For example on my old HTC Imagio:
Currently reporting 36% battery capacity.
DMM on the battery shows 3.760v.
This is perfectly accurate! Let me explain why!
As with most mobile OS's, Windows Mobile 6.5.X warns 10% charge is left in the phone when the battery has 20% SOC left. They cut off at 0% when there is 10% left in the battery. THIS IS GOOD. This keeps your phone from typically being used inside the remaining 20% battery life that quickly kills most chemistry lithium cells.
Whatever the State of Charge (From now own SOC) reported by the os, add 10% to that figure. That's what the battery actually has.
1) Discharging BELOW 20%. This RAPIDLY deteriorates capacity of typical lithium cells. (Stop at 3.2v for lipo)
2) Overcharging, beyond 4.1v (liion) or 4.2v (lipo)
3) Charge state VS age of cell.
Lithium chemistries give the longest lifespan when used & stored at 50% state of charge. The lifespan of the cell is greatly reduced when stored at high, or low capacity. For lipo this would be 3.85v.
There's a reason why hobby people that use lipo's will charge them to 4.2v, while military application lipo's are only 3.92v (and for that mattery NASA's lipo's are only used in a 5-15% window around 50% state of charge!) It greatly extends the effective battery life over the long term!
4) Abusing the C rating of the cell. Either charging OR discharging faster than the battery is designed for.
Keep in mind many smartphones can draw 1amp from batteries that are NOT rated for current draws that high.
To the OP. While the cheap electronics used can & do have some accuracy problems. Everything is done on purpose for battery life issues. High drain electronic devices commonly use batteries that are not up to the C ratings of the devices they're used in. They also tend to be stored incorrectly over long periods of time before the devices are even sold! Plus, in-use the devices tend to be "road hard & put up wet" in nearly all cases.
Devices shy away from using full capacity both low & high for the sake of the long term.
Currently reporting 36% battery capacity.
DMM on the battery shows 3.760v.
This is perfectly accurate! Let me explain why!
As with most mobile OS's, Windows Mobile 6.5.X warns 10% charge is left in the phone when the battery has 20% SOC left. They cut off at 0% when there is 10% left in the battery. THIS IS GOOD. This keeps your phone from typically being used inside the remaining 20% battery life that quickly kills most chemistry lithium cells.
Whatever the State of Charge (From now own SOC) reported by the os, add 10% to that figure. That's what the battery actually has.
Absolutely NOT TRUE for lion or lipo batteries. The largest four factors in the lifespan & performance of lithium batteries are:
1) Discharging BELOW 20%. This RAPIDLY deteriorates capacity of typical lithium cells. (Stop at 3.2v for lipo)
2) Overcharging, beyond 4.1v (liion) or 4.2v (lipo)
3) Charge state VS age of cell.
Lithium chemistries give the longest lifespan when used & stored at 50% state of charge. The lifespan of the cell is greatly reduced when stored at high, or low capacity. For lipo this would be 3.85v.
There's a reason why hobby people that use lipo's will charge them to 4.2v, while military application lipo's are only 3.92v (and for that mattery NASA's lipo's are only used in a 5-15% window around 50% state of charge!) It greatly extends the effective battery life over the long term!
4) Abusing the C rating of the cell. Either charging OR discharging faster than the battery is designed for.
Keep in mind many smartphones can draw 1amp from batteries that are NOT rated for current draws that high.
To the OP. While the cheap electronics used can & do have some accuracy problems. Everything is done on purpose for battery life issues. High drain electronic devices commonly use batteries that are not up to the C ratings of the devices they're used in. They also tend to be stored incorrectly over long periods of time before the devices are even sold! Plus, in-use the devices tend to be "road hard & put up wet" in nearly all cases.
Devices shy away from using full capacity both low & high for the sake of the long term.
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