NiMH Batteries and chargers

  Peter Lanky 20:56 06 Mar 2008

I have a number of 'Better Power' 2700MaH NiMH batteries (from Ebay) and a couple of chargers - one is a USB and the other mains, both are unbranded. The USB charger has a charge level indicator, but currently only charges 2 batteries at once. The mains charger seems to stay on for a fixed amount of time, and eventually the light changes to green when the cells are supposedly charged.

Last time I used my flashgun, the battery life seemed much shorter than before, but I can't judge if it is the batteries or the mains charger that is at fault. The USB charger seems to give the cells more life, so I am assuming it is the charger, but as I said, it only charges 2 cells at once now.

As I cannot afford to be without batteries, even though I take loads of spares, I am looking for a good combination of charger and battery, so I can get the best out of both. Any recommendations?

  MAT ALAN 21:01 06 Mar 2008

click here=

i have been using one of these for some time now, it serves me well...

  peter99co 21:14 06 Mar 2008

Bear in mind that 2700 nmh take a long time to charge completely esp 1st time and will hold up longer as they get older. you should check charger output and this should show how long to completely charge a 2700 I think you will be suprised to see how long it can be.

  Totally-braindead 21:16 06 Mar 2008

Get a different charger, one with Delta V, it doesn't have to be expensive, something like this click here or choose another if you don't fancy here=

You mention a USB charger. I personally would not use a USB charger, to be honest I think theres not enough voltage and there is always the possability of it dragging too much power and damaging your USB. Better with a proper mains charger, and if you plan to go overseas anytime get one that also can use 110v such as the one I linked to.

I use a lot of NIMH and NICAD batteries as well as LiPoly ones as I use radio control models and am wondering how long the batteries were sitting before you used them. I know that NICADs can lose as much as 20% of their charge in a very short period of time and NIMH are the same I believe. Though NIMH are not meant to suffer from the memory effect.

I don't know if its an option but if can't manage to keep a check on your batteries and give them a boost just before you go out with it perhaps you could consider Lithium batteries. LiPolys and Lithium Ion batteries can keep their charge for a year without losing anything at all but they are expensive and I am unsure as to whether you could get direct replacements for what you have. And they need a dedicated charger, use a non lithium charger and they can explode. And I do mean explode. You MUST use a proper Lipoly charger.

  peter99co 21:17 06 Mar 2008

Mat Alan's Click show a charging time of 14 hrs

  Grey Goo 21:30 06 Mar 2008

I use one of these and it works well, you can discharge the batteries with the blue button
click here

  Stuartli 00:05 07 Mar 2008

I have an "intelligent" Fast Charger batteries recharger - it dates back to when the maximum capacity of rechargeables was around half of those today.

All I have to do when the green light comes on is to switch it off for a second or so and then switch it on again.

This is repeated two or three times, depending on the batteries' capacity level, until the green light is on permanently.

Even SWMBO is aware of the routine and does it automatically if I'm elsewhere...:-)

  Peter Lanky 15:20 07 Mar 2008

Totally-braindead - What does Delta 5 mean? The batteries had all been freshly recharged so that wasn't the problem.

Grey Goo - What is the benefit of discharging the batteries before charging? I know this was a problem with NiCad cells, but didn't think it a problem with NiMH. This charger claims to charge 2700 NiMH cells in 220 minutes. Is this for each cell or the total being charged? In other words, if I put 4 cells in the charger, does that mean that it will take 880 minutes?

  Diemmess 15:40 07 Mar 2008

Close to Totally-braindead's second link look at this click here

I've had one for at least a year. It has all the internal sensors and switches. Will charge 1 or up to 8 at a time AA or AAA size and any mix.

It treats each cell individually so that when charged the LED changes to a steady green for just a maintenance trickle

One 2600 NiMh will charge in about 2 hrs from flat and if there are 7 others they will each take the individual appropriate time to charge regardless of how many are being charged, perhaps 2hrs for 8 to be charged!

  Stuartli 19:10 07 Mar 2008
  Totally-braindead 19:18 07 Mar 2008

Its known as Delta V, thats vee not 5, its just a way of describing the technology that an intelligent charger uses. It will charge a battery until it detects that the battery can take no more basically so its intelligent in that way. It also incorperates sensors to detect batterys overheating.
A charger without some sort of intelligence will keep trying to push more power into it causing damage to the battery and perhaps the charger.

They are no more expensive now so if you are going to get a new charger get a reasonable one. The one Diemmess links to looks interesting at the price and can do upto 8 batteries.

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