H600fc mk4 small review and measurements.

Finally H600fc was received after 3 month waiting. I thought ZL spend 3 month to fix bugs and now it is almost ideal) Of course it is not.

Package is standard

Host is the same as later butch of FC mk3 (I have FC from first butch)

The host and button are very good.
Now ZL use pins in head

But FC still have spring in the tailcap. The spring is long and thin.
(Mk4/mk3/mk2 tailcap)

The current in turbo mode is about 6A (4.6A at 4.2 V). Thus in turbo spring became extremely hot, I even smell that something burn. As a result with good cooling stepdown take place after only 10min using new 18650GA

Battery voltage is ~3.8V at that moment. I have tried to change tailcap to AWG18 wire and turbo work without stepdown.
Then I test PID. Facepalm.
Headlamp heat up to 60C(ambient temperature 25C)after 1min,than temperature decreases to ~50C. Output is more interesting.
H1(1400lm not 1600)

~900lm

~500lm

Huge oscillation with period 1min. It is the shame ZL!

Nevertheless I like xhp50.2.
Here the results of measurements in sphere.
At 1sec.

And at 30sec

I send email to ZL with those issues,and waiting for the answer
P.S. Graph made by ceilingbounce great app!

Thanks a lot. Tint on max output looks great at least integrated, but that bad PID hunting looks similar to the SC64c.

Thanks for link, I have missed this review. I’m very surprised that ZL don’t fix this problem.

Thanks for the review. Overall, do you still prefer the mk4 over the mk3?

Great review, I was thinking of buying the new Zebralight MK4 headlamps but I will wait for Zebralight’s response to your review. Thanks so much for sharing the information!

FC mk4 has much better LED and more interesting UI.So I still prefer mk4. But actually I prefer moded H03)

I use H1/H2 mode not often.So above problems do not concern me fully. But if you want to buy mk4 and have 1600lm , you will be very disappointed.

The oscillating PID output seems to be standard for all the current generation Zebralight models. Maukka and I both recorded it with the SC64c, and it’s also present in the SC600w IV HI. The period seems to be long enough it probably isn’t visible, but I returned the lights so I can’t confirm. It’s certainly a far cry from the nice flat outputs in previous generation Zebralights.

If you want to increase PID output, you can raise the temperature up to 55°C.

The spring thing is a problem. I routinely use lights in cold enough weather they don’t step down on turbo, and there should never be a situation where that causes the spring to overheat. Please let us know what ZL says.

Period is 1 min so it takes less than 30c(there is a small plato in highest point) to change from min(Max) to max(min). It is visible.

That’s rather unfortunate :weary:

It wouldn’t be a flashlight company if they didn’t manage to screw something up. So right now, to get the best possible headlamp, I think you need…

This all seems like too much work. I should start a flashlight company and make expensive stuff that doesn’t have anything seriously wrong with it. I’d sell dozens of them, I’m sure.

zak.wilson by the way as you can see at first picture mk4 have clip.
About holder. For outdoor use Armytek holder is the best way to lose headlamp)
The only point I agree with you is LED and MCPCB. It is really great light source.

I haven’t lost a Wizard yet, nor heard of anyone else having issues. I’ll admit it’s more likely to fall out in theory. I also haven’t heard of anyone else getting a clip included with their Zebralight H600-series, but it would be a big improvement if this is standard now.

zl’s reply
“1) We are aware of the high current through the spring, and that’s the exactly why we switched to multiple pins in our flashlight products. High output headlamp models will move to the pin design in the future. Different spring materials or bypass won’t help much because some of our customers will still insist on using their low quality high resistance protected batteries.
2) We are aware of the ringing/oscillating in the Mk 4 18650 lights. We’ll try to fine tune the PID parameters (and possibly setting up a new calibration process) in future. ”

That’s a bizarre response. Nothing will help if the user puts in a battery that can’t handle the light’s current draw, but a better spring will certainly help with the issues you described when an appropriate battery is in the light.

In other words ZL said :“We will do something …in future…may be”

I might buy another zebralight in the future , maybe.

It’s the first time I’ve read that the temperature of the spring affects the stepdown. Happens in all high-drain flashlights with spring?

It’s bad news for me, since I have an H600Fd on the way.

spring isn’t a problem in all modes, except H1.
And we can use any 18650 battery in these headlamps, it’s important point.
thanks, Zebralight.

(2 caps, 1st universal, with long spring, and 2nd special cap with pins for 65mm unprotected, will be better, but 2 caps costs more money).

In IV generation we can simply change modes in G6 and G7 groups, exclude 1560lm mode, change H1 mode to 980/590lm, and solve this problem.

Actually it is the first time when I saw such problem too. Usually high-drain flashlights use CU Be springs (Noctigon) or simply thick springs.

I am pretty sure he is blowing the spring issue out if proportion. He didn’t even say if the spring was discoloured. I am sure ZL tested the light and I bet as long as a good quality cell with an appropriate current rating is used the spring will work fine. Plenty of other users have reviewed this light and no one else has said anything about an issue with the spring. Just use the lights guys and if there is an issue ZL has great customer service and a good warranty.