Originally posted by LittleGiant
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Ans: Lipo packs (eg 3s 1p) are cells (combination), each cell are rated its volume (capacity). Chemical present in the cell is to do chemical conversion storage. Chemical have it own characteristic (different fm MFG in different of purity, quality, chemical and percentage use/mix, forms different grade "A", "B", "C" quality and different discharge rate C's) this is how lipo cells are built. During charging cycle the charger will pump current and voltage slighly higher always to the cell voltage (so that it can charge) feeding process (conversion process). Until the point before fully charge that is the charger triggles off (show cell fully charge) both the voltage and current are till inputing to the cells (it can be triggle- topup slightly charging). At this point (2 things happen)
1)if one of the cells are slightly old/slower it will have to be slightly longer to reach there fully (means the charger have to put a little fews seconds longer before cut off ) result charger will either push the other cells a fews sec longer result more in capacity reading-slightly higher.
2)if all cells are best "A" grade branded ultra quality battery, there are tolerances in each cells MFG by the manufacture (for safety and purpose) can be slightly over charge (can rate 4.25 even 4.3 per cell). Therefore your charger reading is 200mah more (200mah divided by 3 cell = 66mah). To the cells they are still in its tolerances charging range (some have mention in Mfg safety spec- comes with lipo battery safety and handling sheets).
Developement of cell (R&D) spend alot of money in research of the chemical use. During the years of working the cell from hard casing to soft casing lipo. Then from 1C discharge to 30C discharge, the lipo chemical fomulation had change through these years (you may not know the detail fomulation because of company trade patent) also it is fomulate for their brands rights (eg japan-sony. korean-anerland etc).
There is plenty/alot of brand of charger produce in the market nowadays. Charger I.C. circuitry, calibration, safety tolerances are important. But some how some of these are MFG are different in producing readers may slightly out because of (copyied rights issue) it can be due the I.C. chips, it can be due to the circuit board (design), it can be due the componet (china, taiwan , thailand, malaysia component), it can be due to that country MFG voltage 110V (country may using 110v instead 230V during design and MFG- regulating cct is is diff), or can be made without ISO 9002 standards (cheap in cost, cheap price fm China). All this are consideration result of the reading differences too.
Lipo have is own internal resistances during charging and discharging, therefore even the same branded cell can or may varies very slight different. Bear in mind there is this connector call dimms that soldering to be done. Soldering lead there is a percentace of resistances too. Same thing to the gold pins connectors (connectors even is super shine connection there is a percentage of resistances). How abot the solder in the LIPO cells (cell to cell connection that makes 3s, 6s, also battery output wires resistance 18SWG, 20SWG etc.
Alway a fresh lipo the flight timming/power is longest most powerful and older cell will tends to deplet. When the life span reached is time to change. To prolong the life of the lipo is depends on individuals and owner to maintain. Lipo cells never last forever and cheaper good cells are always around.
Enjoy and spend more time in RC flying, hovering, boating, drifting, crawling have more friends in this hobby and keep things simple. Life is short enjoy upmost. cheerz...
Happy CNY year too
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