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Dec 13, 2013, 04:12 PM
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Internal Resistance Meters - Source?


I found this 7 in 1 meter, is it a good one: https://www.hobbyking.com/hobbyking/s...arehouse_.html ?

Here is a link to the 7 in1 Users Manual: https://www.hobbyking.com/hobbyking/s...X250282X36.pdf

Are there others that are worth a look?

Thank you!
Last edited by itsme2; Dec 15, 2013 at 11:39 PM.
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Dec 14, 2013, 01:21 AM
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This is the only one worth buying:

www.rcgroups.com/forums/showthread.php?t=1323465
Dec 14, 2013, 06:56 AM
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@$70-80 an I Charger 106b can read IR,the best part is when you buy it you also get a very nice charger with it.I think the Gens Ace 100watt charger reads IR as well.
Dec 14, 2013, 09:21 AM
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I wouldn't consider the IR from the iCharger anywhere near as accurate at the ESR meter.
Dec 14, 2013, 10:13 AM
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Agreed that the HK meter is borderline useless for measuring individual cell internal resistance. Since it is a simple two wire meter, pack connectors and leads are included and will cloud the reported IR results.

Conversely, the ESR Meter and iCharger use true four-wire measurement methods and the reported results are solely the individual cell resistances. The ESR Meter has higher resolution (.04mOhm) and is much better for high capacity packs that have inherently lower internal resistance than similar cells of lower capacity. The iCharger 106B+ as noted by Tug has 1mOhm resolution is perfectly adequate for lower capacity packs.

I use my iChargers when measuring packs with 2200mAh and lower capacity. I use my ESR Meter when measuring packs with >2200mAh capacity and want finer resolution.

Mark
Dec 14, 2013, 11:30 AM
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Mark, just curious, but have you compared the readings taken with the iCharger to those from the ESR meter? Looking at the specs for the iCharger 106b and 206b, there is no mention of the resolution of the IR measurements, just that the display only shows the nearest 1 milliohm; resolution could be 2mOhm, but still be displayed as shown.
Dec 14, 2013, 11:56 AM
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Does anyone here have experience with the Internal Resistance meter function of the PowerLab 6/8 chargers? How accurate and easy to use are these in measuring individual cell and pack total IR? I'm thinking now it might be a good idea to get a good parallel charger with an internal resistance cell reading function rather than just an IR meter.

Thank you!
Dec 14, 2013, 11:58 AM
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Quote:
Originally Posted by Wintr
Mark, just curious, but have you compared the readings taken with the iCharger to those from the ESR meter?
Yes, I've tested this quite extensively and the ESR Meter and my iChargers are very much in agreement with one another. My iChargers (106B+, 206B, 306B) give readings to the nearest 1 mOhm which is no issue for smaller packs, as alluded above. I will bust out my ESR Meter when checking new packs or if I desire to have finer resolution for whatever reason. My typical packs are 2500mAh or less so I get more than adequate measurements with my iChargers.

Those who fly competitively and have higher capacity packs will certainly appreciate the higher resolution of the ESR Meter but most sport flyers will be perfectly satisfied with an iCharger.

Mark
Dec 14, 2013, 12:29 PM
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Good to know, thanks.
Dec 14, 2013, 01:37 PM
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Quote:
Originally Posted by Ohmic
I wouldn't consider the IR from the iCharger anywhere near as accurate at the ESR meter.
How important is a super accurate IR meter, is it possible that "adequate" IR measurements are sufficient for the average RC hobby guy versus an engineer?
Dec 14, 2013, 04:14 PM
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[QUOTE=Wintr;26898731just that the display only shows the nearest 1 milliohm; [/QUOTE]

That's because that is the resolution, 1 milliohm.
Dec 14, 2013, 04:19 PM
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Quote:
Originally Posted by itsme2
How important is a super accurate IR meter, is it possible that "adequate" IR measurements are sufficient for the average RC hobby guy versus an engineer?
That's a personal decision that that each modeler would need to consider. Many don't care about IR at all. Others feel this it's one of the key indicators of LiPo performance.
Dec 14, 2013, 06:24 PM
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Quote:
Originally Posted by Ohmic
That's because that is the resolution, 1 milliohm.
Well, that doesn't necessarily follow. The digital temperature gauge in my car displays to 1 degree F, but actually measures to the nearest degree C, so resolution is actually 1.8 degrees F. That's why I asked Mark if he had done the comparison to confirm (which I assumed he had).
Dec 15, 2013, 05:43 AM
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For $38.88 I bought this :

http://www.ebay.co.uk/itm/1211507994...84.m1439.l2649

As I already have a couple of balance chargers - I didn't feel it necessary to shell out double that price on the cheapest all in one charger that reads IR.

As to anothers question about accuracy ... my personal opinion is that it's not so much the single reading ... it's the being able to check for CHANGE to that reading ... indicating a decline in battery.

If a battery is performing it's function well and has a reading of xx - does it really matter if it's 0.01% out in accuracy ... as long as its consistent. Then later when reading alters to xx +y ... you know somethings going wrong.

Nigel
Dec 15, 2013, 05:57 AM
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For the packs I have compared (mainly 3-4S, 2200-5000mAh) the iCharger, the Hyperions with the latest firmware and the ESR meter are in very close agreement.

The Powerlab8 reads a consistently slightly lower value of IR but any of the four methods are accurate enough for sensible comparison of LiPo IR in my opinion. For most people the absolute value of IR is less important than a consistent comparison between cells and packs and over time. Since IR is a derived value not an intrinsic property it will always be partly a function of how you measure it. Each of these meter/chargers uses a different method to estimate the IR value.

The iCharger and ESR meter use an instantaneous reading method so are very convenient and fast. As noted below, the iCharger has lower resolution but seems to be accurate. The Hyperions and Powerlab measure IR during the charge so need to be powered up and take much longer. If you observe the Powerlog graph IR vs. time on the PC you can watch it settle to final value. This may take around of the charge cycle.

In practice the big difference is that you can measure the IR of a bunch of unknown packs in a few minutes with an ESR meter or iCharger. You can only measure one at a time during a full charging cycle on a Hyperion or Powerlab. If you consistently record the IR after each charge cycle this is fine as you will immediately notice any changes.

There is some discussion about the various results around this post in the "Simple LiPO performance tool thread' but note that Hyperion have updated their firmware since that post and the IR results now agree very closely with the iCharger and ESR meter.

https://www.rcgroups.com/forums/show...6&postcount=43

Quote:
Originally Posted by itsme2
Does anyone here have experience with the Internal Resistance meter function of the PowerLab 6/8 chargers? How accurate and easy to use are these in measuring individual cell and pack total IR? I'm thinking now it might be a good idea to get a good parallel charger with an internal resistance cell reading function rather than just an IR meter.

Thank you!
Last edited by jj604; Dec 15, 2013 at 06:03 AM.


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