Quick note: for physically tiny batteries and non Lipo packs the resistances can be a lot higher. If you use these really small batteries or non Lipo packs then why not test them and see what their resistance is and post the results here? Happy flying!
A while back I checked ten new 260 mAh 1S lipos (for my 65mm brushed whoops) and got the following (in milliohms): 102, 105, 105, 105, 108, 108, 111, 114, 114, 117
Coming from the RC indoor carpet car racing community lipo internal resistance in spec racing is a huge consideration. We pay over $100US for a good competition 2S lipo. Not only is the internal resistance low, in the 1 milliohm/cell range but resistances are matched cell to cell. We also heat the lipo up by high rate charging which has a huge affect on IR numbers. This is the extreme end of competition RC racing which the average RC hobbyist would not be concerned. Something is not adding up correctly in your SkyRC charger displaying 1-6-7 and 7-0-0 milliohms . The two accepted accurate meters that we use is the iCharger built in meter or a specific IR lipo meter.
I might add that when you snip the battery leads do them one at a time to avoid a short circuit. That can lead to some "exciting" results if you are not careful.
This information is extremely helpful 👍. I recently purchased a 6400mAh 4S2P 18650 lithium-ion pack, and my quadcopter was flying pretty erratically with it, so I checked the internal resistance with an iCharger 206B. The per-cell internal resistance was 26, 29, 29, and 29 milliohms. It is rated at a maximum continuous discharge current of 20A. The voltage of the pack drops dramatically under load; my quad current is around 8A. I have an older 5200mAh 4S2P 18650 Lithium-ion pack, and the per-cell internal resistance for it is 12, 11, 12, 13 milliohms. It flies fine and much longer. Almost forgot to mention that the pack with high internal resistance did get pretty warm. I only flew it a couple times and will retire it, hopefully the place I got it will take it back.
The biggest factor that will affect the IR reading is temperature. The same pack at different temps will have very different IR readings. So compare a pack to previous readings at the same temp if you want to see a trend with that battery.
This is very helpful. I was watching wondering if I should buy a checker for my e-bike battery pack in addition to my single cell tester. Measuring the IR is immediate while doing a load test takes hours. So am thinking it's now a no brainer. I should buy one.
A really good overview of a complex subject - well done! Only a few things I'd mention ... first is balance. All the cells in a new pack should have similar IR ... if they don't it would be a good reason to reject the pack. Second, IR often drops a bit after the first couple of cycles. Third, as already mentioned by others cell capacity affects IR. So small cells (brand new, in good condition) will have higher IR than large cells - hence the use of 'C' ratings (even if these are largely fiction!). Fourth, over time it's quite common for one cell to develop a (much) higher IR than the others (that's what does for most of my packs in the end). This only shows up under load though (e.g. on cell voltage telemetry, if you have it) - the cells will usually look OK (reasonably well matched voltages) after a flight. Finally, cell IR values reported by chargers are normally pretty rough & ready (not very accurate), but probably good enough for monitoring change over time. A guy called Wayne Giles produced a dedicated high quality cell/pack ESR (IR) meter - not cheap, but a great tool. Hobbyking sells it now, although it's currently out of stock. Wayne's threads on RC Groups are well worth a read for more details on this subject (he's a retired power electronics engineer).
just watching videos about lipo batteries after almost half of my room burned down due to a battery blowing up while it was on charge. I wanted to recover the battery after one of the cells went below safe operating voltage and boy was that a bad idea. luckily I managed to control the fire but always be careful. Thanks for the video.
Just joined your patrion because of this video. This was a major topic for us flying yesterday and I was able to chime in. As the only girl flying it's hard to be taken seriously until I smoke them :) or bust out some IR knowledge. Thanks so so much. See you in the patreon.
Very well explained, as always. It's a concept that is usually not taken into account and the truth is that you can live without it, but the correct maintenance of our batteries is vital in this business. Having some basic knowledge is always appreciated. Thank you 😀
crashed on my 1st flight of my new plane....lost all control at the 5 min mark and was in close range, but near the ground , and there was no chance to recover...........checked voltage on my very old 3S 2200mah lipo right after the crash and it read 3.80 per cell......this seemed OK but all indications before the crash were a loss of control ( brown out due to a LVC ) ....now searching for a simple way to check IR on all my LiPos .....thanks for the video..
Great video Lee and well presented, I don't know what you think about maybe doing a video on how to recycle batteries properly, as I for one have been told several different ways? thanks a lot
Smaller batteries have higher internal resistance. Also, the IR is higher when the batteries are empty. Measure it when batteries are full. Whoop batteries are usually over 20mΩ when new. Note the IR when you get them and bin them when it goes up over 2x.
So I'm still confused about what the pack size means. I do not have any flying rcs, but I do have a few ground rcs, that use 7600mah 4s packs. My issue, which is what I'm writing this comment for, is that one of the packs is at a cool 163 for the internal resistance. But I have used these packs for well over 2 years now, so I'm wondering, is it just a fact that the packs are huge? I'm aware that that resistance is super high, but is it insanely high for a pack of that size? Let me know if you can, thanks.
I have noticed that the resistance of the #1 cell is always about twice the value of the other cells on my older batteries. In one particularly bad case, I had readings of 62,10,12! What would be the reason for this?
Same problem might be my imagination but the first cell goes up in resistance after I use battery for low power draw situation like just programing a flight controller for extended time or running a vtx and cam for a while. Until recently I've always had a dedicated beater pack to piddle and it helped but now I fear my charger may have been intermittently glitching cause symptoms are worsening. Who knows?
Having looked at your video and measured the IR on my battery charger it would appear that all my batteries exceed the 20 mh limit. Example 3 cell 2250 35c rated displays 18 16 18 total of 52. Does that require retiring. I have no batteries that display a 01 through 09 on any cell on any battery I posses. Some even display 32 33 32 but it works ok
Several are discouraged with the life of the abundant 1Sv 300mah HV’s. Need to charge it up to storage after running it low. I let it cool bit, then bring it up to either storage or full if I’m still flying. Doing this keeps these flyable for maybe a month!
Agreed! Also, I now fly 75mm rather than 65mm 1s whoop because weight difference is minimal, 41mm blades are way more efficient than 31mm, so overall more efficient, less current for the same speed and acceleration, batteries last more cycles by a noticeable amount
I have pretty new (maybe 15 cycles) CNHL 1500mah 4s batteries and the IR is way off from cell to cell. The one I just charged is 7 on cell 1, 5 on cell 2, 4 on cell 3, and 2 on cell 4. Are these things dangerous? I only charge at 1c and the batteries never get hot or warm when charging. Cell 1 has 350% higher IR than cell 4.
@@Painless360 Thanks. I seen a guy showing a 3s battery where the cells were 17, 18, and 17. I thought he meant it had age because the cells were not all the same IR, but I guess he meant because the IR numbers were so high.
Very interesting video. Thank you. Please can you make a video about how to retire a battery because there are different opinions about how to disharge safely the battery before throwing away in a dump.
Thanks for the video! Are you meaning 20 mohms/cell or for the whole pack is when the battery is toward the end of its life? I noticed the new battery you showed on the charger had over 20mohms for the total pack, which would be at retirement status by what you are saying. I don't see where you addressed this in the video. Please clarify if you get the time. Thanks again.
As packs can have different number of cells then use the resistance measurement on a cell level to check how well matched they are from new and how life and use is impacting the battery.. Best of luck!
LiIon packs are very different as they are not designed for the higher currents like LIPO...looks like a follow up video testing a few LiIon packs may be in order.. Happy flying
I was sat there staring into the middle distance for the second half of this video struggling to work out how internal resistance could possibly be a constant across a 500mah all the way to a 16000mah cell - couldn't work it out at all.. then looked at the comments and saw it's not - what a relief! XD
Really helpful video. Appreciated Lee. Question: You do mention high vs. low current applications. So can I still reliably use a 2S LiPo battery (8.4V) with say 0.1OOhm difference (between the 2 Cells) for a Receiver battery pack. This for a normal 40 Size Nitro plane? Appreciate your reply.
A may do a follow up as that is a horse of a very different colour! :D The type and quality of the cells, along with how they are connected make a HUGE difference. Stay tuned!
I see you've been a subscriber for a few years, thank you. Check out the recent PixHawk builds and the 'Big Buys Toys' playlist where I cover that. I hope that helps..
Hello Lee! I I just did the maiden of my ranger1600 with inav and i have this question: In airmode i get barely any throws on my controlsurfaces, even when flying. And in rth when circeling it dips a little throttles up climbs trottles back and dips again, ... Do you know what might causes these two issues? (I have done the autotune but to litte success) Thank you!
Without knowing a lot more it's tricky to comment. How you've got it setup, the mode you were flying in and how you're measuring 'no a lot of movement' all make a difference. Check out my iNav build for all the steps I use. Check the movement in manual mode to confirm that the travel is ok as step one. Best of luck
What tools do you use to dispose of a battery. I am surprised chargers that can discharge to storage voltage don't also have a mode to discharge to zero volts for disposal. Where do you recycle your batteries? Do you just take them to a computer waist place?
I don't have one of those, all of the 3DXR packs I have are 2P to support higher currents. The type and quality of the cells, along with how they are connected make a HUGE difference. I may do a follow up video showing the difference in a future video.. Stay tuned!
Is there any way to recover puffed lipo ? I have loads of that which cost me a lot of money and would just hate to bin it. Most of them just give me 30 sec to 1 min flight time. May be i can use it somewhere else useful than throw it away ? I checked its resistance and yes its high.
i agreed to all what you are saying. its just the kind of money i spent on those packs.. i am retiring batteries that have higher than 100mΩ. and batteries which i no longer use i am using those unused lipo as a source to charge my tiny whoop 1s batteries.. and i am using all precautions while i do that.
I've got to agree with everything thar MAD GRUMPYMAN said. If your packs are regularly getting into that state then they either are of poor quality or you are pushing them way too hard.. if you are using huge currents then switch to a higher C rating. See my LIPO basics video. Happy flying
A year into the hobby now I got my first good charger that can do resistance check and one of my daily flying batteries is at a little I’ve 100 milliohms I suppose I did get a whole year of rips out of it, time for some fresh ones, it hurts to recycle something that’s still working lol just to junker in me
I think that the smaller the battery the smaller the surface area you have for electrons to flow, thus smaller batteries have higher internal resistance, all other factors being equal. Thus you cannot just say junk batteries at 20milli ohms - pretty sure a brand new 300mah whoop battery will be twice that from new at least, it would be interesting to measure one
Yeah I get 80mOhm off brand new eFlite 150mAh 1S lipos. It's a combination of connector quality and small volume I guess. The bigger the cell capacity, the more area the current has to pass through is my theory.
Quick note: for physically tiny batteries and non Lipo packs the resistances can be a lot higher. If you use these really small batteries or non Lipo packs then why not test them and see what their resistance is and post the results here? Happy flying!
A while back I checked ten new 260 mAh 1S lipos (for my 65mm brushed whoops) and got the following (in milliohms): 102, 105, 105, 105, 108, 108, 111, 114, 114, 117
My 1.5 LiFe radio battery shows 59,41,43
For the Li-Ion packs I get around 25,21,22
These are regularly used batteries 1-2 years old.
Robin Silk greggsgreyg.e
My whoop batteries are around 9 -10, and my fairly new 6s batteries are .8 and 1.0
Several 2s 450mAh LiPo varying between 11-25mOhm, at the end of the charing 14-18mOhm.
Coming from the RC indoor carpet car racing community lipo internal resistance in spec racing is a huge consideration. We pay over $100US for a good competition 2S lipo. Not only is the internal resistance low, in the 1 milliohm/cell range but resistances are matched cell to cell. We also heat the lipo up by high rate charging which has a huge affect on IR numbers. This is the extreme end of competition RC racing which the average RC hobbyist would not be concerned. Something is not adding up correctly in your SkyRC charger displaying 1-6-7 and 7-0-0 milliohms . The two accepted accurate meters that we use is the iCharger built in meter or a specific IR lipo meter.
I might add that when you snip the battery leads do them one at a time to avoid a short circuit. That can lead to some "exciting" results if you are not careful.
This information is extremely helpful 👍. I recently purchased a 6400mAh 4S2P 18650 lithium-ion pack, and my quadcopter was flying pretty erratically with it, so I checked the internal resistance with an iCharger 206B. The per-cell internal resistance was 26, 29, 29, and 29 milliohms. It is rated at a maximum continuous discharge current of 20A. The voltage of the pack drops dramatically under load; my quad current is around 8A. I have an older 5200mAh 4S2P 18650 Lithium-ion pack, and the per-cell internal resistance for it is 12, 11, 12, 13 milliohms. It flies fine and much longer. Almost forgot to mention that the pack with high internal resistance did get pretty warm. I only flew it a couple times and will retire it, hopefully the place I got it will take it back.
The biggest factor that will affect the IR reading is temperature. The same pack at different temps will have very different IR readings. So compare a pack to previous readings at the same temp if you want to see a trend with that battery.
This is very helpful. I was watching wondering if I should buy a checker for my e-bike battery pack in addition to my single cell tester. Measuring the IR is immediate while doing a load test takes hours. So am thinking it's now a no brainer. I should buy one.
Learn something new every day. I bought that charger in January and love it. Had no idea it could test internal resistance. Thanks!
A really good overview of a complex subject - well done! Only a few things I'd mention ... first is balance. All the cells in a new pack should have similar IR ... if they don't it would be a good reason to reject the pack. Second, IR often drops a bit after the first couple of cycles. Third, as already mentioned by others cell capacity affects IR. So small cells (brand new, in good condition) will have higher IR than large cells - hence the use of 'C' ratings (even if these are largely fiction!). Fourth, over time it's quite common for one cell to develop a (much) higher IR than the others (that's what does for most of my packs in the end). This only shows up under load though (e.g. on cell voltage telemetry, if you have it) - the cells will usually look OK (reasonably well matched voltages) after a flight. Finally, cell IR values reported by chargers are normally pretty rough & ready (not very accurate), but probably good enough for monitoring change over time. A guy called Wayne Giles produced a dedicated high quality cell/pack ESR (IR) meter - not cheap, but a great tool. Hobbyking sells it now, although it's currently out of stock. Wayne's threads on RC Groups are well worth a read for more details on this subject (he's a retired power electronics engineer).
just watching videos about lipo batteries after almost half of my room burned down due to a battery blowing up while it was on charge. I wanted to recover the battery after one of the cells went below safe operating voltage and boy was that a bad idea. luckily I managed to control the fire but always be careful. Thanks for the video.
Hi can you do a video on LiPo Graphene batteries? Thank you.
This is not only basic information, but it's essential LiPo information! Thanks mate!
Just joined your patrion because of this video. This was a major topic for us flying yesterday and I was able to chime in. As the only girl flying it's hard to be taken seriously until I smoke them :) or bust out some IR knowledge. Thanks so so much. See you in the patreon.
See you there! Lots of extra benefits to have fun with.. are you 'Chris' in Patreon?
@@Painless360 no I'm Tony it's my dad's patreon. my name is actually Ruby but Tony will work :)
Got ya! Thank you again for taking that step. Let me know if I'm Man-splaining stuff won't you? :D
Very well explained, as always. It's a concept that is usually not taken into account and the truth is that you can live without it, but the correct maintenance of our batteries is vital in this business. Having some basic knowledge is always appreciated. Thank you 😀
crashed on my 1st flight of my new plane....lost all control at the 5 min mark and was in close range, but near the ground , and there was no chance to recover...........checked voltage on my very old 3S 2200mah lipo right after the crash and it read 3.80 per cell......this seemed OK but all indications before the crash were a loss of control ( brown out due to a LVC ) ....now searching for a simple way to check IR on all my LiPos .....thanks for the video..
Great video Lee and well presented, I don't know what you think about maybe doing a video on how to recycle batteries properly, as I for one have been told several different ways? thanks a lot
I discharge them completely using a connected bulb. See my LIPO basics video.. Happy flying
Smaller batteries have higher internal resistance. Also, the IR is higher when the batteries are empty. Measure it when batteries are full. Whoop batteries are usually over 20mΩ when new. Note the IR when you get them and bin them when it goes up over 2x.
Good info.. thanks.
Great additional content. Thanks.
The real number is when battery full?
So I'm still confused about what the pack size means. I do not have any flying rcs, but I do have a few ground rcs, that use 7600mah 4s packs. My issue, which is what I'm writing this comment for, is that one of the packs is at a cool 163 for the internal resistance. But I have used these packs for well over 2 years now, so I'm wondering, is it just a fact that the packs are huge? I'm aware that that resistance is super high, but is it insanely high for a pack of that size? Let me know if you can, thanks.
I have a 3s 450 mah lipo battery and the IR is about 40 milliohms.
Is it good?
thank You
just was missing a hint on temperarure to consider when measuring ir or using for performance. ever tried to fly in winter .....
See my winter flying tips video ;) Happy flying!
There is no way to reduce the resistance per car batterries? I could not find this charger in the USA.
No, see my answer on the duplicate question you posted. Happy flying
I have noticed that the resistance of the #1 cell is always about twice the value of the other cells on my older batteries. In one particularly bad case, I had readings of 62,10,12! What would be the reason for this?
It could point to something with the charger. One of the connections may be better or worse than the others... Happy flying
Same problem might be my imagination but the first cell goes up in resistance after I use battery for low power draw situation like just programing a flight controller for extended time or running a vtx and cam for a while. Until recently I've always had a dedicated beater pack to piddle and it helped but now I fear my charger may have been intermittently glitching cause symptoms are worsening. Who knows?
Sir 1 have a lipo checker can Read MV
Are MV is Ressistance ?
Thanks sir 🙏
Not usually. What does it say in the manual for it?
Having looked at your video and measured the IR on my battery charger it would appear that all my batteries exceed the 20 mh limit.
Example 3 cell 2250 35c rated displays 18 16 18 total of 52. Does that require retiring. I have no batteries that display a 01 through 09 on any cell on any battery I posses.
Some even display 32 33 32 but it works ok
If the batteries are not puffing up then you should be fine to use them. Lower current applications won't show the voltage sag as badly.. Happy flying
Several are discouraged with the life of the abundant 1Sv 300mah HV’s. Need to charge it up to storage after running it low. I let it cool bit, then bring it up to either storage or full if I’m still flying. Doing this keeps these flyable for maybe a month!
Agreed! Also, I now fly 75mm rather than 65mm 1s whoop because weight difference is minimal, 41mm blades are way more efficient than 31mm, so overall more efficient, less current for the same speed and acceleration, batteries last more cycles by a noticeable amount
Thank you very much for this video. Help me understand this subject
I have pretty new (maybe 15 cycles) CNHL 1500mah 4s batteries and the IR is way off from cell to cell. The one I just charged is 7 on cell 1, 5 on cell 2, 4 on cell 3, and 2 on cell 4. Are these things dangerous? I only charge at 1c and the batteries never get hot or warm when charging. Cell 1 has 350% higher IR than cell 4.
Not dangerous. These are nice low values.. Happy flying
@@Painless360 Thanks. I seen a guy showing a 3s battery where the cells were 17, 18, and 17. I thought he meant it had age because the cells were not all the same IR, but I guess he meant because the IR numbers were so high.
That's it. Happy flying!
Very interesting video. Thank you. Please can you make a video about how to retire a battery because there are different opinions about how to disharge safely the battery before throwing away in a dump.
Plug them into something like a car bulb to run them down completely... I've already covered that in Lipo basics videos. Happy flying!
Thanks for the video! Are you meaning 20 mohms/cell or for the whole pack is when the battery is toward the end of its life? I noticed the new battery you showed on the charger had over 20mohms for the total pack, which would be at retirement status by what you are saying. I don't see where you addressed this in the video. Please clarify if you get the time. Thanks again.
As packs can have different number of cells then use the resistance measurement on a cell level to check how well matched they are from new and how life and use is impacting the battery.. Best of luck!
Are we including Li-ion batteries as knackered at 20m ohms per cell also?
LiIon packs are very different as they are not designed for the higher currents like LIPO...looks like a follow up video testing a few LiIon packs may be in order.. Happy flying
I was sat there staring into the middle distance for the second half of this video struggling to work out how internal resistance could possibly be a constant across a 500mah all the way to a 16000mah cell - couldn't work it out at all.. then looked at the comments and saw it's not - what a relief! XD
Thank you Lee...! Batteries need to be placed in "Storage Charge" when they are not being used, say like in the Winter months. =)
Really helpful video. Appreciated Lee. Question: You do mention high vs. low current applications. So can I still reliably use a 2S LiPo battery (8.4V) with say 0.1OOhm difference (between the 2 Cells) for a Receiver battery pack. This for a normal 40 Size Nitro plane? Appreciate your reply.
It should be ok but I'd be wary first time out.. Best of luck!
What about Li-Ion batteries. Rule of thumb for internal resistances?
A may do a follow up as that is a horse of a very different colour! :D The type and quality of the cells, along with how they are connected make a HUGE difference. Stay tuned!
Helpful and informative video as always, thank you Lee !
I e got a couple of band new pyro 5s packs never charged that read 21 to 25 should I send them back?
Depends, pop me details of Patreon.. ;)
Nice informative video ??
Btw would like to ask what are the flight boards which are used on big drone or industrial drones ??
I see you've been a subscriber for a few years, thank you. Check out the recent PixHawk builds and the 'Big Buys Toys' playlist where I cover that. I hope that helps..
This is the way to deliver instruction not the American way that starts with "Hi Guys"
Hello Lee! I
I just did the maiden of my ranger1600 with inav and i have this question:
In airmode i get barely any throws on my controlsurfaces, even when flying. And in rth when circeling it dips a little throttles up climbs trottles back and dips again, ...
Do you know what might causes these two issues? (I have done the autotune but to litte success)
Thank you!
Without knowing a lot more it's tricky to comment. How you've got it setup, the mode you were flying in and how you're measuring 'no a lot of movement' all make a difference. Check out my iNav build for all the steps I use. Check the movement in manual mode to confirm that the travel is ok as step one. Best of luck
that was very useful again, thanks, great question indeed.
What tools do you use to dispose of a battery. I am surprised chargers that can discharge to storage voltage don't also have a mode to discharge to zero volts for disposal.
Where do you recycle your batteries? Do you just take them to a computer waist place?
Check what recycling there is for you locally for batteries. It varies. Happy flying!
Both my chargers have a full discharge program.. I thought they all did.
Great video Lee 👍
what is the internal resistance of the 3dxr pack? 4s1p, thanks
I don't have one of those, all of the 3DXR packs I have are 2P to support higher currents. The type and quality of the cells, along with how they are connected make a HUGE difference. I may do a follow up video showing the difference in a future video.. Stay tuned!
Great video, Lee!
Is there any way to recover puffed lipo ? I have loads of that which cost me a lot of money and would just hate to bin it. Most of them just give me 30 sec to 1 min flight time. May be i can use it somewhere else useful than throw it away ? I checked its resistance and yes its high.
i agreed to all what you are saying. its just the kind of money i spent on those packs.. i am retiring batteries that have higher than 100mΩ. and batteries which i no longer use i am using those unused lipo as a source to charge my tiny whoop 1s batteries.. and i am using all precautions while i do that.
I've got to agree with everything thar MAD GRUMPYMAN said. If your packs are regularly getting into that state then they either are of poor quality or you are pushing them way too hard.. if you are using huge currents then switch to a higher C rating. See my LIPO basics video. Happy flying
Always good information from your channel.
Stay safe
Cheers
Highly usable info, as always.
Thanks!
How much is a 3S 650mah IR ?
It depends on the C rating. The 650mAh 70C pack I have handy here is about 17-20µΩ
@@Painless360 Mine is around 20-35.... And C rating is 75
A year into the hobby now I got my first good charger that can do resistance check and one of my daily flying batteries is at a little I’ve 100 milliohms I suppose I did get a whole year of rips out of it, time for some fresh ones, it hurts to recycle something that’s still working lol just to junker in me
Very informative, thanks for doing the video
good advice. thanks again.
I think that the smaller the battery the smaller the surface area you have for electrons to flow, thus smaller batteries have higher internal resistance, all other factors being equal. Thus you cannot just say junk batteries at 20milli ohms - pretty sure a brand new 300mah whoop battery will be twice that from new at least, it would be interesting to measure one
I measured around 60~70 for brand new 300mah batteries so your right
Yeah I get 80mOhm off brand new eFlite 150mAh 1S lipos. It's a combination of connector quality and small volume I guess. The bigger the cell capacity, the more area the current has to pass through is my theory.
Really enjoyed the video. Thank you for the info!
The short-circuit current is limited by the internal resistance.
Yep, that's right..
Tinywhoop Lipo 1s 2500 mah resistance 195 mOhms
Tiny batteries often have higher internal resistances... Happy flying