Help w 8x 7135 board

[Anto]

Followed the wiring diagram here:

I removed the diodes per the picture and bridged q1 & q3. Emitter does not light up. Was I not supposed to remove the diode for just 2x 7135 boards (no multimode board)?

 

[Drewfus2101]

You can remove them on both boards. Something else must be the problem.

 

[tx101]

A photo of your boards might help us determine what the problem is :)

 

[Anto]

pardon the messy soldering

I had to solder the + and - leads to another board. I checked continuity and it's good.

 

[tx101]

Looking at your photos, I think you really need to check
all the solder joints.
I dont like the looks of all that exposed wire, it is asking for
a short circuit

 

[Hallmcc]

Delete post. after zooming my tired eyes stand corrected.

 

[Justin Case]

Get a meter and test for continuity:

- Ground between the two AMC7135 boards (which should imply a common ground for all of the AMC chips)
- Ground from the bottom AMC board to your contact board
- Batt+ between the two boards
- Batt+ from the bottom AMC board to your contact board
- Vdd pin continuity for all of the AMC chips
- OUT pin continuity for all of the AMC chips

The first photo, showing the wire connections to your contact board, doesn't seem to show any solder joints for those connections. Did you solder the wires on the other side of the board (the spring side), which is not seen in the photo? Otherwise, I would suspect those connections as being the open ones.

Why do you need the third (contact) board? Why can't you use the bottom AMC board, which has perfectly good anode pad to solder a center spring? Also, why are the two AMC boards so loose? Why not put them together tightly, like this:

If you look closely in-between the two boards, you'll see parallel connections for Batt+ to Batt+, OUT to OUT, and GND to GND. The OUT to OUT connection requires drilling a small hole to run the connection to the top board. If you don't have a small drill bit, you can run this connection around the outer edge of the top board. If driver clearance in your host device is an issue, you can file a small notch in the top board to fit your wire.

All of those connections are made using short pieces of tinned, 24 ga stranded wire. I soldered each piece to the bottom board first. Then I slid the top board onto the pieces of wire through the matching holes for the top board. Held the two boards tightly together and soldered the top connections. Then trimmed the excess wire with diagonal cutters.

 

[ti-force]

I know this thread is about 3 months old, but I figured this would be the best place to ask my question. I have an ssc p7 mag that I built a few months ago. I'm using 3 boards (1.4A AMC7135's from DX) with a total of 9x7135's (I've removed 1x7135 chip from each board) which should be close to 3A all total. I'm using 1xD size li-ion to power the light. Current readings on my meter, between the third board and the emitter was 2.7A, so I soldered a 7135 chip back into the Q2 spot on the second board. The current stayed about the same.

I figured I got the chip too hot or something and it wasn't any good so I soldered another 7135 chip on the third board, again in the Q2 slot, whereI removed it from while building the driver. This time the current actually went down to around 2.53A. I checked all my contacts with my DMM before I ever connected power, and everything was making good contact, all the chips, everything.

So is their a procedure to check and see which 7135 chips are bad or should I just start over?

Thanks for the help guys.

Casey

 

[Linger]

If you're using a single cell to drive it the 7135's shouldn't get too hot (not much voltage for them to burn)
could be resistance in the build?
You'd know better that I if your cell will sustain 3A output, some KD / DX won't pass 2.5A when installed.
AFAIK to check each chip you'd have to isolate it which obviously isn't practical. So do you have other options to confirm power supply and emitter aren't the bottle necks?
Can you parrallel to batts, possibly parrallel two emitters too. Possible this will open up your build enough that you'd get a read if it was the driver sandwich that was the blockage.

 

[ti-force]

If you're using a single cell to drive it the 7135's shouldn't get too hot (not much voltage for them to burn)
could be resistance in the build?
You'd know better that I if your cell will sustain 3A output, some KD / DX won't pass 2.5A when installed.
AFAIK to check each chip you'd have to isolate it which obviously isn't practical. So do you have other options to confirm power supply and emitter aren't the bottle necks?
Can you parrallel to batts, possibly parrallel two emitters too. Possible this will open up your build enough that you'd get a read if it was the driver sandwich that was the blockage.

Sorry, I meant too hot from soldering, maybe staying on the board too long with the iron. I should've been more specific.

Last night I remembered you telling me that some cells can't sustain that high of an output, I guess I just assumed a cell that big would, but boy was I wrong:thumbsdow.

I built a new sandwich using 2xAMC7135 boards with a total of 8x7135 chips. The current is still 2.6A :thumbsdow, so it must be the batteries. I wish I would've known that before I ordered them, but oh well. I'll include some pics of my sandwich and the current readings of the pathetic, big fat D sized cell. What I really don't understand, is how a little 14500 cell can supply more amps than a 32650 cell, well, not more amps, but for it's size it's pretty amazing. I would have thought that 32650 cell would support at least 3A. See below:


NOTE: I only run the 14500 at that current for 15 to 20 seconds MAX! Playing it safe.





Sandwich:

Current reading with 32650 cell:

Current reading with 14500 cell (in the modded k-106/MC-E in my other thread):

 

[Justin Case]

You have a lot of potential sources for voltage drop in your circuit, with the alligator clips, DMM probe wires, and DMM itself. And that's on top of any additional voltage drop sources in your Mag mod (e.g., tail spring contact to the bottom battery, Mag switch spring contact to the top battery). If you are measuring 2.65A for an 8x7135 driver, I'd say you are well within spec. The 7135 chips are nominally 350mA per chip, but can be lower than that and still be in spec.

 

[spencer]

I think you gotta take everything out of your light and put everything together with heavy gauge wire (low resistance) and try it again. That big cell should be able to handle the current. The protection circuit hasn't kicked in yet.

 

[ti-force]

You have a lot of potential sources for voltage drop in your circuit, with the alligator clips, DMM probe wires, and DMM itself. And that's on top of any additional voltage drop sources in your Mag mod (e.g., tail spring contact to the bottom battery, Mag switch spring contact to the top battery). If you are measuring 2.65A for an 8x7135 driver, I'd say you are well within spec. The 7135 chips are nominally 350mA per chip, but can be lower than that and still be in spec.

I guess I forgot to mention that I built this new sandwich and tested it. The results are seen in the picture, but then I took one of the 4x7135 boards off of the old sandwich (the one I thought was faulty) and soldered it in and tested that single board. I got around 1.45A with it, so I soldered it onto the 8x7135 sandwich, to see if the current would go up. It did not and the current read 2.65A for 12x7135's. So again, I appologize that I left that part out. Shouldn't the current have gone up from 8x7135's to 12x7135's?

Edit** Do you think the protection circuit on the 32650's is limiting me here? Edit** this was already answered, sorry guys.

Casey

 

[ti-force]

I think you gotta take everything out of your light and put everything together with heavy gauge wire (low resistance) and try it again. That big cell should be able to handle the current. The protection circuit hasn't kicked in yet.

I have a question about this. I tried to check resitance in the spring the other day. I turned my DMM to 2k, touched one lead to the bare aluminum on the tailcap (where it makes contact with the battery) and the other lead to the top of the spring (where it makes contact with the battery) and it showed 0 resistance. I then turned my DMM to 20k and again the same thing. 200k also gave the same reading, so either I'm not doing something correctly or my DMM isn't very accurate. What do you think?

 

[Packhorse]

Resistance will increase with current flowing through it,

And a small level of resistance is hard to measure.
One way of measuring it accurately would be to put a know amount of current through it and measure the voltage drop.

 

[ti-force]

Resistance will increase with current flowing through it,

And a small level of resistance is hard to measure.
One way of measuring it accurately would be to put a know amount of current through it and measure the voltage drop.

:ohgeez:

Silly me haha... I was trying to check without any current at all. Oh well, I guess my newbeness is showing haha..


Thanks for the help.

 

[spencer]

That and you gotta use the 200 Ohm range. Lower is better in this case but it looks like thats as low as yours goes.

 

[Justin Case]

I guess I forgot to mention that I built this new sandwich and tested it. The results are seen in the picture, but then I took one of the 4x7135 boards off of the old sandwich (the one I thought was faulty) and soldered it in and tested that single board. I got around 1.45A with it, so I soldered it onto the 8x7135 sandwich, to see if the current would go up. It did not and the current read 2.65A for 12x7135's. So again, I appologize that I left that part out. Shouldn't the current have gone up from 8x7135's to 12x7135's?

Edit** Do you think the protection circuit on the 32650's is limiting me here? Edit** this was already answered, sorry guys.

Casey

That Mag tube looks like a 3D or longer body. You have it loaded with just one 32650? What is taking up the rest of the space? That could be a source for lots of voltage drop.

What brand of 32650 cell are you using? The fact that it couldn't deliver the goods with 12x7135 suggests it just can't hold enough voltage under the current demand. It can do it for 4x7135 (1.4A). It can barely hold it for 8x7135. But that's apparently the max. Who knows if it is the cell, parasitic losses in your system, or a combination.

You need to remove some confounding variables to narrow the possibilities. Do you have access to a bench power supply?

 

[ti-force]

That Mag tube looks like a 3D or longer body. You have it loaded with just one 32650? What is taking up the rest of the space? That could be a source for lots of voltage drop.

What brand of 32650 cell are you using? The fact that it couldn't deliver the goods with 12x7135 suggests it just can't hold enough voltage under the current demand. It can do it for 4x7135 (1.4A). It can barely hold it for 8x7135. But that's apparently the max. Who knows if it is the cell, parasitic losses in your system, or a combination.

You need to remove some confounding variables to narrow the possibilities. Do you have access to a bench power supply?

It's actually a 2d mag, but for some reason it does look longer in the picture. The battery is this one: Kaidomain. I use one 32650 and to take up the space I use this spacer (scroll to the bottom): Flashlightking. I also had to use this spring because the stock spring is too long: Kaidomain. This spring is really stiff and it takes some pressure to get the tailcap screwed on, so nothing is loose in there. The fact that this cell can't keep up really sucks haha.. Could you recommend a cell that might deliver the current I'm after? AW IMR's? I wish someone made a small li-po, like a 1s2p or something that would fit into the body of a d sized mag. They make tons of different lipo batteries for r/c stuff, but most of it is 2s and up, so the voltage is too high for the 7135's.

I hate to show my ignorance here, but I'm not sure what you mean by bench power supply. I guess that means I don't have access to one:o.

Casey

 

[ti-force]

Is a bench power supply the machine that allows one to put a battery under a set load and test the battery?