Looking for a fast, intelligent charger for AA and AAA NiMHs (and NiCds), with independent charge control for each cell, and effective time and/or temperature safety cutoffs.
I.E. not like
I think it costs around £50, but it was supplied to me by work!
:-)
Richard
Oops!
Don't think that was the entire problem though: it's cooked several other sets of cells (AAs though, which haven't suffered so drastically: just got _very_ hot) and I'm pretty sure it was set correctly on at least some of those occassions.
Point is a charger with an effective safety cutout might not help preserve the cells' lifetimes but could make the difference to ours :-|
charger did all that already. Looks like a refund is in order - you can definitely say that the "temperature sensors to avoid ... over-heating" weren't working!
Maybe it's just a case of cheap = not so cheerful?
Don't need all of that crap. Decent fast delta peak detecting charger avialable from any model shop will charge 4-10 cells in series fast accurately and safely.
You will have to arrange your own cradles, or do as I did, and modify equipment to take model type packs.
I need something that'll charge cells independently because often enough odd numbers of cells get used in kids' toys, so you end up with a handful at different - and unknown - states of charge.
I'm very happy with a "FRIWO Exclusiv" I picked up from somewhere (Canford Audio?) - 4 separate charging ways, each will take an AAA, AA, C, or D cell, each gives a little display of existing state of charge, and alleges to cater automagically for NiMH and NiCd.
So I try typing
FRIWO Exclusiv
into google. It's clear from the results that their prime market is Germany and the Scandinavian countries ;-) Ah, it's called the "FRIWO Gigabox", it seems; and Googling with those two words reveals at least one UK supplier - who wants 95 notes for one!! As the price in its native market seems to be around 90 Euros (still not cheap), I'll leave you to repeat the Googling. (Canford no longer supply the Gigabox, I see).
If you only want a couple of cells individually charging, it'd be cheaper to knock something up yourself using the Maxim charge-control ICs - they're a few quid apiece from RS, plus PSU, cell holders, and so on, plus the time to connect it all together (of course) using the supplied Application Note suggestive circuit diagram.
As our favourite Philosopher Of The Natural World notes, the model-control world is addicted to good fast chargers, though theirs tends to be for whole packs where the individual cells can be expected to be in a similar state of charge, rather than for individual cells in odd-numbered combinations and varying states of charge.
(On the 'dissapointed' front, I did pick up a 10-way charger from one of the better-known UK specialist rechargeable battery shops. Despite the description I thought I'd read, it did cook NiMH cells that were left on charge for a long time - p'raps its idea of "trickle" wasn't the C/50 rate recommended for NiMH but the C/10 one which any "normal" slow charger pushes in, but in any case NiMH cells were getting notably warm to the touch after an extended period in that - which in the Gigabox they certainly don't (but still seem to be fully laden with coulombs ;-)
HTH - Stefek
I have a combination of the above ;-)
An "Ansman Power Line 5" that is supposed to deal with Nicad or NiMh cells from AAA to D. It does get the smaller cells quite warm but does do 4 off individually.
I have a few Uniross 'Plug Top' type chargers that I think charge cells in pairs (but also get the cells too hot for my tastes)
The 'best' charger is an GWS-MC2002 variable current Delta peak one from a model shop. As mentioned you do have to set up clips to take your various cells but it will do any number from 4-10 and at a current rate of your choice. Being 12V powered means you can also charge stuff when in the car and camping etc ;-)
All the best ..
T i m
You can get free samples direct from Maxim if you ask, I got two a while ago, and *lots* of free application notes ever since.
Probably will chrage a single. I've just never tried. The delta peak will be smaller of course.
The switch on the charger is set to 'Ni Cd' and it looks like the batteries are Ni Mh. Also are these new cells? When new cells can have a tendancy to overheat when fast charged.
I wouldn't charge 650mAh AAAs in these anyway, putting 2A into something like that is bound to make it get very hot. If the cells aren't in close contact with the charger there will be no thermal protection.
I have this charger and when the AA cells were new they would get hot and thermal cutout would operate before they were fully charged. I got round this by running a small fan on them.
If you don't need to recharge partially charged cells and aren't in a hurry, a simple timer charger is best. 7 day shop have a good deal on one with 8 AAs. For small sized batteries a plug in 24 hr timeswitch can be used to limit the charge time.
cheers, Pete.
In message , Frank Erskine writes
Second that - I've got an Ansmann charger -very good.
charge NiMh at no more than their capaicity i.e. 650mA in this case.
Packs of these used a lot by modellers. Model style chargers will charge them.
I use a torch to totally discharge all to the same empty status before recharging.
In message , Peter Ramm writes
Yeah but that is another thing to do....., to forget to do, etc.
Yes you can do this, you can use model pack type chargers and fiddle around with moding stuff or makeing up a cradle etc. (and if you want to do this fine, it's a not a criticism of some ones choice)
But IMO it's just so much easier to by decent charger as mentioned, keep it in handy location and just pop the batteries in when they need it
In message , John Stumbles writes
might that have anything to do with it ?
Partly, but as someone else pointed out the mfr claims thermal cutout and this charger obviously doesn't have that. Several other times I've had AA cells (NiMH) cooked so hot the plastic sleeve has split. I'm pretty sure the switch wasn't set to NiCd on all of these occasions.
Not a good idea to run them totally flat.
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