LED and battery selection help

Deal87 · Feb 24, 2010

Hi guys I stumbled across this website while performing online research for a project I am working on at university. It is to design a dive torch. I am struggling to find information on the runtime values and which type of batteries are best to use. I am heavily considering using the Cree MC-E LED's my design currently has 5 of these. The battery choice is still in research, my initial thoughts are they need to be rechargeable and as compact as possible whilst still providing a reasonable burn time of around 1-3 hours on full power. I feel NiMH is a good choice because they do not suffer from memory effect. The runtime calculator proved very useful however because I am studying a motorsport engineering degree I admit to not knowing a huge amount about electronics. I know I need to use a driver, possibly a LED Dynamics Buckpuck. This is where I am open to opinions from you guys as you are likely to know more than me about good combinations of LED's and battery types etc. Any suggestions would be great.
Many thanks.

DM51 · Feb 24, 2010

Welcome to CPF, Deal87

Your project sounds interesting, and I look forward to seeing how it goes!

We have a sub-forum dedicated to Dive Lighting, so I'll move your thread there for comment by other divers.

Some of the information you are looking for is to be be found in other sections, but Dive Lighting is probably the best place to base your thread.

Deal87 · Feb 24, 2010

Hi, thanks for the welcome. I'm sure few people on here will be able to help me out!

350xfire · Feb 24, 2010

Deal87 said:
Hi guys I stumbled across this website while performing online research for a project I am working on at university. It is to design a dive torch. I am struggling to find information on the runtime values and which type of batteries are best to use. I am heavily considering using the Cree MC-E LED's my design currently has 5 of these. The battery choice is still in research, my initial thoughts are they need to be rechargeable and as compact as possible whilst still providing a reasonable burn time of around 1-3 hours on full power. I feel NiMH is a good choice because they do not suffer from memory effect. The runtime calculator proved very useful however because I am studying a motorsport engineering degree I admit to not knowing a huge amount about electronics. I know I need to use a driver, possibly a LED Dynamics Buckpuck. This is where I am open to opinions from you guys as you are likely to know more than me about good combinations of LED's and battery types etc. Any suggestions would be great.
Many thanks.

First: What exactly is the goal for this project???

Battery- If you are doing 5 crees, you'll need either 3.7 volt at 14 amps or 18.5 volts at .7 amps or 13.6 at 3.5 amps or 67.5 at 700ma. Depending on how you wire the individual dies within each LED and how you wire all the LEDs together. Question, why 5 Crees? That is way bright and will also increase the complexity and the heat sink requirements of the project. This thing is going to run HOT!!! Also, expensive and huge batteries.

Second- LEDDynamics buck pucks don't work well in parallel, which you would need to do in order to push 3 amps to a Cree in parallel. In series, you could run the Cree with 700ma driver at a higher voltage. Still the driver is a max of 34 volts, I think.

I think you need to figure out some type of compromise before you end up spending $2000 on a class project. Unless, of course, the school pays for this! I don't think I would use more than 3 Crees. If you really want a top notch super nice light a 24W Brightstar HID with round ballast would also work great. The HID bulb/ballast is about $180.

I would use LiIon batteries.

Codiak · Feb 24, 2010

350xfire said:
First: What exactly is the goal for this project???

I would use LiIon batteries.

As 350xfire states, can you provide a more detailed description of the project? Frankly, you'll get a lot of useful feedback that will save you big bucks and tim.

I second the LiON batteries, more specifically the use of 18650's is common as they are dense little power houses... 3.7volts > 1800mA
Off the cuff, you could look at using the hipCC from taskled as the driver, and put 4 x 18650s in series, then 2 or 3 packs in parallel for better duration.
But then we don't know if you intend to make a hand held or canister.

Btw,
To make things easier, any light component can be purchased from various posters in this thread.
350xfire, Packhorse and MBSub all have nice products, including canisters, batteries and chargers.

gcbryan · Feb 24, 2010

I've helped design students before. In most/many cases the project is to design and not actually build the product.

We need more info here obviously. Why 5 MC-E's for a dive light? That's 3,000 lumens or so. If it's for a video light then SST-90's are probably the way to go.

If it really is a dive light then 3 or 4 XP-G's might be nice. With the new higher current ratings 3 might be fine. Multiple MC-E's don't sound like the best approach to me.

Li-ions do sound like the way to go.

What kind of spec are you looking for with this dive light and how did you come to your conclusions?

Packhorse · Feb 24, 2010

I would agree that multiple MC-Es are not the way to go unless its for a video light.
In which case they only advantage they have over SST's is that you can run them as a higher input voltage by configuring the wiring to the dies.

Deal87 · Feb 25, 2010

Hi first of all thanks for all the help, this is great. It has confirmed my lack of knowledge on the subject. My design project doesnt have to include building although I would like to keep it a possibility and keep a loose price cap on it of around £500. My main reason to post on this forum is to gain the technical knowledge I lack to improve the design of the electronics side of the project.

I have lots of questions but I will start off with the main few (please remember I am a beginner).

How do you guys calculate if the LED(s) will run to 'hot'. Obviously with an underwater application the ambeint temperature is a lot lower.

I also looked at the c123 batteries and 18650 they look like a very good option. Why do you guys think lithium is better than NiMH?

I gathered my first selection of LED's was bad but my research also lead me to consifer Luxeon star setups. Can I also ask is there any major advantage to using a star in the design other than easy mounting and conntection?

Are there any other suggestions to good LED and battery combinations that I can look into?

Thanks very much guys, looking forward to the replys

Doh!Nut · Feb 25, 2010

You still need to define more clearly what you want this light to do and why?

If it is a design project that remains on paper then the only thing they (Cranfeild?) will have to judge you on is what choices were made and why you made those choices.

Is it for recreational diving - or a work light
is it illuminating little things for photography or a spotlight for murky water, are you trying to illuminate a wreck?
Why did you choose LED? efficiency size/ robustness?
look up Cree & Seuol SSC & phatlight & philips lumLED (Luxeon) and download the data sheets, that will tell you about binning and efficiency.
Check the price for Lumen/£
Check data sheets for output/temp to see how much effort you want to put in to cooling. check the overall efficiency of your setup to see how much waste heat needs to be removed.

Burn time is stated but a window of 300% is a bit vague.
How will the battery be charged? - will you have to open the light?

By small do you mean overall size, or size of light head, with a separate umbilical battery pack. You may consider increasing the size of the body to achieve near neutral bouyancy.

etc.
You get the idea :grin2:

Deal87 · Feb 25, 2010

Ok, I will try my best to specify some design details, however my point is; these remain very loose at this stage as I don't know enough about the LED and battery setup options to decide on a final spec. The electronics side of the project are not the main point of marking, however I feel they need to be right to justify other decisions in the design of the overall torch.

Doh!Nut I think by Cranfield you may mean Hatfield, this is the University of Hertfordshire where I study. But I may have got the wrong end of the stick.

Things I know... I want it to be hand held not canister, as close to or actually buoyancy neutral if possible. Again info on techniques used by you guy for this would be great!

No real restrictions on head size possibly need it to be able to be adjusted by a 5th-95th percentile hand so roughly 150mm max diameter. I want it to be a primary dive light and be able to light up wrecks etc and possibly be used for Photography- so quite a high lumen setup.

Battery, I feel is best to be able to remove and recharged this was the user has the option to replace or upgrade. However, again, this is flexible. If anyone has a good option for external charging with a sealed canister then I'm all ears. I basically want to learn as much as possible then make decisions from there.

Any ideas guys?

Thanks

Codiak · Feb 25, 2010

Deal87 said:
Ok, I will try my best to specify some design details, however my point is; these remain very loose at this stage as I don't know enough about the LED and battery setup options to decide on a final spec. The electronics side of the project are not the main point of marking, however I feel they need to be right to justify other decisions in the design of the overall torch.
Doh!Nut I think by Cranfield you may mean Hatfield, this is the University of Hertfordshire where I study. But I may have got the wrong end of the stick.
Things I know... I want it to be hand held not canister, as close to or actually buoyancy neutral if possible. Again info on techniques used by you guy for this would be great!
No real restrictions on head size possibly need it to be able to be adjusted by a 5th-95th percentile hand so roughly 150mm max diameter. I want it to be a primary dive light and be able to light up wrecks etc and possibly be used for Photography- so quite a high lumen setup.
Battery, I feel is best to be able to remove and recharged this was the user has the option to replace or upgrade. However, again, this is flexible. If anyone has a good option for external charging with a sealed canister then I'm all ears. I basically want to learn as much as possible then make decisions from there.
Any ideas guys?

Excellent, Details!!! Well some anyway

Class is open boys!

Let's discuss and finalize the goals and let the solution present itself.
The idea is to make sure you have consider the options, not to change you mind...
There is no real right or wrong answer, there is just YOUR answer
In some cases you will discover that the goals are mutually exclusive in a practical sense.

Goals:

Handheld
Neutrally Buoyant
Headsize smaller than a grapefruit
Rechargable
Lightup an undefined Wrecks
Primary Light and Photograghy
High Lumen output

What about:

Cost?
- Got an idea on Finished Product retail?
Reliability?
- Do you want to be able to turn it on of off at will? Or just on when you enter the water and off on exit?
Durability?
- Do you care if the bulbs are replaced every dive or never in your lifetime?
Overall Weight?
- Neutrally Buoyant is easy, if the light weighed 20stones we'd need 20stones lift bouy though I don't think this is what you have in mind.
Depth?
Rec or Tech?
Duration?
- 1-3 hours from your previous post as noted is too wide a range for design.

Can you clarify the target market and how you'd like the product to benefit your users?

IE.

Recreational dives
- typically last are between 45 and 60 minutes not exceeding 40 meters
- It's been my experience that Most boat dives run 2 boat dives before lunch.
- Using this logic we might want a 2 hour burn time, and expect a recharge or battery swap during lunch
- Divers physical condition span 95% of the population: >= 11years old, skinny to fat
- Water conditions
  - blue or green
  - 100feet visibilty
  - Warm >24c
Cave/Cavern/Deco
- Each dive will be different but you can expect longer and deeper and redundent light sources
- Divers are typically in better physical condition that "rec" divers.
- Water is.... well... it's wet!

Let's start with the form factor: Handheld

Is this set in stone? Please clarify your answer.

Did you consider that typically Canister lights have higher lumen output do to larger power sources? Bouyancy is easier to solve as the canister is attached to the diver and relies on the BCD, Wing or Drysuit for neutral. While there is a cord, heavy powerpacks mean less lead in the weight belt.

Neutrally Bouyant:

We still dealing with handheld?

Headsize:

Is the goal here a small bright compact light? Or the smallest head to get the job done?

Rechargable:

Any desire for off the shelf batteries? D/C/AA/AAA/CR2/CR123 are all nice in a pinch... like I forgot to bring my charger!

Light-up a wreck:

The whole thing or just a section? From what distance? I was diving the HMS Rhone last week, best view was at the safety stop 80 feet above the wreck. Of course the Might-O conning tower is at 100feet depth and you need to get close.

Primary vs Photo:

Look at the threads on Variable Focus. These to goals could be considered mutually exclusive.
Primary lights tend to have a nice hotspot and are useable in great and poor visibility.
Photo lights are wide angle, floody and useless in murky water.

High Lumen output:

Do you have a real requirement here or is this the peter-principle at play?
Do you know the typical output of any dive light?
Do you want to match or exceed some light out there? Which one?

Follow-up discussion to include:

Total Lumen output
Build Materials
Plastics or Metals
Type of Bulb - LED one of several options
Batteries - NiMH, LiON etc
Optics and reflectors
Methods of water-proofing

In case you hadn't noticed if you were looking for people passonate about dive lights you found them! There are many strong view points and approaches to the techicnal items and as I stated earlier the only correct answeris the one that works for YOU.

I encourage you to understand the WHYs of each choice: positives and negitives, first! Then make educated choices, document and stick with them, moving on to your final solution.

If you know the right questions to ask the process is pretty quick, we'll help you ask them.

Deal87 · Feb 25, 2010

[FONT=&quot]Wow, what can I say, just the reply I was looking for! Thank you! I'll do my best to answer the questions you have raised.

What about: [/FONT]

[FONT=&quot]Cost?[/FONT]
- [FONT=&quot]Got an idea on Finished Product retail?[/FONT]
[FONT=&quot]I was thinking a target of £500 as this appears to be a good ballpark figure where a large range of dive lights that are currently available go for.[FONT=&quot][/FONT][/FONT]

[FONT=&quot]Reliability?[/FONT]
- [FONT=&quot]Do you want to be able to turn it on of off at will? Or just on when you enter the water and off on exit?[/FONT]
[FONT=&quot]I was thinking a variable power switch option similar to my Maglite mini LED. i.e. 100%, 50% and 25% options.[FONT=&quot][/FONT][/FONT]

[FONT=&quot]Durability?[/FONT]
- [FONT=&quot]Do you care if the bulbs are replaced every dive or never in your lifetime?[/FONT]
[FONT=&quot]Has to be LED that was the only thing that was fixed at the beginning of the project. So 50,000 hours reliability.[FONT=&quot][/FONT][/FONT]

[FONT=&quot]Overall Weight?[/FONT]
- [FONT=&quot]Neutrally Buoyant is easy, if the light weighed 20stones we'd need 20stones lift bouy though I don't think this is what you have in mind.[/FONT]
[FONT=&quot]With the canister option explained (this is why this forum is valuable to me, a non diver). If the design can be made buoyancy neutral then I am open to change the design to house the batteries etc in a canister. This, as you mentioned would offer the ability for higher lumen output.[FONT=&quot][/FONT][/FONT]

[FONT=&quot]Depth?[/FONT]
[FONT=&quot]Interesting one, again as a non diver hard to say. A guess would be 100m to cover the Rec market and possibly appeal to some of the Tech market too.[FONT=&quot][/FONT][/FONT]

[FONT=&quot]Rec or Tech?[/FONT]
[FONT=&quot]See above.[FONT=&quot][/FONT][/FONT]

[FONT=&quot]Duration?[/FONT]
- [FONT=&quot]1-3 hours from your previous post as noted is too wide a range for design.[/FONT]
[FONT=&quot]Going from your experience (thanks again!) I think a 2 hour burn time is a good aim.[FONT=&quot][/FONT][/FONT]

[FONT=&quot]Headsize: [/FONT]
[FONT=&quot]Is the goal here a small bright compact light? Or the smallest head to get the job done?

I am currently working on a design, not sure how this will go down on here, but it will allow the LED's to physically move to offer a variable beam pattern. Basically they are mounted on spring steel legs and they deform when the head is twisted. This moves the LED's from fully diverged beam to a compact spot. Note this is still in development. Hence the requirement to fit in the hand of 5th-95th percentile.[/FONT]
[FONT=&quot]Rechargable: [/FONT]
[FONT=&quot]Any desire for off the shelf batteries? D/C/AA/AAA/CR2/CR123 are all nice in a pinch... like I forgot to bring my charger!

I will say this area is completely open, taking into account the relatively large current and voltage requirements of high lumen output multiple LED setup- which goes hand in hand with battery selection. 18650 look to be a strong contender. As previously mentioned I am considering NiMH and Li-ION but wary of possible memory effect issues with the latter. [/FONT]
[FONT=&quot]Light-up a wreck: [/FONT]
[FONT=&quot]The whole thing or just a section? From what distance? I was diving the HMS Rhone last week, best view was at the safety stop 80 feet above the wreck. Of course the Might-O conning tower is at 100feet depth and you need to get close. [/FONT]
[FONT=&quot]Primary vs Photo: [/FONT]
[FONT=&quot]Look at the threads on Variable Focus. These to goals could be considered mutually exclusive.
Primary lights tend to have a nice hotspot and are useable in great and poor visibility.
Photo lights are wide angle, floody and useless in murky water.[/FONT]
[FONT=&quot]High Lumen output: [/FONT]
[FONT=&quot]Do you have a real requirement here or is this the peter-principle at play?
Do you know the typical output of any dive light?
Do you want to match or exceed some light out there? Which one?

A loose answer to most of the above would be I want it to enter the Rec market at the higher end and possibly cross over to the lower end of Tech. Again maybe your experience will help me answer this, I don't like answering a question if I know I can't really backup what I'm saying.

[/FONT]
[FONT=&quot]
Follow-up discussion to include: [/FONT]

[FONT=&quot]Total Lumen output[/FONT]
[FONT=&quot]Build Materials[/FONT]
[FONT=&quot]Plastics or Metals[/FONT]
[FONT=&quot]Type of Bulb - LED one of several options[/FONT]
[FONT=&quot]Batteries - NiMH, LiON etc[/FONT]
[FONT=&quot]Optics and reflectors[/FONT]
[FONT=&quot]Methods of water-proofing[/FONT]

[FONT=&quot]I want it to be a metal body, most probably Aluminium as I have some experience in CNC machining and I can also include this information in my project to gain extra marks! The rest hopefully will be answered with more input [FONT=&quot]

Massive thanks to everyone for the help so far especially Codiak![/FONT][/FONT]

Codiak · Feb 25, 2010

What type of class is this for? It'll help us shape our answers.

Deal87 said:
[FONT=&quot]Wow, what can I say, just the reply I was looking for! Thank you! I'll do my best to answer the questions you have raised.

What about: [/FONT]

[FONT=&quot]Cost?[/FONT]

[FONT=&quot]Got an idea on Finished Product retail?[/FONT]

[FONT=&quot]I was thinking a target of £500 as this appears to be a good ballpark figure where a large range of dive lights that are currently available go for.[/FONT]

Okay, from a marketing standpoint it's a reasonable target price and based on general parts costs not unreasonable. However, currently available means your competing against known brands. As such a new product offering in a niche market driven much by word of mouth will make the experience challenging.

[FONT=&quot]Reliability?[/FONT]

[FONT=&quot]Do you want to be able to turn it on of off at will? Or just on when you enter the water and off on exit?[/FONT]

[FONT=&quot]I was thinking a variable power switch option similar to my Maglite mini LED. i.e. 100%, 50% and 25% options.[/FONT]

Not quite what I was asking though knowing this is a desired feature is good. What I was refering too has historically been an issue with HID and other bulbs where cycling the light on and off drastically shortened the MTBF. Nothing worse than turning a light on and POOF

[FONT=&quot]Durability?[/FONT]

[FONT=&quot]Do you care if the bulbs are replaced every dive or never in your lifetime?[/FONT]

[FONT=&quot]Has to be LED that was the only thing that was fixed at the beginning of the project. So 50,000 hours reliability.[/FONT]

Okay, a solid choice though there are other benefits of LEDs which you should understand and document.

[FONT=&quot]Overall Weight?[/FONT]

[FONT=&quot]Neutrally Buoyant is easy, if the light weighed 20stones we'd need 20stones lift bouy though I don't think this is what you have in mind.[/FONT]

[FONT=&quot]With the canister option explained (this is why this forum is valuable to me, a non diver). If the design can be made buoyancy neutral then I am open to change the design to house the batteries etc in a canister. This, as you mentioned would offer the ability for higher lumen output.[/FONT]

Good, a canister it is... though higher lumen output isn't the primary benefit.

[FONT=&quot]Depth?[/FONT]

[FONT=&quot]Interesting one, again as a non diver hard to say. A guess would be 100m to cover the Rec market and possibly appeal to some of the Tech market too.[/FONT]

100m gives us the PSI requirements so good again

[FONT=&quot]Rec or Tech?[/FONT]

[FONT=&quot]See above.[/FONT]

Techincally Rec and Tech has simular issues... light for a duration underpressurized wet environment. Beyond that Rec divers typically never use canister lights, while Tech divers tend to use handhelds only as backups. These are generalized statements and exceptitions exist but they are few and far between.

[FONT=&quot]Duration?[/FONT]

[FONT=&quot]1-3 hours from your previous post as noted is too wide a range for design.[/FONT]

[FONT=&quot]Going from your experience (thanks again!) I think a 2 hour burn time is a good aim.[/FONT]

Okay another closed requirement.... see this is easy

[FONT=&quot]Headsize: [/FONT]
[FONT=&quot]Is the goal here a small bright compact light? Or the smallest head to get the job done?

I am currently working on a design, not sure how this will go down on here, but it will allow the LED's to physically move to offer a variable beam pattern. Basically they are mounted on spring steel legs and they deform when the head is twisted. This moves the LED's from fully diverged beam to a compact spot. Note this is still in development. Hence the requirement to fit in the hand of 5th-95th percentile.
Let's just mark this up as Variable Focus requirement but put it in a parking lot for now. Its a cart before the horse
[/FONT]
[FONT=&quot]Rechargable: [/FONT]
[FONT=&quot]Any desire for off the shelf batteries? D/C/AA/AAA/CR2/CR123 are all nice in a pinch... like I forgot to bring my charger!

I will say this area is completely open, taking into account the relatively large current and voltage requirements of high lumen output multiple LED setup- which goes hand in hand with battery selection. 18650 look to be a strong contender. As previously mentioned I am considering NiMH and Li-ION but wary of possible memory effect issues with the latter.
LiON doesn't have any more memory effect than NiMH, but there are safety concerns with protected vs unprotected batteries. look at Batteryspace.com and Batteryjunction.com for details. Using a canister you have the choice, so park this item for closure after a proper LED is selected[/FONT]
[FONT=&quot]Light-up a wreck: [/FONT]
[FONT=&quot]The whole thing or just a section? From what distance? I was diving the HMS Rhone last week, best view was at the safety stop 80 feet above the wreck. Of course the Might-O conning tower is at 100feet depth and you need to get close. [/FONT]
[FONT=&quot]Primary vs Photo: [/FONT]
[FONT=&quot]Look at the threads on Variable Focus. These to goals could be considered mutually exclusive.
Primary lights tend to have a nice hotspot and are useable in great and poor visibility.
Photo lights are wide angle, floody and useless in murky water.[/FONT]
[FONT=&quot]High Lumen output: [/FONT]
[FONT=&quot]Do you have a real requirement here or is this the peter-principle at play?
Do you know the typical output of any dive light?
Do you want to match or exceed some light out there? Which one?

A loose answer to most of the above would be I want it to enter the Rec market at the higher end and possibly cross over to the lower end of Tech. Again maybe your experience will help me answer this, I don't like answering a question if I know I can't really backup what I'm saying.

School is your opertunity to screwup without getting flamed :thumbsdow That said I'd strongly advise not going to market with a dive product unless you dive! I really can't stress this enough, divers trust divers. Divers who DIY, build for many reasons, some cost (yeah right...DIY costs far more) some because the product doesn't exist that EXPERIENCE has shown they need. A few lucky ones have success personally and manage to do some business as well... don't think any of them are rich with this niche. [/FONT]

Follow-up discussion to include:

[FONT=&quot]Total Lumen output[/FONT]

[FONT=&quot]Build Materials[/FONT]

[FONT=&quot]Plastics or Metals[/FONT]

[FONT=&quot]Type of Bulb - LED one of several options[/FONT]

[FONT=&quot]Batteries - NiMH, LiON etc[/FONT]

[FONT=&quot]Optics and reflectors[/FONT]

[FONT=&quot]Methods of water-proofing[/FONT]

[FONT=&quot]I want it to be a metal body, most probably Aluminium as I have some experience in CNC machining and I can also include this information in my project to gain extra marks! The rest hopefully will be answered with more input

Practical and fairly cheap... also solves the cooling problems.

[FONT=&quot]Massive thanks to everyone for the help so far especially Codiak![/FONT][/FONT]

But wait there's more!
Seriously, that your doing class work got my interest.

So:
Canister Light
2 Hour Burn time
Selectable output 25, 50, 100 and off
Variable Focus
Estimated Retail Price $750 US
Depth Rated for 100m
Good as Primary or Photo Light

Sound right?
For Photo Light your need to decide the color spectrum you want in K and that will be based on Still or Video
With the exception of variable focus everything is common to most canister lights and not difficult.

From a marketing perspective there are a lot off issues, I only briefly touched on a few earlier. There is nothing here that gives differenciates you in the market with this product. Not even cost, your's is high ;-)
Technical divers are just now seriously looking at LED solutions but who wants to replace a 1500$ light!

Again what type of class?

From a build perspective, a single emitter is easier to focus and power and et al than a series of 3-5. LEDs are better focused with lenses than they are reflectors. Choosing a single high output LED like the SSR-50 or SSR-90 would perhaps be a better solution.

If you wanted to build a prototype the SSR-50 is around $30

The switch will be something you need to look closely at... it needs to be sealed against water... the rating with be at least IP-68
Two common options are Reed and Peizo Electrics... each has it's own considerations

Back to you

Deal87 · Feb 25, 2010

Ok the spec list we are building up so far sounds good to me.

I seem to have an issue if I want to have a neutrally buoyant design I choose a canister but then you say Rec divers typically don't use canisters... Neutrally buoyant hand held design, possibly?

I realise the design I will come up with may not be as good as a dedicated divers design but I was given the project to complete from an engineering point of view with the aim of getting a good grade using the knowledge I have built up, admittedly it's not ideal with me not being a diver.

With regards to LED light colour temperature I was thinking a nice cool white but not too harsh say 5000K.

I am pretty set on the idea of having multiple LED's mainly due to the focussing design I have developed, I need one to mount to each arm. I aim to use a lens to focus the LED and physically move the arms to vary the beam. The reason it seems 'cart before horse' is that the project is mainly marked on the product design, mechanical features, material analysis and CAD etc. My tutor said not to worry too much about the electronics as I am not an Electronic engineering student; however I feel to get a solid overall design I need to include this in my project. I think you will agree it helps design other parts of the torch once electronic issues are decided.

I have looked into switches Piezoelectric and Reed switches both appealed to the design because of the non mechanical interaction and easy sealing appeal. I am leaning towards a Reed switch. I have some concepts which allow the user to use a twist switch to move a magnet close to the body of the torch to allow the switch to 'close'. Details again need to be finalised as they depend on batteries and LED's chose to decide the current running through the switch.
Thanks again. Keep the questions answers coming it's all good stuff!

350xfire · Feb 25, 2010

"I seem to have an issue if I want to have a neutrally buoyant design I choose a canister but then you say Rec divers typically don't use canisters"

I'm not sure you are correct here!

Packhorse · Feb 25, 2010

I dont see any concerns with a light being negatively buoyant. In fact I cant think of a single dive light that isnt.
Plenty of rec divers use can lights.
Plenty of "rec" divers use " tech" gear.
I believe there is no such thing as rec gear and tech gear. There is simply gear that is suitable for the dive and gear that is not.

Codiak · Feb 25, 2010

350xfire said:
"I seem to have an issue if I want to have a neutrally buoyant design I choose a canister but then you say Rec divers typically don't use canisters"

I'm not sure you are correct here!

Let's just clarify the issue.

You can have near neutrally bouyant handheld or canister based dive lights. Canisters are easier since the regular dive gear corrects for it.

With 260 dives around the world in the last 3 years, only recreational place I've seen canisters is at Bonne Terre and Melbourne Austrailia and THEY were DIR divers. (For purposes of this discussion DIR = Tech)

Codiak · Feb 25, 2010

Canisters are useful for all types of diving, just not as popular with the Rec peeps. No worries, since this isn't a marketing exercise just stick with a Canister, it Can work for all. (Hah theres a marketing line... "It CAN work for all. :candle:

Deal87 said:
Ok the spec list we are building up so far sounds good to me.

I seem to have an issue if I want to have a neutrally buoyant design I choose a canister but then you say Rec divers typically don't use canisters... Neutrally buoyant hand held design, possibly?
Wrap it in neopheren and maintain trapped air will help.

I realise the design I will come up with may not be as good as a dedicated divers design but I was given the project to complete from an engineering point of view with the aim of getting a good grade using the knowledge I have built up, admittedly it's not ideal with me not being a diver.

With regards to LED light colour temperature I was thinking a nice cool white but not too harsh say 5000K.

I am pretty set on the idea of having multiple LED's mainly due to the focussing design I have developed, I need one to mount to each arm. I aim to use a lens to focus the LED and physically move the arms to vary the beam. The reason it seems 'cart before horse' is that the project is mainly marked on the product design, mechanical features, material analysis and CAD etc. My tutor said not to worry too much about the electronics as I am not an Electronic engineering student; however I feel to get a solid overall design I need to include this in my project. I think you will agree it helps design other parts of the torch once electronic issues are decided.

I have looked into switches Piezoelectric and Reed switches both appealed to the design because of the non mechanical interaction and easy sealing appeal. I am leaning towards a Reed switch. I have some concepts which allow the user to use a twist switch to move a magnet close to the body of the torch to allow the switch to 'close'. Details again need to be finalised as they depend on batteries and LED's chose to decide the current running through the switch.
Thanks again. Keep the questions answers coming it's all good stuff!

So 3 LEDS is a requirement based on you focusing system, fine.

Lots of options available, though the only multiple LED system I built was using a drop-in TerraLux 300 bulb. http://www.batteryjunction.com/tle-300.html simple design with a reed switch in the power loop and 2 x18650 in series and 3 pairs in parallel.

You could use 3 SSR-50s drive them seperately or under drive them in series, 1-3 hipCC drivers from taskled.com should do the trick.

There are other driver options from DX and you need a reed multilevel switch.... Hopefully someone will chime in for these...

I perfer On/Off.... KISS

Deal87 · Mar 1, 2010

Hi thanks again for the replies, useful as always. I have been researching the suggestions made and they appear to be very helpful. My design has a restriction that I cannot use the TerraLux bulb as I need the LED's to be able to move separately from each other. The SSR-50's you suggested (are they more commonly known as SST-50's?) if so then the spec sheet reads well. Nice 6500k colour and high output and efficiency available. This LED choice seems good for my design.

So if the hipCC driver along with the d2Flex is used with 3 SST-50s this will optimise the dimming function of the driver. My question is can this be somehow controlled with a Reed switch or is there a more suitable driver for this job.

Few things to clear up about the LED's to help with battery selection. If they were ran in a series what sort of Voltage and Current would be running through the circuit. Also are there CAD files available which show the LED package well? Lastly do I need to run the LED's with the star board or is that simply for ease of installation?

Thanks again guys I look forward to the replies, things seem to be moving in the right direction

350xfire · Mar 1, 2010

SSR is mounted on a star board!!!

LED and battery selection help

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