Fenix HP11 18650 upgrade.

A few days ago I made some tests with my HP11 to see if it could work on li-ion 18650 packs. That's where/when I got this idea from: http://www.candlepowerforums.com/vb/showthread.php?354012-*new*-Fenix-HP25

I temporary wired some homemade 18650 packs to the light and here are the obtained results:

I was quite satisfied with the running times, so I decided to permanently modify the lamp.
Materials:

• S-Video to 3RCA Adapter Cable From an old video card
• Coaxial audio cable (I don't know if it's the best idea, but it looked sturdier than a normal AV Cable)
• AV cable for the extension cable
• Shrinking tubes
• Electric tape
• 35mm elastic band
• 10mm transparent tube

Here are some images I took:


The wire is cut, warranty lost


The coaxial cable:


Prepare to be soldered!


Cables soldered and some isolation tape added. On left of the image is the first layer of shrinking tube:

First tube shrinked:


Second layer. Doesn't look pretty but I tried to protect the soldered wires from bending and twisting. I'm sure it's quite waterproof:


A tiny bit of plastic hose for waterproofing the contacts:


I tested this on my other devices, it works well.


Some of my parallel battery packs. Simple, cheap and efficient, as long as you're not diving with them. Here you can see the use of the Svideo to 3RCA cable.



A few minutes later and the extension cable is ready. It looks flimsy but I used this type of cable with my bike lamp and it holds up well. Anyway, if it breaks I can still connect the batteries to my lamp directly :


The finished lamp:


A bit of sewing and the holder is done:


The smaller loop for the smaller pack, of course. I have to work some more here, I'm not quite satisfied with this elastic holder with one battery only. The light being lighter, I probably won't use the upper headstrap anymore.


A bit too colourful for my taste, but at least it's colour coded. Useless in the dark.



The original holder prepared to become a member of the new family...But not today.



It was fun, i'm not quite sure if it will hold well on the field, but that's OK, maybe I'll find out why I always carry the backup lamp.
I use the HP11 mainly in the forest and at higher altitudes on the mountain, and sometimes I really need the extension cable in winter and when wearing the climbing helmet.

That reminds me, let's talk about the weight. That's not a light for the ultralight hikers, but is a very good thrower and I prefer it to other lighter lamps.

So with 1s2p 18650 pack it's 60g (2.11oz) lighter and 55% more running time. Actually, if you consider the spare batteries (120g the AA's) but only one more 18650 for the same running time, the modded light is 150g (5.3oz) lighter.
Maybe I'll order some 3400mah Panasonic cells that will double the AA's running time.

Measured drawing current:

675h on low mode? Maybe it's the DMM I used...

Voltage:
4.28V Turbo --> at 3.55V drops to High --> at 3.1V drops to Medium
The light is dimming as the voltage drops, but that also happens with the AA rechargeables.

How cool is that! Thanks for the photos!!

Protected cells only?

More to the point: it has been about 3 years since I poured through the flameout subsection of the Battery Included forum. I don't recall all the root causes of the flameouts, and how violent they may be. I am guessing: shorting the battery, over charging, and over draining can cause flaming. From what I remember, it was more flames than explosion. A protected cell, I would think, would protect against over charging, over drainage (as would the low voltage cuttoff of the hp11, not present in the 16 lumen mode), and short out. Water probably is not a good conductor, so in theory couldn't cause a short. But if it were salt water, perhaps if something torn on the battery and pack, this could cause a short.

I would buy a thin square of aluminum as a firewall to direct any remote possiblity of flaming away from head. You could bum a little piece off any seamless gutter installer or roofer. Or a coil of aluminum can be had at your local big box building suppier. Again, I wouldn't wrap the cells in it, just put a small square as a firewall on one to three side of cells as a firewall.

Even Fenix, for legal reasons, states to use only Lithium Polymer cells in the TK35, which are apparanently flame proof. However the TK stands for Tank, as in, the light shell is super heavy, explosion resistant aluminum. I asume protected cell flameout is rare or non existent. Probably, rare. From the show, "One Way Out", we learn that heat transfer through dry fabric happens fast; so, the thin aluminum should buy enough time to rip it off your head, if it did catch fire. I would better protect cells in a pocket pack by building a case.

Florinache, how is it going? The HP11 handling the heat of 277 for 8 + hours well?

Did you get protected cell, or just managing the unprotected cells with a volt meter and taking your chances?

I got my two 18650 7.4 volt holder yesterday. I am thinking about modding one of my flakey HP11's (not in hurry right now), but I will mod the holder for parallel cell use.

I use it almost every night with unprotected cells, so far no brain burns I'll order some 3400mah protected Panasonic soon, to boost the times and fear no accidents.
I never tried it on turbo for more than 6 hours but the light is fading with the voltage drop so only in the first two or three hours is around 250 lumens (compared to other lights I own).
Good luck with the modding

Not only is a two/one 18650 cell swap option a good idea, but this light (using diffuser with a 150 or 300 hour 12 lumen mode) would make a rock'in pillow reading light--provided the user could temporarily move the battery from the back to, say, the top of the head. (When laying down reading, rear battery just doesn't work. So, I use cheap, frequently charged lights for reading.)

florinache said:

I use it almost every night with unprotected cells, so far no brain burns I'll order some 3400mah protected Panasonic soon, to boost the times and fear no accidents.
I never tried it on turbo for more than 6 hours but the light is fading with the voltage drop so only in the first two or three hours is around 250 lumens (compared to other lights I own).
Good luck with the modding

Click to expand...

You will have to post the 3400 runtimes. ... [Daydream] I am guessing pipe wrenches to mod out the emitter to xpg2.[/Daydream]

I have had at least two NiMH AA nearly start house fires at night, as something in the cell shorted and the battery became boiling hot. I quickly escorted the cells to te bath tub. At least one, single cell lamp has been melted.

Now, new to the LiIon experiment, perhaps my most dangerous light is the four 7.4volt 18650 headlamp, where I wear the battery pack close to my genitals. I wonder why my wife bought me that light.

The xpg-2 will give a little more light, at the lower voltage the 18650 provides. I wonder if the 115 degrees angle will affect the beam.

Now, let the warrantee voiding 3.7 volt current tests begin on the HP25.

Even at 4.8 volts, I part of me is dying to know the HP25 current draw. UKcaver is holding out or stumbled into a mine shaft due to lack of the hp25 flood during his tests.

How do you connect the pack to your charger? Sorry about zombie post

I soldered to the charger an AV jack.

Glad this old post got bumped up. I have been considering doing this with my HP20 for some time. I would like to find a waterproof 18650 holder like is used on the BT20 bike light. The carrier you used specifies flat cells only, and all I have are protected button top 3400s. I may need to do some testing on my own.

Sorry for being a complete newb here but could you post a picture of how you soldered to your charger? Would an intellicharger sense that it is a 1s2p pack or would it not matter?

I don't have a photo right now but it-s very simple. You open up the charger and solder the two wires to the +/- ends. You'll most certainly find some soldered parts there.
It doesen't matter if there are more cells in the parallel pack. The capacity of the battery will grow, but the voltage remains the same. I used a cheap charger, xtar mp1s.