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Old 01-17-2010, 10:12 PM   #1
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Default Lipo Battery question ..NEED HELP

i understand lipo batteries require to be stored about 50% of their rated capacity, how do you determine / find out if my battery is at 50% ? after a practice run ( 5-7 minute ) i noticed my smc 6000 28C voltage is at about 7.6v what does it represents in relation to capacity ?

per smc , it's recommended to store a lipo pack about 6.6V when not use , after a race it has been a pain to have to discharge my lipo down to that point ,mind you my charger can only discharge at 1amp , i really dont want to go though extra 2-3 hours just to discharge my pack, is there a better way to do this ????

thanks for all you help
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Old 01-17-2010, 10:45 PM   #2
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Most chargers with lipo balancing functions will display some info about the remaining charge int he battery be it in voltage or a LED bargraph. One other way is to run your car until the battery dumps if you have a lipo cutoff setting on your ESC and you can set it to the desired level.

But Lipos don't really need to be at a certain charging level when stored as they don't suffer from memory effects or drain problems as the old Nimh or Nicd did. 6.6V is just about dead flat (but not below limit) which is good enough and pretty much standard for Lipos these days (I assume it is a 2S balanced lipo so you're sure to be at 3.3V per each cell. 2.7 V per cell would be the limit below which the battery is basically destroyed, that's why it is important to make sure you're reading 6.6V on a balanced Lipo otherwise you may have below 2.7V on one cell and above that on the other).

The voltage readout doesn't really say much about the remaining charge in the battery (unless as mentioned before, you use a cutoff point when you know the battery is going to be exactly at the point where you want it to be). That is because your ESC will monitor the voltage under load whereas measuring it with a volt meter under no load is going to say next to nothing. The same goes about chargers, they measure voltage at a certain calibrated load, so their indication is even more accurate. You can use a meter (under no load) just to get some data and measure voltage right after discharge to the cutoff point after running the car and after discharge on the charger and compare the two. The one that comes closest to the desired/set value will tell you which way is more trustworthy to use. My money is on the charger/balancer though.
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