Storage NiCad Batteries.



#5

Hello,

Would it be possible to store fully charged NiCad batteries for a prolonged period by sealing them in a vacumised plastic bag in the deep freezer at -28 degrees Celcius ?

Ronald


#6

Everything I have read says do NOT freeze NiCads I repeat "DO NOT" freeze NiCads. You can and should keep them in the refrigerator (about +4 degrees Celsius). You don't need to store them in a charged state but they will stay charged longer if you keep them refrigerated. Either way (charged or discharged) when you take them out of storage you should recharge them and discharge them at C/10 rate a few times. I am assuming by prolonged period you mean 6 months or more.

Chris W


#7

Hi Chris,

Thank you. With prolonged time I meant 5 - 10 years. I am building up my collection of oldies and replacing also the NiCads. It would be nice If I would not have to find again NiCads 10 yers from now, sizes change, technology chnages, so to be safe for later I thouht this could be an option.

I will not freeze them, the message is clear.

Ronald


#8

We need the battery experts, but ...

If you just let them discharge (maybe help them along) and then just let them sit, do they deteriorate (on this kind of time scale - years)? There shouldn't be much internal chemistry happening if they are run down. Refrigeration, of course, also helps slow down any chemical reactions, so I guess that would be a good additional thing to do.


#9

Ni-cads come from the manufacturer in a completely discharged state and will store nicely. Once charged however, it is pretty difficult and time consuming to get them really and truely completely discharged. There always seems to be a tiny bit of charge left. Left to sit, this tiny charge will build up the voltage and promote the growth of dendrites which will short out the battery. If the battery is stored with a good charge, it will burn away these microscopic dndrites as they form.

For long term storage purposes the battery should have from a half to two thirds charge. It should be periodically checked and recharged as required. (A full charge won't hurt, but in practice it seems that most of the milage on a Ni-cad typically comes from over charging.)


#10

re: "Once charged however, it is pretty difficult and time consuming to get them really and truely completely discharged. There always seems to be a tiny bit of charge left. Left to sit, this tiny charge will build up the voltage and promote the growth of dendrites which will short out the battery. If the battery is stored with a good charge, it will burn away these microscopic dndrites as they form."

What if you store them shorted out? Will that keep the voltage &/or charge at (close enough to) zero?


#11

I was always told you did NOT want to discharge a NiCad below a certain point. I'm not sure but if I remeber right, it is something like .7V/cell and .9v/cell was safer.

Chris W

#12

How bout nickel metal hydride batteries, should they be stored the same way?


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