# Cheap DIY 18650 Lithium Battery Charger



## t0m (Jun 27, 2013)

Hi, I'm new here. I made a 18650 Lithium battery holder for a DIY charger for my bike lights and want to share. 









Link: Magic Smoke: £1 Lithium Ion Battery Charger


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## Vancbiker (May 25, 2005)

Excellent DIY project.


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## mattthemuppet (Jul 16, 2004)

neat, I've been thinking about doing that for a while as I've used those little charger boards a bunch. You could always use wires with neodymium magnets glued/ soldered to the ends too.


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## t0m (Jun 27, 2013)

Interesting idea with the magnets, I'll have to give it a try although my understanding is that they are nickel plated which is tricky to solder.


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## Ofroad'bent (Jul 10, 2010)

I just ordered some of those little boards, to make up some emerg chargers for work with connectors for my bike light batteries, when winter commuting time comes around.


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## mattthemuppet (Jul 16, 2004)

t0m said:


> Interesting idea with the magnets, I'll have to give it a try although my understanding is that they are nickel plated which is tricky to solder.


yeah, I'm not really sure about that either. I also read somewhere that heat destroys the magnetism, although I'm not sure if that applies to rare earth magnets or just the normal ones. Still, might be worth a try if you have any to hand.

I love those charger boards, they really are a lot of fun to use. I have them in 3 or 4 lights and they give a lot of "wow" factor for only costing $2-3


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## Terry8x (Dec 6, 2013)

Cool, this DIY idea is great. But is there any good bike charger's brand? Got a RavPower 14000mAh but need another one now.


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## 127.0.0.1 (Nov 19, 2013)

yeah soldering magnets is a fine line between...will the solder stick
and survive the pulling ? or will it be rock solid but the heat needed to bond it destroyed the magnet

will take some experimenting...it is better to use small alligator clips
holding a magnetic ball. guaranteed to work* and no loss of magnetism from soldering

*some batts have non-magnetic caps

FYI---you have a fake cell shown in the pic, no such thing as a 3800mah 18650 as of todays date. might consider sourcing different cells, as fakes might suddenly vent. I have 6 true ultrafire blue wrapped and they print them differently

statement from ultrafire: Beware of fake Ultrafire 18650 batteries
We are the manufacturer and owner of Ultrafire products ,and here declare that we had not manufactured over 3000mAh above for #18650 rechargeable battery, we do not take any responsibility in respect of any fake products.

For your safety, please purchase Ultrafire products from our official dealers and distributors. Please support original products and welcome to email us if you have any questions about our products.

Many thanks!


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## t0m (Jun 27, 2013)

*Solderable magnets*



mattthemuppet said:


> neat, I've been thinking about doing that for a while as I've used those little charger boards a bunch. You could always use wires with neodymium magnets glued/ soldered to the ends too.


I found a source for solderable magnetic connectors in the UK.

Magnetic Electrical Connectors 5 Pairs | Rapid Online


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## Ofroad'bent (Jul 10, 2010)

I made up a bunch of these chargers with 5.5mm connectors for very little $.

I wonder if it would make sense to incorporate these little mini-usb chargers right into battery packs? Might be tricky to waterproof, but perhaps an inner tube could stretch over the opening. Wouldn't be too hard to make a small silicone plug for the connector.


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## t0m (Jun 27, 2013)

Ofroad'bent said:


> I made up a bunch of these chargers with 5.5mm connectors for very little $.
> 
> I wonder if it would make sense to incorporate these little mini-usb chargers right into battery packs? Might be tricky to waterproof, but perhaps an inner tube could stretch over the opening. Wouldn't be too hard to make a small silicone plug for the connector.


They are cheap enough. I'd certainly like to see it if anyone has a go.

By the way you can also hack these boards to charge little Lipo cells more slowly. Bit off topic but I can post details if there is any interest.


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## t0m (Jun 27, 2013)

t0m said:


> By the way you can also hack these boards to charge little Lipo cells more slowly.


Such as LiR2032 coin cells:









Blog post: Magic Smoke: $1 Lithium Coin Cell Charger


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