Fireflies E07 CU Titanium Limited version Preorder interest?

Knowing the shipping from China would be extended with the coronavirus issues over there; I bought a copper E07 with KPL 5k ’s and red LEDs and an E01 with an Osram from the USA store. (Bought a pair of Samsung 50e to run the E01).

That copper is gorgeous! 9/10 machining. It’s not perfect, but as someone with a lot of welding and some machinest work behind him it’s what I would expect and accept for the price. It’s too heavy for most pocket use, but what a show off! The light output for the size, wow. It does have a copper bezel.

Can’t decide on if I should accelerate the tarnishing of the copper or not.

The single Osram in the E01 is just fantastic. It’s my new pocket light. Looking forward to getting the Ti/Cu when it comes.

Jacky emailed me and let me know the Ti/Cu version just shipped; I didn’t ask foot an update & didn’t expect anything with the troubles China is having at the moment. It was a welcomed update.
In the mean time, I bought 4 aluminum sst-20 versions from the USA store to give to friends and family as gifts. The difference in the all copper abilities to heat soak & the lightness of the aluminum models is large!

Hello.

I have not ever used my Ti/Cu E07. I only played with it a couple of times, in the house. Tonight I thought I would take it out for a walk. I took it out of the box and noticed one of the switch LEDs is dead.

What happens now?

I contacted Jacky from Fireflies by email. Communication is a bit slow but he has offered to cover shipping cost both ways and repair the switch LED!
If that actually happens, this is first class after sales service!

Will keep you posted.

goodluck, now with corona it will probably take a while as mail is very slow worldwide… but good they help u atleast.

That cannot be helped. As long as it gets fixed in the end, I will be happy.

E21a emitters now listed on the website for this model.
4500k versions.
I ordered one yesterday. Fingers crossed it’s done right and looks good!

Wow! Looks like Jacky is coming back.

Let’s wait for some other updates like CC driver or buck-boost.

My concern is the FET frying those emitters. I’d be all in, otherwise. Please share a review or update when you get yours.

Me too. I don’t quite understand the Vf requirements and effects, but 7x e21a emitters in parallel should be ok with a 10a battery like a Samsung 50e right? It’s obviously well below the recommend max current of 2a each.

E21 can be run safely up to 2.3A with good HS.

And they will produce more lumens than 219B...

I have asked around with that same questions, and I’ve gotten different answers. If you divide the 50E MCD of 9.8 by 7 emitters you get 1.4 amps per emitter which is perfectly safe for the E21A. However, I don’t think direct drive (FET) works exactly like that.

Worst case scenario is that you’ll need to avoid FET if upon testing turbo the emitters go blue and appear to be overdriven. Please share your findings with the 50E. I’m in for one if everything checks out!

10A isn’t the max current the 50E is capable of but what the manufacturer is saying to stay at or under for continuous discharge, it can be more than that, case in point if you short circuit it it will likely put out a lot more than 10A, DC internal resistance (DCIR) of the 50E is ~30mΩ, with a perfect short that’s 4.2/0.03 = 140A, likely less though, as DCIR can get higher at very high current, and you can’t do a 0Ω short.

In a direct drive led circuit the current is going to be dependent of voltage between the led Vf and cell, and the resistance of the circuit, : the cell DCIR, contacts resistance, springs, wire, traces, mosfet resistance, and the led current/voltage curve, which doesn’t really behave like a resistor, it would be higher at low current, and lower at higher current, between 2 and 2.5A it sorts of looks like a 40mΩ resistance

so :
50E : 30mΩ
spring : ~8mΩ (I measured the PL42G2 spring at 4mΩ each, likely less when compressed, I assume the E07 uses the same springs)
mosfet : I don’t really know, they can be pretty low, like 2~5mΩ ?
7 E21A at more than 2A : 40/7=6mΩ
others stuff : maybe less than 10mΩ ??

total : 59mΩ
E21A Vf at 2A = 3.09V
full cell at 4.18V
(4.18-3.09)/0.059= 18.5A = 2.64A per led (some more, some less due to Vf differences), and the 50E is overdriven

But that’s napkin maths and some resistances are wild guesses (and please correct if I’m wrong somewhere)

Another way to look at it is that in order to no exceed 10A with a full cell, the circuit resistance would need to be arround 110mΩ.

Wow, that’s super helpful. One of the reasons I love this place. So maybe overdriven on FET but not crazily so.

I measured the resistance on my PL42G2 (don’t have a E07) and there is ~18mΩ between the solder joints on the MCPCB, and the body/positive spring, adding the tailcap that I measured separately that’s ~22mΩ, unaccounted for is the mcpcb traces resistance, not sure how much that is, but I assume not a lot, so my previous estimations were pretty close.

Yeah but the 50E isn’t going to like it.

Guys, i don’t think Jacky left FET at full power for E21 setup...justa thought

Ah yes probably.

PL47G2 firmware for the 219B was FET limited to 67%. I assume the E21A firmwares will be likewise.

Still I like thefreeman’s calculation :+1: , and it shows that 67% FET will be a nice sweetspot power for this setup, also for a more high-current battery than the 50E.

How would a reduction like this be done? Out of interest…
Does it reduce the voltage? That would solve everything. Let you stay in spec on a 10a cell and even play with pushing the current with a better cell (cause you know we will do it for fun).

No idea when it will arrive or be shipped for they matter. I’ve paid for DHL but it’s got to get to Australia and global logistics is horrible at the moment, as everyone has likely seen.