Charger for RCR123 3.0V Cells

[roadkill1109]

I recently ordered some 3.0V cells online. Problem is, i realized all my lithium ion chargers charge cells at 4.2 volts. Question: Will i be able to charge these unprotected RCR123 3.0v cells in my 4.2volt lithium ion chargers?

[Draven451]

NO!

Do not try to charge 3.0V cell in a 4.2V charger. That is very dangerous and on the lucky side you fry the cells on the worst side the cells explode and you burn down your house.

Please read - http://batteryuniversity.com/

[texas cop]

No its way over what those cells can take. Some charges do have a 4.2/3.6v switch to allow both cells, but if no switch then a definite NO.

[RBWNY]

If you feel an added investment is necessary, (since you have the cells already) you should look into either the Xtar WPII-2 or the 4sevens Single Bay Charger. They can both switch between the two settings.

[ChrisGarrett]

If you feel an added investment is necessary, (since you have the cells already) you should look into either the Xtar WPII-2 or the 4sevens Single Bay Charger. They can both switch between the two settings.

I have the WP2 II and I think that it's cutoff is 4.2v, so I don't know if 3.0v cells would be safe.

Chris

[roadkill1109]

I have the WP2 II and I think that it's cutoff is 4.2v, so I don't know if 3.0v cells would be safe.

Chris

Hmmm, it would be dangerous to charge 3.0v cells with a charger that cuts off at 4.2 volts. maybe an explosion waiting to happen here.

I'm not keeping the cells, i'll probably use 'em like primaries then throw them after.

[labrat]

http://www.lighthound.com/Nano-3-Vol...er_p_1281.html

http://www.dealextreme.com/feedbacks...ws.dx/sku.1191

Nano charger, 3.0 Volts.
Cheap, small, same item different prices.

[45/70]

Hmmm, it would be dangerous to charge 3.0v cells with a charger that cuts off at 4.2 volts. maybe an explosion waiting to happen here.

road, you never mentioned what cells you actually bought?

If they are LiFePO₄ cells, I wouldn't recommend charging them with a regular 4.2 Volt LiCo/LiMn charger. You probably could get away with it, but instead of the cells lasting "2000" cycles, you'd likely only get 10-20 cycles out of them, and again, I wouldn't recommend doing this.

LiFePO₄ cells are not as prone to "venting with flame" when exposed to higher than recommended charging voltages, as LiCo cells are. I still wouldn't recommend charging them with a regular 4.2 volt charger though, as it will kill the cells.

The biggest danger in using "3 Volt" chargers and cells, is if one attempts to charge a "regular" unprotected 4.2 Volt LiCo, or a 4.2 Volt LiCo cell with protection that has failed, in a charger meant for charging "3 Volt" LiCo cells (not a charger for 3 Volt LiFePO₄ cells). This combination will attempt to charge the cell at 4.4-4.5 Volts, which is well within, or above the "danger zone" (generally considered to be 4.35 Volts+) concerning regular 4.2 Volt LiCo cells.

Again, the reason "3 Volt" LiCo cells, such as the "3 Volt" Soshine and "900mAh" Tenergy cells mentioned previously, are charged with a 4.4-4.5 voltage, is because the voltage going to the cell drops to 4.2 Volts before it enters the cell, due to the diode incorporated into the cell that allows the cell to be charged (the other diode, which is installed reversed in polarity, and lowers the voltage under load to ~3 volts, will not allow a charging current to pass).

99% of "3 Volt" chargers are meant for charging LiFePO₄ cells ONLY. These use a 3.6 Volt charging voltage. The only two chargers that I am aware of that can be used to properly charge "3 Volt" LiCo cells, are the one from Tenergy.... (not this one, which is for LiFePO₄ cells) and ones that appear to be identical, that Powerizer used to sell (I believe they quit carrying these, and the "3 Volt" LiCo cells, because of all the confusion). And again, these chargers utilize a 4.4-4.5 charging voltage.

So anyway,

Hmmm, it would be dangerous to charge 3.0v cells with a charger that cuts off at 4.2 volts. maybe an explosion waiting to happen here.

This isn't necessarily so. Depending on what type of 3 Volt cell you are charging, you will either cause cell damage and run a possible risk of venting (but unlikely) concerning LiFePO₄ cells or, you will only achieve about a 50% charge, if you attempt to charge a "3 Volt" LiCo cell. As I said in a previous post, the later cells will only be charged to about 3.9 Volts, again, because of the charging diode incorporated beneath the positive nipple. It requires a 4.4-4.5 volt charging current to compensate for the diode.

I feel that I am falling on deaf ears here, but anyway, I've been using "3 Volt" LiCo cells with diodes, regular 4.2 Volt LiCo cells, 3 Volt LiFePO₄ cells, all in 16340 size, and their proper associated chargers, for 7 years. If you don't match the correct cells with the correct charger, performance will be lacking due to cells not being fully charged, cells will be damaged, or in the worst case, you may experience a "vent with flame" incident. So, three types of "RCR123" size cells, and three types of chargers. It pays to get it right.

Dave

[Joe Talmadge]

No its way over what those cells can take. Some charges do have a 4.2/3.6v switch to allow both cells, but if no switch then a definite NO.

3.0V RCRs can be recharged at 3.6V? The notes that come with these batteries say to use a 3.0V charger only ... which would rule out the Xtar, 4sevens, and every other charger in the world except the Tenergy (or whatever brand) 3.0V charger. Are the warnings incorrect? Or maybe I'm reading them wrong -- the copy does say max charge is 3.6V, the 3.0V rating is nominal

[45/70]

3.0V RCRs can be recharged at 3.6V?

It depends on what type of "3 Volt" cell you are trying to charge. The Tenergy so labeled "900mAh" cells are LiCo cells with diodes. These cell's require a special charger that uses a 4.4-4.5 Volt CV. This is due to the voltage drop that occurs when the charging current passes through the diode that allows the cell to be charged (the other diode effectively reduces the cell's voltage to closer to 3 volts, when under load). The result is the underlying LiCo cell, behind the diode, is charged at a 4.2 Volt CV.

The Tenergy so called "750mAh" "3 Volt" cells are LiFePO₄ cells. These cells require a charger with a 3.6 Volt CV. Some go as high as 3.8 Volts CV. Most, such as hobby chargers, default at 3.6 Volts though.

Note that neither of these chargers utilize the standard 4.2 Volt CV of a regular LiCo, or LiMn charger. There are three kinds of common Li-Ion chargers, each with a different CV voltage. The proper charger must be used with the proper cell, Life=3.6 Volt CV, LiCo/LiMn=4.2 Volt CV, and LiCo "3 Volt" cells=4.4-4.5 Volt CV.

I'll also note that all chargers that I am aware of, that offer a switchable setting, eg. "3 Volt/3.6 Volt", are meant for charging LiFe, or regular LiCo/LiMn cells only. These chargers cannot be used to charge "3 volt" LiCo cells. You will always have to obtain a special charger for these cells. Most hobby chargers are not capable of charging these cells either, as their charging CV voltage is out of range (4.4-4.5 volt).

Dave

[roadkill1109]

Demmit! I shouldn't have bought these 3.0 RCR123's! No wonder the seller was selling them at a surprisingly low price. I got Soshine RCR123's 3.0 batteries.

I'm glad you guys helped me out as I almost charged these batteries thinking the regular lithium ion charger can charge these cells. Glad I posted the queries here before trying them out!

Thanks a lot for your input. I will look for a 3.0volt charger then.

[Joe Talmadge]

I have a negative opinion of those 3.0V RCRs, and if I"m completely honest, I'm not certain I know exactly why. I know a big part of it is that people using 3.0V RCRs have so many issues -- they can't find a charger, battery life is nowhere near what they thought it was, etc. In fact, there are zillions of folks who will sing the praises of, say, AW 16340s or Redilast 18650s, but I know EXACTLY ZERO people who are happy with 3.0V RCRs and encourage people to adopt them as a good solution. This may also be related to the fact that the companies who make 3.0V RCRs, are the same companies I personally wouldn't buy a (plain-old regular ICR) 16340 from....

[Ualnosaj]

Xtar MP2 charger will do set at 3.0v.


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[Ualnosaj]

Grab the XTAR MP2 charger. Will do both 3v and 3.6v. Can even charge via USB.


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Posted from my phone.

[45/70]

Grab the XTAR MP2 charger. Will do both 3v and 3.6v. Can even charge via USB.

Unfortunately, the Soshine "3 Volt" cells, are LiCo cells with diodes. These cells cannot be charged properly with the XTAR, or any other selectable voltage charger, that I am aware of. Again, these type cells require a charger with a CV voltage of 4.4-4.5 Volts. The XTAR and other selectable voltage chargers are all meant for charging LiFe/IFR 3 Volt cells only, on the "3 Volt" setting.

Also, as far as I know these DX SKU 723 review link (from a reviewer on DX) do not have protection circuits. I would not use them in a series application, it could be dangerous. This is also true of LiFe/IFR cells, although to a somewhat lesser extent, as they do not have added protection circuits.

The only "3 Volt" LiCo cells that have protection circuits that I am aware of, are Tenergy's "900mAh". I have some old AW 3 Volt LiCo cells with protection circuits, but he quit offering these years ago.

Dave

[Ualnosaj]

Good I know. Both the Tenergy LiCo and LiFePO4 charge well with the MP2. The tested capacity of the LiFePO4 is only a sneeze less than the LiCo btw.


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Posted from my phone.

[Ualnosaj]

The WP2II does not have any voltage settings though...


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[ChrisGarrett]

The WP2II does not have any voltage settings though...


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Posted from my phone.

Correct and I should have added that, just a 500mA/1000mA setting, along with the USB charging option.

Chris

[Changchung]

If you dont find the charger yet you can find it in DX sku 1236

I have two of them for charge some 3v cr123 what I bought time ago and they are working great.


SFMI4UT