lipo 11ah packs 18.5v disscharge C rateing ???

[drunkencat129]

oke i got a some new lipo packs and i wasnt to know if theres a way to find out the disscharge rate of them i cant find much info there is no lableing on the cells all i got is that the total pack is 4 cells in parrallel and 1 series to make a single cell at 3.7v all together it makes a massive 5 cell pack at 11ah at 18.5v i am going to take 4 of theas massive packs and do 80v 11 ah what can i saftly disscharge them at with out causeing my own 4TH of july lmao :lol:

 

[swbluto]

Take one cell and hook it upto a shunt for measuring current(and hook up your ammeter). Attach it to a high-power 10 ohm potentiometer and decrease the 'resistance' by "10 amp" increments and hold it there for a minute. Keep repeating until the cell explodes: Record that current. Divide that current by the capacity(actual capacity) and divide *that* by 2 and let's call that the "safe" c-rating.

OR... you can measure the internal resistance of the pack, which can be calculated by (v_2-v_1)/(i_1-i_2) where 'v' is the voltage and 'i' of the current two different currents and voltages obtained by the current test. That way you can calculate how much power the battery's internal resistance is dissipating at a given current which will give you an idea of the "heating" up of the cells. From that, you can ... "safely" guess the current it can safely discharge at.

 

[drunkencat129]

lmao oke id like not to blow up 4 cells in parrallel thay came matched thay where about the cell resistence it was arount 22-30
each 3.7v cell is 11ah i got to do some more testing to find out lol