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FrozenGate by Avery

How healthy are your batteries? (How to measure internal resistance)






And hey, if you need a programmer, I can help. Used to do quite a bit of work on Obj-C and C++ projects, both of which use C as their base. So while I don't use C directly as much, I do know C fairly well.
 
I have tested four 18650 batteries: two used LG batteries, I got with my RPL450 and two brand new great Sanyo batteries from LarryDFW.
I tested all batteries with two different resistors: 4.7 Ohms and 6.8 Ohms.

Here the results:

Pink LG: U0=4.17V U6.8=4.09V RI6.8=133 mOhms U4.7=4.06V RI4.7=127 mOhms RIavg=130 mOhms:yh:

Orange LG: U0=4.14V U6.8=4.02V RI6.8=203 mOhms U4.7=3.96V RI4.7=214 mOhms RIavg=208 mOhms:yabbmad:

Sanyo 1+2: U0=4.18V U6.8=4.13V RI6.8=82 mOhms U4.7=4.11V RI4.7=81 mOhms RIavg=81 mOhms:drool:

Both Sanyo batteries had exactly the same excellent internal resistance. They work great in my RPL, but since I got them yesterday, I can't tell it they last longer - but they should:D

Rep+ for DrLava for this easy and very useful method to test the quality of your batteries.
 
LPF;

I just received and tested a few new cells:

1. Samsung 2800mah #18650 cells
2. Panasonic 2600 mah #18650 cells.

The Samsung had slightly better internal resistance:

V1=4.20 VDC No Load (Rested for an hour) @70° F
V2=4.08 VDC Loaded
R = 3.1 ohms
Internal resistance : ~95 mOhms @ 1.33 amps load (about 1/2 C load rating)

Very good IR, with 200 mah more capacity.

According to 18650 Battery Testing Experts @ Cadex :

50-150 mOhm - Excellent
150-250 mOhm - Good
250-350 mOhm - Marginal
350-Up mOhm - Bad

LarryDFW
 
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Great info, i am glad to be here :D
...the other day i was testing my 18650's and they were all >500mOhms which i scavenged from dead hp dv6 batteries..I couldnt wait for weeks to get these batteries online, So i went to my friends, he repairs all kind of laptops in daytime job.. i asked him if he could sell me some used up batteries, and guess what i found from 3 old (almost dead) batteries..

4x 18650s with IR ~ below 100:beer:
10x 18650s with IR ~ above 150 :( but below 200:beer:
2x 18650's 200+ :undecided:
2x 18650's Dead and rusty:yabbem:

I tried 9V battery, 12V battery-cell, 6x AA batteries... I dont know why using these anymore makes me feel stupid when i have :bowdown:18650's available XD
 
Sinner;

One caution for old laptop cells.

Normal life for #18650 cells is 4 to 5 years depending on the manufacturer.

Laptop batteries are 2-3 years old usually when discarded.

LarryDFW
 
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If their internal resistance is still low it doesn't matter how old they are. Li-Ion's lifespan is measured in charge cycles, not years.. unless the cells have been abused (overcharged or overdrained) in which case all bets are off.
 
Help please,I have a lazerer 100mw green rifle laser and a ultrafire 18650 battery and charger............... 18650 Battery + Charger Set............

Being aware of the dangers posed by overcharging and discharging of these batteries i want to be sure im not doing any of the above.

The laser arrived in the post with battery and charger included but no instructions on using the charger.the battery had some charge in it already but was'nt sure on the stored power in the 18650.
I plugged in the charger and inserted the battery, there is a green LED showing but what does this mean?
Is it fully charged when its shows a green or red LED? Whats the difference.

Thanks
 
m0odv said:
Help please,I have a lazerer 100mw green rifle laser and a ultrafire 18650 battery and charger............... 18650 Battery + Charger Set............

Being aware of the dangers posed by overcharging and discharging of these batteries i want to be sure im not doing any of the above.

The laser arrived in the post with battery and charger included but no instructions on using the charger.the battery had some charge in it already but was'nt sure on the stored power in the 18650.
I plugged in the charger and inserted the battery, there is a green LED showing but what does this mean?
Is it fully charged when its shows a green or red LED? Whats the difference.

Thanks
Click to expand...

You will need to open your own thread in the appropriate section
of the Forum and ask your questions there.

This thread is about How to Measure Batter Resistance...
Your post does not address the subject of this Thread...

Thread Jacking is frowned upon on the Forum...


Jerry
 
I was trying to navigate this website and post my own thread.so i found this on batteries,
Well your comment on thread jacking FINE!! I will not use this site again and will try another laser pointer forum.
Thanks for nothing...........................................................................................................................................................................................................:yabbem:
 
m0odv said:
I was trying to navigate this website and post my own thread.so i found this on batteries,
Well your comment on thread jacking FINE!! I will not use this site again and will try another laser pointer forum.
Thanks for nothing...........................................................................................................................................................................................................:yabbem:
Click to expand...
You've been on the Forum since Sept 28 2011...
You could have easily PMed any member for Help
on opening a thread...

Nice temper tantrum....:gj:

Don't let the door hit you on the way out...

This is no place for spoiled arrogant snot nosed children...

You can come back when you've learned to play nice with
others....

:wave::wave::eg:


Jerry
 
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I just received and tested some promising new cells:

Samsung 3000mah #18650 cell

The Samsung had one of lowest internal resistances I have measured:

Tested with R = 3.1 ohms
Internal resistance : ~90 mOhms @ 1.34 amps load (about 1/2 C load rating)

Very good IR, with 400 mah more capacity and higher charged voltage (4.35 VDC)
Higher cell voltage should improve capability of boost designs.

According to 18650 Battery Testing Experts @ Cadex :

50-150 mOhm - Excellent
150-250 mOhm - Good
250-350 mOhm - Marginal
350-Up mOhm - Bad

LarryDFW

P.S. Just saw some testing on protection circuits.
The ones tested were 60 miliohms.
That means about a 0.12 volt drop at 2 amps current.
 
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It doesn't. It's spam. Both of his two posts are links to that battery site.
 
I am using a 5.1 Ohm resistor, but I'm thinking this load isn't big enough to give meaningful results. Should I use a resistor that would net the max current that the cells can handle, or is shooting for ~1-2 amps high enough? Or perhaps, is my 5.1 Ohm just as good?
 
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