[PSUBS-MAILIST] PWM

Sat Apr 1 18:29:30 EDT 2017

Thanks Alan, I am going to need some hand holding in this area!

Rick

On Sat, Apr 1, 2017 at 11:12 AM, Alan via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Rick,
> I have a good source of information on LEDs.
> These high powered COB (chip on board) LEDs are a reasonably recent &
> evolving
> innovation. They are a number of 1Watt LEDs on a board (COB) Normally
> configured
> 10 x 5 for 50W, 10 x 6 for 60W etc. I have tested one to 2000psi; so they
> can be
> oil compensated & take the pressure.
> As Alec has said, they need a constant current driver, as they suck more &
> more current as they get hotter & burn themselves out. They are reasonably
> Voltage tolerant. I ran a 38V LED at 90 V briefly by mistake & it survived.
> There are more & more LED drivers coming on the market. I bought some step
> / up,
>  step / down constant current drivers for $12- each off Aliexpress.
> The LEDs need to be screwed down to a heat sink, with heat sink paste. If
> they
> aren't screwed down well they can burn out.
> As for PWM dimming; I am getting a unit made up with PWM, & they said the
> dimming
> wasn't as easy as just replacing the trim pot with a length of wire &
> potentiometer.
> However I will test that out & see what the dimming is like.
> Anyway, I will post something when I have my unit with new controller up &
> running; & Alec will have Cliff's Psub design going in the near future.
> Cheers Alan
>
> Sent from my iPad
>
> On 2/04/2017, at 7:24 AM, Rick Patton via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
> Hi Alan,
>
> I have plenty of time before i need lights so no hurry. I just kinda
> wanted to get a complete LED system down so I would know what size to start
> fabricating my housings. I still would like to go with LED as they last
> longer and are brighter than the incandescent bulbs but I have no concept
> of drivers or step up or PWM's so it is a bit frustrating. The guy in
> California that I mentioned was an electrical engineer and knows this stuff
> inside and out so I'll see if I can pick his brain a bit more and see if he
> has any interest in making lights for us Psubs guys
>
> Rick.
>
> On Fri, Mar 31, 2017 at 5:38 PM, Alan via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
>> Rick,
>> how soon do you need to get your lights done?
>> I bought a few step up / step down constant current drivers that can
>> handle
>> a 100W LED. But no pwm dimming on them.
>> Looking at them, you can do as Alec suggested & de-solder the trim pots &
>> replace with wire to a potentiometer. You could use a certain sized
>> resister in
>> line to stop you dialling in more current than you need.
>> I could play around with one & let you know how it goes if you like.
>>    I am using 80W LEDs & get plenty of light from them driving them at
>> 70W.
>> My LEDs are the latest flip chip technology, that keep cooler out front.
>> They are smaller than other comparable Watt LEDs enabling a smaller
>> housing
>> & thinner lens for the same depth.
>> Alan
>>
>>
>>
>> My lights are having pwm dimming put on an led step driver tailored to my
>> voltage. They said it was not that simple to add pwm dimming control.
>> There is the
>>
>>
>> Sent from my iPad
>>
>> On 1/04/2017, at 3:25 PM, Alec Smyth via Personal_Submersibles <
>> personal_submersibles at psubs.org> wrote:
>>
>> Hi Rick,
>>
>> Yes, you need to match them and the assortment of drivers is quite
>> bewildering. I knew nothing of this myself just a couple of weeks ago, so
>> I'll try and summarize my selection logic but if anyone more knowledgeable
>> finds me in error, please do jump in. I haven't even received my drivers
>> yet, so my choice is untested.
>>
>> Generally these drivers are either "step up" or "step down" devices,
>> meaning that they take the battery bank voltage and adjust it upward or
>> downward depending on the voltage required for your specific LED. Not all
>> LEDs of the same output have the same voltage requirement, so I can't
>> provide a standard voltage for 10K lights and you will need to look that up
>> on your LED specs. In most cases it should be clear which of those two
>> varieties of drive you need, so deciding whether you need a step up or a
>> step down driver I would say is the first cut at narrowing your choices. In
>> my case I had an odd situation, because the battery bank voltage was very
>> close to the LED voltage, and since the battery voltage will drop under
>> load and with discharge, I could find myself crossing the threshold from
>> stepping down to stepping up. There are a very few drivers that can step in
>> either direction as needed, but I did find a few.
>>
>> To summarize then... Once narrowed down to step-up or step-down type, the
>> next thing is to look at is voltage ranges. Each driver will have an input
>> voltage range, which needs to cover your possible battery voltages, and it
>> will have an output range, which needs to cover the LED spec voltage. This
>> latter voltage is constant.
>>
>> Then finally, there's a choice of driver current capacity. This is a
>> measure of how much power the driver can handle without burning out. Your
>> LED will tell you how many amps it consumes. A sub in the tropics is a hot
>> and humid environment with minimal ventilation, so I'm inclined to pick a
>> driver that is way over-rated to prevent it from heating up much. Bear in
>> mind you can also drive multiple lights off one driver if their combined
>> current is within the driver's current capacity.
>>
>> As for dimming capacity, most drivers seem to have two pots, one for
>> output voltage and the other for output current. These controls should
>> allow you to dim the lights, but from what I saw they are typically small
>> components on the board, and not something intended for manipulation by the
>> end user on the fly. It may be you could replace a miniature trim pot with
>> one on a cable, mounted on the face of your enclosure, but you would also
>> need to be careful with the adjustment range. You would not want a knob
>> that burns out your lights if you turn it a little too far.
>>
>> Hope that helps, but realistically you might find it'll take a day or two
>> of research to narrow things down.
>>
>>
>> Best,
>>
>> Alec
>>
>> On Thu, Mar 30, 2017 at 1:49 PM, Rick Patton via Personal_Submersibles <
>> personal_submersibles at psubs.org> wrote:
>>
>>> Thanks Jim and Alec,
>>>
>>> Do i have to be concerned about matching the PWM to the specific LED
>>> array I buy as there are so many out there. If so, can someone help me do
>>> the match up as I have NO electrical back ground. I do want to be able to
>>> dim the lights from 10,000 lumans down as much as I want as there will be
>>> times where I won't need that much and it will also be a power savings on
>>> my 36 V battery bank for my thrusters.
>>>
>>> Rick
>>>
>>> On Thu, Mar 30, 2017 at 1:37 AM, Alec Smyth via Personal_Submersibles <
>>> personal_submersibles at psubs.org> wrote:
>>>
>>>> Hi Rick,
>>>>
>>>> LEDs need a driver board to supply them with constant voltage and
>>>> current, and Cliff's design includes an on-board PCB, inside the light
>>>> itself, that does just that. The heat is dissipated by the housing, which
>>>> is aluminum and has cooling grooves. Personally I opted for a larger off
>>>> the shelf driver that will go inside the sub, because I didn't have much
>>>> ability to solder the surface mount components and didn't have the need to
>>>> miniaturize that was one of Cliff's design priorities. There are lots of
>>>> drivers available, and I got mine on eBay like so many other components of
>>>> the sub. This driver has a heat sink, but I don't expect it to heat up much
>>>> at all. See eBay item 302203712954.
>>>>
>>>> Best,
>>>>
>>>> Alec
>>>>
>>>>
>>>>
>>>> On Thu, Mar 30, 2017 at 7:24 AM, via Personal_Submersibles <
>>>> personal_submersibles at psubs.org> wrote:
>>>>
>>>>> Rick,
>>>>> He was referring to a Pulse Width Modulator to adjust the amount of
>>>>> power going to the lights.
>>>>> Jim
>>>>>
>>>>> In a message dated 3/29/2017 11:29:44 P.M. Central Daylight Time,
>>>>> personal_submersibles at psubs.org writes:
>>>>>
>>>>> Alec,
>>>>>
>>>>> I just met a guy in California that made his own underwater housing
>>>>> and LED lighting system for doing video and he is using an LED board that
>>>>> is about 3" square. He has built a PWM for it so he can dim it down and
>>>>> says it's a 10,000 luman 100 watt system that runs on 32 volts.
>>>>>  I don't know what a PWM is but he said that I didn't necessarily have
>>>>> to have one. I can step my thruster motor supply down from 36V but one of
>>>>> my concerns is how to get rid of the heat. He didn't seem to be too
>>>>> forthcoming with the system he built. I think the LED array was something
>>>>> like $15 each on Amazon. How are you controlling the heat in your housings
>>>>> and do you think I would need a PWM for my lite?
>>>>>
>>>>> Rick
>>>>>
>>>>>
>>>>>
>>>>> On Wed, Mar 29, 2017 at 3:34 PM, Alec Smyth via Personal_Submersibles
>>>>> <personal_submersibles at psubs.org> wrote:
>>>>>
>>>>>> My lights are done, I put them on Shackleton earlier today and they
>>>>>> are wired through the hull with penetrators. However, the wires end inside
>>>>>> the hull because I'm waiting for the drives to arrive, which will be
>>>>>> installed inside the sub. I was able to test them with a lab type power
>>>>>> supply on a table top, and must say these Bridgelux leds are like a little
>>>>>> sun in a can, I love them. These two lights I made are 5K lumens, and I
>>>>>> already have 10K lumen Bridgeluxes which I bought by mistake. So I'll test
>>>>>> these, and probably make another set with those more powerful ones. If I
>>>>>> do, the 10Ks will be the forward lights and the 5Ks will be oriented out to
>>>>>> the sides for "peripheral vision". A dimmable driver is sounding like a
>>>>>> good idea, or maybe just sunglasses!
>>>>>>
>>>>>>
>>>>>> Best,
>>>>>>
>>>>>> Alec
>>>>>>
>>>>>> On Wed, Mar 29, 2017 at 9:10 PM, Alan via Personal_Submersibles <
>>>>>> personal_submersibles at psubs.org> wrote:
>>>>>>
>>>>>>> Thanks Hank,
>>>>>>> Alec has been making good progress with Cliff's light.
>>>>>>> Last I heard 2 housings were being anodised.
>>>>>>> Any update Cliff / Alec ?
>>>>>>> Alan
>>>>>>>
>>>>>>>
>>>>>>> Sent from my iPad
>>>>>>>
>>>>>>> On 30/03/2017, at 1:30 PM, hank pronk via Personal_Submersibles <
>>>>>>> personal_submersibles at psubs.org> wrote:
>>>>>>>
>>>>>>> You will be our go to guy for lighting!
>>>>>>>
>>>>>>>
>>>>>>> On Wednesday, March 29, 2017 6:15 PM, Alan via Personal_Submersibles
>>>>>>> <personal_submersibles at psubs.org> wrote:
>>>>>>>
>>>>>>>
>>>>>>> Still building lights Hank,
>>>>>>> have built a couple of housings but are doing a third revision &
>>>>>>> hopefully this one will be perfect. I am pretty happy with how it's
>>>>>>> going.
>>>>>>> Am getting a different LED driver made up with PWM dimming.
>>>>>>> Got off the motor project temporarily as my brother wanted one of
>>>>>>> the lights for his boat. 😐
>>>>>>> Alan
>>>>>>>
>>>>>>> Sent from my iPad
>>>>>>>
>>>>>>> On 30/03/2017, at 12:35 PM, hank pronk via Personal_Submersibles <
>>>>>>> personal_submersibles at psubs.org> wrote:
>>>>>>>
>>>>>>> Alan,
>>>>>>> Are you back to work on your motor?   or are you still building
>>>>>>> lights?
>>>>>>> Hank
>>>>>>>
>>>>>>>
>>>>>>> On Wednesday, March 29, 2017 4:44 PM, hank pronk via
>>>>>>> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>>>>>>
>>>>>>>
>>>>>>> Thanks' Greg
>>>>>>>
>>>>>>> Alan, my answer is who cares if some water gets between the seals.
>>>>>>> The important part is to keep the oil inside the motor.  When the motor
>>>>>>> starts up at the surface, there is significant centrical force that pushes
>>>>>>> the oil out with the seal in its original orientation.  I should actually
>>>>>>> remove one of the seals and just have one seal holding oil in, just like a
>>>>>>> submersible well pump has.  Those pumps are VERY reliable.  Now having said
>>>>>>> all this, I could be wrong ;-)   Stay tuned for test results.
>>>>>>> Hank
>>>>>>>
>>>>>>>
>>>>>>> On Wednesday, March 29, 2017 4:31 PM, Alan via Personal_Submersibles
>>>>>>> <personal_submersibles at psubs.org> wrote:
>>>>>>>
>>>>>>>
>>>>>>> How are you doing that Hank?
>>>>>>> Are you compensating the gap between the two seals?
>>>>>>> Otherwise you are in the same situation as the Minn kota motors
>>>>>>> where one of the two seals will fail when you go beyond it's depth
>>>>>>> rating.
>>>>>>> Cheers Alan
>>>>>>>
>>>>>>> Sent from my iPad
>>>>>>>
>>>>>>> On 30/03/2017, at 10:40 AM, hank pronk via Personal_Submersibles <
>>>>>>> personal_submersibles at psubs.org> wrote:
>>>>>>>
>>>>>>> Greg,
>>>>>>> Good points, but I personally am not ready to give up on oil
>>>>>>> filling.  I have reversed one of the two seals in my new motors for
>>>>>>> Elementary.  One seal keeps the oil in and one seal keeps the water out.  I
>>>>>>> am confident this in addition to the compensation system will make for a
>>>>>>> clean leak proof set up.  The ice is off the lake by my house, so my test
>>>>>>> lake should be open in a week or so.  I will know then if my idea works.
>>>>>>> Hank
>>>>>>>
>>>>>>>
>>>>>>> On Wednesday, March 29, 2017 7:03 AM, james cottrell via
>>>>>>> Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>>>>>>>
>>>>>>>
>>>>>>> I have to say, I no longer think that WD40 is the best for
>>>>>>> compensating things underwater. Over time it causes plastics and rubber to
>>>>>>> harden and become brittle.
>>>>>>> Silicone oil is better but the other problem with oil compensation
>>>>>>> in general is that the smallest drop/leak makes a very visible oil slick
>>>>>>> around your sub (not good). Most guys are using trolling motors and they're
>>>>>>> not really tight enough to hold thin oil without leaks.
>>>>>>> Back in the 90s I was using air compensation- and it actually worked
>>>>>>> really well. As far as I know, Karl Stanley has also been using air
>>>>>>> compensation for a long time without problems.
>>>>>>> It's a clean system that's not hard to set up and a small bottle of
>>>>>>> air lasts for many dives.
>>>>>>>
>>>>>>> Greg C
>>>>>>>
>>>>>>>
>>>>>>> ------------------------------
>>>>>>> *From:* "MerlinSub at t-online.de via Personal_Submersibles" <
>>>>>>> personal_submersibles at psubs.org>
>>>>>>> *To:* Personal Submersibles General Discussion <
>>>>>>> personal_submersibles at psubs.org>
>>>>>>> *Sent:* Tuesday, March 28, 2017 12:55 PM
>>>>>>> *Subject:* Re: [PSUBS-MAILIST] WD - 40
>>>>>>>
>>>>>>> On a brushless motor it will maybe work with mineral oil.
>>>>>>> On motors with brushes I have bad expierence with that.
>>>>>>> Mineral oil is a big problem in a lake if a motor is even a little
>>>>>>> untight.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> -----Original-Nachricht-----
>>>>>>> Betreff: Re: [PSUBS-MAILIST] WD - 40
>>>>>>> Datum: 2017-03-28T17:15:59+0200
>>>>>>> Von: "Brian Cox via Personal_Submersibles" <
>>>>>>> personal_submersibles at psubs.org>
>>>>>>> An: "Personal Submersibles General Discussion" <
>>>>>>> personal_submersibles at psubs.org>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Hi Carsten,
>>>>>>>                         I did a small test trying to light the WD40
>>>>>>> on fire.  It's not as flammable as I thought it would be.  I think they
>>>>>>> have improved it's non-flammability with new formulation. It's still
>>>>>>> somewhat flammable however.
>>>>>>> I will be using a light mineral oil in my motors.
>>>>>>>
>>>>>>> Brian
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> --- personal_submersibles at psubs.org wrote:
>>>>>>>
>>>>>>> From: "MerlinSub at t-online.de via Personal_Submersibles" <
>>>>>>> personal_submersibles at psubs.org>
>>>>>>> To: Personal Submersibles General Discussion <
>>>>>>> personal_submersibles at psubs.org>
>>>>>>> Subject: Re: [PSUBS-MAILIST] WD - 40
>>>>>>> Date: Tue, 28 Mar 2017 07:22:02 +0200 (MEST)
>>>>>>>
>>>>>>> Heat Vapor is may a problem with WD40.
>>>>>>> May ensure that the compensating back is big to handle that..
>>>>>>> We change to silicon oil for that reason.
>>>>>>>
>>>>>>> vbr Carsten
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> -----Original-Nachricht-----
>>>>>>> Betreff: [PSUBS-MAILIST] WD - 40
>>>>>>> Datum: 2017-03-28T04:56:46+0200
>>>>>>> Von: "Brian Cox via Personal_Submersibles" <
>>>>>>> personal_submersibles at psubs.org>
>>>>>>> An: "PSubs" <personal_submersibles at psubs.org>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> I just ran one of my motors filled with the WD40.  It seemed to be
>>>>>>> very happy.  I mainly just did it to clean the carbon build up out of the
>>>>>>> motor.  I was surprised how sealed the motor was, it is open at one end
>>>>>>> where it mates to the gear box.  I was able to fill it up without it
>>>>>>> leaking out anywhere.  That could be an issue later when I want the mineral
>>>>>>> oil to fill all the voids.  I might need to actually drill some holes to
>>>>>>> get some circulation .
>>>>>>>
>>>>>>>
>>>>>>> Brian
>>>>>>> _______________________________________________
>>>>>>> Personal_Submersibles mailing list Personal_Submersibles at psubs.org
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>>>>>>> 
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>>>>>>
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>>>>>>
>>>>>>
>>>>>
>>>>>
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>>>>>
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>>>>>
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