For a 3s lipo we can approximate the voltage to remaining capacity ... by calculating single cell voltage we can also make same table for 4s ,5s or any number of cells....

source:internet and little personal experience 

Sorry, but the figures should have a heading. Like what is 12,60  (i know a full charged lipo is 12.6V but you should state that.)

regards
Arpit

well the IMAGE posted by me is "open source"  ,so you can modify it and post it so that it is  more useful to ens user ....  

Alright , i will try modifying it and will post it up soon.
Thanks

Well, the topic says it all! 

Quote from: vinay on December 29, 2010, 02:03:14 PM
Well, the topic says it all! 

i got confused,
the beginner can surely get confused then...

Hmm, may be.

if some one could find the volage drop at a particular c-load for a 20 c battery, it would be great.

This would be quite dependent on the battery itself. The better ones would drop less for a given load vs time.

Quote from: vinay on December 29, 2010, 03:33:56 PM
if some one could find the volage drop at a particular c-load for a 20 c battery, it would be great.

well the percentage is in no way related to the "loaded" voltage in my diagram ..it just shows the remaining juice in the battery ... and this should be same dor any C rating or any manufacturer ....

low voltage drop is the main advantage of lipo so drop must be less and i think can be measured easily ...

Pankaj

Please read my reply to Vinay, carefully. He wanted to know if if some one could find the volage drop at a particular c-load for a 20 c battery.  In short he would like to have a graph of Voltage vs time for a given (could be one or several) discharge current. This would not necessarily be linear and would definitely be battery dependent. Ergo there could not be a single "universal" table.

Your table just shows what x% of the battery translates into in terms of voltage. Which is straightforward arithmetic.

sushil_anand

Please read my reply ,Very carefully . i never said that the table is voltage drop,as it will of course depend on so many factors,and we can not have a general table .

i was just doing "straightforward arithmetic" for beginners like us.

thanks

Hey Anwar read this. 11.1 V = 10%. that like 3.7 V/cell = 10% charge.

So it means discharging a battery below 3.7 V = not a good thing. Said this coz u said its ok to go down till 3.3V

Quote from: pankaj on December 29, 2010, 04:38:50 PM
Please read my reply ,Very carefully . i never said that the table is voltage drop,as it will of course depend on so many factors,and we can not have a general table .

i was just doing "straightforward arithmetic" for beginners like us.

Whatever you say. Discretion is - at least sometimes -  the better part of valour.

Quote from: vinay on December 29, 2010, 05:14:47 PM
So it means discharging a battery below 3.7 V = not a good thing. Said this coz u said its ok to go down till 3.3V

That is assuming this chart is accurate in ALL cases   For example, Rajesh posted in the same thread that he follows the 80% rule, and ends up at 3.7v.  So there you have someone confirming that at 3.7v (11.1v for 3s), 20% charge is remaining ! 

My comment was mostly about what is the low voltage below which a battery would grow less efficient over time.  That reminds me, I need to test the 80% rule on the newer batteries, especially the HK ones.

it is impossible to say a sertain  volt is safe after a flight. id all depends on your set up and how much burst u r using and should b checked with a eagle tree or similar to c volt under load . for example a heli flying 3d u need to use less mha from the battery do a high burst can make a cell go low while some 1 that will hover can use more do it will b no burst. best is try to c how much u put back in to the battery even do it is a bit miss leading do some batteries not have correct c rating and actually have more mha just to have a higher c rating

20% rule is a good average safe limit and set the timer to it and if u do a harder flight then normal u have to keep that in mind and stop earlier  but if u want to use maximum mha in a safe way u need something like a schulze lipodimatic who monitor each cell and will slow down head speed when 1 cell reach 3,3v under load mean with modern lipo it is totally empy and u have enough power to land but u have to b quick and if volt get under 3v in 1 cell it will cut off power to motor and u have to auto

Quote from: anwar on December 30, 2010, 02:22:18 AM
My comment was mostly about what is the low voltage below which a battery would grow less efficient over time. 

I agree.

EDIT: No, its 10 to 15% at 11.1 V(3.7/cell) and @ 3.6/cell it has barely 5 to 7%, thats why battery drop voltage very fast below 3.6.

Once I get the icharger, let me do a test and put up the graph. Hope that would be helpful.

Quote from: vinay on December 30, 2010, 08:42:17 AM
No, its 10 to 15% at 11.1 V and @ 11.6 it has barely 5 to 7%,

How would 11.6V have less capacity than 11.1V? Some error, I presume.

sorry 3.6 

Quote from: clayboy on December 30, 2010, 03:42:51 AM
if u want to use maximum mha in a safe way u need something like a schulze lipodimatic who monitor each cell and will slow down head speed when 1 cell reach 3,3v

That is what I was trying to say in effect.

And it looks like if one strictly follows the 80% rule, then that monitor should have been activated at 3.7v/cell instead of 3.3v/cell.

observe that it is under load not after flight , mean if u get a high burst with almost empty battery it will reduce power so volt never go under 3v in any cell under load witch what it is all about, that is the only thing that matters.3,3 after flight will guarantee be under 3v with load

80% rule is just a guide line, if 1 want to use max of the mha monitor volt under load in each cell in the battery is the only way

So 3v no-load is the cut off that you are worried about.  I was suggesting that it should be more like 3.3v to keep in mind as the cut off, for the long term health of the lipo. 

no 3v under load is what matters.

With or without load, under 3v is not good.  And I would try anything I can to not take them to 3v, period.

as i explained in previous post 80% rule and check with eagle tree the volt under load if possible is normally a safe way

but if u want max out of a battery, monitor volt in each cell separate  is the only safe way and it is 100% safe to go to 3v under load but can never go under