battery tester and charger for 18650's and similar

[djans1397]

I'm sure this has been asked before, but I can't seem to find the info I'm looking for. Any refferal to known threads or links would be much appreciated.

I'm looking for a simple no nonsense answer to what battery tester I need to check my 18650's. I have a pretty good knowledge base on what levels are acceptable for minimum discharge and maximum charge levels as well as long term storage levels. I was thinking that a simple volt/amp meter would suffice. What are you guys all using to test?

I also have a Ultrafire WF 139 charger; Pila IBC has been rec to me as being a better charger as well. I'm just getting started in my collection of lights and want a decent charger that won't break the bank. Any suggestions on a charger would also be appreciated.

Thanks in advance for anyones advice and help to a newbie to lights. I've searched for awhile now in here and haven't found much info...unless I;m looking in the wrong place.

Dan

 

[djans1397]

Anyone with info would be appreciated.

 

[SilverFox]

Hello Dan,

If you let the cells rest, open circuit, for around 15 minutes and then measure the voltage, you will get a very good estimate of the remaining capacity left in the cell.

There are threads where resting voltage versus remaining capacity have been discussed.

Also, you can play with this formula...

State of Charge in % =
100(0.1966+square root of(0.0387-1.4523(3.7835-resting voltage)))

The Pila IBC is a very good inexpensive Li-Ion charger.

Tom

 

[djans1397]

Thanks Silver Fox.

1.) Where can I find the Pila chargers at? I've had a hard time locating them...and why are they better than my current Ultrafire WF139.
2.) What does "resting, open circuit" mean?
3.) Any recs on a good battery tester?

Thanks you much!

Dan

 

[SilverFox]

Hello Dan,

I am not sure where you get the Pila chargers, but I believe there was some talk of a group buy in the CPF Marketplace. You may want to check over there.

If you put a battery in a flashlight and turn it on and measure the voltage, that is voltage under load. On the other hand if you remove the battery from the light and set it on the counter to rest for a few minutes, that is open circuit resting voltage.

When checking Li-Ion cells, a volt meter works well as a battery tester. If you want to check NiMh, NiCd, Alkaline and Lithium cells, ZTS makes a good battery tester.

Tom

 

[djans1397]

Thanks much Silver Fox!:thumbsup:

Dan