Hardwiring a Torch light

[Deleted member 4366]

I just got my 2000 lumen 3 Cree R5 torch today. The one that Frank reccommended.
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It's as bright as my single Cree T6 light, but a much broader beam, and that's before I charged the batteries. I guarantee that you wouldn't need a light more than this for a bike. Luckily it fits directly in a mount that I got with one of those torch type bike lights. However, I'm still awaiting delivery of my 4000 lumen 3 Cree T6 torch. I reckon that the force of the light coming out of it will push me backwards.
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I don't know how long the batteries will last. I'll let you know when I've tested it, but I've got a feeling that I'm going to be drilling holes in it to wire in a few more in parallel.

 

[Scottyf]

Hello all,
Quick update. I received the additional Cell from the original supplier and also have a few cells from D8veh (Thanks very much by the way). Its evident that the original cell was just clearly not up to the job.

I believe its failing when its discharging. Its quite possible there may be something wrong with the protection of the cell. Its possible the cell is just pants.

Without stripping it down and taking a look I wont know.


Anywaythe light is much much brighter using D8veh's cells and the new cell. Horrendously so to the point where I think i'm now blinding people and only have it on low for commuting now.

So with all the good cells I will now over the xmas period parallel them up and hard wire my lights with some simple connections from my back pack to bike. Saves finding a waterproof space on the bike and also means i won't loose the batteries when off the bike. (Or forget to charge them for that matter).

I hopefully then will have 3.7v and roughly 10ah of battery power which should see me through winter.
I'll keep you posted on my progress.

 

[Deleted member 4366]

If anybody has any torch-type light with single or multiple individual 18650 cells, you should measure their voltage when you take them out because there may not be any low voltage protection. 3.0v is an absolute minimum, so make a note of how long you've used them so that you can get an approximate max safe running time.

 

[Scottyf]

Or buy 18650 cells with a protection circuit enabled.
Usually slightly bigger than a standard 18650 cell and should say on the label.

 

[Scottyf]

Finally got around to putting the cells D8veh sent me. Bodged together all linked in parallel to create an 8 cell 3.7v nominal battery. I used very basic soldering skill and some braided wire to link the cells together.
As they will perform like one larger cell I've not used any balance wires.

As the one newer protected cell I have using the torch does work it only just about makes my total journey and starts getting dimmer after 30mins. With this newer pack I should get about 8hours high use. Which is overkill really. But I might as well have used up the cells that save sent me.

Just linkinking it to a single cell charger and making sure it doesn't charger much higher than 4.15v. I doubt I'll ever use up the capacity in one week but it's nice to know it's there.
The only downside is that it's pretty heavy when comparing it to lipo. Just those 8 cells weigh a fair amount for there size.

So there we go, 3.7v 16amp ish battery done.

Excuse the amount of tap I've used. Just wanted to make sure it was ok.

 

[Scottyf]

Also thought I can use this in about 6months time when I go to download festival as a portable charger for my other single cell batteries. Like my phone since I'm sure they will charge it if I add tue correct connector.

Failing that a small bomb if I get bored.

 

[steve.c]

18650

Hi.Dont know how you only get 10mins out of your 18650??? i have 2 Ultrafire 502b torches rated at 1000 lumens and use the 18650 4000mAH 3.7v li-ion protected batterys and they will last me for about 90min on a mixture of say 30% medium power and 70% full beam which gets me the 10mls to work twice and back once before I have to charge them again.Regards Steve.

 

[wurly]

This probably won't interest you now Scotty, but i bought one of those dc/dc converters. I wanted to see if they can really output 3A.
After some experimenting, i found they can......but.....the heatsink gets pretty hot. If you can manage current consumption down to around 2-2.5 A i am sure they will survive ok. Because it's a switching device, should anything short circuit the dcdc converter shuts down. I didn't test it to see what happens if it does overheat though. The output is set using a variable 20k resistor you will have to solder in yourself. the lowest voltage i could adjust it down to was 5.98 volt. With my 900 lumens torch it was drawing 2.8A and getting hot pretty quickly.
By adding a 3R3 resister inline the current dropped to 0.7A. I paralleled another resistor to make 1.65ohm and the torch now draws 1.1A and still give out enough light. I also connected a 36 array led that i am going to use as a rear light. It will save me charging the light batteries for 2 bikes every week.
Current draw from the my pack was approx 0.5A at 39V

 

[NRG]

Nice one Mel, my one arrived just before Xmas, not got around to testing it yet....

 

[Scottyf]

Wow impressive. Glad I revisited thus old thread and now have some pretty decent info!
Thanks for your tinkering.

I do get more than30mins on high but after that you cab see it getting dimmer. That's with the 3000mah ultrafire cell. However the pack I've bodged together should give high beam for my commute for over a week. Only issue now is charging it will take about 24hours.

 

[Scottyf]

Hello all,
Finially go round to hardwiring it incorrectly. Should give me a good few hours worth of light...
Although its now getting lighter. But its nice to know I can go on longer rides without running out of battery.

Here's a video