Emisar D4Sv2 Driver Confusion

LED Flashlights – General Info 26650 Flashlights
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I have two D4Sv2 lights. Both were ordered with XPL-HI 4000k emitters. Neither is supposed to have tint-ramping and I did not choose a boost driver. However, I ordered one with a backlit button after hearing it was an option, so the drivers may be different models. Nevertheless, my understanding is that performance-wise, these two lights would be the same.

So the weird thing is that the one with the backlit button seems to be getting hotter a lot faster. The low end of ramp is also higher on the D4Sv2 with a backlit button… Does this mean I have the tint-ramping driver? That doesn’t make sense to me since I thought that driver was supposed to be more efficient and ought to be cooler. Could a difference in battery resistance be the cause? Or maybe the first light with the non-backlit button has the boost driver for some inexplicable reason?

Maybe someone familiar with the specifics of these different boards can chime in and let me know what is going on here. Thanks!

Edit: I am using QB26800 batteries that both arrived from AloftHobbies in the same shipment. I haven’t had a chance to swap the batteries around and eliminate that cause yet.

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First, check the firmware version and post it here. There is some button sequence (I think 15C from off) which will display it.

Second, take photos of the drivers and post them here. If you cant remove it then at least post the backside.

Third, make sure both are similarly calibrated and with same temperature limit.

Fourth, ensure both cells are full charged and indeed swap them around to make sure they are not the cause.

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This won’t answer why one is getting hotter than the other, but if you order a normal single channel D4SV2 with no driver upgrades and you request a backlit switch, you will get a K9.3 driver with K9.3 firmware and nothing connected to the second channel. You can verify this yourself. On your sample with the backlit button, do 3H from on. The main emitters will turn off but the aux LED’s won’t turn back on. Then 3H again and the main emitters will turn on. This is the light switching to the other channel (not connected to anything) and then switching back.

1 Thank
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They may not have the same thermal calibration.

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  1. Does the firmware check exist on Anduril 1 too?

2. Pics of the back of the driver I can do, but it sounds like Grizzly knows which driver I have in the one with a backlit switch.

3. The temperature difference appeared almost immediately and I don’t think any stepdown had occurred yet. Now that I know it’s a totally different driver, I speculate that the top ends of ramp are configured differently. Maybe by reducing the max ramp I can mimic the operation of the vanilla D4Sv2.

4. They should be similarly charged but I’ll definitely top them off before testing tonight.

Thanks Grizzly! That is a pretty big clue. Hopefully this comes down to firmware configuration and not hardware issues. This is otherwise a nearly perfect pocketable walking light. The new arrival is grey, has a steel bezel, 26800 tube, magnetic tailcap and an amber button. Absolutely beautiful. :smiley:

I took the vanilla one for a walk on Sunday and it maintained max ramp for the entire walk. Granted, it was breezy and 40 degrees F/4.44 degrees C, but here in my northern state I will get plenty of opportunities cold enough for this kind of operation.

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New one most likely drives led with 9A at the top of the ramp and maybe the old one is 1+3+Fet driver. I don’t know to which level of the ramp the old drivers regulation ends, but most likely top of the ramp is less than 9A.

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I have a similar light. D4SV2 with 4xW2, but a lighted switch. The 3H trick indicates a tint ramping driver, but a single channel. I was wanting to order a similar light but with 4xW1, but was thinking I would order a dual channel light. Would the dual channel light give me more light? It seems like the driver would be the same, but on a dual channel light, only 2 LEDs would be sharing the current on each channel, while the single channel light has all 4 LEDs sharing the 9A, or whatever channel 1 can provide. Any insight would be appreciated.

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I believe that is the best course of action for four W1’s. Get the dual channel version with W1’s on both channels. That will effectively give you an 18A linear driver.

If you get a single channel version, it will only be driven at 9A because the FET will have to be disabled to protect the LED’s.

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I don’t think an 18A linear driver is a good idea.
That’s going to have to dissipate a massive amount of heat into the head lmao.

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How is it different than a FET driver dumping a ton of heat into the head? My D4SV2 with W2’s is pulling ~25A.

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How can you test your light to see how many amps your drawing I’m curious on how to do so

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You use a clamp-style digital multimeter. I don’t have one, so I’m estimating based on Djozz’s CSLPM1 test below.

I’m getting 4900lm OTF with a full battery. Assuming a 20% output loss from the lens & optic, that means lumen output from the LED’s is about 6125lm. 6125/4 LED’s is a little over 1500lm per LED. On Djozz’s graph, 1500lm lines up nicely with 7A. 7A per led times 4 is 28A. Since this is a guess and not a true measurement, I’m estimating it’s pulling ~25A from a full battery.

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I think I read somewhere here that Hank himself wrote that the 9a dual ch was 9 amp on one channel, but if both channels were active, then they shared on the 9 amps. I hope it was for an early edition or something and I find seen to find the post either.

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They don’t share the 9A. It’s 9A per channel. On level 150, it’s 18A total (if the battery can supply that much).

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Great to hear. Can’t recall exactly where I read the post. An yes, that would not have made super much sense.

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Driver from my standard single-channel D4Sv2:

Driver from my single-channel D4Sv2 with a backlit button.

Can anyone positively identify which driver that is on the bottom?

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@tactical_grizzly, if both channels are active at once in PWM, you’re pushing the LEDs into a very innefficient range :stuck_out_tongue:

There’s also the fact that the linear driver will be burning a lot of power there as well.

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The dual channel version uses two constant current drive circuits so there should be no PWM. I still don’t see how this is any worse than running W2’s via FET drive on the standard D4SV2 driver.

Is your point that both are an equally bad idea? Perhaps I just misunderstood what you were saying initially. I thought you were saying that running two 9A Linear channels simultaneously was worse than running a single FET channel at similar amperage.

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Yeah with 4x W2 at 18A you'd be dissipating like 10W just at the driver lol, maybe sticking some of these between the FETs and emitter shelf would help? https://www.mtnelectronics.com/index.php?route=product/product&path=25_74&product_id=105

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Can someone positively ID the driver in the second picture? I just want to confirm which one it is for sure. Sorry they are upside down. I didn’t think of letter orientation till later.