Ooops, I overcharged it again ...

First of all, don`t worry too much, sice I`m talking about a single Lipo cell, only 350mAh, but 15C rated.
Long story short, I left it charging at 1C, I came back after 80 minutes, expecting to find the green light
and a ready to fly cell, but it was still charging, I quickly took it out, checked the voltage and it went
to 4.35V full.full.full charged
Well, my fault, was not one with internal BMS, but one modified for high current, so without it.
Hence it went slowly up till the charger max voltage of 4.35V. It stayed there no more than 20 minutes,
but the result is Shockingly Selfexplanatory <<.>> plated anode, incredible loss of capacity, no use of it. :?
Just for the bin and in fact it was the right time to shop on HK for some micro Nanotech cells of better capacity.
Still, that made me to think that if it was not 350mAh, but 66Ah of Leaf module ...UGH

peace and love!

Good reminder unlike days of SLA and Nickel chemistry, Lithium is very unforgiving in regard to V min/max.

ya, just mere 15 minutes made the internal resistance to rocket up to the sky!
never to bulk charge without HVC cell level cutoff, in my future plans

will get two of those

to have more funtime and hopefully ending the flight with a less hot battery.
the standard helicopter is sucking 3 Amps and the microdrone up to 5 Amps, poor Lipo.
with flight weight between 30 and 60 grams
Lot of failure modes even in the small scale world, but luckily small money involved too.
If in the future I'll have time I'll complete a small RC motorbike too !
Will put few 100 Watt brushless on few 100s grams weight weelieeeee 8)

have fun!

i had a lot of early failures of the nanotech pouches. the 8Ah 25-50C version but it may be because of my assembly practice since the failures all seem to be the pouch where i soldered to the negative electrode.

dnmun said:

i had a lot of early failures of the nanotech pouches. the 8Ah 25-50C version but it may be because of my assembly practice since the failures all seem to be the pouch where i soldered to the negative electrode.

Click to expand...

ok, thanx, I will check!
Still should not be a problem since I put on the equipment exactly the connector that HK
is already fitting on the cells. Secondary, the cells are costing in total 5 $ .... no great loss.
But, just to be careful, probably I'll cycle them few times with the RC charger at lower current,
instead of using them directly at full blast.

have fun!

you should not discharge your lipo packs through the discharge function internal to the balancing charger. you should use an external shunt to absorb the power because the internal shunt is not able to handle the power and they burn up.

dnmun said:

you should not discharge your lipo packs through the discharge function internal to the balancing charger. you should use an external shunt to absorb the power because the internal shunt is not able to handle the power and they burn up.

Click to expand...

don't worry, I plan to discharge with less than 2 watts ... as I wrote, they are very small cells ...
even a battery medics would do it to allow few cycles for forming. I'm not in a hurry
ps. they are 750 mAh cells, 1s1p

have fun!

Overcharged or Turbocharged?
I'm so happy I damaged that Lipo, otherwise I would never come to know how good those Nanotech
are! They turned some flimsy performance devices in amazing fun with incredible
flight time with the added bonus or having a normal temperature at the end of the flight!
If the big lipos nanotech give the same advantage over the regular, I see it is good to lead that
way in case the application is demanding in Aamps. :wink:

Only one caution, the polarized connector of all 4 cells I bought was having the polarity the
other way around of my devices, don't know if there is no standard or they just screwed up.
I realized it by chance and I avoided charging with reverse polarity just by a slim poooffff

have fun!

Sometimes it's good to damage stuff because you find better stuff.

I am happy to have damaged my 19" motorcycle rim for my ebike, because the smaller 17" rim and tire are so much better.

Sometimes it's good to damage stuff because you find better stuff.

I am happy to have damaged my 19" motorcycle rim for my ebike, because the smaller 17" rim and tire are so much better.

yeah, sometime it helps
those nanotech are really top stuff.

have fun!

i have a lot of early failures of the 8Ah turnigy nanotech and will never buy them again. cost me almost $1k to buy replacement packs and then still have to cut my 21S3P pack down to 21S2P. will do a thread on it when i finish.

My "rule" is to avoid weird/oddball RC Lipo packs. Best buy versions produced and sold in large quantity. 5Ah 20C/25C pouches often seem to be good performers with low dud rate. 4S hardcase 20C brick's very good, if not the best, value IMO.

Forgot to report back about the HobbyKing turnigy nanotech 750mAh 1s1p cells I bought in 2014....
In less than 20 cycles and in no more than 16 months of use they all (5 exemplars) puffed...
They are of no use now, but were exceptional in performance when they were new.

Have fun!