This started off as a test to see if the re-purposed lithium phone cell in a solar charged LED lamp did have built-in overcharge protection.
It then evolved into a lithium cell capacity test with an improvised USB charge hack.
By request, here's a link to the ebay listing for this lamp. http://www.ebay.co.uk/itm/351467607543
It then evolved into a lithium cell capacity test with an improvised USB charge hack.
By request, here's a link to the ebay listing for this lamp. http://www.ebay.co.uk/itm/351467607543
I have one of those, I love it.
I may upgrade the Battery now that I know it is that easy.
I wonder how difficult it would be to use the 3rd connector to show charge status? If that is what it is for!
Thanks!
Later, FW.
thanks for the video. I think I bought the same light. It was only $6 including shipping from china from ebay. So you think a potentiometer to replace the resistor controlling the current would work?
hi clive. this is a great light. any chance you could leave a link of where to buy it? many thanks.
Thanks Big Clive, you gave me a ton of ideas!
You might consider one of these. Nice little thing for doing automated battery capacity checks — West Mountain Radio Computerized Battery Analyzer. They're a lot of fun. Constant current draw down to a set cut-off voltage. Produces a nice graph.
Great videos,Thanks..
I do wonder if the cell is intentionally that small to give the solar panel a chance to charge it fully if its pretty much discharged.
He never says how much the light is and where he bought it.
The batteries could be old stock such as for obsolete mobile phones, but rather than dump them, this is probably one of their creative ideas to make use of their unsellable batteries. In this case, the battery capacity would have deteriorated over the years in storage as Lithium Ion batteries lose recoverable capacity each year even without use, probably accelerated by the warmer Chinese climate.
Hi Clive, that was an interesting way of determining that capacity that I had not thought of before. I think you will however find that the actual capacity is lower than you measured. I've tested a few batteries on my load tester and I find that you get less power back out than you put back in, I assume there is going to be some energy loss as heat and some consumption of the protection circuit, they are almost definately going to give you less than 500ma back
I bought some Trustfire 18650 battery's, they too have the protection circuit.
After finding these battery's to be total pants, I took off the protection circuit.. Now these battery's are great, at what risk, I'm not sure but they work now.
Personally I think the protection circuit on them is a bit enthusiastic, is there any way of checking it?
My mate bought one of those a week ago, looks identical.
The battery does sound a bit farty but it does sound safe.
You could bung another resistor in series with the original limiter and add a tiny slide switch to short it out, the delux dual brightness version lol 😀
Chinese batteries tend to claim twice to five times their actual capacity, so that Samsung-branded battery (which could be fake, there's a lot of branded fakes out there) could be accurate if it's used or not genuine…