Right size resistor

JimmerG

Newly Enlightened
Joined
Oct 1, 2008
Messages
55
So I understand that to correctly measure a battery's charge (Volts) you need to stick a resistor across the terminals (briefly) whilst checking with a DMM.

I'll be checking 2500mah protected 18650s, and I've got a 10ohm 3 watt resistor - should this do the job?

Will this also work with Nimh AA's?

Thanks for your help.
 

Mr Happy

Flashlight Enthusiast
Joined
Nov 21, 2007
Messages
5,390
Location
Southern California
The use of a resistor to provide a small load is mainly applicable to primary CR123A cells and alkaline cells.

With a lithium ion cell like an 18650 you can just measure the voltage directly. No resistor is required.
 

lctorana

Flashlight Enthusiast
Joined
Jun 28, 2007
Messages
2,123
Location
Melbourne, Australia
JimmerG said:
...I've got a 10ohm 3 watt resistor - should this do the job?

10 ohms will be fine. Observe the no-load voltage, and then see how far it drops with your ~0.4A load.

JimmerG said:
Will this also work with Nimh AA's?
Yes. You can also use a 1.2V bulb.
 
Top