# Zebralight H600Fd III stepping down when first turned on in H1 or H2



## Collins (Feb 8, 2017)

I just got the Zebralight H600Fd III.

Here's the output on High:

High: H1 *870* Lm (PID, approx 2 hr) or H2 *560* Lm (PID, approx 2.5 hrs) / *255* Lm (3.9 hrs) / *117* Lm (11 hrs)

When I first turn the light on High. When in *H1 870* or *H2 560*. After a few seconds, the light starts stepping down in output. I counted it stepping down in around 11 steps. Whatever that means.

It appears it steps down in output to somewhere between *H2 560* and *H2 255*.

Is this normal? Looks like I can't have the light in *H1 870* or *H2 560* as it automatically steps down in output. I timed it and the light shut off in 3:06 hours.

Also when it drained the battery all the way. The light just shut off. I thought at the end of the battery, it was supposed to step down to medium and then low? It didn't appear to do that, it just shut off. I don't really like that. As if I'm outside at night working on the car. At the end of the battery, I'd like it to step down to medium or low to give me a warning the battery is about dead. That way I still have light to be able to see to walk back into the house to swap the battery.


----------



## scs (Feb 8, 2017)

In theory, if you keep it cold enough, it'll maintain 870 or 560 until the cell doesn't have enough juice.
So your light maintained constant output noticeably above MEDIUM and LOW and then shut off without warning? Not even a flashing warning?


----------



## Connor (Feb 8, 2017)

Collins said:


> When I first turn the light on High. When in *H1 870* or *H2 560*. After a few seconds, the light starts stepping down in output.



Please define "after a few seconds". I don't own a H600Fd III myself but my SC63w runs about ~45 seconds on H1 before stepping down. 
What kind of battery are you using?


----------



## Collins (Feb 8, 2017)

Connor said:


> Please define "after a few seconds". I don't own a H600Fd III myself but my SC63w runs about ~45 seconds on H1 before stepping down.
> What kind of battery are you using?



2-3 seconds. Then it starts stepping down. I counted around 11 steps. It steps down when in *H1 870* or *H2 560*. So the light won't run in *870* or *560*. So I'd say max lumens the light will run is around *400* or so.

Batteries I'm using are unprotected *Panasonic NCR18650B*. And protected *Orbtronic 3500*.

Panasonic: http://www.orbtronic.com/batteries-chargers/panasonic-3400mah-18650-li-ion-battery-cell-ncr18650b

Orbtronic: http://www.orbtronic.com/18650-protected-battery-3500mah-lithium-ion


----------



## Collins (Feb 8, 2017)

scs said:


> In theory, if you keep it cold enough, it'll maintain 870 or 560 until the cell doesn't have enough juice.
> So your light maintained constant output noticeably above MEDIUM and LOW and then shut off without warning? Not even a flashing warning?



I'm going to have to test it again. I had the light sitting off on a table while I did other things. And I didn't notice a drop in output before it shut off. Just noticed it shut off suddenly. But I'll test it again a few times. Will probably partially charge a battery to test so I don't have to watch it for 3 hours every time.


----------



## Connor (Feb 8, 2017)

Collins said:


> 2-3 seconds. Then it starts stepping down. I counted around 11 steps. It steps down when in *H1 870* or *H2 560*. So the light won't run in *870* or *560*. So I'd say max lumens the light will run is around *400* or so.



2-3 seconds is too fast, it's normal that a flashlight of this output/size steps down quickly and then runs at 400-500 lumens when it reaches a thermal equilibrium (the ZLs are temperature controlled) .. but not after a mere 2-3 seconds. As I mentioned above my SC63w with similar output and mass runs about 45 seconds on H1 (it's quite warm by then) and *then *steps down .. I would expect approximately the same from the H600Fd III. 

I'd say test with a few more freshly charged cells if possible and then send Zebralight an email about this.


----------



## Collins (Feb 9, 2017)

Connor said:


> 2-3 seconds is too fast, it's normal that a flashlight of this output/size steps down quickly and then runs at 400-500 lumens when it reaches a thermal equilibrium (the ZLs are temperature controlled) .. but not after a mere 2-3 seconds. As I mentioned above my SC63w with similar output and mass runs about 45 seconds on H1 (it's quite warm by then) and *then *steps down .. I would expect approximately the same from the H600Fd III.
> 
> I'd say test with a few more freshly charged cells if possible and then send Zebralight an email about this.



Why would Zebralight say *H1* will run for 2 hours if it's going to step down in 45 seconds? Sounds like false advertising. They should put *H1* will run for 45 seconds then step down, etc.

I did read there being a problem with these new H600 models early in their release that they ended up having the wrong firmware or something installed.


----------



## Connor (Feb 9, 2017)

Collins said:


> Why would Zebralight say *H1* will run for 2 hours if it's going to step down in 45 seconds? Sounds like false advertising. They should put *H1* will run for 45 seconds then step down, etc.



If you switch it on on H1 at ~21°C ambient temperature and keep it on it will run for 2 hours, as advertised. Unfortunately everyone is advertising their lights like this. 
Note that the ZLs are PID controlled, if you use your light outside well below freezing temperature it will keep running at ~1000 lumens until the battery is empty (~20 minutes). In a very hot environment it would run longer than advertised but less bright.


----------



## Tachead (Feb 9, 2017)

Collins said:


> Why would Zebralight say *H1* will run for 2 hours if it's going to step down in 45 seconds? Sounds like false advertising. They should put *H1* will run for 45 seconds then step down, etc.
> 
> I did read there being a problem with these new H600 models early in their release that they ended up having the wrong firmware or something installed.



You don't seam to understand. Unlike many other manufacturers lights and headlamps that have a timed stepdown, Zebralight uses realtime thermal regulation. There is a temperature sensor on the circuit board that the electronics and emitter are mounted to and the light monitors the temperature and automatically adjusts the output to allow for the highest possible output that conditions will allow. It will lower and increase the brightness in realtime as conditions permit to keep the temperature at safe levels that won't harm the light or battery(the battery is the limiting factor as most Li-ions have a max temperature of 60C). If there is adequate cooling it will not lower the output at all. It completely depends on the conditions. You can test this by allowing the light to heat up to its max where it has stepped down and then blowing on the light. You will notice that when you blow on it it will ramp the brightness back up a bit. You have to watch closely because ZL uses 384 different levels to make the changes smooth and less visible to the user. 

Zebralight clearly states in their literature "Runtimes of the two PID controlled levels (870Lm and 560Lm) vary greatly with ambient temperature and air circulation.". 

Your runtimes will completely depend on the conditions and ambient temperature as will the output on H1 and H2. Under adequate cooling, for instance, you might only get 35-40minutes of runtime because the brightness will stay closer to it's max output. Here is a couple of runtime charts to show you the runtime with adequate cooling and the thermal regulation(PID) working.











Charts courtesy of maukka.

In case you didn't know, you can also adjust the PID target temperature to allow the light to run 5C hotter or 5C cooler then the factory settings. Setting the PID target temp higher will allow the light to run at a higher output but, the light will run hotter(but, still within safe limits) and you will get shorter runtimes. Setting the PID target temperature cooler will make the light run at a lower output and step down sooner but, the light will run cooler and you will get longer runtimes. Here is how you adjust it...



PID Thermal Regulation Temperature Programming for two highest output levels:
Turn off the light from H1 and then turn back on to H1 
Press and hold to cycle from Low to High 6 times 
On the 7th (or more) cycle, release the switch
when High to add 1 degree C (up to 5 max) 
when Med to revert back to the factory default 
when Low to subtract 1 degree C (up to 5 max) 
 
 


Now, it does sound like there may be something wrong with your light if it is stepping down in a couple of seconds. It should take longer then that even when sitting idle in warm ambient temperatures. I can check how long mine takes if you would like?

Anyway, I hope this was helpful:thumbsup:


----------



## Collins (Feb 9, 2017)

Thanks. I sent a message to Zebralight and will see what they say.


----------



## Collins (Feb 10, 2017)

I ordered the H603d III to see which one I like better. But I'll check that one to see if it has the same problem.


----------



## Andrey (Feb 13, 2017)

Collins, it appears your batteries might be weak. E.g. with time and use cell's internal resistance increases. Due to higher IR, under significant load, like ZL high modes, voltage falls, the light will detect depleted battery and step down.
I suggest testing the light with some new cells.


----------



## Collins (Feb 14, 2017)

Andrey said:


> Collins, it appears your batteries might be weak. E.g. with time and use cell's internal resistance increases. Due to higher IR, under significant load, like ZL high modes, voltage falls, the light will detect depleted battery and step down.
> I suggest testing the light with some new cells.



All of the batteries are brand new.

I'd say thinking about it. It's probably not too big a deal of it dimming down as it's still bright enough and I get longer run time. The run time on high is 3 hours.

Something else I noticed. Is when the battery is about dead. The light is supposed to step down to medium and then to low. On the H600Fd III, it doesn't do that. When the battery is about dead. The light gets really hot. Hot to where you can't hold it as it feels like it will burn you. And the light doesn't step down to medium and then low. It just shuts off.

I just got in an H603d III, which is about the same light. And it doesn't get real hot when the battery is about depleted. It does step down to medium and then low.

I like it to step down at the end to give me a warning the battery is about dead and so I can still see. I'm thinking there may be something wrong with the H600Fd III as the H603d III steps down to medium then low when the battery is about depleted.


----------



## Collins (Feb 28, 2017)

Got word back that the at the end of battery life, the headlamp getting really really hot and then just shutting off and not stepping down at the end was a defective headlamp.


----------



## jorn (Mar 4, 2017)

What batteries are you using? Brand new dont mean nothing if it's a crappy brand that wont deliver the current needed. The zebra h600 III needs really good batteries to not step down.


----------



## Tachead (Mar 4, 2017)

jorn said:


> What batteries are you using? Brand new dont mean nothing if it's a crappy brand that wont deliver the current needed. The zebra h600 III needs really good batteries to not step down.



See post #4. He is using high quality batteries. Not that this light needs anything special really, it doesn't draw very much current. Sounds like it was defective and ZL is going to replace it for him.


----------

