battery intetnal resistance????
11-26-2012, 04:14 PM
#1
battery intetnal resistance????
I have a question about battery intetnal resistance on the LRP touch charger it gives the IR in micro ohms. So I have some packs at 10mohms some at 15mohms and some at 25mohms.. So what good and bad and ok I guess.. Just looking for the range where packs are good, OK, or terrible..
11-26-2012, 06:13 PM
#2
The M is actually short for Mega ohms. Most all my good packs are between low 12's to mid to low 14's.
They will vary with the milli amp, C rating and Mfg. Also each charger will vary so the best way to know is through usage & time spent comparing charge & actual run results.
The lower number is always better
Your average voltage the higher the better
With all this said, my race results show that my 7000 ma. battery with a 14.2 mega ohm IR is much faster on the track than my 6200 ma. 13.3 M. Ohm battery.
The 7000 holds a higher voltage longer even with more IR. The composition of the cells are different allowing this as my6200 battery has a considerable voltage drop near the end of my run.
Both batteries are new.
Hope this helps
Tom
They will vary with the milli amp, C rating and Mfg. Also each charger will vary so the best way to know is through usage & time spent comparing charge & actual run results.
The lower number is always better
Your average voltage the higher the better
With all this said, my race results show that my 7000 ma. battery with a 14.2 mega ohm IR is much faster on the track than my 6200 ma. 13.3 M. Ohm battery.
The 7000 holds a higher voltage longer even with more IR. The composition of the cells are different allowing this as my6200 battery has a considerable voltage drop near the end of my run.
Both batteries are new.
Hope this helps
Tom
11-26-2012, 06:34 PM
#3
The M is actually short for Mega ohms. Most all my good packs are between low 12's to mid to low 14's.
They will vary with the milli amp, C rating and Mfg. Also each charger will vary so the best way to know is through usage & time spent comparing charge & actual run results.
The lower number is always better
Your average voltage the higher the better
With all this said, my race results show that my 7000 ma. battery with a 14.2 mega ohm IR is much faster on the track than my 6200 ma. 13.3 M. Ohm battery.
The 7000 holds a higher voltage longer even with more IR. The composition of the cells are different allowing this as my6200 battery has a considerable voltage drop near the end of my run.
Both batteries are new.
Hope this helps
Tom
They will vary with the milli amp, C rating and Mfg. Also each charger will vary so the best way to know is through usage & time spent comparing charge & actual run results.
The lower number is always better
Your average voltage the higher the better
With all this said, my race results show that my 7000 ma. battery with a 14.2 mega ohm IR is much faster on the track than my 6200 ma. 13.3 M. Ohm battery.
The 7000 holds a higher voltage longer even with more IR. The composition of the cells are different allowing this as my6200 battery has a considerable voltage drop near the end of my run.
Both batteries are new.
Hope this helps
Tom
+1 Varies significantly by charger, lipo temperature, some by state of charge, etc.
With a Hyperion charger my best 2S packs read 4-5 mOhms at temps in the mid to low 70s F. Last weekend at a cold track, not sure of the temps, I was seeing 8. A buddy's ThunderPower charger gave similar numbers, but his other said around 40!
Last edited by Dave H; 11-26-2012 at 07:28 PM. Reason: sloppy decimal point
11-26-2012, 07:48 PM
#4
milli Ohms. (Even 1 Mega Ohm of internal resistance would limit a fully charged 2S to 0.0000084 amps!)
+1 Varies significantly by charger, lipo temperature, some by state of charge, etc.
With a Hyperion charger my best 2S packs read 4-5 mOhms at temps in the mid to low 70s F. Last weekend at a cold track, not sure of the temps, I was seeing 8. A buddy's ThunderPower charger gave similar numbers, but his other said around 40!
+1 Varies significantly by charger, lipo temperature, some by state of charge, etc.
With a Hyperion charger my best 2S packs read 4-5 mOhms at temps in the mid to low 70s F. Last weekend at a cold track, not sure of the temps, I was seeing 8. A buddy's ThunderPower charger gave similar numbers, but his other said around 40!
Thanks Dave
LOL
Tom
11-26-2012, 08:31 PM
#5
So for instance all charged on the same charger at the same temp about 65deg.. one 3800 65c shorty 24.7mohms one 5000 90c 10.2mohms and 5000 40c 15.5mohms.. Also about the same mah put back in 2000mah or so at the same amp rate... how many mohms is bad???? do the mohms go up the older the lipo is???? when is it time to buy a new pack??
MEGA ohms yeah..
MEGA ohms yeah..
Last edited by JPKinsella; 11-26-2012 at 08:33 PM. Reason: add
11-26-2012, 09:07 PM
#6
So for instance all charged on the same charger at the same temp about 65deg.. one 3800 65c shorty 24.7mohms one 5000 90c 10.2mohms and 5000 40c 15.5mohms.. Also about the same mah put back in 2000mah or so at the same amp rate... how many mohms is bad???? do the mohms go up the older the lipo is???? when is it time to buy a new pack??
MEGA ohms yeah..
MEGA ohms yeah..
Seriously, in my 1 cell racing I feel a huge difference around 16 mohms & it is noticeable around 14.5 to 15.0 I use them as long as they are competitive. That is in on-road & oval where it is critical to have the best. I TQ'ed and won my last 2 wd sc race with a 4 year old thunder power 5000 ma in a sc10 and the IR was 22.0 MO. I had a brand new battery, but the track was very slick & less wheel spin was a life saver. As long as they have not puffed I store them each in their own container & use them as a tuning device. The only lipos I have disposed of have been damaged physically.
These are the numbers my charger show & may not be the same as yours.
Tom
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