Discharge for 18650 recharger?

I have looked at several chargers for the 18650 Orbtronic batteries and I don't see a discharge listed. I usually change my batteries once every 2 weeks on habit alone, just so I know I have fresh ones. But my drain them in my C9000. Is there a charger I can discharge my 18650 Orbtronic batteries?

Lightingman said:

I have looked at several chargers for the 18650 Orbtronic batteries and I don't see a discharge listed. I usually change my batteries once every 2 weeks on habit alone, just so I know I have fresh ones. But my drain them in my C9000. Is there a charger I can discharge my 18650 Orbtronic batteries?

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You do not need to discharge them, but if you really want to, get a hobby charger.

Charging batteries every two weeks might be hard on their lifetime, especially if you store them in a warm place.

HKJ said:

Charging batteries every two weeks might be hard on their lifetime, especially if you store them in a warm place.

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Sounds like good advice. L-Ions like 18650s are better stored with a partial charge rather than topped off. In my experience, 18650s seem to have a lower self discharge rate than standard NiMH batteries do.

If you have so many batteries that some are always in storage, it might be better to use the ones in your lights, at least the 18650s, until they are only partially discharged, maybe down to, 60 or 50% of charge, then replace them with a freshly charged set and let the ones just removed sit without charging until it's about time to again change out the partially used ones that are currently in your light. That practice should leave you with plenty of reserve power for emergencies unless you're in a search and rescue organization where you routinely are called on for high battery power usage. More experienced CPF members have recommended storing L-Ions at 40% of charge to minimize their chemical stress.

If you're obsessive about keeping track of your batteries state of charge (like I am ), then the ZTS battery tester is the next toy you should invest in. :devil:

Li-Ion cells (all varieties) do not benefit from occasional deep discharges, as NiCd, and to some extent, NiMH cells do. The only time you may want to discharge a Li-Ion cell, is if you are planning to store the cell for some period of time. In this case storing in a 40% state of charge will extend cell longevity appreciably.

In the R/C hobby (the "hobby" in "hobby charger"), battery packs that are still charged up at the end of the day, are often discharged to an appropriate charge level for storage. This is because once at home, you do not have any other way to discharge the packs. In the flashlight/torch hobby, it works out a whole lot better to simply discharge your cells in a light. That way you actually get some use out of them. Discharging cells any other way, just adds unnecessary wear to the cells. One exception here (and it still adds wear to the cell), is if you are attempting to determine the capacity of a cell for the purpose of matching cells for use in series.

As has been mentioned, probably the best way to discharge cells without actually using them, is to obtain a hobby charger. Another good device is the West Mountain Radio CBA series of battery discharge analyzers. These offer a few more options than most hobby chargers, however their cost may be a bit prohibitive, unless you're really into analyzing battery pack/cell behavior, under discharge.

Dave

HKJ said:

Charging batteries every two weeks might be hard on their lifetime, especially if you store them in a warm place.

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I replace them every two weeks because I use around 30-45 minutes of my turbo, and usually a couple hours on low. From my previous testing, this is what it takes to drain roughly 40%-50%. I am a preparedness guy, and would hate to have to use an almost dead flashlight in an emergency. But as I said before, it's habit now, so if I don't use that much it gets changed anyway.

One question. if the battery claims 1500 recharges before expiring, then that should be 57 years worth of recharges. Is there some information I am missing here?

Thanks for the responses. I will pick one of those up soon.

Lightingman said:

One question. if the battery claims 1500 recharges before expiring, then that should be 57 years worth of recharges. Is there some information I am missing here?

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LiIon is more like 300 to 500 charge cycles or 5 years, whatever comes first.
Storing them at high temperature fully charged can reduce the 5 years to less than a year.

HKJ said:

LiIon is more like 300 to 500 charge cycles or 5 years, whatever comes first.
Storing them at high temperature fully charged can reduce the 5 years to less than a year.

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I didn't know there was a difference. I use Sanyo AA eneloop Ni-MH.


So here is the big question. I am a preparedness guy, and having a bunch of drained batteries around the house just doesn't work for me. So what is a good solution for me? Should I give up on the 18650's and look for a 123 battery?

Lightingman said:

So here is the big question. I am a preparedness guy, and having a bunch of drained batteries around the house just doesn't work for me. So what is a good solution for me? Should I give up on the 18650's and look for a 123 battery?

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If you keep them cool, they last much longer. Try reading on battery university.

CR123 are great as emergency batteries.

HKJ said:

If you keep them cool, they last much longer. Try reading on battery university.

CR123 are great as emergency batteries.

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Thanks for the help. That site is great. Now I am really hoping Sanyo comes out with a 18650 rechargeable battery at some point. Would seem like a good option for me as they claim to be good for storing long periods of time charged.

Hello Lightingman,

I use a little different approach to being prepared.

Storing Li-Ion cells fully charged is not a good idea. However, if you reduce the charge you reduce the amount of damage. In my emergency kit I have lights that are reasonably bright. That results in longer run time over lights that are extremely bright. When you charge your battery to 4.2 volts, you end up with an amount of run time. If you reduce the charge to 4.0 volts, that amount of run time is only about 80% of the initial amount.

After doing testing and making a guess of how much run time I need, I charge my batteries to 4.0 volts, and have a spare at that voltage. So far, my cells are holding up well.

Since most chargers don't allow you to charge to a specific voltage, this method gives you a chance to play with your emergency lights to make sure they are working. You know what the expected run time is with a full charge, so you charge the battery then use it for 20% of that run time and you end up with the storage voltage.

Tom

Lightingman said:

I have looked at several chargers for the 18650 Orbtronic batteries and I don't see a discharge listed. I usually change my batteries once every 2 weeks on habit alone, just so I know I have fresh ones. But my drain them in my C9000. Is there a charger I can discharge my 18650 Orbtronic batteries?

Click to expand...

This is important

Do not treat Li-ion batteries same as Ni-Mh batteries. They are two completely different worlds.

I think that folks who are trying to give some advice assume that OP knows what he is doing.

OP is obviously looking for "discharge" function on Li-ion charger (which doesn't exist), so he can completely discharge (refresh) them same as Ni-Mh.

Many uninformed new to li-ion users destroyed their li-ion (unprotected) batteries by discharging them completely (refreshing them).

This is not Ni-Mh chemistry.

Lightingman, let us know if I am wrong.

Good points, space.:thumbsup:

Lightingman, if you haven't already, I highly recommend that you read through the relevant threads in the "Threads of interest" and "Smoke and Fire" threads located at the top of this Forum, if you are unfamiliar with the use and care of Li-Ion cells.

Also, as has already been mentioned by HKJ, Battery University is often referenced here on the Forum, and is an excellent source of information, regarding all types of rechargeable cells.

Dave

space-cowboy said:

This is important

Do not treat Li-ion batteries same as Ni-Mh batteries. They are two completely different worlds.

I think that folks who are trying to give some advice assume that OP knows what he is doing.

OP is obviously looking for "discharge" function on Li-ion charger (which doesn't exist), so he can completely discharge (refresh) them same as Ni-Mh.

Many uninformed new to li-ion users destroyed their li-ion (unprotected) batteries by discharging them completely (refreshing them).

This is not Ni-Mh chemistry.

Lightingman, let us know if I am wrong.

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You are correct.

Do they make 18650 or 123 NiMH?

18650 NiMH's exist, but what's the point? At 4Ah they're just 1.2*4 = 4.8 Ah, while high quality Li-Ion 18650's are double that (and some are even 2.5 times that)