One thing that impressed me was that across 16 cells, the voltage as received was a span of 3mV! When fully charged the voltage is higher and then drops to about the same as the original value. NiMH cells have high voltage, a bigger range and the drop-off is irregular. The Eneloops that I bought are the MkII, so good for ~1500 cycles. Sanyo gives a min. capacity of 1.9Ah which is probably more than some 2.7 - 2.8Ah cells.
Are Eneloops a different type of cell? NiMH are basically a 1.2v cell. If a device is designed for primary cells, ie 1.5v, the NiMH may well appear to be flat before they actually are. But that's poor design of the device, as it should be capable of getting the last drop out of a 1.5v cell.
=A0 London SW
Eneloops are low self discharge NiMH, so still nominally a 1.2V cell, datasheets here:-
RapidRecall have a load of special offers on batteries at the moment, they're not quite as cheap as that but they have deals like 4 x
1800mAh plus a charger for £4.93.
Rapid Recall have 8750mAh D cells at £7.70 at the moment so they're sort of in the gap.
Ah, same brand as Rapid Recall and quite a bit cheaper.
I had an old Philips digital camera that said NiCds were flat as soon as you put them in. It would still work but you had no idea when they would stop working.
The biggest problem with rechargeables is the internal resistance (or lack of), some devices rely on it to limit current and don't last long when you put rechargeables in.
That sounds like incredibly poor design. If the internal resistance is limiting the current the batteries won't last long. Except on something like a drill where the load varies and you need maximum power at times.
It was Dennis. Hence every word was total and utter bollocks.
Quite common. You can even get adaptors to fit your own AA cells. In fact the modern NiMH high capacity AA cells often outperform the earlier NiCd D cells (which were often only 2.4Ah).
I have bought a few with the Vapex brand on them, and the capacity (as indicated by by clever charger that records these things) was genuine on the new cells. They have performed ok although after a few hundred cycles some are now down to 1.8Ah ish rather than the original 2.5 or
2.8. About 3 (of about 20) have died completely. So in general, not bad considering the price (about a quid each IIRC)Personally I have always found that GP branded cells are absolute crap. Their dry cells significantly under perform other alkaline cells. Shelf life of their lithium coin cells is poor, and their rechargeable are really nothing to write home about with high auto discharge, poor capacity, and limited life.
It varies: one device has 2x2AA batteries (alkaline) (Drayton RF3 'stat) that last ~3 years and 'die' at about 1.4V - and will then run clocks for 6 months+; a clock will give up at about 0.95V but most clocks are around 1.1
- 1.2V. ATM I have an Eneloop in the clock that runs down to 0.95V, but only since mid-May so the experiment is ongoing.
electronics bits are usually dirt cheap to make. Ten years ago it cost less than 50p to make a mobile phone in Taiwan that sold for £70 in the UK. As long as the order was for a million units that is. All the profit went on distribution, inventory, research etc.
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I can assure you that 10 years ago a (complete) mobile phone did not cost
50p to make. It might have cost 50p to put together (in China) but the component costs are priced the same wherever you buy them and the total BOM is of the same order of magnitude as the selling price (because the selling price isn't a true reflection of the cost).tim
Funny enough the camera would manage about 50 pictures from 4 alkaline AAs and about 200 from rechargeables.
Shouldn't you be out pressing olives?
I've heard of it happening, but only to *very* early flashguns, from before the days of rechargeables. The transistors couldn't cope with the current available from rechargeables, and the design relied on the internal resistance of the primary cells to limit the current drawn. As soon as rechargeables became readily available, the designs changed.
Petzl Tikka Plus LED headtorch has some dire warnings about using cells with lower internal resistance than alkaline. So I feed it with pound shop Kodak alkaline AAAs.
Update.
I don't have a tester to check the capacity of these batteries but I decided to see how many pics I could get out of the camera with them before they went flat. Fuji Finepix 1400z btw which I guess is horribly outdated now but takes pics as good as I'll ever require. I sat it on my desk focused against a darkish background so the flash would operate every time and just sat there pressing the button until the Smart Media card filled up which given it's only a 4mb one doesn't take long. Then I'd delete all the pics and carry on. It finally gave up the ghost after a staggering 550 photos. God knows how many it would have taken without flash. The manual says the original 1800 mAh ones should take 450 photos at 50% flash usage so 550 photos at 100% flash usage seems pretty damn good. As the 4mb Smart Media card the camera came with will only store about 16 high res pics, 45 medium res or about 90 low res ones the batteries are definitely not my limiting factor.
I think I can safely say the batteries are seriously good uns regardless of what their actual mAh rating is. This was only the first battery charge too and as I understand it they take a few cycles to reach full capacity. I think I'll be buying a second set for back up purposes.
As an aside if anyone has any old Smart Media memory cards they don't want that would work in a Fuji camera (max 64mb the manual says) I would be interested.
Love to help but mine are in constant use in my old Olympus digital I bought
10 years ago for my daughter's wedding. Only 1.3mp but the pictures are extremely good quality.
Rig up an LED set to draw 20mA attached to a battery holder?
Don't do too many more tests, might shorten the life of your flash tube.
I'll have a look for any SM cards ...
If you want to do it accurately, there are fairly simple-to-use chips to do that (if you can cope with the package and have a means of reading a serial bus like I2C). Randomly selected example:
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