Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Lipo battery mAh vs Wh

Status
Not open for further replies.

vinodstanur

Advanced Member level 3
Joined
Oct 31, 2009
Messages
751
Helped
114
Reputation
234
Reaction score
114
Trophy points
1,333
Location
Kerala (INDIA)
Activity points
7,054
Hi,
I am a bit confused about the the mAh and Wh specifications for a 3.7v lipo.

For example I have a routejade battery YE402025C 3.7V 160mAh, 0.592Wh.

Now I have a varta batter VKB: 56416 201 026 which is 3.7v 150mAh, 0.6Wh.

So is there no relation between mAh and Wh for a battery ?

Till now I thought if we know mAh we can calculate Wh since the average voltage is 3.7v but now I am a bit confused how can these two things (mAh and Wh) is not relative ?
8-O:-|

My assumption till now was that ( 3.7 * mAh (in A ) * 3600 ) Joules is the total capacity of battery in terms of energy. Is this not correct ? Coz the Wh is not matching properly with this value.
 

It is just rounding of the results of V * A * 3600 - or at least that can be part of the reason for the difference.
Additionally, the Watt hours is the volts * amps under the area of the discharge curve, which is not maintaining a constant 3.7VDC as the battery discharges - and the voltage will change depending on the rate of discharge.

To get a completely accurate result, one would have to apply a constant current load and integrate the voltage curve to obtain the result. But, this level of accuracy is seldom necessary, and the simple
V*I*3600 is often sufficient.

Additional note - one cannot FULLY discharge a LiPo battery without incurring some amount of permanent damage/diminished capacity. Discharge below 1V / cell will almost surely reduce capacity, and generally it is avoided to discharge below approximately 1.7V to 2V per cell to maintain longer life.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top