C8, 2x18650 build question

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Senna Fan
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C8, 2x18650 build question

I want to build a 2×18650, xhp70.2, Convoy c8. I have all of the body parts including a choice between an o.p. and smooth reflector.

Finding a 17mm driver for this build has proved to be an exercise in futility. I wound up finding some 17 to 20mm brass ring adapters on eBay and bought them – I hope the threads match!

Well, I think I may still have the same problem. Am I able to use a 6v emitter with a 3v rated, 2 cell driver? In other words, why would an 8.4v – or more rated driver power a 3v emitter but not a 6v one?

Sorry in advance if this is a challenge to my own common sense, but I’m really trying to grasp the electronics end of building these lights while trying to be safe at the same time.

Thanks!

Engine Guy
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If you’ve never built a xhp70 light, you will be impressed with a C8.
The reflector is big enough to give you a good hotspot and plenty of spill. With around 5000 lumens it will be fun.
Try the smoke reflector!
You can also do 2 18350s without the extension tube. It’s a great build with a DD driver, which I assume you can get right now? Hence your driver question…. which I can’t answer.
Or you can skip the driver, and run straight power to the led from 2 cells for now and stick a driver in it once you get one.

MOD noob

nmbusa
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look up zener modded fet+1 drivers many 17mm options
https://budgetlightforum.com/node/57324

Senna Fan
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Thanks for both of your responses.

I was looking at this driver for my c8 2 cell build. It doesn’t mention anywhere that it can or can’t be used with a 6v emitter.

https://m.aliexpress.com/item/4000060669238.html?spm=a2g0n.shopcart-amp....

- I have a high power, multi emitter drop-in that I believe is direct drive. It’s power is awesome, but drops way too quickly and steadily – something I want to avoid.

- As far as running 2 18350’s, I actually want the the longer body and longer runtime.

- I never heard of a “smoke” reflector. What’s its effect and where can you buy them?

- I considered FET drivers but I felt the driver I listed here would yield better
performance.(??)

nmbusa
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many drivers are available all depends on what you can fit in a c8 i’ve used a similar driver 22mm in a blue laser c8 build works great.
thought you were looking speifiall for a 17mm
cheers

Rayoui
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I built a 2 cell C8 with an extension tube for 2×18650 and a sliced LH351D. I used Mtn’s 17mm MTN-MAXlp 2s buck driver which worked great. Excellent driver with great firmware.

Senna Fan
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That’s the driver I wanted to use with their 4.5 amp build – their highest recommended for a 6v emitter, but it’s not available right now. It is available in 3.5 amp, though. The driver from AliExpress is rated at 5 amp. How much difference in performance will I see between 3.5 and 5 amps?

MascaratumB
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Have you seen the C8.2 versions, instead?
https://www.aliexpress.com/item/33003864234.html

Suited for 1, 2 or 3 batteries

Senna Fan
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MascaratumB wrote:
Have you seen the C8.2 versions, instead?
https://www.aliexpress.com/item/33003864234.html

Suited for 1, 2 or 3 batteries

Ok, now I’m thoroughly depressed!

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I think is what you are looking for. https://www.mtnelectronics.com/index.php?route=product/product&path=67_1...

You can order it with the Zener mod for 2s input. So if you select “yes” to the Zener mod and 6v lvp. Then you can do two 18650’s in series to power a 6v XHP70.

Senna Fan
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Superstocker wrote:
I think is what you are looking for. https://www.mtnelectronics.com/index.php?route=product/product&path=67_1...

You can order it with the Zener mod for 2s input. So if you select “yes” to the Zener mod and 6v lvp. Then you can do two 18650’s in series to power a 6v XHP70.

Thanks, but for this build I’m gonna stick with my original choice provided it works with a 6v emitter. Does anyone know the answer to this $64,000 question?

https://m.aliexpress.com/item/4000060669238.html?spm=a2g0n.shopcart-amp....

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Senna Fan wrote:
Superstocker wrote:
I think is what you are looking for. https://www.mtnelectronics.com/index.php?route=product/product&path=67_1...

You can order it with the Zener mod for 2s input. So if you select “yes” to the Zener mod and 6v lvp. Then you can do two 18650’s in series to power a 6v XHP70.

Thanks, but for this build I’m gonna stick with my original choice provided it works with a 6v emitter. Does anyone know the answer to this $64,000 question?

https://m.aliexpress.com/item/4000060669238.html?spm=a2g0n.shopcart-amp....

That’s a buck driver for running a 3v emitter. So it is meant to run off either one 18650 or two and step the voltage down.

Senna Fan
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I’m using this driver in another build

https://m.aliexpress.com/item/32848673663.html?trace=wwwdetail2mobilesit...

Other than the size difference of the 2 drivers, one description mentions “6v/xhp70.2” and the other doesn’t. I’m using the same 8.4v battery/6v emitter combo in both lights. How do I find out for certain if the driver I want to use will or won’t work with a 6v emitter?

beam0
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Same question here, hoping to get some ideas too.

My 2S C8 build is with an SST70 so I’ve also been looking for a suitable driver.

Mine is the older style Convoy C8 (not C8+, not sure there is an ext. tube for C8+?) Does your C8 have a 17mm or 20mm driver space?

At one point the older Convoy C8’s only had a 17mm driver space, I guess that was upgraded to 20mm at some point? I got mine shortly before the C8+ came out so it’s a later model of the older style. The best I can tell the stock driver space in my C8 measures 20mm but I haven’t been able to get the driver out, the retaining ring is very tight so I need to make a pliers/tool to fit the small holes better.

I looked at the 20mm MTN-MAXlp Driver in 6V output the maximum drive current is 5A, but I’m thinking I’ll want more than that to drive the SST70, so I’m also looking at the MTN 20mm FET/Zener If I go that route I may need to limit current so the led doesn’t fry.

I also was looking at the 20MM Lexel Buck driver 2S into 6v XHP50/70, Adjustable input and output voltages and current up to 8A, looks like $21 (euros) shipped, sounds perfect! however Lexel hasn’t been around for months (it was mentioned he may have been ill)

Senna Fan wrote:
I’m using this driver in another build

https://m.aliexpress.com/item/32848673663.html?trace=wwwdetail2mobilesit...

Other than the size difference of the 2 drivers, one description mentions “6v/xhp70.2” and the other doesn’t. I’m using the same 8.4v battery/6v emitter combo in both lights. How do I find out for certain if the driver I want to use will or won’t work with a 6v emitter?

I would just message them and ask to be sure, but the question was answered in the Q/A: “3v” (Scroll all the way down below the reviews)
By the way “LHT Flashlight store” on aliexpress is actually Kaidomain or “KD”, they always reply to my questions via the aliexpress message center,

Here’s a link to that driver on the KD website: KD 20mm P4000 Driver, you can check out all their drivers here

 

Engine Guy
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Auto correct…. SMO reflector.

MOD noob

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Senna Fan wrote:
I’m using this driver in another build

https://m.aliexpress.com/item/32848673663.html?trace=wwwdetail2mobilesit...

Other than the size difference of the 2 drivers, one description mentions “6v/xhp70.2” and the other doesn’t. I’m using the same 8.4v battery/6v emitter combo in both lights. How do I find out for certain if the driver I want to use will or won’t work with a 6v emitter?

Unless it says for 6V emitter it is probably for a 3V emitter.

In principle a buck driver should work for both a 6V and 3V emitter, but there is some configuration in the driver which determines the max output voltage. That is pretty much all I know about it, but I wouldn’t count on it working for a 6V emitter unless it says it does.

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nmbusa wrote:
many drivers are available all depends on what you can fit in a c8 i’ve used a similar driver 22mm in a blue laser c8 build works great. thought you were looking speifiall for a 17mm cheers

My C8 has a 17mm driver pocket. How were you able to fit a 22mm driver in there? Did you bore the head and tap new threads? The adapter rings I just ordered are going to be useless. I thought they would adapt a 17mm opening to accept a larger board, but it’s actually the opposite.

Superstocker
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Senna Fan wrote:
I’m using this driver in another build

https://m.aliexpress.com/item/32848673663.html?trace=wwwdetail2mobilesit...

Other than the size difference of the 2 drivers, one description mentions “6v/xhp70.2” and the other doesn’t. I’m using the same 8.4v battery/6v emitter combo in both lights. How do I find out for certain if the driver I want to use will or won’t work with a 6v emitter?

As EasyB said the default is 3v but most drivers should list input and output voltage. If you look at the driver you listed it says “Output 6v” so that is what needs to match your LED. It also says “Input 6V-12.6V” that is what needs to match your battery voltage. That driver could run a 6V LED off of 2 or 3 li-ion cells in series. the other driver you linked to is not labeled as clearly. It gives us two important pieces of information (1) it is a buck driver, that means it is meant to step down the voltage and (2) it will take 1 or 2 cells and so it goes from 3V-9V input. So since it does not step up the voltage and it can run on one cell, it is not meant for 6V LEDs (The pictures also show output at roughly 4V). So again EasyB gave a good short answer, if it does not list output voltage you can probably assume 3V. Looking at specs., learning about different driver designs and making a few inferences can aid you too. Hope that helps.

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First, I want to thank everyone on this thread for sharing and helping. Nice people – Good help!

Ok, 6v driver it is – or is it? After reading everyone’s comments, I was thinking of just scraping the xhp70.2 all together.

Finding a 17mm, 6v, 2 cell, buck driver is impossible. Mt. Electronics is the only place that offers something that may or may not workout. This is their only 17mm buck driver that will support a 6v LED. The 4.5 amp build is sold out and Richard doesn’t know when he’ll have more. So I need to step down to 3.5 amps. As I posted earlier, I’m new at this so be patient. Ok, here it goes: I don’t know if 4.5 amps is too much current, enough or too little for an xhp70.2 with 2×18650/10 amp batteries. More importantly, what percentage of performance can I expect to lose going from 4.5 to 3.5 amps (best guess)? In lumens maybe?

Thanks again

https://www.mtnelectronics.com/index.php?route=product/product&path=67_1...

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Senna Fan wrote:



First, I want to thank everyone on this thread for sharing and helping. Nice people – Good help!

Ok, 6v driver it is – or is it? After reading everyone’s comments, I was thinking of just scraping the xhp70.2 all together.

Finding a 17mm, 6v, 2 cell, buck driver is impossible. Mt. Electronics is the only place that offers something that may or may not workout. This is their only 17mm buck driver that will support a 6v LED. The 4.5 amp build is sold out and Richard doesn’t know when he’ll have more. So I need to step down to 3.5 amps. As I posted earlier, I’m new at this so be patient. Ok, here it goes: I don’t know if 4.5 amps is too much current, enough or too little for an xhp70.2 with 2×18650/10 amp batteries. More importantly, what percentage of performance can I expect to lose going from 4.5 to 3.5 amps (best guess)? In lumens maybe?

Thanks again

https://www.mtnelectronics.com/index.php?route=product/product&path=67_1...

(1) If you want to simplify things, do FET driver, 3V XHP50, and use one battery. With a good high drain battery (Molicel P26, VTC5, etc.), that would probably make about as much light as as an XHP70 at 4.5A.
(2) It doesn’t have to be a buck driver, the FET driver I linked above from mountain will work too. It will almost certainly pull more than 4.5A though (Like closer to 10A with good high capacities 18650’s that will handle 10A. If you want max output, that’s the ticket. That’s a super hotrod though.
(3) If you can find a zener modified constant current driver that would work too. Those drivers are very common but if you don’t want to do the mod. then that might be a deal breaker. It would be hard to find a modified one ready to buy.
(4) XHP70 has been tested as making 4,110 lumens at 4.5A and 3,380 at 3.5A.

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I’m seriously bummed out!! When I said I had all of the C8’s body parts, I spoke too soon. I had Convoy’s UV C8 on order (to use as a donor/$30) from AliExpress and just found out they’re unable to ship it to me. Why can’t this light be shipped to the U.S.? It’s offered on just about every website that sells Convoy flashlights? I have a regular C8 but really wanted to build a 2 cell variant. The single cell version just feels too short in my hand. I also wanted to stay with an 18mm battery – so the convoy C8 was the obvious choice.

If anyone knows how and where I can locate a 2×18650 C8 style host, I’m all ears.

Thanks again.

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It can’t be shipped to the US because of a ridiculous patent that was issued to some chuckle head who uses it to hold his own personal monopoly on UV flashlights with ZWB2 filters.

I haven’t been able to locate any more extension tubes for the C8 for quite a while. There are some similar 2-cell hosts available, like this one.

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Rayoui wrote:
It can’t be shipped to the US because of a ridiculous patent that was issued to some chuckle head who uses it to hold his own personal monopoly on UV flashlights with ZWB2 filters.

I haven’t been able to locate any more extension tubes for the C8 for quite a while. There are some similar 2-cell hosts available, like this one.

Well that sucks. I really wish Convoy – or anybody, would at least offer a simple extension tube to fit the newer c8+ threads. The c8 has been a mad, popular platform for the longest time.

I saw the Manta Ray c8-2 and really like it. I already have a 2×26650, L2 host, that’s why I’m interested in a 2×18650 host with a 41mm head.

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Senna Fan wrote:
I’m seriously bummed out!! When I said I had all of the C8’s body parts, I spoke too soon. I had Convoy’s UV C8 on order (to use as a donor/$30) from AliExpress and just found out they’re unable to ship it to me. Why can’t this light be shipped to the U.S.? It’s offered on just about every website that sells Convoy flashlights? I have a regular C8 but really wanted to build a 2 cell variant. The single cell version just feels too short in my hand. I also wanted to stay with an 18mm battery – so the convoy C8 was the obvious choice.

If anyone knows how and where I can locate a 2×18650 C8 style host, I’m all ears.

Thanks again.

Banggood used to sell the C8 extension tube, but when I search for the C8 extension tube now, almost all sources indicate “discontinued”.

However, since Convoy still sells the Convoy C8 UV, which uses the regular tube + extension tube, you can probably directly contact Simon from Convoy/AliExpress and ask to sell you the Convoy C8 host + extension tube (you don’t need the UV, which as you mentioned is unable to be shipped to your country).

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Thanks d_t_a

How do I get in touch with Simon? When I go to his AliExpress store and click “ask seller”, I get a window that says “safari can’t open this page because the address is invalid “.

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I’m kind of bummed out. I just received 2 xhp70.2, c8 o.p. reflectors from AliExpress and they’re almost 2mm shorter than the stock reflector that came with the light. Even with the reflector pushed down directly against the head of the flashlight, it doesn’t reach the centering gasket. Has anyone here had this problem?

https://m.aliexpress.com/item/32839891222.html?trace=wwwdetail2mobilesit...