Id still love to have a C-9000 for my NiMHs. Im currently using a varta 2 channel NiMH charger off my USB port (and 12V when convenient). Overall the plug and play chargers are more convenient for NiMH, which have never really been too fussed about what charger you use, only thing i dont like is the fact that each channel is a 2 cell series charging setup, which is less convenient when all my torches are singe cell things. Anything bigger is lithium.
Heres a pic of my iCharger setup, nice safe flammable battery holder... with tactical crenelations at the +ve end.
Nice setup there. I think I have to copy it. :)
Are you using both the balance lead and the temp probe? I've been thinking about making an adapter to be able to use the balance lead and charge in series but haven't gotten around to do it...
Very nice. I’m too lazy. I just charge multiple cells in parallel or if I’m being daring (very rarely, and only with IMRs) I’ll charge in series and skip the balancing. I have a C9000 and use if for charging AA/AA, but I really could be just as happy with a lesser charger (except the LaCrosse I had that like to melt itself.)
BTW, I have a Bantam clone .. its a Battman actually :p, and has been perfect with everything I throw at it. I just wish I could make it do NiZn!
You can see the display showing individual cell voltages, with the series charging setup. balancing works by discharging via the balance power leads, so its still a good idea to charge cells with similar charge levels, and capacities.
Ill swap you a basic AA charger for your C9000 if you don't need it ;)
Hi i just got one of the turnigy chargers which i am using to charge nimh batteries, since there are no instructions with the charger i would like some advice on charging/discharging rates.
1. What current should i discharge nimh cells at ?
2. What voltage should i set the discharge too?
3. what rate should i re-charge the batteries ?
4. is there anything i need to know about using this type of charger with NIMH batteries?
1.As high as it'll let you, usually one amp. Anything up to 5A should be fine.
2. I prefer 1.0V, many prefer 0.9V
3. Around 3/4 of capacity - but Sanyo say Eneloops should not be charged above 950 milliamps. For a non-LSD cell like my old NiCd Ds, I charge them at 4-5A (4-5Ah capacity). for my LSD Ds I charge them at 2A which is tedious as it takes 4hr to charge them from flat.
4.Best not to charge them in series if you have the time. I have charged up to 10 in series, but prefer to charge them individually if I have the time. Since I can charge 20 AAs at a time or 8 Ds and 12AAs simultaneously, I rarely use the hobby charger for those. If I'm in a hurry I'd happily connect ten NiCD Ds in series and charge them at the highest current the charger will support. After all, they get discharged in series - in my ROP high 6D at 4.5A.
Discharge is limited by the thermal dissipation of the charger. This is usually limited in Watts, for most budget chargers, this might be 5-10 watts, 20+ in some actively cooled chargers.
So the max discharge current is dependent on the what the charger can handle. A 5W discharge limit means, 1 cell, 1V 5A, or 10 cells, 10V, 0.5A. assuming 1V discharge voltage for simplicity (hehe or bad cells)
Charging in series is not as much of an issue with NiMH, unless charging at high rates (above 0.25C) with imbalanced cells. NiMH dissipate the energy when fully charged as heat.
I have some 3.6V Versapak batteries from Black and Decker for a few different cordless tools. When it was first introduced the batteries were NiCad, but later they introduced "gold" batteries that are NiMH. So I'm guessing 3 1.2V cells in series. Will a hobby charger be able to charge them? I figure that would be better than using the original charger which is made for NiCad.
Technically, charging at lower amps shouldn't be harmful to the cell though, right? As long as it's not so low that the charger fails to detect proper cut off signals, shouldn't it be better to charge slower, time allowing?
You got it! As long as the charger can pick up the peak, the charge rate doesn't matter. About 2/3C is usually recommended for giving the charger the best chance to pick up the peak. If the charge rate is low enough, this matters not a lot.
If you are draining the cell prior to doing a forming charge to try to regain some lost capacity due to age or lack of use then you want to drain it to a resting voltage of .9 or 1.0 volts. To do that in one discharge cycle you want to discharge at a lower rate, say .25C or less, to avoid voltage sag due to load.
If you're trying to determine useful capacity for a given application, then you're better off discharging at the same rate that your flashlight or radio will draw current.
If you are simply exercising a cell before putting it back in storage then a .5C or 1C discharge rate will get it done.
I don't know if the hobby chargers do this, but a lot of NiMH chargers use pulse charging where they charge at a high pulse rate and then back off. This is supposed to be good for breaking up the crystals (or whatever) that cause memory problems and reduce battery capacity, and also gives a cleaner signal that the battery is full. But if you sustained that pulse the battery would get too hot.
I like the idea of these chargers. I would like to charge 4 x 18650 (or 18700) batteries at once. Or at least 2. Also a range of AA and AA NiMH. It would be nice to simply have one charger that did it all well.
I understand that these units basically only charge one cell at a time. Or perhaps 2 in parallel. This does not sound all that brilliant. I guess you could get a 4 or 6 channel one.
The other issue is getting the thing connected to your batteries. There do not seem to be any handy adaptors for batteries other than the standard r/c ones.
You could charge up to 6 cells at once with this charger. The holders can be made cheap by using these Ultrafire battery holders with some sheet metal screws and small springs. For $1.36 you get two battery holders so get six of them some extra wire and alligator clamps hook them all together and you can do it no problem. By using long screws I can adjust them to fit different size batteries with a screw driver in a matter of seconds and yes I can fit the biggest 18650s in there no problem.
Purchased an IMAX B6. Those Universal + Smart NiMH chargers to do D are wayyy too expensive esp if you need them to be ready in 6 hrs.
Actually wanted to go for IMAX B8 but i figured I won't be doing much discharging / charging large packs. So discharging at 1A is fine for me to test the batteries capacity.
