User Manual

7
(d) Error Warnings
(i) If you try to measure a pack which has an ESR >250milliohms or
a cell of >35milliohms, the meter will display an “Over range”
warning.
(ii) If any cell is less than 3.20V, the meter will display “Cell
Voltage Low” and the meter will not measure ESR. Pressing the
button will display the actual cell voltage for 3 seconds and then
default to the low cell warning. Note that the meter will only read
cell voltages down to 1.5V as a minimum voltage is necessary to
change the meter to Cell mode.
Disconnect the search lead and toggle the meter to return to normal.
(e) “Max I” and “αC” readings
These readings are calculated using the Lipotool which is a rule of
thumb, albeit a surprisingly accurate one. Approximations within the
digital maths processor will result in the same “Max I” for slightly
differing ESR values – This is not a processing error.
“αC” is a practical real value of C as it is understood by users ie it
is the number you can multiply the pack capacity by, in Ah, to give a
safe maximum current which will not have a deleterious effect on
pack life. Read more details below under (g) The LiPotool.
(f) State of Charge
The ESR of a LiPo is largely independent of its state of charge but a
fully charged pack will be 5 – 10% lower than one at storage charge.
I would recommend measurements at the fully charged state for
Lipotool use, although measurements at storage charge are equally
useful for purely comparative purposes
It is possible to connect the meter in parallel with a working load
(ESC + Motor) and monitor the ESR as the discharge proceeds.