I think I know the answer, don't use them, unprotected 18650 in my setup.

LED Flashlights – General Info 18650 Flashlights
1

The following light started me on a path of enjoying riding my bicycle at night.

Several of these lights were purchased from Home Depot for about $10 bucks each, some for use and some as backups. They are no longer available and have many flaws. Time and money should have probably been spent on quality stuff. What I did like about the light was the large amount of light and the ability to focus.

The AAA rechargeable batteries in the light did not last long which led to an AA battery pack,

http://www.ebay.com/itm/like/371294088019?ul_noapp=true&chn=ps&lpid=82

I eventually added a second light and with some additional tinkering the final result is,

I carry a spare battery pack when riding. I like the ability to project the beam where I want it.

Hooked on LED lights, Googleing led me to 18650 powered lights from China,

http://www.everbuying.net/product261749.html?currency=USD&gclid=Cj0KEQjwy92wBRCl7trx4PaIo8EBEiQASPhtC7Bw6o4rhK1h8nx9Te3NjfG9kjaE4cFWRVaS2tJwsE4aAmrn8P8HAQ

I have purchased several of these and for a while have used it for work when I paint. I also mounted the guts of several of these to another bicycle helmet,

I have harvested unprotected 18650 cells from a fully charge unused laptop. I have ordered a smart charger that I think was recommended here,

http://www.gearbest.com/chargers/pp_173012.html

After Googling about the horror stories with these batteries I worry about having these little unprotected time bombs strapped to my head. Should I stop using my 18650 light even with protected cells? The 18650 cells are wired in parallel. For more safety the 18650 battery pack and controllers could be mounted on the frame.

Thanks for your thought!

P.S. With all the time I spent attaching these lights to my helmets I could have worked a couple of days and bought good lights but I like to think I honed my tinkering skills instead.

Thanks for your thoughts.

2

IMO I would run a parallel battery pack of 18650s off of the frame & DEFINITELY NOT off the helmet. I would also run a high enough # of cells so that you wouldn’t run the risk of overdischarging the cells too low during a ride.

Too be overly safe you could also build in a cheap voltmeter display off of the batteries. Sort of like this thing.

3

First, we feel your pain/urge for projects, you are among like minded addicts.

Second, turn the screws the other way! much better to have your home made job, look more home made then to “use” the helmet and end up with screws in your head! :slight_smile:

Third, run in parrallel they are very safe. If you know that you have not over discharged them (pick a number say 2.5 volts) at the end of your ride, recharge and no issue.

Its all about managing the last few percent of charge, if you can manage it, then you dont need protected cells but if you cant or want some tech in the system then use protected cells and they will cut out when too low.

4

Ermm, how long are those screws? Look like pointy wood screws. Which are aimed for your skull. :ghost:

During severe impacts the expanded foam of a helmet compresses to spread and slow the sudden force. Like a car crumple zone. A couple attachment clips mounted with epoxy might be better.

5

And screws in a helmet weaken it. Even after one knock you are supposed to discard the helmet.

6

You would be amazed how much that hard white foam compresses when you ram your head against it at speed.

7

I like that volt meter! Thanks.

8

They actually are not that long, they are sheet metal stud screws. I used them while the clear silicone set up. I will remove them before the next ride. Thanks for the good advice.

9

I read the specs. On the voltmeter and am confused. Operating range is 0 to 30 volts but the minimum voltage is 4.5 volts. I would think the electronics would need some minimum voltage to operate?

10

This one has a minimum operating voltage of 3 volts,

http://www.gearbest.com/development-boards/pp_54463.html?currency=USD&gclid=Cj0KEQjwy92wBRCl7trx4PaIo8EBEiQASPhtC1y1o9OGqTanUtFU3Um6VzyH6x-Nrav0evvkg4pcyVUaAqmC8P8HAQ

11

I wear a hydration pack and keep the cells I it. A bit of a nuisance putting myself together but it keeps the helmet lighter and better balanced. I’ve tried it with the button on the lamp head and remote on the shoulder strap and both work ok.

12

Oh man, that helmet with a light screwed to it looks scary. I am sure the helmet manufacturer would not approve. You should check out this subforum which has a lot of good info about cheap lights.

There’s a magicshine clone on amazon that is highly recommended and pretty cheap.

Personally, I have an Xtar XinTD on my bars (800 lumens?) and an S-mini (400 lumens?) on the helmet. I have a $2.50 rubber U mount on the bars which works great for flashlights with 1” diameter. On the helmet I have a double velcro thing (http://www.dx.com/p/flashlight-universal-bracket-mount-holder-with-velcro-123733#.VhtS4-eqrpI) that holds a smaller cylindrical flashlight. I am sure you can get 600 lumens in this form factor.

I can’t stand battery packs that use real estate on my frame. Toss a couple of spare 18650s into the seat pack and you are all set.

13

I can see one of the XinTD 18650 Flashlights on my handlebars, $30!,

http://intl-outdoor.com/xintd-c8-v5-xml2-u4-multioption-18650-flashlight-p-308.html

And holder, $4.31 for 2,

http://www.dx.com/p/universal-bicycle-flashlight-lamp-nylon-velcro-clip-mount-holder-black-2-pcs-252680#.Viw33dJViko

Edit, sold out :_(

More lumens! Thanks!

And maybe two on a new helmet if I can figure out an adjustment mechanism.

14

I find a lipo alarm significantly more useful than a volt meter alone. This model is what I have and the voltage the alarm goes off at can be changed if you wish by pressing a little button.
.
Personally, I have no issues using a home made 18650 headlamp, or a thrunite T10 headlamp or my S2 or BLF X6, SE on my helmet. If I need to use a 2S battery pack, I make sure to connect the lipo alarm.

15

That is crazy inexpensive. $2.04 and free shipping. Do you need to reprogram the set point each time it is reenergized or does it stay connected to power all the time, the info is not clear?

Use all the “gas in the tank” without damaging your batteries or self and I guess you can extend the life of your batteries! Thanks for that heads up!

16

Once you set the alarm voltage to 3.5V for example, it always stays at that point. Potential negatives: Alarm is loud, (can be made quieter with tape over speakers) , not water proof and always uses energy when connected.,
(sorry for bad typing, phone giving trouble)