how close to stated capacity do your packs get?

[kevinpratt823]

Just curious what others experience.
With most of my packs, (most are Thunder Power 65c), when I run(usually hard) all the way down to LVC(set at 3.2v/cell), my packs take back right around their labeled capacity, some maybe even a touch more, but usually a touch under, and this has been fairly consistent with boats, but more so with cars for me. Personally I would consider this a properly labeled pack, but I was recently told that these packs must be mislabeled, as (for instance) it was said, a 5400mah pack should only take back 5100mah or so. Does this make sense? Shouldn't the label show the usable mah, not an inflated version? Which pack would you call mislabeled? Is the 5400 that will only take back 5100 labeled correctly, and therefore my Thunder Power's are underrated? Or is the 5400 overrated?

[JimClark]

I never run down that low only take out probably 2000 to 2500 of 5800 mah packs

[785boats]

Kev.
The capacity of a pack is the amount of m/amps put back in the pack from zero m/amps, which is usually around 3.2V per cell. If the packs weren't run down to that then they won't take on the full rated capacity because there's still some m/amps in the pack.

[martin]

You shouldn't use more than 80% max of the pack capacity ie 20% left in the pack or you will damage the packs.

[785boats]

Yes Martin that is correct. Sorry, I was talking about the 5400mah packs in the first post.
But Kevin, if you are taking your packs down to 3.2V LVC & putting back in their full rated capacity, then it seems that you are fully depleting your packs.
As Martin pointed out, it's best to leave a bit in the tank. 20% it the norm.

[kevinpratt823]

I pretty much know the answer to the question, and I do shut down early most of the time with boats, I don't think it's as big of a deal with the lower and much less consistent draw of the cars. I really just wanted to see which pack you guys would consider mislabeled, as the company selling the 5400 that only takes back 5100 from 3.2v lvc is telling me that is all it should take, and that all my other packs are mislabeled because they take back what they are labeled. Doesn't sound right to me.

Sent from my SCH-I535 using Tapatalk 2

[Cooper]

In my personal opinion there is NOT any batter manufactured today that is labeled correctly. But when it comes to the capacity a battery can/will hold it is not a precise definitive number. As the reason is a chemical reaction is taking place and this really cannot be quantified to a definitive number. Even on high end batteries (not to be confused with price but quality) you could have four same packs and all four will show different mah numbers say from 20% to full charge. And when you think of the numbers on a 5000mah pack drawn to 3.2v that is 1562.5 mah per volt now fully charged to 4.2 that is 6562.5 mah. Doesn't make sense by the numbers, my point is these are just numbers that can give an educated guess as to where the battery stands. Batteries are storage tanks for electrons, and in order for those electrons to be used a chemical reaction take place, which is not always the same as every time these reactions take place some of this energy is lost to other factors, heat, ect. Eventually resulting in the decay of the battery's chemical reaction process.

[kevinpratt823]

I actually understand batteries pretty well, and I am very well schooled in electrical theory. And I know the varying voltage comes into play as well, meaning that a pack wich holds it's voltage longer could still be producing more whatt-hours even though it actually put out less mah over a run.
But back to my basic point, I would consider my packs which actually take back close to what the label says when drawn down to 3.2v/cell labeled more accurately than a pack labeled 5400 mah which only takes back 5100 mah(at best)when drawn down to the same (standard) lvc,....... would you guys agree with this statement?

[kevinpratt823]

In my personal opinion there is NOT any batter manufactured today that is labeled correctly. But when it comes to the capacity a battery can/will hold it is not a precise definitive number. As the reason is a chemical reaction is taking place and this really cannot be quantified to a definitive number. Even on high end batteries (not to be confused with price but quality) you could have four same packs and all four will show different mah numbers say from 20% to full charge. And when you think of the numbers on a 5000mah pack drawn to 3.2v that is 1562.5 mah per volt now fully charged to 4.2 that is 6562.5 mah. Doesn't make sense by the numbers, my point is these are just numbers that can give an educated guess as to where the battery stands. Batteries are storage tanks for electrons, and in order for those electrons to be used a chemical reaction take place, which is not always the same as every time these reactions take place some of this energy is lost to other factors, heat, ect. Eventually resulting in the decay of the battery's chemical reaction process.

I'm not sure where you're coming from with some of those numbers, as when a LiPo cell gets close to the threshold of 3.2v, I'm pretty sure it's not going to put out the same 1562.5 mah per volt below that level, it would drastically reduce exponentially until zero, likely only putting out a fraction of that original 1562.5 mah in the process, so that 6562.5 is not a relevant number in the real equation. From my perspective, the only portion worth discussing is the discharge from 4.2v down to the threshold of 3.2v.

[Cooper]

I'm not sure where you're coming from with some of those numbers, as when a LiPo cell gets close to the threshold of 3.2v, I'm pretty sure it's not going to put out the same 1562.5 mah per volt below that level, it would drastically reduce exponentially until zero, likely only putting out a fraction of that original 1562.5 mah in the process, so that 6562.5 is not a relevant number in the real equation. From my perspective, the only portion worth discussing is the discharge from 4.2v down to the threshold of 3.2v.

that was my point. The numbers of the manufacturer, stated numbers.

Personally I would consider this a properly labeled pack, but I was recently told that these packs must be mislabeled, as (for instance) it was said, a 5400mah pack should only take back 5100mah or so. Does this make sense? Shouldn't the label show the usable mah, not an inflated version? Which pack would you call mislabeled?

Again I was just agreeing with your original post, also stating it isn't always exact.

[kevinpratt823]

that was my point. The numbers of the manufacturer, stated numbers.

Personally I would consider this a properly labeled pack, but I was recently told that these packs must be mislabeled, as (for instance) it was said, a 5400mah pack should only take back 5100mah or so. Does this make sense? Shouldn't the label show the usable mah, not an inflated version? Which pack would you call mislabeled?

Again I was just agreeing with your original post, also stating it isn't always exact.

OK, I got ya. And I do understand it isn't always exact, and there will be variances, even between identically manufactured and labeled packs.

I suppose though, it could be argued that the mah rating of the 5400 could be based on a discharge down to 3v(bad) instead of 3.2v, not sure if there is a standard there or not.

[785boats]

Kevin.
As you are aware an older pack would have a higher resistance & that limits the total mah that it can hold. Or even if one cell has developed a higher resistance the overall pack capacity is diminished.
On the other side of the coin, brand new packs can have a higher internal resistance that reduces over half a dozen cycles. The pack then can take on more milliamps.
So the age & discharge history can determine whether those 5400mah packs will get better than 5100mah if they are new, or if they will get worse if they are building a higher internal resistance with age & cycles.
If neither of the above scenarios applies to those packs, then your first thoughts are probably correct & they are mislabeled.

I do remember that 3.0V/cell was once considered to be a totally discharged pack. That was with 15C, 20C, 25C packs etc. But now, with the higher C rated packs, 3.2V seems to be the value that is regarded as totally discharged.
If I remember, the last time I completely drained a pack to 0% on the charger the voltages were 3.06V/cell to 3.02v/cell. It was an old Zippy 4s 5000mah 45C pack that was getting a bit squishy after a run.
It surprised me by taking on about 4,895Mah. Only 100mah or so less than its rating. Can't remember the exact numbers but I do remember it was just over 100mah difference.

Discharging down to 3.0V isn't bad as long as it is done at about 0.5A, & recharged at only 1/2C.

[kevinpratt823]

Kevin.
As you are aware an older pack would have a higher resistance & that limits the total mah that it can hold. Or even if one cell has developed a higher resistance the overall pack capacity is diminished.
On the other side of the coin, brand new packs can have a higher internal resistance that reduces over half a dozen cycles. The pack then can take on more milliamps.
So the age & discharge history can determine whether those 5400mah packs will get better than 5100mah if they are new, or if they will get worse if they are building a higher internal resistance with age & cycles.
If neither of the above scenarios applies to those packs, then your first thoughts are probably correct & they are mislabeled.

I do remember that 3.0V/cell was once considered to be a totally discharged pack. That was with 15C, 20C, 25C packs etc. But now, with the higher C rated packs, 3.2V seems to be the value that is regarded as totally discharged.
If I remember, the last time I completely drained a pack to 0% on the charger the voltages were 3.06V/cell to 3.02v/cell. It was an old Zippy 4s 5000mah 45C pack that was getting a bit squishy after a run.
It surprised me by taking on about 4,895Mah. Only 100mah or so less than its rating. Can't remember the exact numbers but I do remember it was just over 100mah difference.

Discharging down to 3.0V isn't bad as long as it is done at about 0.5A, & recharged at only 1/2C.

Thanks for the feedback. These 5400'3(there are 3 of them, 2 mine, and one is my buddy's), all have over 15 cycles on them now(not including 5 break in cycles each on the charger). They started out only taking 4800 mah, and the best one seems to have leveled out at 5100, the worst one now has a bad cell and took over 3 hrs. to balance.

[Brushless55]

along with the OP of this thread, some labels are incorrect in the sizing of the cells vs what is printed on the packs
and the C rating are another bogus claim... IMO

[MarkF]

To figure out the total mah a pack has to offer you need to discharge down to 3.0 volts per cell. This is considered an empty pack. Now only do this with the discharge function on a quality charger and not in your car or boat. Todays higher C batteries are at 80% when you reach 3.4 volts per cell and this should be your set cutoff voltage for your speed controll as well. I hope this helps.

Mark