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Author Topic: d.i.y. chargers for 18650  (Read 950 times)

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Offline xj35s

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d.i.y. chargers for 18650
« on: October 24, 2017, 03:21:51 PM »
I had a Ryobi 18V lithium pack that wouldn't charge. It got wet outside in a flash rain storm while building our barn. I took it apart and found the large I.C. chip had evidence of the magic smoke. Upon inspection I found all the cells had over 3.75 Volts. 10 of them to be exact.

So having 10 18650 batteries and no charger I started to investigate and found this video. I built it and it works perfectly. I use a USB to Micro usb to power the first board and the other 4 boards are fed from that.

Not my video...


 I bought 10 of those little charge boards for $1.99 and I think $1.99 shipping. From ebay seller onfine2008 . I used 4 and have 6 left. So I took a solar panel that puts out 6 volts in bright sunlight from a harbor freight 36 led security light. Our horse beat the light with a stick and we never found it, It had a lithium battery!! I saved the solar panel that was mounted outside the barn. I haven't used it to try and charge a battery yet as it's overcast. But in the little sun we have today it lit the blue l.e.d. on the board saying it is ready to charge. I'm sure it will only charge ONE 18650 but if the sun can do it, it only cost me two pieces of trash and a $0.20 circuit board.

My goal is to get a better flashlight for the 18650. Right now I'm using a $20 atomic beam from walmart.
« Last Edit: October 24, 2017, 03:31:43 PM by xj35s »
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Offline Unknown

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Re: d.i.y. chargers for 18650
« Reply #1 on: October 24, 2017, 03:43:14 PM »
I really like it when you get creative. Can't watch the vid now but will certainly keep it in mind.
 Just a week or so ago I dropped my last 18650 and killed it. I need to get some more, got any tips on where's the best place to get that done?
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Offline xj35s

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Re: d.i.y. chargers for 18650
« Reply #2 on: October 24, 2017, 04:26:00 PM »
Maybe,...
https://www.batteryjunction.com/18650.html

Old laptops and cordless drills have them inside if you can get one. Simply test each battery with a voltmeter to see they are NOT below 2 volts. If so, they will likely not recharge.

I bought a battery for my wife's laptop and it idn't fit. If I tear it apart I'll send ya a couple.
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Offline Unknown

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Re: d.i.y. chargers for 18650
« Reply #3 on: October 24, 2017, 04:52:29 PM »
I will accept if it comes to pass. So if a battery is discharged too low it can shorten the lifespan? I might have done that.
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Offline xj35s

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Re: d.i.y. chargers for 18650
« Reply #4 on: October 24, 2017, 05:24:25 PM »
critical with lithium. My Ryobi drill and drivers have a low voltage cut off that protects the battery from getting too low. They recommend the first 4 to 7 cycles not to let them get below 50% before charging.
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Offline xj35s

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Re: d.i.y. chargers for 18650
« Reply #5 on: October 29, 2017, 08:39:52 AM »
So the sun was hiding some yesterday.


There was enough sun to light the blue ready charge light. and the red led charging. It started out at 3.66 volts and in about 4 hours of fading sun it got up to 3.98. 3.7 is full but the usb charger will bring them to 4.25. I have a bunch of solar cells from the little garden lights that I soldered in series and parallel and may add to this panel for a more robust 6 volt output with higher milliamps.



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