Dudes with a bit of basic electronic skill required

Efour

Efour

Efour

Caporegime
Joined
8 Sep 2005
Posts
30,559
Location
Norrbotten, Sweden.
I recently bought a solar rechargeable temu wall light but the battery is not lasting too long and I'd like to replace it with something longer lasting.

This is the battery a larger than normal.
Purple cell.
HONGLI
HL IMR18650-1200mAh
1200mA 1200mAh
4.44Wh
3.7V
2025.07.10

Google suggests a 3500mAh is the most ill get from one of these size batteries. But as it's charging from solar, dumb question, will it take 3x longer to charge? Is it that linear?
Will the crappy little charger even do it?
How do I check the battery is max charged. I have a multimeter, is that useful :p

Can u suggest a replacement battery for me. Maybe im chucking too much at a < 7 quid plastic light.....?
 
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Basics.

If it's a lithium 18650 then it will be 3.7v nominal so will be compatible.

Obviously if it has more capacity it will take longer to charge. :)

I'll see what I can find to link you, but perhaps it will be almost the same price as the £7 light.
 
Journey said:
Basics.

If it's a lithium 18650 then it will be 3.7v nominal so will be compatible.

Obviously if it has more capacity it will take longer to charge. :)

I'll see what I can find to link you, but perhaps it will be almost the same price as the £7 light.
Click to expand...
It's such a perfect size and tbh it's pocket change so yeah sure, if I can just solder it in and seal it back up yeah whatever it'll be harder to get a new light ...

So is it just a case of find a "18650"
With as much mAh as I can and.... That should work .
 
The only thing to watch is if the current 18650 cell is protected or unprotected, because that stops overcharging. All 18650s need charge control, but it could be on the lights own PCB so an unproteted cell can be used, or they might just rely on using a protected 18650. You definitely do not want to replace a protected cell with an unprotected one!
 
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It will cost you more in tooling and high capacity 18650s than it would to buy something better I expect, not to mention the danger of soldering something together that is possibly already on the edge of electrical safety compliance! ;)
 
Ok I'll have a look, maybe post a pic for you ...
I expect it to be unprotected cell cos it's the cheapest of the cheapest:p

If it explodes I'll just bin it
 
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