Marui discharger destroying my batteries...huh?

[Silverthorn]

Hello,

I recently purchased a Marui discharger. Not having discharged my batteries before I tought it was a good idea to do them all now that I had a discharger. Some had been charged 3-4 weeks before, other the week-end before.

Much to my dismay, discharging them literally destroyed them. They can't hold a charge anymore (1 large and 3 stick-type, all 8.4 V and between 1100 mA to 3800 mA). Only one large battery survived.

What happened?

[Jimski]

Hello

are they Nicad or Nimh ?

[Crunchmeister]

If you're using NiMH cells, then discharging them completely destroys them. Discharging is only needed for NiCad cells.

[Donster]

im glad i found that out after i just discharged my NIMH battery. i literally read this, and then i threw it out.
At least my NICD battery will be ok.

[kalnaren]

Even then, modern Ni-Cad technology has progressed to the point where the memory effect has almost been eliminated. If the battery is charged every month or two, over a period of several years you'll see maybe a 20% loss in power, without ever discharging. One of my friends has been using the same Ni-cad in his upgraded gun for 5 years, never discharged it, and has never had it fail at a game.

A good charger will do far more for the life of your batteries than a discharger ever will.

The only reason I see to discharge a battery is a "deep cycle." Even then, doing it with a charger that has a dedicated deep cycle function is advisable over using a discharger.

[coach]

I have discharged my NiMH 8.4's with my TLP fuzzy logic charger and no issues. The dedicated discharger's shouldn't cause problems but I have no first hand information on them. I could easily speculate but I won't.

Silverthorn - it's possible that some of your batteries are or were at the end of their life.


"You can buy chargers that will fully discharge batteries before it starts charging them. Or you can connect something to the battery to discharge it. I wouldn't recommend simply shorting it. The best way to do this would be to use a small light bulb or a coil or something that will serve as a load to discharge the battery without creating a dead short, else you run a moderate risk of causing a problem with the battery, the least of which might be current leakage, or possibly causing the battery to explode."

"NiMH batteries don't suffer from the 'memory' effect that NiCd batteries are prone to. You don't need to discharge NiMH batteries for them to be at their best, and in fact fully discharging them may damage the cells. If the cells aren't holding equal charge, then maybe your battery is reaching the end of its life. If you are getting a decent run time when fully charged, then they are probably fine. Ignore trying to discharge them, as you won't gain anything by doing this.


Something you could try is to put your battery into the freezer overnight, then remove it and let it come back to room temperature. This 'trick' can apparently help to break up any crystals that form in each cell and so help to revitalise poor performing cells. Let us know if this works, as I've never tried it myself. "

Reference: http://www.techspot.com/vb/all/windo...ry-safely.html

The freezer trick does work. I don't know how often this is successful but I do have a friend that used this method and successfully got his iBook battery up and running again.

[Crunchmeister]

I have a couple of NiCad batteries. I've never discharged them. I used them till they're too weak to turn over the gun, then recharge. Never had a problem with them as of yet.

[Silverthorn]

Yep. they were NiMH and pretty new (less then 6 months). I thought I read that they should be discharged sometimes on the battery thread here.

I had discharged them in the past with a small resistor I bought at radio shack. Never did them, Maybe it was too weak to have this effect.

Oh well... Quite a few dollars down the drain but a lesson learned

[ILLusion]

Marui chargers/dischargers are built only for Ni-Cad

On top of that, their dischargers are dummy dischargers. You just plug it in and it dissipates the energy as heat. There is not undervoltage cut-off circuitry that Ni-MH requires to prevent the polarity from reversing.

If you HAVE to discharge a Ni-MH cell, do it with a smart charger/discharger.

[Skladfin]

you dont need to discharge Nimh batteries... they don't have memory effect

[venture]

Here is a link that lets you discharge a nimh battery properly. Complete discharge will indeed damage your cells but a periodic discharge to 1.0 volt per cell(that is 7 volts for your 8.4 volt packs) is supposed to help. This guy's solution is smart and easy to build, I built one myself for about 10 bucks.
Read the page whether you want to build one or not though, because there is good information there.


Try:
http://unconventional-airsoft.com/20...ry-discharger/

[Styrak]

The thing is, you don't NEED to discharge NiMH. Every once in a while you can run it down to nothing in your gun while playing, but yeah.

[arcanuck]

There are alot of myths and enternet babble out there. NiCD NiMH do have memory effects though in the higher quality brands it isn't so severe as it used to be. The NiCD and NiMH cannot be fully discharged as it will eventually distroy them, if not immediately. I have no idea who these people are that make the sites that confuse people. Please don't believe everything you read out there!