[Review] Astrolux C8 Flashlight - Compact Thrower

If you’re familiar with the BLF A6, the Astrolux C8 has the same performance and drain characteristics. Max drain depends on what your cell can deliver, but a rough ballpark is about 5 amps when fully charged. This drops as the battery depletes, due to the FET driver. On medium and lower modes, the 7135 chip uses a constant draw (for example, 350mA on the middle mode).

Due to the 45-second step-down to the second highest mode (which will either be level 6 in the 7-group mode, or level 3 in the 4-group mode), you’ll get decent run times of about an hour or more. But if you run it on max the whole time (definitely not recommended for more than about 3-minutes at a time), it will be about 30 minutes until you’ll want to change the battery. It takes a long time to drain completely, as it will drop output as the cell drops below about 3.0v. IIRC, it doesn’t shut off completely until 2.7v or 2.8v. But, yeah, for a thrower, moonlight mode on a depleted cell isn’t much use.

If you want longer run-times, the Convoy C8 makes more sense. It’s slightly better regulated, and is more efficient than a FET driver. And, of course, it has lower output which certainly plays a big part in run time.

On medium and lower modes, the Astrolux uses its 7135 driver, so performance is identical to the Convoy. Though, the Convoy’s medium brightness is about half the output (and current) of the Astrolux, so you can’t really compare them at the same output level.

Yeah, I know, it’s not much help. But FET-driven lights are really hard to quantify exactly.

Is it the exact same driver used in BLF A6? it still uses ATtiny MCUs? if so I would reprogram the low mode in the 4 mode group to a shine a bit higher. Also would make the step down timer to 2 minutes.

Just wanted to make sure whether my ICR LG cell could handle this thing. It tops out at 4.7A max discharge or something.

I should have been more clear when I meant runtime I meant their runtimes at similar brightness levels. :frowning:
I thought a FET based driver should give more runtimes at similar output since a linear regulator maintains brightness at the expense of runtime?

I believe it is the exact same driver. I’m looking at them both right now, and the markings and layout are exactly the same. The Astrolux C8 even has “BLF” inscribed on the board, just like the BLF A6.

Yes, if you can reprogram it, I’d definitely increase the step-down to 2 or 3 minutes.

Oh, I see. Well, the only modes you can really compare them are the medium and lower modes, since they both use 7135 chips at that level. However, they don’t have any brightness modes the same.

On higher modes, they’re also very difficult to compare, because both lose output as the battery drains, but at different rates.

If I understand the 7135 chip, it will draw 350mA (so 2800mA for 8 of them) at a constant rate until the voltage drops low enough that they can no longer supply a constant current to the LED. Unfortunately for the Convoy with 8 of these chips, this seems to happen fairly quickly. I don’t have a Convoy with less than 8 chips (I never really understood the benefit of it), but it may give a much longer regulation time with 4 or 6 chips instead. In a perfect world, the Convoy would draw 2800mA until it dies, but the world is not perfect.

A FET driver will just suck as much power from the battery that the LED can take. As the battery voltage drops, it supplies less current to the LED.

You’re right that a FET driver doesn’t “waste” any power (like the 7135 does with excess voltage). However, the LED is much less efficient at the high current that is supplied to it. So, you’ll get less run-time with a FET at the same brightness (if you could maintain that brightness), because the LED is being over-driven (and brightness controlled by high frequency PWM).

I’m not sure if I’m making sense, but hopefully it makes some sense. And I’m probably missing some points that others can expand on.

Nice review, my friend.

Good to hear that. I guess I might buy Astrolux version after all. Only thing is I also have a Sofirn C8F in mind too. Side clicky looks damn attractive to me.

If the current draw is the same from the battery perspective then the FET should be more efficient at higher voltages the linear regulator tends to waste more power. That is if example the battery voltage is let’s say 3.7V and current draw is 2.8A for both FET and 7135 then I think FET should theoretically provide more current to the LED. I might be wrong maybe??

For a dedicated thrower, I prefer a tail switch, because it is easy to find quickly. I normally carry my C8 on a lanyard around my neck, and only use it for quick looks at stuff in the distance. If I could get one with a forward clicky, that would suit me even better. But the reverse clicky is far better than a side switch for my usage.

I recently ordered a Zebralight SC600w MkIV HI for my side-switch “all purpose” light. It won’t be suitable as a “thrower”, but should throw far enough for most purposes. Since I’ll be using it as a hand-held light, the side switch makes a lot more sense. I’ll still couple it with the Astrolux C8, for when I need to see farther.

There probably is a voltage range where the FET is more efficient, but I’m not sure what that range is. It would depend on the LED’s performance characteristics.

In the end it’s always personal preference. I don’t mind tail switch but the older folks in my home can never find the tail switch no matter how hard they try to find it, they’re used to old classical style side slider switches so the only thing that comes close is a side clicky. So I guess a side switch is something evryone in my home can use.

As for the efficiency the FET just acts like a gate so the efficiency is decided by the battery and the LED. A linear regulator maintains the output and as a result wastes some power if the battery voltage is higher than LED forward voltage.

Great review. I got one yesterday.

I finally got mine today, cant wait for it to get dark.

Its smaller than i thought.

I forgot to ask, does Astrolux C8 use integrated head heatsink like the upgraded convoy C8 or does it still use the pill design?

I’m not quite sure what you mean, but it looks very similar to the “silver” Convoy C8 design, except the retaining ring is a much thicker piece of brass.

If it helps, I think it’s the same kind of design as the BLF A6 uses.

We’re still talking about a flashlight, right? :wink:

thanks for the review.

  1. will the stainless convoy bezel ring fit properly?
  2. does the LED sit on a threaded brass pill or an integrated aluminum shelf inside the head?

Well, yeah, it came from china, how big did you possibly expect it to be?? :disappointed:

That’s exactly what I meant.

Does the head look like this?

They look very similar to me. Here’s a image I took of both the Astrolux C8 LED board and the Convoy C8 (silver) LED board.

First the Astrolux C8:

Next, the Convoy C8:

Is it the same? Both are stuck onto a chunk of metal underneath.

Yepp, as long as that chunk of metal is not removable they are stuck on to the head itself. +1 for heat dissipation.

Mine also steps down from high to medium after 45 seconds, while the head is nowhere close to warm. If it had a 3 min timer it STILL wouldnt feel “hot” (as it too hot to touch).
Im guessing that heat sinking has something (or a lot) to do with it.
Its an amazing thrower for the size.

It’s the same generic host obviously.
Sofirn has an unbranded one, Convoy has “Convoy” on it, ThorFire has “ThorFire” on it and they use a different tail cap, and now Astrolux has one with “Astrolux” on it, and they put their cheap FET+1 DD ‘driver’ in it and an AR coated lens which might or might not help up to 1%, making it a couple of bucks more expensive.
It’ll obviously out perform other C8’s as long as you have a full battery…

OP has a point about 7135 drivers also dropping in output half way, but that’s because the XP-L HI has a high Vf and the 7135s eat away 0.2 Volts iirc.
An XM-L2 will do better in that regard.
A CC FET driver will do better still.

for DD drivers the XP-L (and lossy springs plus thin wires) is a good choice because of the high Vf.
Otherwise it would go up in smoke on a fresh battery.
But in all, from what i have read here and there, XP-L (HI) DD lights usually don’t push out more than some 1400 lumen on a fresh cell.

(You can probably tell i don’t like DD drivers…)

Good explanation, especially about the poor performance of multiple 7135 drivers in an XPL-HI, which I wondered about. It sounds like a FET (DD) driver, such as the one used in this light, is pretty optimal for the XPL-HI LED, driven from a single 18650 cell.

In a perfect world, I’d rather not overdrive the LED either. But, it does let us get quite a bit more output, so I’m okay with the compromise.

You can do the same output without overdriving, if you use an XHP35 LED. But, you need a much more complicated (and expensive) boost driver to get up to the 12v needed. Zebralight is doing this with their latest lights (I get mine delivered next week!), but they’re a lot more expensive than the Astrolux (or Convoy) lights that use an XPL.

For a bright budget light, I don’t think you can beat an XPL and a FET driver. Works great in the BLF A6 too.

Can’t decide should i buy this Astrolux c8 or Zanflare F1 or something else, most important is a throw, so is this astrolux c8 the best thrower on a market for 20 usd or is it maybe better to add about 10 usd more for some other model.

And about light tint, which one is best 3B (5000-5500K), 1A (6500K-7000K),3A(5500K) at the momment only 1A is on a stock, but i’m affraid that the colour is too much blue or not?

Thank you.