How should I store rechargable batteries?

[Yzzim]

Got a cordless tool set and am wondering how I should store the batteries.

Store them with a full charge? No charge? In the freezer? Heard so many things 😕

Dunno if they are NiMH or NiCd....I know for sure they are not Lithium.

 

[TastesLikeChicken]

Doesn't really matter what charge state you store them in. The secret to keeping batteries viable is to charge them fully and deplete them as far as possible before recharging again. Store them in a cool, dry place. Definitely do not put them in a freezer. If you did you'd have to let them thaw out prior to use anyway or else condensation from warming could wreak havok with the innards of your cordless tools; unless you commonly work in sub-freezing environments. In that case, freezing your batteries is not a problem.

 

[OUCaptain]

I just store mine in the drill case in what ever state they are in when I finish with the drill. My Milwaukee packs have lasted on average about 4 yrs of heavy use. Like chicken said, always drain them completely and charge them fully. I also firmly believe you get what you pay for. A few of the guys at work bought some offbrand crap drills. Their new state of the art LiIon packs didn't make it 9 months and never had much power even new.

 

[Jeff7]

Originally posted by: TastesLikeChicken
Doesn't really matter what charge state you store them in. The secret to keeping batteries viable is to charge them fully and deplete them as far as possible before recharging again. Store them in a cool, dry place. Definitely do not put them in a freezer. If you did you'd have to let them thaw out prior to use anyway or else condensation from warming could wreak havok with the innards of your cordless tools; unless you commonly work in sub-freezing environments. In that case, freezing your batteries is not a problem.

My understanding: Deep discharge is a bad thing, and that the memory effect came to be public knowledge mainly because of the Hubble Telescope. It goes through an orbit about every 90 minutes - 45 minutes of charging, 45 minutes of discharging, day after day. It was discharging to very nearly the exact same level several times per day. It did develop a memory in its batteries. Consumer devices will generally get discharged to fairly different levels before the user decides or remembers to charge the batteries, thus the risk of "memory" developing is low. NiMH cells are even less susceptible to this effect than NiCads.

Deep discharging a pack of cells (multiple cells wired together = battery) can be a problem if one of the cells is weaker than the others, and it happens to discharge fully before the pack is removed from the device. It is either this, or else the impending charge cycle, which causes that cell to become reverse-biased, causing permanent damage and loss of capacity.

Li-ion packs do not even permit very deep discharges, courtesy of their protection circuitry. This circuitry is used due to the volatile nature of Li-ion cells, and it also serves to prevent damage to the pack. It monitors charging current and voltage, as well as voltage during discharge. If the voltage of the pack, or the voltage of an individual cell, drops below a preset limit, the circuit will shut off the flow of power to the external device.

NiCad or NiMH, I think they should be charged fully and stored that way; they'll leak charge though. I think conventional NiMH loses around 1% per day. Also invest in a good charger. Over the years, I've lost quite a few batteries to poorly-made chargers. A slow charge is gentler on batteries, and the charger should have some kind of ability to sense when the charging cycle is complete.



Now I must go activate the Rubycon Signal, and hope she shows up to either confirm what I've said, or tear it to shreds. 🙂

 

[TastesLikeChicken]

Originally posted by: Jeff7

Originally posted by: TastesLikeChicken
Doesn't really matter what charge state you store them in. The secret to keeping batteries viable is to charge them fully and deplete them as far as possible before recharging again. Store them in a cool, dry place. Definitely do not put them in a freezer. If you did you'd have to let them thaw out prior to use anyway or else condensation from warming could wreak havok with the innards of your cordless tools; unless you commonly work in sub-freezing environments. In that case, freezing your batteries is not a problem.

My understanding: Deep discharge is a bad thing, and that the memory effect came to be public knowledge mainly because of the Hubble Telescope. It goes through an orbit about every 90 minutes - 45 minutes of charging, 45 minutes of discharging, day after day. It was discharging to very nearly the exact same level several times per day. It did develop a memory in its batteries. Consumer devices will generally get discharged to fairly different levels before the user decides or remembers to charge the batteries, thus the risk of "memory" developing is low. NiMH cells are even less susceptible to this effect than NiCads.

Deep discharging a pack of cells (multiple cells wired together = battery) can be a problem if one of the cells is weaker than the others, and it happens to discharge fully before the pack is removed from the device. It is either this, or else the impending charge cycle, which causes that cell to become reverse-biased, causing permanent damage and loss of capacity.

Li-ion packs do not even permit very deep discharges, courtesy of their protection circuitry. This circuitry is used due to the volatile nature of Li-ion cells, and it also serves to prevent damage to the pack. It monitors charging current and voltage, as well as voltage during discharge. If the voltage of the pack, or the voltage of an individual cell, drops below a preset limit, the circuit will shut off the flow of power to the external device.

NiCad or NiMH, I think they should be charged fully and stored that way; they'll leak charge though. I think conventional NiMH loses around 1% per day. Also invest in a good charger. Over the years, I've lost quite a few batteries to poorly-made chargers. A slow charge is gentler on batteries, and the charger should have some kind of ability to sense when the charging cycle is complete.



Now I must go activate the Rubycon Signal, and hope she shows up to either confirm what I've said, or tear it to shreds. 🙂

It seems that the Hubble batteries did a pretty good job, considering their design life:

http://www.nasa.gov/mission_pa...n/Battery_FS_HTML.html

Besides, you're aren't really going to get a deep discharge on power tool batteries. They'll get to a point where the batteries aren't viable for use long before a depleted stage is reached.

 

[0roo0roo]

http://www.batteryuniversity.com/

 

[theflyingpig]

Consult the bible. God will guide your hand.