3.2v - 3.7v

[auraslip]

Hey guys, I just read a post where some one tested the voltage of a battery and was very surprised to find the voltage was 3.2v.

I come from an electric vehicle background, and I can tell you that a li-ion battery can not have a nominal voltage of 3.2v. These are not li-ion batteries. These batteries are lifepo4 which have a nominal voltage of 3.2.

This is a GOOD thing. Lifepo4 has a cycle life of 2000, as opposed to li-ions 600-1000.

 

[Rocketman]

No, it is probably NOT LIPO.

 

[Gestalt]

Auraslip, you are right in that lithium ion batteries are 3.7v and LiFePo4 is 3.2v. However, I don't know of any e-cigs that use LiFePo4. You are probably thinking of the eGo, which is 3.2v-3.4v. It uses pulse width modulation to go from 3.7 down to the lower voltage. The idea, at least in my mind, is to keep the experience constant over the whole battery instead of it gradually dropping from 3.7v down to 3.2. Do you have a link to what you were reading? Its also possible that it was tested under load or something.

Also Rocketman, LiPo is different than LiFePo4 (at least from what I've read).

LiPo = Lithium polymer
LiFePo4 = Lithium iron phosphate

 

[Rocketman]

Sorry if I came across a little rough. Sometimes I read between the lines and see something that might cause someone harm and I jump in with both feet

 

[Gestalt]

Nothing wrong with trying to keep people safe.

The LiFePO4 chemistry is actually one of the safest Li-ion based batteries around. The battery university has a good article that compares various chemistries:

Types of Lithium-ion Batteries

LiNiMnCoO2 is another interesting battery chemistry.

 

[Rocketman]

LiNiMnCoO2 is another interesting battery chemistry.

Like these?

 

[wv2win]

Use a good variable volt PV and it all becomes a "moot" point.

 

[dormouse]

I am no expert but that is UNDER LOAD

3.2-3.4 under load and they start a bit higher right off the charger and plateau around 3.4. And the regulation causes it I think. I think it is a 3.7v battery regulated to be 3.4. That is what Ego is.

Then there are mods that can use high drain AW IMR's and hold 3.7 pretty well and can alternately use protected Lithium Ion batteries and those don't hold the voltage up there as well but last longer.

here
http://www.e-cigarette-forum.com/forum/joye-510/65055-battery-voltages-surprise.html

some oscilloscope stuff here
http://www.e-cigarette-forum.com/forum/joye-510/65055-battery-voltages-surprise-42.html

some stuff about the New Rivas being 3.7
http://www.e-cigarette-forum.com/forum/joye-510/65055-battery-voltages-surprise-40.html

Interesting thread