What does 15s mean for Li batteries?

[mastershake916]

First off, don't jump on me for not looking it up, I've been lurking for a while and tried to look it up a few times.
So what does the "s" mean? What is the voltage per "s'"?

Thanks.

 

[Ypedal]

Series

Number of cells strung in series to increase voltage.

Example, Lipo cells range from 3.0v( empty) to 4.2v ( full )

15S would mean 15 cells in series so a pack that would be :

15 x 3v = 45v empty and
15 x 4.2v = 63v Fully charged.


The " P " portion is for Parallel, increasing capacity..

so 15S 3P is 15 in series x 3 in Parallel

using 5ah lipo cells this is :

15S ( 63v fully charged ) and 3P ( 3 x 5ah = 15ah )

 

[neptronix]

S is the amount of batteries in series.

What voltage that is depends on the cell chemistry.

Lifepo4/li-co/etc tend to be around 3.65v at full charge and 3.1-3.2v nominal.
Lipo/li-mn tends to be around 4.2v at full charge and 3.7-3.9v nominal.

So 10S of lipo = approximately 38v; 10 x 3.7v
12S of lifepo4 = approximately 38v; 12 x 3.2v

 

[voicecoils]

S is the amount of batteries in series.

What voltage that is depends on the cell chemistry.

Lifepo4/li-co/etc tend to be around 3.65v at full charge and 3.1-3.2v nominal.
Lipo/li-mn tends to be around 4.2v at full charge and 3.7-3.9v nominal.

So 10S of lipo = approximately 38v; 10 x 3.7v
12S of lifepo4 = approximately 38v; 12 x 3.2v

Lithium Cobalt (LiCo) batteries (like most of the hobby city packs) are 4.2v charged and lumped into the 3.7v nominal category (although they hold a higher voltage then that throughout most of their discharge).

Strictly speaking, there is:

Lithium Ion (usually cylindrical) and Lithium Ion Polymer (usually a flat foil pouch).

Lithium chemistries available in the above forms come in various flavours including LiMn, LiCo, LiFePO4 among other variants which have their own electropotentials and corresponding charged, discharged & 'nominal' voltages.

 

[neptronix]

my bad, i thought lithium cobalt was 3.2 nominal

 

[voicecoils]

my bad, i thought lithium cobalt was 3.2 nominal

no probs, here's a horribly formatted table from wikipedia:

Electrode material	Average potential difference	Specific capacity	Specific energy
LiCoO2	3.7 V	140 mA·h/g	0.518 kW·h/kg
LiMn2O4	4.0 V	100 mA·h/g	0.400 kW·h/kg
LiNiO2	3.5 V	180 mA·h/g	0.630 kW·h/kg
LiFePO4	3.3 V	150 mA·h/g	0.495 kW·h/kg
Li2FePO4F	3.6 V	115 mA·h/g	0.414 kW·h/kg
LiCo1/3Ni1/3Mn1/3O2	3.6 V	160 mA·h/g	0.576 kW·h/kg
Li(LiaNixMnyCoz)O2	4.2 V	220 mA·h/g	0.920 kW·h/kg

http://en.wikipedia.org/wiki/Lithium-ion_battery

 

[neptronix]

Hmm, that page has seen a lot of updates recently and the numbers and info are all over the place now O_O...

Take with a giant rock of salt..

 

[mastershake916]

Thanks! I'm stuck with SLAs right now but look forward to working with less archaic battery technologies soon!