# LiFePO4 batteries



## Tjin (Aug 12, 2007)

Has anybody have any experians with LiFePO4 batteries? I have seen them popping up on several site's:

http://www.all-battery.com/index.asp?PageAction=VIEWPROD&ProdID=1877
http://batteryjunction.com/2rc375reliba.html
http://www.e-lectronics.net/cr123a-lifepo4-rechargeable-volt-p-146.html

Although they are lower in capacity, there voltage are closer to primiary lithiums and are claimed to be very safe.


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## AndyTiedye (Aug 12, 2007)

I have used some of AW's LiFePO4's.

They seem to have about 500mah capacity.

Charge on an Ultrafire WF-138 in the "3.0v" position.


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## edc3 (Aug 12, 2007)

I bought a pair of AW's and a charger to play with. I charged them up and got around 35 minutes of runtime on a Wolf-Eyes Sniper with HO Cree. It doesn't seem like much, but in real life usage I can go three or four days between charges. Although I feel pretty comfortable using protected [SIZE=-1]Li-ion I [/SIZE]like the peace of mind in charging and using these cells. According to what I've read they will not vent or explode. See AW's sales thread here for more info.


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## TorchBoy (Aug 13, 2007)

Some more offerings I saw recently (added a day or two ago):

18650 pair: https://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=2867
14500 (AA) pair: https://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=2868
RCR123A pair: https://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=2869

I'm glad this sort is becoming more common as I've heard it's much safer. I can't remember if they need a special charger.


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## Fallingwater (Aug 13, 2007)

The kaidomain cells seem good.
I'd like to get some to experiment, but the lower voltage is a problem for devices expecting normal LiIon cells.

On the other hand, gadgets that use two AAs in series could be rewired to use two LiFe 14500s in parallel...


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## Northernflame (Aug 13, 2007)

INQUIRY:

I too noticed the KaiD lipo **14500** I'm interested in buying a few.

https://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=2868

My first questions is. Can the Ultrafire/Darin wf-139 charger charge these 3vdc lipo's? Safely.

I've heard rumors that a special charger is needed. Unfortunately there is little data (white papers) on the charging requirements of li-pos.

I use currently 14500 li-ions (3.7vDC) 1Xli-ion + a dummy battery with a resistance in an ex: ultrafire-606A FL and it's wonderous.

My main question about the LI-POs is if they would give any better runtime (1li-po cell) over a 2xAA nimh @ 2000mah each setup (averaged out common ni-mh)?

Last question: Would it be safe to run a single 14500 LI-PO in a single AA FL?

Thanks.


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## jeremyison05 (Aug 13, 2007)

So could you safely run these in Incan lights like a SF 6P with stock bulbs and not instaflash them or reduce the life of the bulb? If so this will be a great rechargeable solution for "stock" lights.


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## Northernflame (Aug 13, 2007)

jeremyison05 said:


> So could you safely run these in Incan lights like a SF 6P with stock bulbs and not instaflash them or reduce the life of the bulb? If so this will be a great rechargeable solution for "stock" lights.



Hi.

Based on the limited specs on lipos (why does that sound like a medical procedure  Heh, they sucked (liposuc...) the extra fat out of the li-ion to make a li-po... OK you can groan now  .

LI-POs have a lower discharge rate. However they have a very smooth and safe flow rate. This is why sony and others are switching thier li-ion's for li-po (after that li-ion distaster Sony underwent).

I would be concerned if you used 14500-18670 "li-ions" in your sf-6p without some form of resistance.

I've ordered a few of the li-po 14500's . From the tech specs i should no longer need a resistance in my 2xAA FL, that was needed when li-ions were used.

Thanks


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## TorchBoy (Aug 13, 2007)

Northernflame said:


> LI-POs have a lower discharge rate. However they have a very smooth and safe flow rate.


 Do you mean Li*Fe*POs? (With or without the 4.) Your mention of safety implies yes. So do you mean a lower *self* discharge rate? LiFePOs have a higher discharge rate. Wikipedia:


> LiFePO4 cells have *higher* discharge current, do not explode under extreme conditions and weigh less, but have lower voltage and energy density than normal Li-ion cells.


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## jrv (Aug 15, 2007)

I don't see any chargers for these batteries on the Kai site so you're probably going to have to use magnets & wires with the 3v 123 chargers.


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## protein_man (Aug 15, 2007)

If you live in Australia you can get them cheap here found them while doing a search. It looks like they put the real capacity on them, not an exaggerated one! 

These things would be awesome for a bike light battery pack, it would be great if somebody made 18650 battery holders for such applications!


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## Northernflame (Aug 15, 2007)

jrv said:


> I don't see any chargers for these batteries on the Kai site so you're probably going to have to use magnets & wires with the 3v 123 chargers.



According to the specs the manf provided the 14500 li-po kai sells are identicle to AA alkalines in form. Therefore no magnets required.

I'l provide a review when my order comes in.


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## TorchBoy (Aug 15, 2007)

Northernflame said:


> According to the specs the manf provided the 14500 li-po kai sells are identicle to AA alkalines in form.


Now, you don't mean lithium ion polymer, do you?


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## musicalfruit (Aug 18, 2007)

So what can you use to charge these batteries?

Also, are these batteries shorter than Li-Ion 14500s? The AW 14500 that I have seems a touch longer than my Eneloops so my L1D can't go into turbo mode when the 14500 is in there.

Thanks.


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## Fallingwater (Aug 18, 2007)

musicalfruit said:


> So what can you use to charge these batteries?


RC charger meant for A123 cells will charge them.
You can also probably use chargers meant for regulated LiIons; the voltage specs are very similar.


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## jrv (Aug 19, 2007)

To stress what TorchBoy said:

*LiFePOs are not the same as Li-Po!
*
Moreover, LiFePO batteries have a nominal voltage of 3.2v, quite a bit lower than Li-Ion's 3.7v. You can't charge a LiFePO in a Li-ion charger (there is one RCR123 charger that has a 3v switch and can be used for 123-size cells, otherwise you're the world of exotic RC chargers).

Expect to get half of the Li-ion capacity in a LiFePO of the same size.


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## AndyTiedye (Aug 19, 2007)

I use LiFePO4's in lights that don't like the Li ion voltage
(if replacing 2xCR123 with 1x17670 is not an option).


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## jbierling (Aug 19, 2007)

Do LiFePO4 batteries need to be protected from overcharging and deep discharging? If so, are they available as protected cells? I've only seen what I think are unprotected ones.

I've read that they are resistant to overcharging, but I haven't seen a reference to the possible dangers of over discharging.

Can LiFePO4 cells be used in series without protection circuits (like nimh), or do they need to be protected like normal Li-ion packs?

-Joel


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## LA OZ (Aug 21, 2007)

I have received 3 sets from Kai today. I ran the first set without first charge, It measured 3.33V on my multimeter. In my A2, it lasted 20min on incan and start flashing. I took it off and check the voltage. It reads 2.8V and kai mentioned that it is safe to discharge to 2V. I am in a process of charging up the first set and ran Gladius on the 2nd set.

Edited
It lasted 40min on the Gladius and the end voltage read 2.7V.


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## jrv (Aug 21, 2007)

I don't think the LiFePO4's have any undercurrent protection so it's not obvious to me why the lights cut out - do these lights cut out with Li-ion too?

Which size cells are these, and how are you charging them? I order a pair of 18650 LiFePO4 and am wondering how to verify they really are LiFePO4 and not low-capacity unprotected Li-ion. I intend to charge them with a Triton.

PS. Oops - I don't think Triton has a LiFePO4 program


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## LA OZ (Aug 21, 2007)

The LiFePO4 batteries have no current protection. However, the torches that I am testing these cells in are quality torches and hence they issued a low voltage warning. I could continued to let it run and it will no doubt reached below 2V and that will destroyed the batteries. I got these batteries from Kaidomain.com. I only got the Cr123 and I am charging it on the ultrafire 3V charger. At the end of the charge the battery reads 3.6V. I am now testing it on the U2 at Max brightness.

The U2 ran for 20min on Max and its brightness reduced gradually thereafter. I decided to removed the batteries and it registered 2.06V . That was lucky.


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## jrv (Aug 21, 2007)

You might try recharging a discharged Li-ion at the 3v setting to see what voltage you read when it's done. That might prove if the so-called LiFePO4 is really LiFePO4 or just a rebadged Li-ion.

AW says his LiFePO's can be run down to 2.0v.


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## LA OZ (Aug 21, 2007)

On fully charged, it registered 3.6V. I guess these batteries are more suitable for the Gladius.


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## SilverFox (Aug 21, 2007)

A general point of clairification...

Keep in mind that when the specifications refer to the low voltage that a Li-Ion cell can be run down to, it is referring to voltage under load. When you remove the load, the voltage should bounce back up.

If you measure the open circuit voltage of a Li-Ion cell, and it is at the low voltage cut off, you have over discharged the cell.

Tom


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## MattK (Aug 21, 2007)

<soapbox>

Misinformation abounds...

1 - LiFePO4 is a type of lithium ion aka li-ion battery. There are DOZENS of chemistries, construction methods, etc for li-ion batteries. Li-Poly batteries are another type of lithium ion chemistry. 

2 - Different chemistries/capacities and cell types require different charging methods, voltages and input currents. Buy the charger specifically offered by a reputable seller as matching the cells you are purchasing. MAKE NO ASSUMPTIONS.

3 - The cheapest price isn't always the best value. The highest price doesn't necessarily indicate additional value. MAKE NO ASSUMPTIONS.

4 - Even 'safe' chemistries need PCB's. Failure to use a properly designed protection circuit may result in injury or death. Use protected cells/pack.

5 - PCB's can affect how a cell should be charged. See rule #2.

6 - Never charge Lithium ion batteries unattended. Do not charge them on flammable sufaces. 

7 - With great power comes great responsibility. Arm yourself with knowledge from a reputable source. Assume everything you read here is wrong - for every person here who is correct and armed with knowledge there are 10 who are not (no offense intended). Educate yourself - don't rely on information learned 2nd hand and oft repeated - it's often wrong. MAKE NO ASSUMPTIONS.

</soapbox>


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## TorchBoy (Aug 21, 2007)

MattK said:


> 6 - Never charge Lithium ion batteries unattended. Do not charge them on flammable sufaces.


Would you say that applies to video camera batteries (and the like) also?


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## MattK (Aug 21, 2007)

Technically yes but it's certainly a practice I am guilty of (unattended/flammable surface charging of cell phones, laptops, camera batteries, etc...

Hrmm not common by any streatch but food for thought: http://www.youtube.com/watch?v=QJCZ4ayioCU

Rule 8 - I am a hypocrite.


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## TorchBoy (Aug 21, 2007)

MattK said:


> Hrmm not common by any streatch but food for thought: http://www.youtube.com/watch?v=QJCZ4ayioCU


Wow. That's a very graphic example of why I don't want a Li-ion headlamp. Bring on the LiFePO4 cells.



MattK said:


> Rule 8 - I am a hypocrite.


Hey, join the club, I don't think my membership is going to expire anytime soon.


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## Thujone (Aug 22, 2007)

Northernflame said:


> INQUIRY:
> 
> I too noticed the KaiD lipo **14500** I'm interested in buying a few.



Not LiPo, they are LiFePo HUGE difference. You about made me do a backflip. LiPo are super light with high energy density and charge to 3.7v.


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## barkingmad (Aug 22, 2007)

jrv said:


> You might try recharging a discharged Li-ion at the 3v setting to see what voltage you read when it's done. That might prove if the so-called LiFePO4 is really LiFePO4 or just a rebadged Li-ion.
> 
> AW says his LiFePO's can be run down to 2.0v.


 
Why do people seem to 'assume' these are fakes - saying 'so-called' etc.


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## TorchBoy (Aug 22, 2007)

barkingmad said:


> Why do people seem to 'assume' these are fakes - saying 'so-called' etc.


Maybe they've had bad experiences with finding their favourite NiMH cells are actually NiCd? :shrug:


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## jrv (Aug 23, 2007)

barkingmad said:


> Why do people seem to 'assume' these are fakes - saying 'so-called' etc.


My "so-called"  LiFePO4 cells were ordered from Kaidomain, but like Dealextreme not all has been as claimed in the past. Even Kaidomain seems to acknowledge that at his prices he can't be sure what his suppliers are sending him: he's stamping many specs with "manufacturer claimed" these days because of this.

I don't have them yet and have no reason to suspect them but since these are "safe" cells prudence is indicated...


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## barkingmad (Aug 23, 2007)

TorchBoy said:


> Maybe they've had bad experiences with finding their favourite NiMH cells are actually NiCd? :shrug:


 
Is that something you know to have happened with DX or KD?

I ordered some LiFEPO4 cells from KD - they certainly 'seem' to be LiFEPO4 from the voltage etc.


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## TorchBoy (Aug 23, 2007)

barkingmad said:


> Is that something you know to have happened with DX or KD?


There was a thread here on CPF recently where we were discussing that. See http://www.dealextreme.com/details.dx/sku.72 (real capacity 350mAh) and http://www.dealextreme.com/details.dx/sku.73 (real capacity 800mAh) for examples of claimed NiMH which actually appear to be NiCd.


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## NA8 (Aug 23, 2007)

I was surprised to hear last week about that guy they took out and SHOT in China. After reading some of these threads, I'm beginning to get the picture. 

BTW this isn't something new in Chinese management. I recall back in the 80s they lined up the top officials at a refrigerator factory and shot them for making bad products. Maybe they should add that nuance to all that six sigma voodoo.


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## LA OZ (Aug 25, 2007)

Those LiFEPO4 from KD are real to me . The voltage measured up and the runtime is not bad either. It seems to be higher quality than many of the RCR123s I got from them in the past. The size of this LiFEPO4 is exactly the same as the non rechargeable CR123s and therefore fit nicely into my two Gladiuses, U2, and A2. I feel safe using these lower voltage on these lights.

I am considering to order more from him but will wait for higher capacity in future releases. If I find them while I am in China, I will grabbed a dozen.


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## Fallingwater (Aug 25, 2007)

barkingmad said:


> Is that something you know to have happened with DX or KD?


Lookie here.


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## recDNA (Jan 3, 2010)

MattK said:


> <soapbox>
> 
> Misinformation abounds...
> 
> ...


 

I don't think there are any PCB's in LiFePO4 batteries. They are all unprotected. As I understand it the worst thing you can do with them is over discharge them and then even if you charge them again in that state they can't explode. Please correct me if I'm wrong.

I'm more than willing to risk overdischarging a battery that merely costs me more money if it prevent the risk of blowing my hand off or burning my house down.

Is it worth starting a thread saying how well various types of flashlights work with LiFePO4 cells? I'm very curious if flashlights designed for Li Ion 18650 will produce as much output on high setting with the LiFePO4 18650 installed. I don't mind charging more often. I DO mind losing modes or output.


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## MattK (Jan 4, 2010)

Perhaps there may not be PCB's in some of the LiFePO4 offered for sale but that doesn't mean they should not have them. A PCB for LiFePO4 protects against overcharge, over discharge and over-current discharge.

As I understand it the LiFePO4 have IMPROVED resistance to thermal runaway - they are not 100% 'safe' - just safer.


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