Quarantine Project UPDATE!

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Sirstinky
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Quarantine Project UPDATE!

So some of us are stuck at home due to the Coronavirus and what not and I get cabin fever really bad, so I figured it's a good excuse to start a project I've been pining on for a while. I love the BLF GT concept and wanted one, even more when the BLF GT70 came out. What a bonkers light with a single emitter! Then I saw the price...north of $350. Boo. My wife won't let me sell our son, and I need all my body parts, so I thought, hey why not build one (or one like it). It's a work in progress so check back for updates. Obviously it's based on a direct-driven xhp70.2. The emitter is a 6000k xhp70.2. I decided to do 12 volts for this one since it keeps the current pretty tame (easier on the batteries and wiring). The power source is a 4S2P lithium ion pack of eight VTC6's (can't think of a better way to spend my stimulus check). It will have a BMS and all that.

The driver was tricky since I wanted one that did 4S input and was guaranteed to give crazy output. So I went with Richard's FET+1 26mm driver from Mountain Electronics with Bistro.

Cooling the thing was tricky too since I'm dealing with close to 60 watts or more. My host will be plastic so I'm limited to a heatsink and fan arrangement. For the cooling, I went with an old Intel stock cooler for a high end Core2Duo. It's huge and can easily handle 120W or more. It weighs a ton. I removed the fan since I'll be using a slim one.

The host? Nothing less than the halogen (formerly) powered spotlights. I found this one in the thrift store for like $1. It's got a rotatable handle and a stand (I took it off temporarily) and it's huge with lots of room inside for a heatsink and big battery. It was powered by a 6V lead acid cell that someone took out. Not really waterproof, but that's okay.

3000000 CP? Woah.

First was figuring out the electrical connections. I used my experience with the last project and built a driver holder out of some copper sheets salvaged from laptop PC coolers. I cut them out and soldered them together. I drilled out 2 parts to make the top part and the "shelf" or ground ring that the driver sits on. The negative from the battery will solder to it somewhere.

The driver fits into the bottom part of the heatsink that's hollow. It's a pretty much perfect fit. It will be secured with screws and extra mounts later.

This is the first test of everything. Wires will be 18 gauge for the battery and LED. Yep. It's bright. I'm using an old battery from the 100W flashlight project made from a mix of really tired laptop pulls so I know it has more to give. It's so bright. I can't shield the light without it burning my hand. The alligator clip that connects the driver gets hot and the plastic cover on the clip gets soft and smelly after a couple minutes of turbo. It easily gets the heatsink up to 135 degrees after 3 minutes of turbo (before the stepdown). That's like 500 grams of aluminum and copper heating up. The driver doesn't hardly heat up at all though. I'm excited to see how bright it gets with proper batteries. I still haven't figured out the firmware though.

That's it for now! Still need to dig into the host and figure out mounting the cooler and fabricobble the reflector. Proper reflectors for this are stupid expensive, so I'll make one. 

Stay tuned for more.

Edited by: Sirstinky on 05/26/2020 - 00:07
Sirstinky
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Here's an update. I had a chance to do some tinkering today and after some deliberation, decided to use a different host, since I have plans for the yellow one later. I'm using this one instead. I found it in the thrift store. The reflector was broken where the bulb holder sat, which I later cut out carefully. It's huge inside, covered with a really tough rubber skin, and is waterproof. The reflector is big too, but I don't think I'll be using it. It has a lot of room for a 4S2P battery pack, wires, and a big heatsink and fan. There's one issue though...

 

The issue is the original heatsink won't fit now (too tall), so I had to dig into my stash for a shorter one. I found one made by Silverstone that's a direct replacement for the original, and is even better. It's solid copper in the middle and works better than the big one. It had a really low-profile fan on it, but I won't be using it since it's still too tall.

The bottom part is different from the original Intel so I had to make a new mounting ring out of a 2-3/4" bushing that I hogged the inside diameter out to 30mm to fit. It will help support the reflector. 

I will be using a reflector from a leftover project for this. I melted one side of the emitter hole during testing (got too close to the LED), so I had to repair it by reaming out the damaged area. I'll fix it later once my centering rings get here from China. 

I made some improvements to the driver holder as well by adding some mounting tabs. I also soldered the driver in. I had originally planned on mounting the driver holder directly to the heatsink through the hollow cavity on the base, but the new heatsink doesn't have one, so I had to improvise a spacer to keep the top of the driver from touching the heatsink base. The plastic spacers are super-glued to the heatsink (out of JB Weld!). 

Right now I'm figuring out how to route the wires from the driver to the LED. I'm using 18 gauge wires for the lowest voltage drop at high current so it makes mounting the reflector tricky due to clearance. I might get creative with that! Up next: LED wires, reflector mounting, hopefully battery pack!

Stay tuned!

MRsDNF
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You have gone totally mad. Love what your doing. Thumbs Up

 

djozz quotes, "it came with chinese lettering that is chinese to me".

                      "My man mousehole needs one too"

old4570 said "I'm not an expert , so don't suffer from any such technical restrictions".

Old-Lumens. Highly admired and cherished member of Budget Light Forum. 11.5.2011 - 20.12.16. RIP.

 

Sirstinky
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Thanks! I’m excited. Right now waiting on parts from China for major work to move forward. The biggest issue with getting it right is the reflector for the throw. I priced one for like for the MF04 and it’s $125 Oops the GT reflectors are about the same and Lumintop is the one making them. I’ll make it work though. Just won’t throw as far as the GT.

pinkpanda3310
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Nice project Thumbs Up Good luck with getting the right reflector Beer

Sirstinky
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Here's some work I did tonight for a few hours. I ran into some issues...

First was wiring the driver to the emitter through the heatsink. I planned on drilling holes through the copper part, but that would have caused clearance issues with the bottom of the reflector because I'm using 18 gauge wires. So I'm using some insulted solder tabs from some (what were probably really expensive) industrial tablet PC battery packs that were hiding in a box of computer junk I got from a guy on Craigslist. I stripped off the insulation and soldered them to the MCPCB and wires from the driver. 

In the process, I managed to rip off the battery negative solder pads yell so I had to switch things around. That's why the LED is positioned differently in the other photos.

Done! Now on to the part I was dreading. Wiring up the driver. This took about an hour of positioning wires, trimming, and rearranging things to get it to work...

Nope! Backwards!

The right way...My fingers got burned quite a bit holding wires while soldering them into place without bridging pads or connections. 

It's a tight fit, but there's enough clearance for the wires. I did put a strip of electrical tape on the bottom of the heatsink for extra protection against shorts. The wires pass up through the fins in the heatsink to the tabs that go to the MCPCB.

Done! Well at least this part. Still a long ways to go.

I mocked it up and tested everything. It works fine! That white switch is the one that came in the host. Looks like an Omten 1288 clone or something. It's really sturdy and has a super nice clicking action, nice and precise (reverse clicky). It's meant for 4.5v and about 350 or 400ma to the incandescent lamp. I'll be putting close to 6 amps through it about 60 watts or so. So far it survived some testing really well. 

Tomorrow, I'll build the battery pack as I got a special delivery Wednesday! 

Sirstinky
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Today was time to do the battery. As I said, I'm using 4S2P made of Sony (actually Murata) VTC6's. I got these from Lithium Ion Wholesale for a decent price, but still not cheap! At least I know they're real and not fakes. That's the most expensive part of this whole deal since everything else is around $5 to $12.

Time to disrobe the old battery. I will be re using the BMS board and balance plug. Kind of bittersweet since this was the 2nd battery I ever built in 2017 I think for the 100W flashlight as an upgrade from the 3S2P original. It's made up of green Samsung 22F and I think LG salmon colored ones of the same capacity laptop pulls. A couple of the series cells and probably a parallel one got damaged from the 10 amp input required by that flashlight and started to read under 3.5v while the others read over 3.8. I built a 5S battery for it.

Naked! You can see some of the connections for the BMS. The balance plug sticks out the back. The blue wire is the 2S, and the red wire is the battery+ (14.8v) and the black wire is battery- (gnd). On the other side is the 3S and 1S connections. 

The BMS board. 15A continuous rating and it does have reverse polarity protection unlike a lot of Chinese electronics. I got it for around $5 on eBay. On the bottom you can see the connections for the balance leads. The charging input is on the bottom oddly.

The only thing I like more than my soldering iron is my hot glue gun tongue-out Laying out the cells for series/parallel configuration. I use tape to hold them together before gluing. The battery + is on the bottom left, and battery- is on the top left. The 2S is on the right side. It has an extended tab for the balance connection.

Joining the batteries. Disclaimer: I don't recommend soldering. To do it right, get a spot welder made for this. You risk overheating your batteries and damaging them (over 60C to 100C is fatal to a li-ion battery), or worse, you might get a thermal runaway, which is bad. I do it this way because a spot welder is like $250 even for a cheapish decent one that won't kill you, burn your house down, or die after 30 minutes. I use a 72W soldering iron (crank it up to 350C), high quality .032 63/37 sn/pb solder (Kester 44 eutectic) and am very careful. I let the batteries cool down between each connection and make sure they don't get hot. I even use a paper napkin soaked with rubbing alcohol to cool them off if needed. I scuff the contacts with 500 grit sandpaper for a better surface to solder on. 

I make the tabs from pure nickle strips. I got a 10 ft. roll of it from eBay. 8mm wide by .15mm thick. You have to get pure nickle since it solders really nice, is ductile/flexible, corrosion proof, and holds up under high current better than steel or plated steel. I drill holes where I solder to the battery contacts. It drastically cuts down on the amount of time the heat is on the battery and it's easier to get strong joints without putting a lot of heat in the battery. 

Tin the contacts of the batteries and let them cool a bit before doing the connections. Be quick! Only keep the heat on enough to wet the solder. I tin the battery-side of the strips as well. 

Battery output side, B+ on the top, B- on the bottom. 

Other side finished with the 1S and 3S contacts. 3S is on top, 1S on bottom. 

All finished! I checked the voltages at the terminals to make sure it was all correct before soldering the connections to the BMS board.Put it on the charger to verify no shorts or bad hookups. Looks good. Charges fine. 

I put electrical tape and then masking tape over areas that might short. It will me semi-permanently mounted in the host. The charging leads are exiting the left side of the BMS. Those will go to a barrel jack for charging. The balance port and charging port will come out the back of the flashlight body. The battery outputs aren't on yet because I haven't figured out how to connect them to everything yet. Next was supposed to be figuring out the reflector, but I ruined it earlier because I melted it and hogging out the melted part was a fail undecided so I'll get another one from a donor light. I won't be fiddling with it until my spacer/centering rings get here from China sometime the first week in May (I hope) though since the edges of the die touched and melted the reflector. I decided to do the fan mounting, but the fan I got was also too big. I need a 70mm, not 80mm. Hurry up and wait...Say tuned.

Sirstinky
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I did some more work the last 2 days. While I'm waiting on parts from China, I decided to mod the host a bit for the battery pack. Time to cut openings for the charging port and balance socket. I decided to keep the cutouts attached to act like covers for the openings for water resistance. I made a template as a guide and used a really thin, crazy sharp razor blade to cut these out. First the balance port.

Then the charging port. It's a barrel jack.

You can see how it looks when done. I will add some cut outs to make it easier to open the flaps, and glue raised rubber seals that cover the openings to the ports later.

Time to figure out the electrical connections for the LED and fan (it arrived Wednesday-I bought it from a US seller).

The white JST-HX connectors are for the fan. I actually used the fan's connector leads and ditched the 3-pin connector that connects to a motherboard. The fan leads just slid into the JST connector and I added some heat shrink insulation and glued them in place. Works awesome. The Molex connectors are donors-I will be using the metal connectors inside. 

Fan connector done! Now to the driver connection. The switch is the one that came with the host and has a nice holder for it, which makes it easy to take in and out.

The Molex connectors are removed from the plastic plugs ready for soldering. 

Done. You can see how it all fits together. I soldered the ground connection to the driver holder. This connects directly to the switch return. The positive comes right off the battery to the driver.

I got everything connected and went to try it out. Turned it on...nothing. Turned it off and turned it on again, after a second or two, POOF! Sparks and some fire came out of the BMS board and a hole was in the electrical tape where there wasn't one before...Oops. I think something was shorted somewhere. 

Took the tape off and pieces of the MOSFETS went with it. I think the reverse polarity failed at some point. I never get tired of the smell of burned electronics. 

So hurry up and wait for a new BMS. I'll order one from eBay from a US seller and pay 3 times as much for it. Oh well. Hopefully the China parts will be here in a week or so. I hope nothing else is fried! 

Stay tuned!

 

MtnDon
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Aw, darn. Too bad about the fried parts. (been there, done that, it sucks but it happens from time to time)

Sad
Sirstinky
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Yah. I got 2 Bms boards from eBay from a US seller for like $10 for both. Not a bad deal, but twice what 2 from Aliexpress cost. I say if you aren’t breaking stuff you aren’t making stuff. If I has a dollar for every time I broke, fried, shorted, cut, burned something I could almost buy a GT70.

xevious
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Man, that sucks — the sound of popping electronics is heartbreaking. The damage can end up so extensive. I hope you’re able to salvage most of it. What a fun project!

Sirstinky
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True! It really is annoying when you think everything is right, then you plug it in or hit a switch and poof, the magic smoke comes out that makes electronics not work anymore. It’s humbling for sure. This has beena fun project for sure! Not as bad as the 100W flashlight though. That was a deuzy.

Sirstinky
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So I checked things out and connected the driver and fan directly to the battery and everything works! Modes are fine, etc. Fan spins fine too...too good. At full battery power it will be overspeeding and even at 12v it's noisy (small fan with lots of blades). 

I dug through my resistor stockpile and found a 120 ohm resistor maybe 3 watts? I forget. I tried a 100 ohm (the blue one in the picture), but it didn't slow it down enough. 

All done! The fan is slowed down enough that the whine is mostly gone, but still pushes enough air. The batteries are only 75% charged, so I know it will be more than adequate when fully charged. 

I don't know what I'll tackle next. Waiting on the new BMS and my Chinese parts now. 

Stay tuned! Thanks.

Sirstinky
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Alright, so time to get back at this. I had been chipping away, but hit a roadblock waiting for parts due to a short circuit that killed my BMS. I mounted the battery pack and glued in the charging jack and the balance connector and made the gaskets for their cutouts. I finished devising a mounting system for the fan, so that's done.

In case you're wondering why the fan's important here's why. I ran it on turbo to see how hot it would get. The driver has a thermal stepdown that I haven't figured out how to change (it's Bistro), so it steps down at around 130 degrees F, but it gets there quick. Without the fan on, it's at 179 degrees on the MCPCB within 3 minutes and 134 on the heatsink itself. 

I switched the temp gun to Celsius and took measurements with the fan on. I ran it for 4 minutes on turbo (before the stepdown) near the MCPCB and it never went over 55 C and stayed between 51 and 54  so about 130 degrees F. Yep, the fan works.  

Since I got the reflector spacers from overseas finally (took a month and a half), so on to getting that sorted! I had planned on making one since suitable reflectors were either 1. too tall, 2. too expensive, or 3. too small (not wide enough). I am getting tired of making reflectors (it's the most tedious and boring part of these builds) so I decided to try one that was a similar size for the host. You might recognize it from the SST40 modded floating lantern.

I bought another one for the reflector and tried it out. It ran for maybe 2 minutes before I realized it was melting again. Even with the spacing ring it was so hot the plastic reflector melted. Scratch that. Back to the original plan...make one. Step 1: cut down the base of the original reflector until the focal length of the LED matches up well. 

Good enough.

Step 2: make a base for it to sit on. I decided to use the top cover from a dead SSD drive I had lying around. It's cast aluminum or maybe even magnesium because it's really light, but really rigid. Maybe magnalium alloy? It will polish nicely. I traced around the opening of the reflector and did some geometry to find the center for the emitter hole. 

In case you wonder how to do that, there are several ways, and the easiest is to use a center finder or a computerized measuring device, or you can do math, but I don't have a machine and I'm bad at math, so let's use chords. Draw 2 lines of a specific length between two edges of the circle parallel to each other. I drew 2 inch chords. Make sure the lines are the same length and distance from each other. T"hen draw a diagonal line from the origin of the first chord across to the terminus of the parallel chord. Repeat this on the other side, from the terminus of the first chord to the origin of the second parallel chord. The point where they  intersect is the center of the circle. You can measure it to be sure, but it's always super-close. I can only tell a difference when I break out my calipers, so you're talking thousands of an inch. 

That's as far as I got. I spent most of my day working on this and some other light projects. Next is polishing the reflector base and figuring out how to mount it and stick the whole thing together. I am waiting on my taps so I can properly tap the holes in the heatsink for the mounting screws holding the LED down. It's been almost 2 months since I ordered them from AE. Ugh. I'd have been better off spending the extra $5 and getting them from a stateside eBay seller. 

I'll update soon! 

Sirstinky
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Quik update. I ran into a major roadblock with mounting the cooling fan. The original design didn’t account for the fact the reflector and heatsink had to be centered in order the screw the bezel on… a big DOH! Oops

So back to the drawing board on that. I’m probably mount it inside the housing, but that has it’s own issues! I may use a different fan also, but probably not. I don’t know. At this point I just want to finish it, but between work getting and rain, and other things it’s stretching me. Good news is reflector is mounted to the base! I have all the wiring figured out too.

Stay tuned!

MtnDon
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Sirstinky wrote:
… a big DOH! Oops
I hate those DOH! moments. I’ve had a few too
Sirstinky
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So I’ve been working in this in bits !!! and pieces. I spent way too much time fooling with a way to mount the fan, but make it so its able to be removed. I had to make a bracket for it, and two mounting points to secure it to the host. I got that done. Then I had to improvise with the switch mou ting as well since the stock mount didn’t clear the heatsink. I didn’t feel like grinding off 1/2” off the heatsink to make it fit, so I hacked off the lower part of the switch mount and made a shelf. I cut the middle out and cut parallel grooves in a base the switch sat in and slid it into the gap in the shelf. That works great.

My mini taps showed up from China and I tapped the holes for the mcpcb screws and got that mounted properly. Got everything hooked up and ran a test. Bright flash from the led then only one die lights up so somethings not right now! Grrr. !!! Not sure what happened since it worked fine before. Tired I’m thinking the led was overstressed or something since I don’t think anything was shorted? Ugh. Back to the drawing board. New xhp70.2 coming! From America this time. It’s not much more expensive than from China.