On Wed, 7 Feb 2018 11:23:23 -0800, sms
wrote:
This is the battery in the original pack:
http://www.gebc-energy.com/Uploadfile/pdf/ICR18650/ICR18650H3.pdf
4.3V max seems rather high and unsafe.
I disassembled the pack. The batteries are completely discharged, 0V. To
me this indicates a failure of the protection circuit which normally
would not allow discharge below 2.8V.
0V is an important clue. The undervoltage CID (current interrupt
device) protection of the battery has kicked in and disconnected the
positive terminal. How to recover:
https://www.youtube.com/watch?v=AWmu3U7tndA
https://www.youtube.com/watch?v=1w3Tv1Jg0ps
https://www.youtube.com/watch?v=h9BTNrJ0C_U
https://www.youtube.com/watch?v=9OKz3LpNHRg
https://www.youtube.com/watch?v=deDP7Q3v3xA
https://www.youtube.com/watch?v=YOi0hepEtYo
I see this 0V problem quite often on brand new clone laptop battery
packs. I use a small jewelers screwdriver to recover.
I don't know exactly why the CID tripped, but my guess(tm) is that the
BMS (battery management system) has a low voltage trip point BELOW the
voltage of where the CID trips. The BMS probably has an accurate low
voltage disconnect voltage of 3.00vą0.1V. However, the CID on the
battery is a mechanical device which can vary. I do not currently
have numbers on it's trip voltage but if it's over 3.00V, the CID will
trip before the BMS.
Do any manufacturers not lie?
Everyone lies, but that's ok because nobody listens.
It's a matter of degree. Tenergy is an
industrial supplier of batteries with a real building in Fremont, and
not like buying no-name batteries on Aliexpress.
Yep. I have quite a few Tenergy battery packs and chargers mostly
purchased from HobbyKing. Two of the really simple chargers blew up
and killed some battery packs. The batteries have been fine. All of
them met their capacity specs (tested at 0.2C).
The charge voltage from the plug that connects to the battery was
4.19V. I checked that before I ordered a new battery because I thought
that the problem with the light might have been with the charging circuitry.
The BMS overvoltage disconnects the battery at 4.28Vą0.025V so you're
probably ok with the charger. I prefer a lower voltage for the EoC in
order to get a longer battery life.
This morning I put the light on the maximum setting and it ran for just
about exactly two hours before it stepped down the intensity.
5200 mAH [rated]
3.7 V [rated]
19.24 Watt-Hours [calculated]
2.0 Hours [measured]
9.62 Watts [calculated]
2.6 Amps [calculated]
1390 lumens [measured by mtbr.com]
144.5 lumens/watt [calculated]
3 LEDs
48.2 lumens/LED [calculated]
Of course the reality is that the batteries were not fully discharged
when it dropped the output, so the lumens per watt was likely quite a
bit higher.
Those numbers look quite sane. The 144.5 lumens/watt seems a bit
high, especially when measured through a lens, but are not
outrageously inflated.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558