Picture of PowerTube Vr. 1 for bicycle headlight

Recently purchased one of those bicycle lights using the XML T6 LED x3.

Came with a 18650 8.4v 6400mAh Battery Pack and a Pouch with Velcro.

The headlight has a voltage status function via a multi color LED but to be honest i am not satisfy with what function so i decided to add a voltage meter.
Furthermore, i decided to forget the pouch as a battery case and make a new one instead.

So, the new battery case it has to be cheap, durable, waterproof, nice, with some extra space and easy to work with.

The answer came from the plumbing tubes!

I have included a lot of pictures, so the whole assembly process is fairly easy to follow.



For those who wish to follow me on this project here is the instructable and the materials needed.


fsdredd1 year ago

elaa ree patridaaa !!!!

frapedia (author) 2 years ago
Output: Voltage = 8.4 DC, Current = 1000mA.
fast charging for (18650 x 4) approximately 3-6h depending on battery pack discharge status.
nominal battery pack voltage = 7.4V
nominal battery pack current = 6400mA
It is always best to use protected cells. A little circuit is added at the top of the battery to protect it from overcharging / discharging cycles.
Also, do not discharge/use a cell below 2.7 - 3V.
Thnks for specs ;) (you should better use "reply" button so peopleget noitified when you reply their comment )
kondzio292 years ago
thanks for replying and one more question- can you tell me what is the output voltage at the AC charger ? you know, voltage, current etc. and again- Thanks a lot!
frapedia (author) 2 years ago
actually it is from a bicycle headlight kit. Those sets consists from the headlight itself,the battery pack which is a set of 4x(18650) type cells. Each cell have 3.7V x 4 = 8.4V and the AC charger.
Laptop battery packs also use those 18560 type cells.
kondzio292 years ago
is that battery pack made out of laptop cells?
frapedia (author) 2 years ago
we are talking about the battery pack's diameter here which is almost 13.5 cm.
The shrinkwrap tube should be wider in order to shrink and fit on the battery.
See the updated pictures.
monty3242 years ago
With the shrinkwrap that you put around the battery you said 20cm diameter, should that be 20mm diameter?
Treknology2 years ago
This is a very neat and likeable project. My only disappointment is that I've never seen a pipe fitting like that in a local plumbing store.
frapedia (author) 2 years ago
Thank You for your advice on vinyl dye spray paint.
The JST micro connectors supply power to the voltmeter,so there is no need for high current connectors.
ac-dc2 years ago
Are you sure the micro connectors are rated for enough current?

Also, try using "vinyl dye" spray paint, available at automotive stores. It bonds with the plastic so it is permanent, won't flake or scratch off nearly as easily as other paint options, even more durable than paint claiming to be for plastics and no clear coat is needed, you may not even need more than one coat in total, and the tube would not need sanded, only washed first.

The downside is you have limited color options since most people wouldn't want orange upholstery, but it does come in some desirable colors like black, silver, etc.
electro ac-dc2 years ago
It would seem that the micro connectors are just for the digital voltmeter, as is the clicky switch. I would assume that you merely switch it on the see the voltage reading and then back off again.
The main lead for the supply to the headlamp is piggybacked off the battery pack and exits the tube on its own, with the on off for the headlight being controlled by its own clicky switch mounted at the back.
frapedia (author) 2 years ago
sBlended: Σε ευχαριστώ, Thank you!
sBlended2 years ago
Συγχαρητήρια για την κατασκευή σου! Πολύ έξυπνη κ πιο βολική από την ένδειξη με LED.
frapedia (author) 2 years ago
thank you!
agis682 years ago
nice job done
rimar20002 years ago
Wow, magnifical work, master.