InHisName
Enlightened
Many folks have referred to internal resistance being a key factor in battery cell condition etc, that I purchased a PLDaniels IRM v005R2 from: http://nqrc.com.
This measures internal resistance 3 ways: 1 ohm load, 0.5 ohm load, and 0.5 ohm load 50% duty cycle. See his web site for pdf manual for further details. I have bought 16 AAA NexCell precharged 7 months ago. I just bought 16 Duraloops 3.5 months ago. I cycled each cell twice then did a full break-in at 800Mah to measure capacity.
The NexCells came in at 775, 25 above the 'minimum' capacity. The irm measurement for these cells typically came to
1.43_________1.19_______1.08
155-209____175-222___170-216 milli-ohms
0.5/50%_____1.0ohm____0.5ohm test load
I have been using the cells in a FRS radio (walkie talkie) and every 2-3 days it says batteries need charging. I remove them and recharge them in my C9000. All 'seemed' to go well until I tried them in a high current need device, ran down in very short while! Worked great 7 months ago, though!
New irm measurements are:
1.44__________1.00________.83
225___________229________780
Looks like these things are loosing their abilities. Still great in the radio though.
So to compare to my Duraloops (in use similar radio for 3.5 months) and got the following measurements:
In Sept 09:
1.42-146____1.03-1.18______1.02-0.82
67____________74__________329-460
Just now:
1.42___________1.02_________0.84
158____________114_________609
These were charged very 3 days / 90 days for 30 cycles
The MAH hours put 'in' was usually 800-850 MAH so they weren't fully discharged.
=====
So folks are there 'tricks' to partially restore cells back to near original health ? If the resistance gets near or over 1,000 milli ohms the C9000 says "HIGH" and refuses to charge older cells.
I am experimenting by discharging a really weaker cell at 1,067 mo via a flashlight bulb until 'dead' then recharge on my MHC204F which doesn't 'care' about the 'high'. I'll do it 3x cycles and then test the internal resistance to see if there is any difference.
===
Any engineer types care to comment with formulas explainations etc ?
This measures internal resistance 3 ways: 1 ohm load, 0.5 ohm load, and 0.5 ohm load 50% duty cycle. See his web site for pdf manual for further details. I have bought 16 AAA NexCell precharged 7 months ago. I just bought 16 Duraloops 3.5 months ago. I cycled each cell twice then did a full break-in at 800Mah to measure capacity.
The NexCells came in at 775, 25 above the 'minimum' capacity. The irm measurement for these cells typically came to
1.43_________1.19_______1.08
155-209____175-222___170-216 milli-ohms
0.5/50%_____1.0ohm____0.5ohm test load
I have been using the cells in a FRS radio (walkie talkie) and every 2-3 days it says batteries need charging. I remove them and recharge them in my C9000. All 'seemed' to go well until I tried them in a high current need device, ran down in very short while! Worked great 7 months ago, though!
New irm measurements are:
1.44__________1.00________.83
225___________229________780
Looks like these things are loosing their abilities. Still great in the radio though.
So to compare to my Duraloops (in use similar radio for 3.5 months) and got the following measurements:
In Sept 09:
1.42-146____1.03-1.18______1.02-0.82
67____________74__________329-460
Just now:
1.42___________1.02_________0.84
158____________114_________609
These were charged very 3 days / 90 days for 30 cycles
The MAH hours put 'in' was usually 800-850 MAH so they weren't fully discharged.
=====
So folks are there 'tricks' to partially restore cells back to near original health ? If the resistance gets near or over 1,000 milli ohms the C9000 says "HIGH" and refuses to charge older cells.
I am experimenting by discharging a really weaker cell at 1,067 mo via a flashlight bulb until 'dead' then recharge on my MHC204F which doesn't 'care' about the 'high'. I'll do it 3x cycles and then test the internal resistance to see if there is any difference.
===
Any engineer types care to comment with formulas explainations etc ?
