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I have an old magic shine ssc p7 light single led) that will run on low setting but shuts down on high after about 5 mins. I assume the led is getting hot (casing is warm.but not to hot to hold).
So can a replace the led or is it the power driver (?) That is the issue? If it is the led what are the best options for? It is a 20mm round base and runs of a 18650 battery pack? Led is easy to get to so can replace.
It is old and not that bright now days but it seems silly to throw away what can be fixed.
Is that with it on high with no air flow? Mine would trip the thermal cutout if on high and not moving (sat on a table for instance).
mine aren't magic shine - but they get hot with no airflow ...
Get plenty air moving over it and I suspect the thermal cut-out bit has probably deteriorated (somehow) over time and is a bit more sensitive.
It isn't just the battery is needing replaced i.e. the battery is so old and not holding a proper charge that running on high is draining it too quickly?
As others have said, do not test without some air moving over the case.
Might be worth checking the thermal conductivity between LED and exterior case.
As above if you run them indoors on a table any LED overheats and dims to protect itself. Shouldn't be a problem when riding. Apparently some people who live in hot places and night ride with big lights on full blast can also have the problem on climbs.
Thanks for the replies. It runs on low for a long time so battery is fine.
Tested on the move and it still cuts out. How do I check the conductivity? Tye chip sits on a metal disk.
mrl
Full MemberThanks for the replies. It runs on low for a long time so battery is fine.
You're probably right but it's not quite so simple- sometimes a battery can deliver a low current without issues but ask it for more and it'll fail. I've got a couple of well-used lipo packs that are still useful in low drain jobs but useless at anything that wants more.
Thanks. Will take another look at the battery. I have some other 18650 batteries I can use.
Took it apart and behind the led and around the metal countersunk case it sits in was a wet powder. I guess this is the paste used to allow conductivity between the metal back plate of the LED and the case. There was not much and it was completely dried out. Will replacing this potentially solve the problem?
Apologies for the tile spelling, walking and typing is not my strong point!
Replacing the thermal paste should help if it is the high temp causing the cutout.
Yup, can't hurt to replace it. Clean both parts really well. Then apply a THIN layer. The paste there to fill in all the little gaps and fissures between the two mating faces. Too much and it starts acting as an insulator. But that's when there is loads.
Do you have a multimeter? You can measure the voltage of the fully charged battery pack. You're looking for 8.4v fully charged.
Turn your light onto max. Measure. If the voltage drops below 6.2v, the battery pack is likely goosed. A li-ion cell below 3.1v is knackered. The magic shine batteries are 2 cells in series, with 2 in parallel.
Thermal cutoff will be above 60 degrees, so you can also touch the heatsink and see. It it's too hot to touch, it'll likely be around 60 degrees. Unless you have asbestos fingers!