Math Help ( Hey, I'm new to this stuff ) Thought it was a simple multiplication problem

4 posts / 0 new
Last post
scouttster
scouttster's picture
Offline
Last seen: 13 years 1 month ago
Joined: Monday, December 19, 2011 - 06:20
Points: 14
Math Help ( Hey, I'm new to this stuff ) Thought it was a simple multiplication problem

Gentleman is selling batteries as reads:
$58.20 for 28 = 3.7v 2400mah batteries.
Enough to make a 25.9v 9.6ah pack that works with the EZip 24v controller!

I figured he arrived at his figures by 28 X 3.7 for the voltage and 28 X 2.4 for the amphours. I was way wrong.. Can someone explain, how he arrived at 25.9 Volts and 9.6ah?
Thanks, I'm new to all this and just trying to learn.

Spaceangel
Offline
Last seen: 9 months 4 weeks ago
Joined: Wednesday, July 15, 2009 - 15:49
Points: 500
Re: Math Help ( Hey, I'm new to this stuff ) Thought it ...

I think I lost you in your typing of the number of cells and voltage pack? I want to convert my scoot to LiFePO4 and I know 4 lithium cells = 12.8 volt nominal so times 5 = a tad more than 60 volt pack but close enough I think. What exactly do you need? I am going to cut my frame to make testing and replacing easier.
Russell

KB1UKU

mf70
Offline
Last seen: 7 years 2 weeks ago
Joined: Friday, December 1, 2006 - 09:01
Points: 712
Re: Math Help ( Hey, I'm new to this stuff ) Thought it ...

He's building four serial strings of seven cells, and running the four strings in parallel:

7 x 3.7V = 25.9V

4 x 2.4AH = 9.6 AH

The math is correct.

Mark

mf70
Offline
Last seen: 7 years 2 weeks ago
Joined: Friday, December 1, 2006 - 09:01
Points: 712
Re: Math Help ( Hey, I'm new to this stuff ) Thought it ...

Oops. The board won't let me edit. To add, now, whether your simple charger will keep all these cells balanced without a BMI is another question. I don't think it will, and that's part of the reason I've still got lead in my sled.

Mark (again)

Log in or register to post comments

Buy Ecotric bikes, get free accessories!


Who's online

There are currently 0 users online.

Who's new

  • eric01
  • Norberto
  • sarim
  • Edd
  • OlaOst

Support V is for Voltage