Olight SR90 battery pack failure


SR90’s battery pack shows 0 volts.
I disassembled pack (2s3p) and cells shows correct voltage.
I believe BMS has failed.
I measured FETs, one pairs shows 1.5 continuity and the other 0.660
Do you believe this is the reason of failure?
Can I replacr the 2 with the known FET purchase from mtn?

Bump,any ideas?

My gut says yes.

I to have an SR90, but luckily so far it works fine. I have not had the battery pack apart yet to have a look at it.

I have searched for a BMS replacement but all I have found don’t have this triple 18650 shape, they are parallel and will not fit in the battery tube.
Does any expert know which is the correct continuity of these FETs?

If I remember correctly gearbest sells replacement packs for your light

can you show us a zoomed in picture please? should be able to look up the specs from the numbers on the FET?

Goinggear.com not gearbest

Have you contacted Olight about it? they could possibly send you a new board.

I haven’t contacted olight but I doubt they are gonna help me.

aosemi
thats the specs for your part.
only way to check them correctly is out of circuit.
its more likely the protection ic failed.
mosfets usually fail dead short or burned up/blown to bits.
how is the voltage balance between the cell groups?

I am not home right now but as far as I can remember i measured the total 1s and 2s voltage and it were 4.1 and 8.2, so it looked correct.
Battery failed with fresh charged cells, when I replaced the sst90 led.
Flashlight works with my power supply.

then an error resulting in a short likely did the damage.its a cheap fix to shotgun the ic and 4 mosfets.

Details on fixing this?
Where can I find this IC & MOSFETs?

My Olight SR90 battery pack is almost dead. The flashlight itself has mint state. Olight just abundoned this $400 costing flashlight.
The rather sell new new new ones then showing a decent backup of old but expensive products…

Gonne try to rebuild the battery pack with new cells.
Need to buy a welding device probably to point-weld the cells together.

My next flashlight won’t be an Olight again.

My 16 year old Volvo just came from the garage.
They swapped a motor part that still was on stock.
My next Car will be a Volvo again.

As simple as that

How did that work out?

This is one huge disadvantage of buying an expensive flashlight with a built-in battery pack. Cannot replace it with ordinary rechargeable battery cells. :rage:

Agreed the LED will outlast the battery pack. Olight helped me realize do not to buy lights with built in or proprietary batteries. There’s plenty of other choices out there.

I finally succeeded to rebuild the battery pack with 6x Panasonic 3400mAh cells and gave the flashlight an upgrade to 10+Ah instead of the 7,2Ah original cells.
It was an exiting journey from opening the pack with a lot of violence, finding a pointwelder, buying a Li-Ion pack and two fireproog BatSafe boxes (don’t want t burn down my house) getting used to spotwelding without killing too many cells :frowning: and getting al the stuff back into place.

It took me a long time but the next would be done in less of the half time needed for the first time.
Learn and proceed with your life :beer:

Since I have no photobucket I cannot post pictures here.
If needed, I can send them on request.