Hello. I'm fairly new to diving and keen on wreck diving(dove the Ex-HMAS Brisbane a few months ago, heading to Chuuk in May). I have a couple of basic dive torches. A Big Blue AL1200 main and 450 backup(model numbers refer to lumens) I have a few other lights, an Olight M20, another "tactical" light that DOESN'T need $20 worth of batteries(can't remember it's name and it's locked away), a 3D Led maglite, various head-torches...and, the reason for this thread...a busted P7 Ledlenser(pulled it apart and the plastic switch cylinder was broken allowing the switch contact to seperate from the light head contact). So I was searching for ways I can use the torch coupled with current diving needs and I came across copious amounts of dive canister builds....so I followed down the rabbit hole...and now I'm stuck in limbo between having found enough information that I want to build a powerful light for a lot less than I can buy one for, and having found enough information to realise just how much more I need to know, which leads me to asking you guys for help. I've been trawling through the forums picking up bits and pieces of info, but I cant keep it all together(and I'm easily distracted. I spent 2hrs last night looking into IR emitters...just because) I have about 40 tabs open, and can't remember what half of them are for.
My understanding of electronics is nearly non-existent. I have a basic understanding of the relationship between volts/amps/watts from auto electrical DIY, but nowhere near enough to work it all out myself. I understand a lot of the questions are going to be rehashing old stuff for you guys, and I'm happy to be told to go and search for it(some direction would be appreciated, links would be awesome) I'll bold the questions to hopefully make it easier to find the answers(but please watch out for the questions that I don't know to ask
So, where I'm at.(cant work out how to attach images, so more typing) I have cut the head off the torch (110mm long, worried now it's a bit short but was limited due to the shape of the torch), removed the old LED and machined a new end cap/lens holder.(the ledlenser one had breather holes behind the lens. Not ideal for a dive light) I have allowed room for extra o-rings but might end up JB welding it together anyway. There is an aluminium heat-sink(41mm OD) which threads into the torch body 15mm. Will I need some sort of thermal compound on the threads to assist in heat transfer and is this enough contact area? Does thermal paste set hard or would I still be able to unscrew the parts?
I've been searching for 35-40mm MCPCBs, preferably with LEDs already mounted. Initially I found a 38mm, 8up XHP50.2 on Cutter Elec, so of course figured that was definitely the go(20k Lumens, 140w...good beginner project)After much soul searching, I put that idea aside for a later date. More realistically there are a couple of options in the XHP35 range that I now have my eye on. There is a 40mm 7up which is probably still a bit much, butit says they can be run in parallel, series or independently addressed. I'm assuming this means i can run them separately, which leads me to a couple more questions...If I run 2 SEPARATE series, one with 3leds and one with 4(by seperate, I mean one on, one off, not 2 parallel series)? If so, can they be run off the same CC step up driver? (different forward voltage across the circuits). If this can actually be done, where/how can the switching happen? Can I have a toggle switch after the driver? Is it possible to get optics that have different spread angles? i.e. 3 at ~10deg and 4 at ~90deg. The idea being that I use switching between circuits to change focus, giving the light more functionality, and also not trying to run 7x13w lights all at once(I get that I CAN run them at a lower power, but dont see much point having powerful lights without at least having the option to run them at full power) If this isn't a valid option, there is a 4up and 3up on 32mm(although it says they are both 36v, which is confusing. I'm assuming that's total Vf and the 36 for the 4up is a typo) which I think I can safely fall back on.
So the other questions I can think of right now:
Do boost drivers work more efficiently with closer Vin/Vout relationship, like buck drivers? I don't want my input to be higher than 12v and even 3 XHP35s are going to be 36v.
Is it feasible to run 7 12v LEDs from a 12v or smaller power source? Alternatively, the XHP50.2s ARE available in 3v, that would make the 8up 24v at 6amps...batteries could be an issue though. (or was it 2 series of 4? Cant remember and too late to go looking)
Do most LED drivers do all the low battery/high temp warning stuff? Where's a good place to find such a creature? Is this a good start? http://www.taskled.com/hbflex.shtml
Is it doable to mount the driver in the canister with the battery? I would then have to allow for voltage drop across the leads when working out the driver output, which increases the difficulty, but not sure I have enough room in the head unit for too much stuff.
Batteries...I assumed I could just get whatever batteries wanted, mounted however I wanted as long as the voltage and current was right when it got to the LEDs, but I've been reading stuff that says otherwise. How do I work out what sort of batteries I get. I was looking at LiFePo(lighter, safer?) I haven't managed to do a great deal of research into batteries.
PWM dimming. Is it too hard for me to worry about, or is there "plug and play" options that I can use?
A bit of daydreaming...has anybody looked into wireless controllers? I'm thinking like a wrist mounted device with selectable power level(touchscreen, slide the powerbar?), selectable mode (different colours, different flash sequences, type your msg and it sends it in Morse code displays battery levels, run time remaining at (x) level.
Anyway, it's late here and I can't think of any more serious questions. Thanks in advance for anybody who can help in any way and I'll work out how to upload the pictures of my small amount of progress at a late date.
Matt
My understanding of electronics is nearly non-existent. I have a basic understanding of the relationship between volts/amps/watts from auto electrical DIY, but nowhere near enough to work it all out myself. I understand a lot of the questions are going to be rehashing old stuff for you guys, and I'm happy to be told to go and search for it(some direction would be appreciated, links would be awesome) I'll bold the questions to hopefully make it easier to find the answers(but please watch out for the questions that I don't know to ask
So, where I'm at.(cant work out how to attach images, so more typing) I have cut the head off the torch (110mm long, worried now it's a bit short but was limited due to the shape of the torch), removed the old LED and machined a new end cap/lens holder.(the ledlenser one had breather holes behind the lens. Not ideal for a dive light) I have allowed room for extra o-rings but might end up JB welding it together anyway. There is an aluminium heat-sink(41mm OD) which threads into the torch body 15mm. Will I need some sort of thermal compound on the threads to assist in heat transfer and is this enough contact area? Does thermal paste set hard or would I still be able to unscrew the parts?
I've been searching for 35-40mm MCPCBs, preferably with LEDs already mounted. Initially I found a 38mm, 8up XHP50.2 on Cutter Elec, so of course figured that was definitely the go(20k Lumens, 140w...good beginner project)After much soul searching, I put that idea aside for a later date. More realistically there are a couple of options in the XHP35 range that I now have my eye on. There is a 40mm 7up which is probably still a bit much, butit says they can be run in parallel, series or independently addressed. I'm assuming this means i can run them separately, which leads me to a couple more questions...If I run 2 SEPARATE series, one with 3leds and one with 4(by seperate, I mean one on, one off, not 2 parallel series)? If so, can they be run off the same CC step up driver? (different forward voltage across the circuits). If this can actually be done, where/how can the switching happen? Can I have a toggle switch after the driver? Is it possible to get optics that have different spread angles? i.e. 3 at ~10deg and 4 at ~90deg. The idea being that I use switching between circuits to change focus, giving the light more functionality, and also not trying to run 7x13w lights all at once(I get that I CAN run them at a lower power, but dont see much point having powerful lights without at least having the option to run them at full power) If this isn't a valid option, there is a 4up and 3up on 32mm(although it says they are both 36v, which is confusing. I'm assuming that's total Vf and the 36 for the 4up is a typo) which I think I can safely fall back on.
So the other questions I can think of right now:
Do boost drivers work more efficiently with closer Vin/Vout relationship, like buck drivers? I don't want my input to be higher than 12v and even 3 XHP35s are going to be 36v.
Is it feasible to run 7 12v LEDs from a 12v or smaller power source? Alternatively, the XHP50.2s ARE available in 3v, that would make the 8up 24v at 6amps...batteries could be an issue though. (or was it 2 series of 4? Cant remember and too late to go looking)
Do most LED drivers do all the low battery/high temp warning stuff? Where's a good place to find such a creature? Is this a good start? http://www.taskled.com/hbflex.shtml
Is it doable to mount the driver in the canister with the battery? I would then have to allow for voltage drop across the leads when working out the driver output, which increases the difficulty, but not sure I have enough room in the head unit for too much stuff.
Batteries...I assumed I could just get whatever batteries wanted, mounted however I wanted as long as the voltage and current was right when it got to the LEDs, but I've been reading stuff that says otherwise. How do I work out what sort of batteries I get. I was looking at LiFePo(lighter, safer?) I haven't managed to do a great deal of research into batteries.
PWM dimming. Is it too hard for me to worry about, or is there "plug and play" options that I can use?
A bit of daydreaming...has anybody looked into wireless controllers? I'm thinking like a wrist mounted device with selectable power level(touchscreen, slide the powerbar?), selectable mode (different colours, different flash sequences, type your msg and it sends it in Morse code displays battery levels, run time remaining at (x) level.
Anyway, it's late here and I can't think of any more serious questions. Thanks in advance for anybody who can help in any way and I'll work out how to upload the pictures of my small amount of progress at a late date.
Matt