RING LCD torch misbehaving - is it saveable?

[Mikezoe65]

I am trying to decide whether to repair a RING lcd inspection torch/lamp. On switching on the lamp lights for a few seconds then goes out. Ditto with torchlight on two presses of switch. On connecting to a charger the red light (presumably partially discharged needs charging) comes on but after a few seconds the green (fully charged?)light comes on. I’ve unsoldered the Lithium ion battery and checked its voltage as just over 3v (supposedly 3.7v fully charged)

Questions.
Is the problem the battery is misbehaving or the controller board misbehaving?
is it worth buying a new battery (c£7)?

 

[Bluejets]

Sounds like the battery.....did you test the battery under load of any kind?
If not, it will give a false reading.

 

[Mikezoe65]

Sounds like the battery.....did you test the battery under load of any kind?
If not, it will give a false reading.

You could well be right but how do Li-ion batteries tend to fail? Don’t they just like phone batteries need recharging much more often? My money’s on the pcb but I have no idea how to test it to be sure. What is an easy way of putting the old battery under load?

 

[Bluejets]

You could well be right but how do Li-ion batteries tend to fail? Don’t they just like phone batteries need recharging much more often? My money’s on the pcb but I have no idea how to test it to be sure. What is an easy way of putting the old battery under load?

They fail because they are knackered.
No they do not require recharge more often however a trip over to batteryuniversity web site will educate you.
Pcb components these days are a favourite fail point for those who do not know any better. The cell is still my suspect item btw.
Test with load, now what could that mean...? A bulb, a motor anything electrical within the voltage range of the cell and enough current, in this instance 500ma or so should suffice.

 

[Martaine2005]

I 2nd the battery being half dead.

 

[bertus]

Hello,

You can have batteries almost for free.
Many disposable e-cigarettes contain rechargable li-ion batteries.
The capacity of these batteries that I found is between 500 (13350) and 1500 (22300) mAh.

Bertus

 

[Harald Kapp]

+1 for the battery

 

[Mikezoe65]

Thanks for comments! Will be soldering in a new battery Saturday and will report the results here soon after.

 

[Mikezoe65]

Sadly the LED torch is for the scrap heap. I connected the new battery and the torch lit ok initially but after 5 mins went out. On attempting to charge it initially showed red (charging) but soon went green (fully charged). I then tried to run the torch again (to run down the battery) but after about 10 mins the light went out again.
I’ve concluded that the pc board is misbehaving and intend to scrap the torch unless anyone has a bright (sorry) idea.

 

[Bluejets]

From current info, charger is kaput or "new battery " is knackered el cheapo.($3 from Amazon or similar ???)
Looks mean next to zero in electrical, it's why we use test equipment.
In this instance the test equipment does not have to be anything special. A $20 multimeter and a few loose components and some knowhow.