no way to make a quality safe product with chemistry that can react very badly when things go wrong.
Chargers: You'd think this is a simple thing to get right, given that there are charger-on-a-chip components available for pennies in volume that properly implement the Constant Current/Constant Voltage algorithm.
CC/CV is *the* proper way to charge li-ion cells. In addition any decent charger needs to be on the look out for under and over voltage situations. In one case wildly out of spec voltage can indicate a serious problem with a cell or pack and that deficiency must be made known to the user so that the user can take appropriate action: safely dispose of the cell/pack. In the other case the cell/pack is slowly or rapidly becoming a small time bomb at worst, presenting a vastly increased risk of fire while still on the charger at best.
Do no-name chargers properly implement the CC/CV algorithm and do they enforce charging cut off at a sane maximum voltage and do they never do anything remotely looking like "trickle charging" and do they warn of under and over voltage situations when a cell or pack is placed in the cradle?
The answer is: you just don't know. Nor do I, unless I am given a charger for testing.
I can tell you that across dozens of chargers commonly sold for use in a non-photographic part of my life, only one properly implemented the right charging algorithm and safety protocol. One out of dozens tested.
Another was close enough to be considered safe to recommend to others to purchase. A handful were actually dangerous if used without monitoring closely by someone equipped with both knowledge and a digital multi-meter.
Others did bad things like keep a constant but low voltage on the cell even after the charging light went out... leaving a cell/pack on such a charger will ultimately lead to the cell reaching a critical voltage threshold where it starts to break down rapidly as heat reaches a point where thermal runaway occurs. Big shooting flames and toxic, caustic, fumes are the byproduct of this reaction.
A bunch of others couldn't be called time-bomb makers but failed to even approximate the CC/CV charging algorithm that lithium ion technology requires.
To my knowledge no one has undertaken a serious review of camera power packs and chargers. Maybe by virtue of the consumer nature of this market, there are fewer really bad actors out there. Maybe.
Recommendations:
Personally I'm not willing to assume anything about the too-cheap li-ion pack and charger products out there - I try to source the best deal I can on OEM power packs, and I only use OEM chargers. That would be my best recommendation for anyone.
However... if you are going to dabble in third party power, at least consider buying a third party power pack that is sold by reputable retailers and has been sold through the retail channel for a long time. At least then if there are problems detected, the retailer might just be in a position to contact its customers of these products. As well, hopefully the larger retailers are establishing relationships with more solid producers of packs.
And chargers: unless you've got the knowledge and equipment to test them yourself, I just can't see a way to recommend buying a third party charger from a no name / brand of the day/year internet marketed entity.
If you are at all worried about the gear you already have, and happen to have a digital multimeter, check the open circuit voltage of your lithium ion power pack. As long as it near or below 4.15 - 4.19 volts per cell then the charger is at least signalling to you, correctly, when the pack is charged. The NEX-5N pack contains two cells wired in series, so divide the measured voltage by two to come up with a per cell estimate. Note: the nominal voltage printed on the pack (usually 3.6 or 3.7V) is not the charged voltage of the pack. Standard li-ion cells commonly used in these packs should never be charged beyond 4.2V per cell as they start to become dangerously unstable not far after that operating maximum.
When the charge light goes out, remove the pack from the charger. Don't leave packs in chargers overnight or over a weekend unless you are certain that the charger absolutely 100% stops the charging process completely when the charge light goes out.
Phew. I'm taking my camera outside now.
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