One of your best videos Julian. I think I understood internal battery resistance for the very first time. Of course one needs the difference in voltage because X & R essentially create a divider.. all makes sense quickly when I think about it for decades.
8 ปีที่แล้ว +10
Will there be a Building a Battery (Cell) Internal Resistance Tester #2 video? :)
Thank you Julian... your work is much appreciated! Thanks for the tip on the IRL mosfets too... I didnt realize that they are logic level ... learn something new every day!
Did you ever follow up on this? I am thinking that I might be able to program the CR mode of my "East Tester ET5410" electronic load for measuring internal resistance.
Great idea! Many of my AA rechargeable batteries are practically useless. They lose the charge while lying on the shelf. When I use them in my camera I see the low battery sign almost all the time. I've tried so many brands (among them Sanyo, Samsung Pleomax, GP and more). Even the POWEREX MH-C9000 battery charger didn't change much. I tried the Refresh & Analyze and Break-In modes. It takes so much time, and the effect is disappointing. Do you know of good AA rechargeable batteries that would not lose the charge?
I did build Adam Welche's very accurate 18650 capacity meter and now I would like to expand that project with an ESR measurement and a charge circuit, so 18650's are pre-charged before testing. (Using the MP1405 charge board - I can use it's leds indicating charge and charged for the arduino control.) Your low current measurement for NiMH batteries, is that also applicable for 18650's? Most instructions I can find are either high current discharge and disconnected measurements. The low current measurement you mention makes a lot more sense replacing the disconnected measurement. Love to see you pick up #2 and maybe expand it to other battery types.
Interesting project Julian. Kirchhoff's second law should be able to calculate the internal resistance of the cell. Just getting into LiPO batteries and trying to get as much background technical information about charge/discharge cycles and suitable chips for charging like the generic TP4056 china modules for building usb/solar charging units.
Love the video and the detailed description of it! Just found your channel today and watching all I can! 👍👍 So far! Did you ever finish the resistance tester?? Can't find part 2. I'm a modder, newbie still, but I've got into sub-ohm building heavily. And with battery manufacturer's "supposed" rating being all I have to go on it's a little dangerous. I build anything I can and would love to see how you finished your tester! And keep the DIY videos coming!!
nicl8098 Thanks. No I didn't follow that idea up - I think there may be problems with precision measurement of the cell voltage. Also, I saw an internal resistance tester on eBay, although it was quite expensive.
Julian Ilett so surely we can manually do this with a multimeter to get the accuracy? be awesome to see this maths work in practice just on your wood breadboard and paper. love your videos.
lotsarats You can definitely do this manually however you end up setting it up, the materials and meters involved will affect the accuracy obviously but depending on your scenario it may not be a big deal. If you primarily care about finding the bad cells even with the cheap bare basic entry level stuff such as: cheap multimeters, a high value resistor and a lower value resistor (make sure it has a high enough power rating, although it should be able to handle a brief high load depending on the values). You won't get an accurate or precise result if you're gonna do the short high drain one manually but you can get a pretty good idea especially once you know how a healthy cell of each chemistry behaves to weed out the bad ones. To get a proper measurement you'll need to put some more effort in I guess, but it all depends on your objective. The crucial part would be to get the timing consistent of the high load and be able to get a readout of it in time, if you want to go bare basics you could go with a switch (that can handle the current) and meters that have the ability to capture peak values they'll retain the lowest current and voltage with the pulsed load. That's just my quick thoughts on the manual method, it shouldn't be too hard to make it semi-automated really and get the timing consistent. But the subject for me has never been more than a curiosity, I hope my silly random ramblings might be of some use to you or others.
nice work Julian, Just 3 question... 1) what protocol do you think you'll use to comunicate with the LM096 OLED module..? 2) It's should be possible to connect this Module with an Atmel 328...? 3) Where do you get it this module..? thank you for the time you dedicate in making videos..! Paul.
r=(ε - V) / I The formula I see on the net does not have any ΔI, just ΔV. If ε is the open circuit voltage V is the voltage under load I is the current under the same load r is the internal resistance, the formula is... r=(ε - V) / I So they don't bother with ΔI which makes sense as the gradient on that curve you see in that document of yours is locally flat (ish). I am guessing though that if you take 2 readings with different loads and keep ΔI then it will be more accurate. Am I right?
I have over 1100 ,,,18650's I am building a pack from. I was thinking about trying to match the IR as much as I can. To help keep the bank balanced. I am capacity testing every one of them!!! Big job!! BIG!!! I am capable of charging 18 at once independently. And testing 15 independently. It still takes a long time. In fact I get up in the middle of the night to do a cell change. It takes about a month to test 200 cells. I'm using 98% of the cells. The 2% are 0 volt. Or under 2200mah. The useable cells are usually 2300-2925 mah. So it should be 29.4v and well over 500 ah when done.. Great old video. I'd like to see more!!
Why wouldn't this work: X=Vb-R We know the open circuit voltage Vb. So the difference between Vb and V is a voltage drop across the 'internal resistance' is it not? I have to build some test geer...
Interesting project, looking forward to updates! A while a go hack-a-day featured this LiPo IR meter: cseb.hu/rc_modell/multi_instrument/index.htm This one doesn't use the pre-load though, but seems easy to add. It is also using several FETs in parallel to reduce the resistance even further. There is some interesting timing info how voltage drops and stabilizes, which may be useful too.
I learned a hard lesson on the 1st flight of my new plane.......CRASH near the ground, as I lost all control at the 5 min mark of flight and I was very close ( range wise ) .....I was using a very old 3S 2200mah LiPo....pretty sure the ESC went into LVC, although after checking the battery after the crash it showed voltage was 3.80 per cell ........I am now searching for a simple way to check IR in all my LiPos .......
Excellent show. Please don't stop. I chased internal resistance on my li-po batteries for my rc airplanes. (engineering can be a curse) I had a big table full of data on XLL. I was already to plot it out when common sense kicked my butt. DA, Amp-hours out to your load is all you care about. I use a rc watt meter and 12v halogen light to get the capacity. Internal resistance changes like a hookers panties. Good luck and keep up the fantastic work. p.s. current flows from + to -. Who ever heard of politically correct electrons ?
There is a custom firmware for imax B6 style chargers which adds Internal Resistance test. Havent tried it though... Maybe you could test this on your accucel, Julian? :) github.com/stawel/cheali-charger
One of your best videos Julian. I think I understood internal battery resistance for the very first time. Of course one needs the difference in voltage because X & R essentially create a divider.. all makes sense quickly when I think about it for decades.
Will there be a Building a Battery (Cell) Internal Resistance Tester #2 video? :)
This is great start - I'd love to see the rest of this project!
Looking forward to seeing the next part to this :) Keep up the videos, they're right up my street of interest!
Great video as always Julian. Looking forward to the execution of this one!
Did you get this working?
Thank you Julian... your work is much appreciated! Thanks for the tip on the IRL mosfets too... I didnt realize that they are logic level ... learn something new every day!
julian, I am missing part 2... do you have a link?
Get it work man and have a kickstarter's week to fund this tiny DIY.
did you ever finish this?
I was just about to ask the same question.
Jeff Merlin Seemingly there is no answer to this 😢
Good stuff Julian! Cheers
Hey J, where is part 2? Thanks
robii387 , julian, I am missing part 2...
Did you ever follow up on this?
I am thinking that I might be able to program the CR mode of my "East Tester ET5410" electronic load for measuring internal resistance.
Julian did you ever finish this project?? Many people are asking!
Great idea! Many of my AA rechargeable batteries are practically useless. They lose the charge while lying on the shelf. When I use them in my camera I see the low battery sign almost all the time. I've tried so many brands (among them Sanyo, Samsung Pleomax, GP and more). Even the POWEREX MH-C9000 battery charger didn't change much. I tried the Refresh & Analyze and Break-In modes. It takes so much time, and the effect is disappointing. Do you know of good AA rechargeable batteries that would not lose the charge?
It's no contest - Sanyo eneloop. 70% charge retention over 5 years - nothing else comes close.
Julian Ilett
Thanks.
Did you ever complete the project? How about part 2?
I Hi Julian- will there ever be a part 2? Please!!
I did build Adam Welche's very accurate 18650 capacity meter and now I would like to expand that project with an ESR measurement and a charge circuit, so 18650's are pre-charged before testing. (Using the MP1405 charge board - I can use it's leds indicating charge and charged for the arduino control.)
Your low current measurement for NiMH batteries, is that also applicable for 18650's?
Most instructions I can find are either high current discharge and disconnected measurements.
The low current measurement you mention makes a lot more sense replacing the disconnected measurement.
Love to see you pick up #2 and maybe expand it to other battery types.
nice to see another build, esp as we cant do much about the solar one yet
Great job Thank you I understand know cristal clear. Why!!!! Looking forward for more videos
Hi I would like to know what oled display that was?
Most are too small.
Where can i find part #2 ?
Interesting project Julian. Kirchhoff's second law should be able to calculate the internal resistance of the cell. Just getting into LiPO batteries and trying to get as much background technical information about charge/discharge cycles and suitable chips for charging like the generic TP4056 china modules for building usb/solar charging units.
Part 2 please.
Love the video and the detailed description of it! Just found your channel today and watching all I can! 👍👍 So far! Did you ever finish the resistance tester?? Can't find part 2. I'm a modder, newbie still, but I've got into sub-ohm building heavily. And with battery manufacturer's "supposed" rating being all I have to go on it's a little dangerous. I build anything I can and would love to see how you finished your tester! And keep the DIY videos coming!!
nicl8098 Thanks. No I didn't follow that idea up - I think there may be problems with precision measurement of the cell voltage. Also, I saw an internal resistance tester on eBay, although it was quite expensive.
Julian Ilett so surely we can manually do this with a multimeter to get the accuracy? be awesome to see this maths work in practice just on your wood breadboard and paper. love your videos.
lotsarats You can definitely do this manually however you end up setting it up, the materials and meters involved will affect the accuracy obviously but depending on your scenario it may not be a big deal.
If you primarily care about finding the bad cells even with the cheap bare basic entry level stuff such as: cheap multimeters, a high value resistor and a lower value resistor (make sure it has a high enough power rating, although it should be able to handle a brief high load depending on the values). You won't get an accurate or precise result if you're gonna do the short high drain one manually but you can get a pretty good idea especially once you know how a healthy cell of each chemistry behaves to weed out the bad ones.
To get a proper measurement you'll need to put some more effort in I guess, but it all depends on your objective. The crucial part would be to get the timing consistent of the high load and be able to get a readout of it in time, if you want to go bare basics you could go with a switch (that can handle the current) and meters that have the ability to capture peak values they'll retain the lowest current and voltage with the pulsed load.
That's just my quick thoughts on the manual method, it shouldn't be too hard to make it semi-automated really and get the timing consistent. But the subject for me has never been more than a curiosity, I hope my silly random ramblings might be of some use to you or others.
nice work Julian,
Just 3 question...
1) what protocol do you think you'll use to comunicate with the LM096 OLED module..?
2) It's should be possible to connect this Module with an Atmel 328...?
3) Where do you get it this module..?
thank you for the time you dedicate in making videos..!
Paul.
wow this is great! i am building a battery cell for 100w led inspired by your video.
r=(ε - V) / I
The formula I see on the net does not have any ΔI, just ΔV.
If ε is the open circuit voltage
V is the voltage under load
I is the current under the same load
r is the internal resistance, the formula is...
r=(ε - V) / I
So they don't bother with ΔI which makes sense as the gradient on that curve you see in that document of yours is locally flat (ish). I am guessing though that if you take 2 readings with different loads and keep ΔI then it will be more accurate. Am I right?
opus bt-c3100 v2.2 is pretty nice liion charger and can calculate capacity and internal resistance.
I have over 1100 ,,,18650's I am building a pack from. I was thinking about trying to match the IR as much as I can. To help keep the bank balanced. I am capacity testing every one of them!!! Big job!! BIG!!! I am capable of charging 18 at once independently. And testing 15 independently. It still takes a long time. In fact I get up in the middle of the night to do a cell change. It takes about a month to test 200 cells. I'm using 98% of the cells. The 2% are 0 volt. Or under 2200mah. The useable cells are usually 2300-2925 mah. So it should be 29.4v and well over 500 ah when done.. Great old video. I'd like to see more!!
Why wouldn't this work:
X=Vb-R
We know the open circuit voltage Vb. So the difference between Vb and V is a voltage drop across the 'internal resistance' is it not?
I have to build some test geer...
did you test this??
No part 2 yet- a pity
And the finished circuit is....??
Still waiting for part 2 🙂
I had the exact same curiosity when capacity testing my collection of 18650 cells.
Interesting project, looking forward to updates!
A while a go hack-a-day featured this LiPo IR meter: cseb.hu/rc_modell/multi_instrument/index.htm
This one doesn't use the pre-load though, but seems easy to add. It is also using several FETs in parallel to reduce the resistance even further. There is some interesting timing info how voltage drops and stabilizes, which may be useful too.
Nice!
The Opus BT-C3100 smart charger can test internal resistance. It's a great charger, you can charge Li-Ion as well as Ni-Mh and N-Cd.
I learned a hard lesson on the 1st flight of my new plane.......CRASH near the ground, as I lost all control at the 5 min mark of flight and I was very close ( range wise ) .....I was using a very old 3S 2200mah LiPo....pretty sure the ESC went into LVC, although after checking the battery after the crash it showed voltage was 3.80 per cell ........I am now searching for a simple way to check IR in all my LiPos .......
Excellent show. Please don't stop. I chased internal resistance on my li-po batteries for my rc airplanes. (engineering can be a curse) I had a big table full of data on XLL. I was already to plot it out when common sense kicked my butt. DA, Amp-hours out to your load is all you care about. I use a rc watt meter and 12v halogen light to get the capacity. Internal resistance changes like a hookers panties. Good luck and keep up the fantastic work. p.s. current flows from + to -. Who ever heard of politically correct electrons ?
There is a update (not by Julian) on this Topic by learnelectronics. You can view the Video here: th-cam.com/video/W9bMmcnHi28/w-d-xo.html
There is a custom firmware for imax B6 style chargers which adds Internal Resistance test. Havent tried it though... Maybe you could test this on your accucel, Julian? :) github.com/stawel/cheali-charger
It was very good for my ears but my eyes will shake the rest of the day.
LSD???
Julian, get and USE a tripod,,, please!
Where can i find part #2 ?