Flashlight progress comes in unpredictable spurts, interspersed with long plateau periods where little notable progress occurs. The first generation of LED lights used several batteries and a current-limiting resistor. The second generation used several batteries and a fairly crude electronic chip to provide current-limiting. The Freedom chip used in the ReX is a third generation device that is somewhat more sophisticated - and it shows.
Slightly larger than their existing Photon line of button-cell flashlights, the ReX differs in three significant respects: its battery is a single rechargeable lithium-ion cell, it has four (instead of the usual one) good white LEDs, and the ReX can be recharged on the go using common inexpensive batteries.
The ReX is fitted with the LRI Freedom controller chip. This chip is reportedly also used in the LRI Photon Freedom Micro single-LED light, but that unit does not have the recharging facility. The battery in the Photon Freedom Micro unit is replaceable, while the battery in the Photon ReX unit is not. The Freedom chip delivers "stepless" variable output and a number of flash modes as well, all operated via the single button. The button is phosphorescent, by the way, making the ReX a little easier to locate in the dark. A spring clip connected to the ReX with a split-ring gives one a way to anchor the little flashlight to hopefully keep from losing it.
The ReX is charged by connecting to a battery (1.2 volt to 3 volt, see below) using a pair of magnet-tipped wires. The wires are anchored to a yoke that connects magnetically to the ReX itself, and the other ends attach to the donor battery terminals. To keep the positive and negative separate, one yoke terminal has a small plastic collar to prevent it from being reversed inadvertently, creating a polarized connector. This is where several of us had some problems: a mismatch in the dimensions of the polarized connector can actually prevent a connection from being made. At the very least, some fiddling is required to seat the yoke correctly and complete the circuit. Proper connection is clearly signaled by a slow flashing from the ReX, which ceases when charging is complete (in approximately two hours with a fresh battery, according to LRI). This is further discussed under the 'Problems' section at the end of this review.
The Freedom chip does far more than just control the flashing, however. It is a fairly sophisticated switch mode controller chip, and actually performs four distinct functions:
- Sensing the button to turn the power on and vary the power level
- Converting the four volts from the little cell to a variable mark/space ratio supply to drive the four white LEDs at varying power levels
- Converting the incoming battery voltage to the required voltage to recharge the internal cell
- Monitoring the charging process and turning it off when the cell voltage is high enough
It is, therefore, far more sophisticated than the more common chips found in other LED headlights, which just turn the LEDs on and off at three different brightness levels. This is clearly a third generation device.
LRI claims two full charges from an alkaline AA battery and twenty or so full charges from an alkaline D-cell battery. They champion the use of NiMH rechargeable cells for the least expensive and most environmentally friendly approach (with an average three charges from an AA cell). The ReX onboard Li-ion battery is claimed to have a useful life of three hundred to five hundred charge cycles.
The little charge wire assembly comes with a snap connector that can (and should!) be anchored in some safe place to prevent its loss - it's hard to envision fashioning temporary connectors from stray or salvaged bits you might have in your pack! The ReX is too small to store the wires on board, unlike the rechargeable Aquastar mUV, for instance.
Interestingly, the ReX isn't water-resistant, despite not having a battery door. It may be they weren't able to sufficiently seal the two halves of the clamshell around the four-LED bezel to supply this desirable trait, which is a shame, since the Freedom is splash-proof. However, it seems likely that a few splashes would not do much harm to the unit. The ReX ships with a clip similar to that of the Freedom's for attaching to a hat, etc. (ReX accessories, including a clip, headband, and solar charger, are promised in the future.)
At the time of writing this review, the LRI website was claiming that "The ReX will charge from any standard battery of six volts or less." This is not strictly correct and should not be followed. Previously, the website was claiming a maximum of three volts, which is correct. The six volt claim relates to charging from a USB connector, but the supply on a USB connector has a protective ten ohm resistor in series, and this reduces the output to under three volts when used to charge the ReX. Our understanding is that a USB charger is planned for the ReX in the future, along with a solar panel.
However, in bench testing, we were sometimes unable to get the charging circuit to start working when the incoming voltage was much above 2.5 volts. The microprocessor is a shade cautious about overload. On the other hand, we found it would work at very low incoming voltages, down to almost 0.6 volts, which approximates a very flat single alkaline cell, which is actually more important.
ARTICLE OUTLINE
- Overview
- Operation
- Basic Performance
- In the Field
- Rick's Experiences
- Roger's Experiences
- Laboratory Testing
- Measurements
- Discharge
- Recharging - Basics
- Recharging - Experiments
- Choice of External Battery
- Problems when Recharging and Recovery
- Enhancements for the Dedicated Ultralighter
- Specifications: Manufacturer:, Year/model:, Battery:, LEDs:, Battery life:, Weight:, MSRP:
- What's Good
- What's Not So Good
- Recommendations
# WORDS: 5560
# PHOTOS: 12
# TABLES: 1
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Companion forum thread to:
Photon ReX Review
I bought one of these earlier this year and initial brightness was very impressive but then it wouldn't re-charge. Since then Photon / LRI have replaced it twice and none of those would re-charge either. I'm now waiting for my 4th ReX to turn up.
Anyone else had similar issues?
I still like Photon as a company and their customer service is good but maybe they've been a bit over ambitious with the ReX.
Hi Sebastian
> but then it wouldn't re-charge. Since then Photon / LRI have replaced it twice and none of those would re-charge either.
I would be interested in more details about this. In particular:
* Did each Rex work when you first got it?
* How much use did you give it before it refused to recharge?
* How were you trying to recharge it?
* How long did you leave it each time before giving up?
* Did you ever get it to recharge at all?
Lithium rechargable batteries are actually rather complex beasties, especially when run right down. And the connector thing is not as straight-forward as one might like either. But I have got every one I have (3) to recharge successfully.
Cheers
Looks like too much fiddle factor for me. If your going to carry a battery anyway why not just change it in the field. And shouldn't you check your lights,batteries before you leave the house? I have rarely if ever needed to change headlamp batteries on trips of a week or less.I just do not see a real advantage. Nice try, but no.
I found this is the review section of the REI site:
1) press the button rapidly 6 times, which puts the light into "signal mode."
2) Then press and hold the button for about 5 seconds until the light goes out (this takes the light back out of "signal mode").
3) Continue holding the button for another 5 seconds until there is a brief flash of light.
Now the light is in "auto off" mode.
To return the light to normal operation without auto-off, Repeat steps 1 and 2 above without doing step 3.
This procedure was for the Photon X-light Micro. Maybe the same chip and firmware?
I have had a ReX for about ten months, and I can speak to its durability and water resistance. One day I left it in my pocket through a wash and drying cycle, and found it hanging by the recharging yoke magnets on the inside of the dryer. It turned right on, and I assume it was submerged for a least a time in the washer.
Hi Ken
> shouldn't you check your lights,batteries before you leave the house?
Too right! I check through all my batteries the day before.
> I have rarely if ever needed to change headlamp batteries on trips of a week or less.
Same here – for headlamps using AA batteries.
But the ReX is a shade smaller and **lighter**. The small size and weight is its advantage. On a trip of a a few days you wouldn't need to recharge it at all – save that for home.
Cheers
the idea of being able to carry something smaller and lighter than the headlamp that I current use, but I can't get around the hands-free operation of headlamps. It's simply much nicer to use it without hands than to have something lighter.
Even if this were the lightest light known to man, had unlimited battery life, and produced enough light to hike by night, I would still prefer a headlamp.
Surprise! I just spent more then 2 hour researching on LED headlamps with built in rechargeable li-ion batteries in vain. I assume Photon is first to come out with this tech even though it is a keychain….kudos.
> I just spent more then 2 hour researching on LED headlamps with built in rechargeable li-ion batteries in vain
Likely. The ReX is not really a 'headlight' and probably would not appear in such a search. Any similar competitors would not appear either. A Google for 'keychain light lithium' gave the ReX for the first four hits.
Just what do we call something the size of a ReX? "Keychain' is possible, but who carries a keychain when walking?
Cheers
I own one of these from the first batch, and have also had slight problems getting the charger to connect properly.
I have attributed this to dirt/trash/gunk on the contacts on the light. A quick cleaning of the contact with something (even a tiny stick or the like) gets it going. Sometimes just a little "jiggle". I've been reluctant to squeeze it too much when I saw the rather flimsy polarity scheme, just in case I had it backwards.
That is the only (very slight) issue I have with it.
I love this light!
Meant to add this:
Another undocumented "feature":
If the button is continuously pressed (like if something was shoved against it) it will cycle through all of its settings several times and then just shut off, so the battery is less likely to be exhausted by accident.
>the idea of being able to carry something smaller and lighter than the headlamp that I current use, but I can't get around the hands-free operation of headlamps. It's simply much nicer to use it without hands than to have something lighter.
Even if this were the lightest light known to man, had unlimited battery life, and produced enough light to hike by night, I would still prefer a headlamp.<
Just attached it to your hat/hood brim with a velcro dot and voila.. u have headlamp.
Roger, the only thing I dont like about it is that you cant use a >3v battery to recharge. Its sad.. mUV has been around for over a year and it can do that. I think it would be really nice if it could be recharged via UL 3.7v li-ion batteries, especially if I were carrying a cell phone anyways.
> you cant use a >3v battery to recharge
True.
Probably a limitation of the little microprocessor used to drive it. Next generation maybe?
(I have no knowledge of what the nexgen might bring.)
Cheers
Hi Roger
1. Each ReX worked when 1st arrived – after initial confusion about getting out of demo mode. My last one wouldn't come out of demo mode not matter what I did.
2. I used it mostly at full charge until flat, possibly 30 minutes. I got either one or two full discharges before I couldn't recharge it.
3. The normal way, charger connected correctly to ReX and either one or 2 AA or AAA rechargeable NiMH batteries at max recharge themselves, also tried Alkaline equivalents. There was no dirt on any of the ReX's either.
4. Sometimes left it 6 hours or more to see if it would recharge.
5. I sometimes managed to recharge one once or twice & then maybe by tiny amounts not worth mentioning.
If I have trouble with my next one (still waiting) I'll try cutting some of the plastic sleeve off the small recharger contact (I have a lot of spares now :-)).
I personally think a micro LED lamp that used one AAA rechargeable battery with head attachment would be a lot easier. The magnetic recharger is fiddly and I'm concerned the strong magnets might interfere with some of my other electronic gadgets.
I once saw a micro LED light that had a mini solar panel built right into the back of it, can't find the original now but found these:
http://www.amazon.com/gp/product/B0014GEJ06
http://www.wildday.co.uk/ProductDetail.aspx?id=5972
Don't know how well they work.
I suggest to Photon / LRI before they even made their ReX that they could do something similar.
moved to MYOG
deleted
Hi Sebastian
> My last one wouldn't come out of demo mode not matter what I did.
Return it for a refund.
> I used it mostly at full charge until flat, possibly 30 minutes. I got either one or two full discharges before I couldn't recharge it.
I do not know the exact characteristics of the Li battery they are using, but taking it to really flat may be your problem. Sometimes when they get really flat they are VERY hard to recharge. Don't let them go right down.
> If I have trouble with my next one (still waiting) I'll try cutting some of the plastic sleeve off the small recharger contact (I have a lot of spares now :-)).
I think they may be about to alter this connection…
My two good ones are still working fine. A pre-production one had a battery problem and seems to have died, but LRI suspect the batteries may have been shorted during production in that batch.
Cheers
Hey Rog
Already returned.
Not letting it run to flat is too much of a limitation for me.
I like LRI but not impressed with the ReX, battery life too short & recharging too fidly & unreliable.
my ReX 'died' too…I sent mine back (it seems others didn't..and still had theirs replaced?) and had it was replaced with an explanation that it couldn't be run to completely flat.
They have also informed me that they will send me the new model after they have resolved this problem.
Cheers..
I'm resurrecting this old thread because Photon has -finally- released the solar and USB chargers for the Rex. Both chargers and a headstrap are bundled for $20. I've been holding off on buying the Rex because the battery connection sounded too fiddly, but I just ordered one with the chargers. Coupon code "laborday" saved me 15%. I have no connection with Photon except as a customer.
http://www.photonlight.com/products/Photon-ReX-Solar%7B47%7DUSB-Charger-Accessory-Kit.html
For the record, here are the weights for the Photon Rex and accessories on my scale:
Included with Standard Photon Rex package:
Photon Rex 16.5 g (0.58 oz)
Charge cord 3.8 g (0.14 oz)
Typical Batteries Used with Photon:
NiMH AA battery 27.4 g (0.97 oz)
Lithium AA 14.9 g (0.53 oz)
Photon Rex Accessory Pack:
Solar Charger 40.0 g (1.41 oz)
Headlamp strap 13.2 g (0.47 oz)
USB Charger 11.3 g (0.40 oz)
The manufacturer's description says you get about 3 full charges out of a typical NiMH AA, so I presume you would get 4-5 charges from an Energizer lithium AA. So, to justify carrying the solar charger, you would need to a) be planning to charge the Rex many times, and/or b) want to charge it during the day while you're hiking. Charging while hiking is difficult to do with a AA and the standard Rex charging cable, because the magnetic contacts can easily disengage if bumped. The solar charger holds the Rex firmly and is made to clip onto a pack or strap so you can charge on the go. Both Rex and solar charger can also be tethered to the pack so you won't accidentally lose them if they get knocked off during some bushwhacking.
One other factor might make the solar charger more attractive, and that is if your group has more than one Photon Rex, one charger might offset the weight of several batteries. The solar charger is reported to give the Rex a full charge (from dead) in 2 hours with direct sunlight, so you could easily charge a few Rexes during a given day on the trail. In my informal tests with the solar charger, I found it will readily charge the Rex on a cloudy day, though it won't start until later in the morning and ends earlier in the evening. I would think you could still get in multiple full charges on a cloudy day. And if it's raining, I would think you could put it in a plastic bag and still charge, though I haven't tested that.
The headlamp strap is light and effective. It has a clip for the Rex which pivots to allow the light to be angled up or down. The Rex is mounted on the side of your head, rather than on your forehead like the typical headlamp, but it is still very effective.
The USB charger works great when you're at home. I suppose if you're already carrying some sort of USB solar charger (maybe for a GPS, or for you iPod people), the USB charger might make sense to take on the trail instead – it certainly is lighter.
There is a nice general review of the accessory kit over at the EDC Forums web site. See
http://edcforums.com/showthread.php/76913-Review-of-LRI-Photon-Rex-and-Solar-Charger-USB-Accessory-Pack
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