What is a nominal battery voltage?

[Fordulike]

For example, looking on Ping's website, he has batteries at 24v, 36v, 48v and 60v.
Are these figures classed as the nominal voltage of a pack, even though hot off the charger, the voltage will be higher?

 

[NRG]

Yes, its a reflection of the type of cells used in the battery, so 10 cells of 3.7v nominal = 37v

The nominal voltage is given by the manufacturer and represents the average or typical voltage of the cell during use.

 

[jerrysimon]

As NRG says. Most standard batteries on EBikes are Li-Ion and their nominal voltage is 3.3v. Li-Poly are 3.7v nominal.

Pings batteries are Lifepo4 which again are Li-Ion based so each cell is 3.3v nominal.

In 36v Li-Ion batteries for ebikes they tend to use 12 cells in series (12* 3.3 = 39.6v), whereas like NRG says those using DIY 36v Li-Poly batteries need less cells because of the slightly higher nominal voltage of each cell. Thus only 10 cells in series are used for thier 36v pack.

Regards

Jerry

 

[flecc]

Slight correction, our e-bike li-ion batteries from the beginning have been with ten 3.7 volt cells, whether cobalt, manganese or compound cathode. It's the chemistry which determines that, not polymer which is just a construction method.

It's the iron based cathode batteries (LiFePO4 also known as lithium iron phosphate) that have had the 3.3 volt cells, sometimes built with additional cells to make good the voltage shortfall.

Here's a 36 volt typical li-ion non-polymer hard cell battery interior with ten 3.7 volt cells for example.

And here's a li-poly with 2 parallel banks of seven 3.7 volt soft cells to make it's 26 volts.
.

 

[jerrysimon]

Yes of course Flecc is right its the LiFepo4 batteries and A123 cells that have a nominal voltage of 3.3v.

Regards

Jerry