AA Li-on - how can they be AA

no

Reply to
The Natural Philosopher
Loading thread data ...

The reason I think it's dodgy, is whilst you are right, I have this nasty suspicion that the embedded electronics are going to be a source of trouble because they'll be cheaply done.

Reply to
Tim Watts

They aren't in fact cheaply done at all and are in fact a very decent buck converter and not just a primitive passive regulator.

Reply to
JHY

How do you know? Stuff from China is so variable. Does this particular company have a good reputation?

Reply to
Tim Watts

No, but someone has taken one apart and published the results.

Its a one chip regulator. The charge circuitry is additional to that.

Reply to
The Natural Philosopher

The teardown shows that.

formatting link

Yep.

Reply to
JHY

That is interesting. I guess the terminal voltage of 1.5V is a boon. I assume it's reasonably abuse-proof (short circuit protection and over-discharging protection)?

Reply to
Tim Watts

That's what the teardown says. I haven't actually checked the datasheet on the ic use myself.

Reply to
JHY

Is exactly right! :-)

Really efficient buck converters can attain better than 98% efficiency so, assuming a worse case 90% efficiency (at the full 2A limit), is a fairly conservative estimate.

It's a nice idea, spoilt in this case by the abysmal lack of WH capacity

- it needs to be at least double to make it worth the expense.

I notice the use of gold plating on the battery contacts, a justifiable expense in view of their already premium price point. A premium NiMH

2.4AH LSD with gold plated contacts would be a far more cost effective solution to the problem of AA powered kit since it's the increasing contact resistance with age/usage of the LSD NiMH (aggravated by the low initial cell voltage) that causes their seemingly early demise.

The end point of 1.2v for both NiCad and NiMH isn't the issue compared to the endpoint of 1.0v typically chosen for Zinc/Carbon or alkaline cell powered kit. It's the increasingly unreliable contact resistance due to tarnishing of the contacts of a cell type that's expected to be good for at least 10 charge/discharge cycles or more (500 to 2000 cycles) compared to the one time use primary cell where you get a brand new untarnished set of battery contacts every time you replace an exhausted cell.

TBH, I'm surprised no entrepreneur has stepped in with an "AA Cell contacts Gold plating kit" (using scrap gold as the 'feedstock' to minimise running costs, possibly including electro-plating 'recovery' from truly worn out cells to minimise running costs even further).

Gold plating the contacts aught to take the re-cycling life in a high current device such as a camera up from the 3 to 5 discharge/charge cycles typically experienced in this usage case to something more like 3 to 5 hundred cycles.

Reply to
Johnny B Good

ISTR that gold electroplating involves some rather toxic chemicals, cyanides or some such, which would probably discourage most entrepreneurs.

Reply to
Windmill

Not necessarily.

formatting link

Odd that it doesn?t with electronics.

Reply to
JHY

====snip====

After reading a couple of wikipedia articles on the subject of plating in general and gold plating in particular, this doesn't seem to be a viable after-market project. It looks like an option best left for the battery manufacturers to implement as a 'premium grade' offering.

It's such a cheap way to allow NiMH cells to realise their promised 500 to 1500 charge/discharge cycle lifetimes and solve the problem that the lithium + buck converter chip cell is attempting to solve (that looks

*so* like "A solution looking for a problem to solve"), I'm surprised such 'premium cells' aren't already being marketed.

Perhaps the advent of the lithium AA cell will awaken the NiMH cell manufacturers to the need for such tarnish proofing of AA NiMH cells' contacts.

Reply to
Johnny B Good

It's a red herring as the entrepreneur would contract that out anyway, like they would with PCB manufacture and probably a good deal of the rest of the manufacturing process.

Reply to
Tim Watts

I'm not convinced that a chinese battery manufacturer would do that.

Reply to
JHY

FS312F-P is commonly used

Reply to
Steve B

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.