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"Good" IR for common 18650 cells
#11
Nemo Read the post from intra that i answered.
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Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 83kWh LiFePo4 | 10kWh 14s 18650 |  66*260W Poly
Upcoming: 14S 18650~30kWh | Automatic trip breakers, and alot more
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#12
only use yr10** , more and more users are coming.
Why not as a mark or standard.
There is a lot of data based on this ir tester, the tester is tested a lot.
The tester is had a lot comparative research with a lot of other testers.
Why don't you make this as a standard tester for your data?

Don't forget the 10% rule, if factory dictates 26 mohm min/max is ~24 to 28.8 mohm.
Or factory dictates 68 mohm it would be ~62.2 to 74.8 mhom for a giving cell.
But this is what I applied in my pw

thanks in advance
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#13
Because in a DIY community we have varying levels of commitment, time, money and risks.

I think overall we all want the same thing, a safe and happy community doing what we enjoy as a hobby, pushing a 'standard' is hard work and i think all we can do is suggest better ways to do something and let the end user decide on what fits them best.

I settled on the SM8124A by seeing a video from daromer and its helped me understand the relationship/trend in IR for my cells. I'm sure it would have been different if daromer did a YR1030 instead, but thats just how it worked out! Smile

The positive thing was that i moved away from using the OPUS as it was insane some of the number i was getting back, it would have made me junk atleast half the cells i have currently.
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#14
At this point the standard is a 4-wire kelvin type IR tester. To push that a bit farther I'd say one that's been tested and found to be acceptably accurate. Making it any more restrictive limits the amount of data that can be collected, and I think more data (within an acceptable margin of error) is worth it. Considering the margin of error is already set by the chargers themselves being out up to 10% there's a pretty wide acceptable margin.
Mobilis in Mobili
 
Cell count as of 10/10/2019
234 Cells >2000mAh, >80% Rem. Cap., 14 day resting voltage >4.12V
191 Cells of Everything Else
68 In progress
 
Aiming for 8 cells tested a day
More info on my Google Drive
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#15
the SM8124A is pretty much same as the YR. I doubt you will have any issues with either or. They may not be on same point but they are most likely accurate enough depending on the version you have. The first one of the SM had bad design tips but the later versions was better.
The Ultimate DIY Solar and build place
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 83kWh LiFePo4 | 10kWh 14s 18650 |  66*260W Poly
Upcoming: 14S 18650~30kWh | Automatic trip breakers, and alot more
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#16
(10-25-2019, 05:33 AM)daromer Wrote: the SM8124A is pretty much same as the YR. I doubt you will have any issues with either or. They may not be on same point but they are most likely accurate enough depending on the version you have. The first one of the SM had bad design tips but the later versions was better.

Agreed.
I have tested pretty much all the most common (reasonably priced) IR testers.
 
Here are the results.                (Skip the BVIR-2018 it is Junk)

Although my favorite is the YR1035+ (not shown) 
See https://secondlifestorage.com/showthread...1#pid53191

Wolf
100kwh-hunter likes this post
If 18 X 650 = 2200+mAh then we have power! 
May all your Cells have an IR of 75mΩ or less Smile
Last count as of 8/7/2019
Total Number of Cells Recorded and processed                 6149
Total Cells required for PowIRwall                                   2856
Total Cells ≥2200mAh, ≥80%, ≥35mΩ, ≤75mΩ, ≥4.12V   2760
For Info Google Drive
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#17
I am curious if you ever tested the accuracy of the YR1035+ against any popular RC chargers which have 4 wire IR or the manual method by adding a known value resistive load and looking at the voltage drop.

I typically use an RC charger for these measurements but I have been curious about accuracy or how it might stack up to the testers you reviewed here. I can at least do the manual method for comparison and report back.
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#18
I compared the SM8124A with my Icharger DUO 308 with attached 4 wires and its pretty even.
Crimp Daddy likes this post
The Ultimate DIY Solar and build place
YouTube / Forum system setup / My webpage  Diy Tech & Repairs

Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 83kWh LiFePo4 | 10kWh 14s 18650 |  66*260W Poly
Upcoming: 14S 18650~30kWh | Automatic trip breakers, and alot more
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#19
(10-30-2019, 05:17 PM)Crimp Daddy Wrote: I am curious if you ever tested the accuracy of the YR1035+ against any popular RC chargers which have 4 wire IR or the manual method by adding a known value resistive load and looking at the voltage drop.

I typically use an RC charger for these measurements but I have been curious about accuracy or how it might stack up to the testers you reviewed here.  I can at least do the manual method for comparison and report back.


I have not. 
The only RC charger I have is an iCharger X6 and it does not do 4 wire.
I have compared it to the ZH-YU ZB206+ https://secondlifestorage.com/showthread...5#pid52825
Other than that just testing 4 different IR testers and coming within ± 3mΩ of each other is a pretty good indication of the accuracy of a sub $100.00 tester. I guess the next step would be a Keithley DMM7510 at ~ $4000.00. 


But there is a review of the YR1030 by this guy. (The YR1035+ is the same just bigger screen and better resolution on Voltage.)
https://lygte-info.dk/review/InternalResistanceMeterYR1030%20UK.html

H
is conclusion was:
I like this meter, it is very useful for a lot of stuff, not only batteries. It can measure the resistance in a switch, a tail spring, a atomizer and a lot of other stuff.
When used to measure resistance it will give same value as an ordinary DMM except for much better resolution at low values. On batteries the value cannot be compared to the values chargers measures, but usual the datasheet value is measured this way.
His Notes:
I got the meter from Vapcell.
As reference I used my Keithley DMM7510, it can do 4 terminal ohm measurement.




Wolf
If 18 X 650 = 2200+mAh then we have power! 
May all your Cells have an IR of 75mΩ or less Smile
Last count as of 8/7/2019
Total Number of Cells Recorded and processed                 6149
Total Cells required for PowIRwall                                   2856
Total Cells ≥2200mAh, ≥80%, ≥35mΩ, ≤75mΩ, ≥4.12V   2760
For Info Google Drive
Not your average Wolf       
            Cool
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#20
Wolf,

I actually learned this from @daromer but you should be able to connect two JST balance leads from your iCharger X6 to create a 4 wire system.  I have done it on both my iCharger 4010Duo and 206B



Just for fun... I did a quick test and wanted to share the results.  Note:  This Samsung 25R cell under test is kinda beat up / fatigued.  When it was newer, the IR was better. (Too many high drain stress tests)

iCharger 4010 & 206B both put the IR of this cell around 60 to 65 mOhms

Manual reading (multimeter + resistor) yielded some varying results.

With a 2.05 ohm resistor as a load, I got a IR reading of about 131 mOhms
With a 10 ohm resistor as a load, I got an IR reading of about 63 mOhms

2 ohm resistor puts the discharge at about 1C, which isn't unreasonable for this cell, but could be considered aggressive for a laptop cell.

I guess my questions is the IR measurement can vary depending on the load.  Should I be testing my IR with a standard like a 10 ohm resistor to it somewhat aligns with my chargers, or should I apply a real world load and use those IR measurements.

My smaller packs will obviously see higher discharge rates than some of the powerwall projects here.
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