Sofirn C8F host. 21700 C8F Available

Yeah mine too, specially when you can visually see it. Does it still do the gradual climb in output now after you swapped the FET??

Sofirn battery is a very decent cell, prolly a IJOY? Well they match my abused IJOY’s anyways…

It climbs a little, but not the minutes it did before. Gets warm now too.

Double click it’s very apparent. Exactly like hid car headlights. Ramped to the top it wasn’t really noticeable before, but the meter just kept increasing. Like the was reading temp or something.

Battery is back on the charger. I’ll check it over time in the current configuration to see if it’s still climbing.

Got another of the same light inbound on the slow boat. It’ll be nice to compare the two. I grabbed this current light from Amazon. Way to go if you’re in the US. Three days.

Wow, your low output and slow climb is really strange.

Mine climbs up over maybe 2 or 3 seconds and hits 2600 lumen.

Did you measure the tail cap amp draw after the upgrades?

The last time I talked to Sofirn they said their tests showed about 3500 lumen.

I wonder if they are testing production lights or prototypes? Maybe they got some low quality FETs that’s really reducing output. It doesn’t seem likely the led wires are causing such a huge difference in output.

Anyway, it’s nice to see the stock driver (modded) can put out big numbers. You retain the battery indicator function.

Tested it after the fet and wire upgrade. Battery fresh of the charger.

|0 seconds|3920|

|15 seconds|3740|

|30 seconds|3600|

|45 seconds|3520|

|60 seconds|3480|

12.4a at start on turbo.

Climb seems to be completely resolved.

Ill check the next one too.

Regarding the climb, I wonder if the stock FET has a high turn on voltage. This would explain the low output. Then the high channel resistance would cause the FET to get hot, and I believe this causes the channel resistance to go down which would increase the output.

Hey guys, sorry that C8F 21700 version has this issue. I was told it’s caused by MOS component. I don’t know what MOS is but I would love to send new driver to whose C8F max output lower than 3000 Lumens via 21700 battery.
Please PM me.

This is what we were suspecting. The MOSFET or FET for short.

The big black component labeled 2D030L. I’m going to try out my hot air station and see if I can swap it out for a better one.

Sofirn, thanks for your excellent customer support as always! PM sent!

I just contact Cissy of Sofirn and she told me to send a new driver :+1: Never disappoint with Sofirn service and fast respond ,looking forward for new Sofirn light :blush:

same here thank you sofirn!

Hi Sofirn

I want to purchase a C8F 21700 from Aliexpress but am now concerned about this defective driver issue.
Can you advise if their stock is being checked/replaced/fixed ?

Thanks

Wow! What great customer service.

I’m happy with swapping the fet myself, but I appreciate sofrin looking to address the issue nonetheless. That’s awesome, as usual from them.

Another point worth noting is that I’m really happy with the ramping on this light. It’s much smoother and a good speed. Compared to the sp32a v1, I feel this light has much improved ramping.

It’s pretty close to the d4. Not quite narsil, but very close imho.

It’s getting more and more rare for companies to listen to customer feedback. Sofirn seems to be doing it right.

So what can we do about this giant retaining ring? Think i can grind it down at an angle on the inside edge to fit a driver with 7135 on the bottom?

Also mind the other side of the driver: the edge on which the driver rests is wide too and may touch driver traces and components.

I have a 20mm lexel driver so it might be ok on that side but this is a good point. Overly complicated driver shelf and Alu ring. Almost better to use 17mm and spacer

Sure.

Any suggestions for a 17mm constant current driver that works with an E-switch? I’m really interested in this host…

Use fet+1x7135 driver with no parts on spring side.