When’s the group buy gonna start?

In my experience, (making note that I know not what I say) when the meter shows that “-” in front of the amperage number the current is being read in the wrong direction. Changing the position of the wires fixes that and almost always shows a different number, usually lower.

Hhmm, I always set up to read positive amps - thought negative readings were worse. Ohhh!! Also forgot () -- got my UNI-T clamp meter coming in today - in the local Post Office this morn - ordered out of US warehouse from TomTop.com, pretty good price - $33.85 shipped w/tracking, ordered Jan 6th.

TomTop is one of those familiar look'n sites - seems to have a lot in common with BangGood, both started biz in 2004, but seem quite different in policies. Could just be sharing the same storefront web tools or web services.

Also, lumens/throw measurements seem to track well with my tail amp readings, so I think I'm in the ballpark - for high amps, I've seen gains of 0.1A - 0.2A by cleaning up contacts with the DMM leads and cells (using a little bit of NO-OX-ID helps at times).

I read from the negative when testing at the emitter to prevent a short if something slips or otherwise accidentally makes contact, but that’s not what I was referring to.

Reading the current backwards shows a negative reading on the meter, reversing the position of the probes removes that minus sign and gives a different reading. I don’t know electronics, so I don’t know what it means EXACTLY, but it’s about direction of flow I think. The clamp meter reads from positive on the face of the meter to negative away from the meter or the back side. Since it’s designated on the meter, I assume it matters.

Edit: That’s why I said anything, hoping someone could explain it. When I see a reading like that –5.41A above, in my own experience if I switch positions of the leads to get rid of the negative symbol the amperage will be lower. I don’t wish to report a higher reading in error, I fall under enough scrutiny as it is.

EditII: Testing a Courui L2 with XM-L2 emitter and Efest 3500mAh 26650 I get 4.84A if the facing wire is on the rim of the light and the backside wire is on the neg end of the cell. Reversing positions and getting the negative symbol, I only get 3.95A. So, it matters. Why, I do not know.

Hhmm, assume you mean Convoy L2, not COURUI L2 - I don't think I ever saw a difference that large, but not sure - I never look for it because as soon as I see the negative sign, I reverse the leads, so I only read and record positive amp #'s. I'm talking about using a regular UNI-T DMM, not a clamp meter.

Also wait'n on freeme for the group buy - see here: https://budgetlightforum.com/t/-/35973. Nothing new posted, but freeme posted he's getting a bit burnt out on these, I'm sure some frustrations...

Herewith 2 recent builds I did with dedomed XP-G2 S4 2Bs from IOS…

4.7 Amps - Jacob A60 Build
5.1 Amps - Convoy S2 Build

Both measured with my Fluke 376 True RMS AC/DC Clamp Meter

is there a group buy on a new brain? Yes, I meant the Convoy L2. Geesh.

Nice Shrick! Right up there where that little bad boy is screamin! :slight_smile: Bet it’s a pencil beam in the Jacob huh? (Love my Solarforce M8, always found the Jacob A60 to be a cheaper copy of the M8, awesome though in the tight pencil beam department)

Thanks Dale! Its a pity I can’t take beamshots yet, need to sort out a camera for that. What’s the best budget camera you’d recommend to get going with above standard (acceptable) beamshots?

Regarding the A60, the beam is actually not that bad. It has a flawless hotspot (pencil-ish) with good usable corona which makes it quite practical. Probably took me 2-3 hours to get that A60 focussed properly. Its just those damn rings - really not a fan of them rings! I still can’t believe what that little A60 is doing, 242k lux! Crazy…

I'll re-measure when I get home from work tonight, with leads reversed to see if the DMM gives a different reading. I don't think it does, at least on this meter, so I don't worry about the lead orientation.

On that note, when testing amps at the emitter, has anyone noted different readings taken from each side? Is there a preferred side to take the reading from?

I'd assume not, being the one circuit, but someone might know otherwise.

Dang schrick, 4.7A and 5.1A are great #'s for the S4 2B. Unfortunately I don't have any right now - should order 5 from Hank... Were these cherry picked or did you get these amps from other XP-G2's? We are just trying to figure out what's goin on. If you get high amps or low amps, there still seems to be a significant range of measured amps each guy is getting on these.

I totally missed those 2 threads btw, really nice results though!

Yes, that's the one. It has been sold in a few different flavors; Large coil, small coil, with/without contact plate, 3/5 Amp. They all appear to have the same components.

If anyone is interested, Richard lists them as well.

FMC, there may be a difference as one side is supply and the other side is after the diode is using it, perhaps some inefficiency in the diode could cause the negative side to be lower than the positive side? Since current flows positive to negative, reading the negative side is actually what the emitter is using.
Reading the positive side is a good way to fry your light, slightest mishap and there’s smoke and melted things. Touch something on the negative side and you just go direct drive, no biggie. (unless you’re in a smaller light that can’t handle direct drive, then, biggie)

Hi Tom. No, not cherry picked. I think I have around 5-8 of them left. I bought them reflowed on 16mm noctigons - did not reflow myself. Will it help if I run the remaining XP-G2 S4s through my bench power supply and take amp readings? I’ve recently built myself a small amp reading setup - would be nice to use that now. I’ll take photos of each LEDs readings. Would be interesting to see how all of them compare…

I really wish I had not read this thread. I really never intended to mod anything again.

Ordered one of these from GB tonight

  • Have to make a new Copper shelf for the led.
  • Modify the Reflector - take out the center flat area in the bottom and make a custom thin centering ring. Stipple the reflector. Not going for max throw obviously.
  • XHP70 led and custom mcpcb.
  • Time to go look at what I got for drivers for the XHP70, or email RMM.
  • Rework the spring plate 2S/2P. Actually, the batts will probably load from the tail end now, like the modified SRKs I've done.
  • Make a different handle maybe.

I hate you guys. (Not really, but the wife will hate me ).

EDIT: NO STOCK AT GEARBEST. As usual, they are selling stuff that there is no stock on and as usual, I canceled the order. Thank's Gearbest, you are my best line of defense when ordering, because you never have anything in stock.

Ok - Just took measurements of the same setup back to back to back, & using my meter, there is no appreciable difference with the leads reversed.

Well, I can’t speak for anyone else. But for me, it’s good to see you back in the game. I’ve missed reading your awesome build threads! :bigsmile:

+1 - it really is an inexpensive platform for something of this size. Looking forward to O-L's results - sounds like a plan .

NO STOCK AT GEARBEST. As usual, they are selling stuff that there is no stock on and as usual, I canceled the order. Thank's Gearbest, you are my best line of defense when impulse buying, because you never have anything in stock.