Lipo battery discharge is a trouble things, sometimes we plane to fly outdoors with our full charge battery, but at this time you have some other reasons had to cancel this plan, you may wait a long time to flight, so a full charge lipo battery is not good for storage, Lipo battery guide said the voltage for a long time storage should be 3.6V~3.9V range per cell, so we need to discharge the battery to reduced the battery’s voltage. And there is a test about used lamp to discharge the battery.I have bought a used Gens Ace 2600mAh 6S battery on GensTattu, this is my first time to use Gens Ace 6S lipo, but it is a used battery, the new battery need about 50$, I bought it or my Protos 500.
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There are two bulbs, put them in series.
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First: charge the battery; I used a 12V power to charge my battery, so the max input power is about 180W, max charge current is 7A.
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This is the Internal resistance of battery.
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It spend about 17mins to finished fast charge.
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Because this battery is an used, I spend about 5 mins to charge my battery’s voltage form 3.8v to full, the capacity is about 1560mAh.
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This is a 2600mAh battery, according to the relationship between voltage and capacity of the lipo battery, 36% capacity’s voltage is about 3.8V, the real capacity is 2600 * 36% = 936mAh. So in theory, starting from this voltage charge until full charge in about 2600-936 = 1664mAh.Using 6S battery discharge, the Lamps are very bright.
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But after a short time, the lamps get very hot;
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The battery’s voltage drops quickly,
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After about 20 minutes, the battery voltage drops 3.75V, you can see the b cell 3 and cell 5 still uneven,
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Pull the bulb and the voltage back to 3.83V.
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Then plug in the bulb for about less than 1 minute, the battery voltage below 3.71V, pull the bulb the voltage back up to 3.8V, then use the charger storage balance feature to finish it.
Through this test, I get two tips:
  1. If the battery is new and the balance is good, the charger’s storage mode should be not used after the discharge has been completed;


  1. In the course of the discharge, the balance plug can be connected to the battery tester, and the alarm voltage of the battery tester is set to 3.7V, so that when the discharge reaches the value, the electric battery tester alarm will be taken!

In general, use the bulb to discharge is cheaper and faster than chargers, and it will not cause any loss. If you don’t want to cost to much, this way is as good as a cheap and practical solution, it is worth a try. You can read more on here.