SimplePanda
Second Officer
Flight distance : 1719062 ft
Canada
Offline
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So DJI won't tell you this, but here it is:
DJI's "intelligent batteries" are very poorly designed. The charging circuit constantly drains the pack (probably to keep the intelligent circuit powered) and, left alone, the pack will quite literally discharge itself to death. I had 2 packs come out of storage with the exact same symptoms you have.
So, if you've tried all the usual stuff (power on while charging, leave on charger for a couple hours, etc) and you still are under warranty (DJI only warrants their batteries for 6 months, which makes sense because they're badly designed and are prone to failure) you can have them replaced.
Otherwise:
1) Pry off the white plastic top.
2) Use a multimeter to check the actual pack voltage. "Dead" under normal circumstances means you're going to see about 22v from the pack, but I've had two "intelligent" batteries literally murder themselves to sub-10v levels, so you may have any amount of voltage in those packs. As an aside, <10v coming out of a 6s LiPo pack is a real no no - it can damage the pack and potentially be dangerous. I guess this is why DJI doesn't talk about this issue too much...
3) If they're really dead, disconnect the balance cable (it's the cable on the connector with 7 or 8 thin wires heading to the charging circuit).
4) Use a wire to jump the negative terminal on the charging input to the negative terminal on the battery.
5) Connect the charger and, with your multimeter, test the pack every 5-10 minutes until it reads about 22v. It'll take about 45-60 minutes to revive the pack.
6) Re-assemble the pack and charge as normal.
7) Discharge in a low hover to 5% or so.
8) Recharge completely.
We had a lengthy discussion about the crappiness of DJI batteries and how to fix them here:
http://forum.dji.com/forum.php?mod=viewthread&tid=59802
That includes a photo that shows the jumping of the negative terminals.
I recovered two batteries this way. |
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