ZL H502 on 14500?

My question: do any of you have any experience running the Zebralight H502w on 14500 cells?

The ZL H502w info page says the following:

• Operating Voltage Range: 0.7V - 4.2V
• Battery: One 1.5V AA (NiMH, lithium or alkaline). 14500 Li-ion batteries are not supported.

So I can tell they don't *recommend* using 14500s. And if I blow up my light with a 14500 and complain to them, they're going to say "tough luck--we warned you." But if the voltage range is up to 4.2v, then presumably it's possible?

Basically I am hoping that some of you have already taken the risk, so that you can report back to me.

Maybe if I run it only on medium and low settings? Certainly the high is where I would worry about it, esp. if it does not have the 1-minute timer to step-down that the H52w has.

Sigh....

12 hours later, 101 people have viewed this thread, and everyone has had the same reaction:

"hell noes! I ain't that stupid. You blow up your *own* light, sucker!"

Okay, I'm getting the message....

Well I don't have the H502, but I have a SC52 that has the same voltage range and it is just fine on 14500's. I believe they say that the SC52 supports Li-Ion though. I would just send them an email and ask. I wouldn't hesitate if it were my light, but it's easy to confirm with an email.

eraursls1984 said:

Well I don't have the H502, but I have a SC52 that has the same voltage range and it is just fine on 14500's. I believe they say that the SC52 supports Li-Ion though. I would just send them an email and ask. I wouldn't hesitate if it were my light, but it's easy to confirm with an email.

Click to expand...

+1 for my sc52, used almost exclusively on 14500 for past 2 weeks without issue

14500s work fine in mine. However you have a couple things to consider. The battery tube is short. My protected cells are too long for the tailcap to tighten fully which mean no worky since it has annodized threads.

Also, the positive contact can be finicky. Some flatter top cells may not make contact.

If you put it in and the light turns on, its fine. If it doesnt, then try another cell. The circuitry can handle the voltage as long as you can find a cell that will actually connect positive and negative.

mitro said:

14500s work fine in mine.

Click to expand...

That's awesome, mitro! Thanks so much for this info!

Do you have any sense of whether H1 is brighter with a 14500 than with an Eneloop? In the H52 and the SC52, the 14500 triggers a 1-minute burst of turbo, like 500 lumens.

If the battery is to long you can cut a paper clip and wrap it around the end of the battery to make contact.

My new H502w came, and I can confirm that it works with a 14500.

Or at least I can tell you about my experience: it did not blow up, and it put out a *lot* more light, i.e. roughly the 500 lm that the H52w puts out with a 14500.

Will using a 14500 have other bad effects? Will it overheat? I don't know, and since ZL does not support the 14500, I should not pretend to know.

But here's one thing that is relevant to the question: ZL sells a 14500 battery (ZL584), which works very well in the H52 and SC52.

And it is too long to use in the H502. You cannot screw down the tailcap to make contact.

So I used a shorter, AW red-label IMR 14500, and it worked like a charm.

With a calipers, my Eneloop is 50.5mm long. The AW red-label is 49.4mm (it's unprotected).

And ZL's 14500 is 51.9mm long, almost 52mm, presumably because of a protection circuit.

SO: one reason why ZL might say that the 14500 is unsupported, even if the light and the circuit can handle many 14500 cells, is because *their own* 14500 cell is not compatible with this battery-tube. If they said it was supported, then customers would naturally think that they can purchase both the light and the cell from ZL, and then would find that the two do not work together.

Should ZL go back and add 1.5mm to their battery-tube, in order to make this light compatible with a protected 14500? Nah. The incredibly small size of this light is part of its charm.

Now that my AW IMR is drained a fair bit (down to one blink on the battery-charge indicator mode), I can also confirm that the light itself automatically switches into a lower level when the 14500 cannot sustain the high output. As usual, ZL's circuits build a lot of battery-protection into the circuit itself.

So perhaps they should change the 14500 cell that they carry, and start selling an unprotected 14500?

In any case--I think I now know the answer to the question that I first asked upthread.

Thanks for the report. I wish they had made the H502 a little longer to accommodate the 14500 battery they sell.

Does the H502 turn off at 2.6V with the 14500?

Steve

In another thread on this forum i think i read that its a fit issue, not a voltage issue as others have already input. I have an older H502d that has different voltage ranges, thus if it fit, it would fry the light so i'm not taking chances. Still I've been looking at getting a H502w if i run across them on sale and trying the 14500 cells i have. Would be interest to know what cells people have used that work. I have four different brands to try when i finally pull the trigger

I have a few of the unprotected AW 14500's mentioned.

I'm pleased to confirm that it works fine, and is much brighter, in the H502, but I think it wasn't making contact in the H502c I have.

Question. What run times do you expect?
The eneloop is rated at 2500mah and the AW at... 600mah!
What am I missing?

mico said:

... Question. What run times do you expect?
The eneloop is rated at 2500mah and the AW at... 600mah!
What am I missing?

Click to expand...

Voltage. The AW has about 74% (not 24% that you assume by only seeing the mah) the capacity of the Eneloop.

eraursls1984 said:

Voltage. The AW has about 74% (not 24% that you assume by only seeing the mah) the capacity of the Eneloop.

Click to expand...

Right! Thanks. (I read these numbers as a vaper...)

Had a thought about this today.

The new SC600 line is optimized for unprotected cells (shorter length, pogo pins, etc.), and that's okay for safety, because the ZL's own circuit does most or all of the work that a protected cell would do--prevents the cell from getting drained too far, prevents it from drawing too much current, shuts off in case of internal shorts, etc.

Perhaps the circuit in the H52 and H502 simply does not have that kind of extra protection built in for protecting a Li-Ion cell. After all, they are primarily designed for 1.5v AA alkalines, or 1.2v AA NiMH cells.

So in order to use these lights safely with a 14500, the protection has to be built into the cell. Which it is, with the 14500 cell that ZL sells for the H52 (and SC52).
But the H502 has the shorter battery-tube that will not accommodate a protected 14500. That did not bother me, because I have shorter, unprotected AW IMR 14500s that work fine.

Now I think maybe I should be careful on this front--if the circuit in the light's head does not have Li-Ion protections built into it, and the unprotected cell that I am using does not either, then I could get into trouble if I do not use it carefully. E.g., I could over-discharge the battery, if nothing worse.

I said upthread that the light was dropping down to lower output levels as the 14500 discharged. That's a good sign! But that's not all the protection that a Li-Ion battery needs.

So: For all I know, the H502 may not have any of the standard over-discharge and over-current protections that a Li-Ion battery needs. In that case, don't use it with a 14500, even one that fits (like the IMR). Or if you do, then be extra careful, and don't over-discharge it.

I knew i had read this infor elsewhere:

http://www.candlepowerforums.com/vb/showthread.php?392332-Zebralight-H502-14500-Li-Ion

Reported a test of over-discharge protection in another thread.

Andrey said:

Unprotected UR14500P cell works perfectly in my H502c L2.

Its positive 'flat top' contact, however, is just a fraction of a millimeter above the plastic wrapper. So you need to attach a tiny magnet to it to ensure reliable connection with recessed conductor in the H502 head. Or, like I did, insert a small piece of wire through the went holes.

There are reports that H502 lights work with unprotected 14500 cells, but I could not find a confirmation of the over-discharge protection.
So I had to test it myself. My H502c L2 does have a safety feature similar to '52' lights. As battery voltage drops, light switches from high to medium mode at 3.4 V, then to low at 2.9 V, and turns off at 2.87 V.
I monitored the battery voltage in the headlamp under load via a tiny wire attached to the cell's positive contact.

H502c brightness is relatively same on 14500 compared to Eneloops. High mode just 10% brighter as measured with my phone luxmeter.
On max, light gets as hot as on Eneloops -- hard to hold it with bare hand.

Click to expand...

Andrey said:

Reported a test of over-discharge protection in another thread.

Click to expand...

Wow! That is great news, and a huge favor that you did the rest of us by testing it out and reporting it back.

I also like the wire arrangement that you have in place of a magnetic button. I worry that the magnetic button may introduce significant resistance, and also that it might slide off and cause trouble. This looks like a more secure and lower-resistance solution.

One point of disagreement, though: when I use the 14500 instead of the Eneloop, I see a *huge* difference on H1, which very much looks like it is going into 500 lumen mode. On the other hand, I am using a H502w, not the H502c, and perhaps with the Luxeon emitter the difference is not as big as it is with the XM-L2?

lampeDépêche said:

Wow! That is great news, and a huge favor that you did the rest of us by testing it out and reporting it back.

I also like the wire arrangement that you have in place of a magnetic button. I worry that the magnetic button may introduce significant resistance, and also that it might slide off and cause trouble. This looks like a more secure and lower-resistance solution.

One point of disagreement, though: when I use the 14500 instead of the Eneloop, I see a *huge* difference on H1, which very much looks like it is going into 500 lumen mode. On the other hand, I am using a H502w, not the H502c, and perhaps with the Luxeon emitter the difference is not as big as it is with the XM-L2?

Click to expand...

Can't believe I haven't subscribed to this thread.

lampeDépêche, What specific 14500 can you recommend for the H502w? Any besides what you list up above?

roger-roger said:

lampeDépêche, What specific 14500 can you recommend for the H502w? Any besides what you list up above?

Click to expand...

All I know is that the ZL 14500 are too long (though they work fine in the H52), and the AW IMR 600mAh works fine. Haven't tried others yet.