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Oct 18, 2012, 01:07 PM
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United Kingdom, Aviemore
Joined Feb 2005
2,559 Posts
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Quote:
Do you have some numbers mixed up somehow? you list the battery as a 4300 but then say its a 5300. Even then with a cell IR of 1.8 the 4300 would come out at FOM1.55 , MaxA120 and a true 28C At 5300 it would be FOM1.26, MaxA133 and a true 25C. |
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Oct 18, 2012, 01:37 PM
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USA, GA, Marietta
Joined Aug 2005
3,987 Posts
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Quote:
5300mah 1.9 mohm FOM = 1.19 Max current = 129 True C = 21 Glen |
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Oct 19, 2012, 12:14 AM
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Australia, WA, Perth
Joined Feb 2003
761 Posts
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Just a quick question. How sensitive are IR measurements to temperature? I've noticed some of the measurements in the database are done at temps ranging from 70f to 75f. Is there a large distortion comparing the True C of a battery measured at 70f to another at 75f?
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Oct 19, 2012, 12:29 AM
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So. Cal.
Joined Oct 2004
6,179 Posts
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Lipoly performance is definitely temperature dependent. Any modelers who fly in the winter or cooler climates can certainly attest to this fact. It's for this reason that I specifically requested in post #2 of the data thread that measurements be taken within 2 degrees of 72F (or within 1 degree of 22C). Within this narrow range, internal resistance does not vary much but I still requested that the temperature be noted so that the posted data would be of most value to the reader.
Mark |
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Oct 19, 2012, 05:41 PM
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NE Ohio
Joined Apr 2003
3,662 Posts
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nice diagrams in post 2 and 3.
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Oct 20, 2012, 05:20 PM
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NE Ohio
Joined Apr 2003
3,662 Posts
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When looking for "cell damage,degradation,increased IR" is it more likely that it will show up at higher temps or lower temps? How about high voltage or low voltage? I'm reading mine with i-charger so I read only 1mv increments.
I 'think" I know the answer should be at the lowest temp and voltage since the IR is going to read the highest under those conditions. |
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Oct 20, 2012, 08:05 PM
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So. Cal.
Joined Oct 2004
6,179 Posts
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It's generally easiest to track performance over time by being as absolutely consistent as possible with respect to measurement temperature. Charge state does not matter much at all as long as the pack has had the opportunity to stabilize. I typically measure at storage voltage (3.8-3.9 volt/cell) as I do not like to leave my packs at full charge any longer than necessary.
Fortunately, my living room is typically with 1-2 degrees of 72 F so maintaining a consistent test temperature is easy for me. If your packs are truly degrading, the 1mOhm resolution of your iCharger will be more than sufficient to tell you this, unless your packs are huge (>5000mAh). Mark |
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Oct 25, 2012, 08:03 AM
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Land O' Lakes, FL
Joined Aug 2003
754 Posts
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I have been spot checking my HAIYIN packs IR during charging. So far, NONE has exceeded 1.0! When compared with my hyperions and various Hobbyking packs, the HAIYINs are MUCH lower in internal resistance. Just one more reason I have totally switched to HAIYIN for all new pack purchases.
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Oct 25, 2012, 08:42 AM
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Joined Mar 2012
2,950 Posts
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Where do you buy them?
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Oct 25, 2012, 11:27 AM
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Land O' Lakes, FL
Joined Aug 2003
754 Posts
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Quote:
Be sure to select USA Warehouse if you are in the US or European Warehouse if you are in Europe. Other countries can use HONG KONG Warehouse. |
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Oct 25, 2012, 04:49 PM
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Australia, New South Wales, Sydney
Joined Jan 2011
2,034 Posts
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Quote:
Out of curiosity, what's the capacity of these cells with a <1mOhm IR? |
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Oct 26, 2012, 08:03 AM
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Land O' Lakes, FL
Joined Aug 2003
754 Posts
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4S 5000 30C and 40C packs, 4S 2650 packs, and 6S 5000 packs.
Quote:
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Oct 26, 2012, 08:14 AM
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Australia, New South Wales, Sydney
Joined Jan 2011
2,034 Posts
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Quote:
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Oct 26, 2012, 08:26 AM
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Land O' Lakes, FL
Joined Aug 2003
754 Posts
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Yes, the 2650's I have checked were below or right at 1.0 mOhm
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Oct 26, 2012, 09:04 AM
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Australia, New South Wales, Sydney
Joined Jan 2011
2,034 Posts
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Quote:
What are you using to measure IR? |
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