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View Full Version : CC/CV Chargers how do they know cell count?


JimClark
12-09-2005, 03:15 AM
I am totally confused on chargers. I have the Multiplex LN5014 and it is a CC/CV charger that you plug in the type of lithium battery the MAH capacity and the voltage. I see on the Astroflight it selects how many cells there are on the lipos. The LN5014 will handel to 5 cells but how does it know how many cells you have?

Jim

ForestCam
12-09-2005, 03:35 AM
Voltage and if it comes up with an odd voltage that's not within their programed perameters for a given cell count it should come up with an error and refuse to charge.

Fred Marks
12-09-2005, 06:01 AM
I am totally confused on chargers. I have the Multiplex LN5014 and it is a CC/CV charger that you plug in the type of lithium battery the MAH capacity and the voltage. I see on the Astroflight it selects how many cells there are on the lipos. The LN5014 will handel to 5 cells but how does it know how many cells you have?

Jim


Look at the charge algorithm in Section III , page 7 of the Li Po handbook.
http://www.fmadirect.com/tech_data/techdocs/

The charger puts in a low level current at the start of charge to sense voltage and volyage rise over a short period. if, e.g., a 3S pack is fully discharted, it has 7.5V. If a nearly charged 2S pack is put on charge, it too will have 7.5V so the charger could be confused and select wrong count. But, if the pack is near ful charge, voltage will rise only about 1/20 the rate it will rise at if it is a depleted pack. The charger can use this logic to validate the count and prevent mis-count. The Astro 109 has some problems with this logic.