Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

LPF Donation via Stripe | LPF Donation - Other Methods

Links below open in new window

ArcticMyst Security by Avery

In search of 22A 4V buck driver.

AaronT

0
Joined
Jun 12, 2016
Messages
320
Points
28
I'm looking for a 22A 4V driver. (2 26650s as power source)

A small driver with the ability to use an external adjustable pot (as blackbuck M8) would be great.

Any designs for such a driver would also be useful.
 





Joined
Sep 20, 2013
Messages
17,254
Points
113
If you are trying to get a driver the size of the BBM8 that can deliver 22 amps, that is going to be a problem. It would take maybe three ICs in parallel to do it and would need significant heat sinking.
 

diachi

0
Joined
Feb 22, 2008
Messages
9,700
Points
113
If you are trying to get a driver the size of the BBM8 that can deliver 22 amps, that is going to be a problem. It would take maybe three ICs in parallel to do it and would need significant heat sinking.


Yup, 22A current, 7.4V in (or more, if you're using unprotected cells at 4.2V each), 4V out gives you 74.8W waste heat. Not something you can dissipate in a tiny package.
 
Last edited:
Joined
Jan 29, 2014
Messages
12,031
Points
113
Might be able to pull it off with several drivers paralleled, they might not like being attached together like that, if so they can be isolated from one another with a diode. Just turn each driver up to some set current level, i.e. 5.5 amps if using four in parallel, then they each cannot supply more than that. This might work, I've done it before and gotten it to work for high power 100 watt LED's, but not for a laser diode.
 
Last edited:
Joined
Jul 10, 2015
Messages
9,799
Points
113
2 x 26650's are not going to like putting out that power but in short bursts, even fully charged you will have some sag and be drawing around 14 amps, that's around a half ohm load on the batteries, they will do it but it's a strain and you wont get much runtime between charges depending on your drivers minimum, if your driver/drivers need 6.5 - 6.8v minimum you may only get a few 30 second cycles before they are sagging under the minimum, I would run 3 x 26650's at the least....your talking about the equivalent of 4 x nubm44's, I would use two strings of 3 for a total of 6 batteries in series parallel, 2 strings of 3, but 3 x 26650's in series at a bare minimum and good IMR cells.

----

@ Alaskan: I have some 100w leds and IIRC they take around 36v.
 
Last edited:
Joined
Jan 29, 2014
Messages
12,031
Points
113
Might consider a custom battery pack being made for you too, this guy makes them: https://www.ebay.com/itm/Custom-Li-...-bike-e-motorbike-e-car-solar-Po/182586121720

edit: just saw the added question;

Yep, those are the ones, I used six each ten amp capable constant current regulators because I had lots of those LED's, not just one. I used diodes to isolate each cc power supply from another. https://imageevent.com/qdf_files/te...dandlaserproject?z=9&c=8&n=1&m=-1&w=4&x=0&p=4

These are not them, but look much the same and rated for higher current: https://www.ebay.com/itm/DC12-60V-t...t-Step-Up-Converter-Module-BQLZR/162438035915 - Doesn't mean you can run them at that high of a current, depends on the input voltage, the more the voltage boost, the less output current they can do.
 
Last edited:
Joined
Jan 29, 2014
Messages
12,031
Points
113
I wanted to do the same thing, I saw a youtube video a couple years back where a guy did just that, he shot it over a lake or harbour entrance right over a passing boat, just watching it make me nervous.

On that beacon, it worked well, but due to the amount of voltage boost, I remember the current from each power supply being fairly low. Anyway, just keep in mind if someone uses these power supplies, when supplying at 12 volts input, the stated current capacity is wrong, you don't see what it can really do until you buy it and get a manual. I haven't seen this beacon in two years, buried in storage.

EDIT; I remember now, I ended up adding two more supplies, using a total of eight cc power supplies to allow the current I needed and believe they were each putting out close to 3 amps.
 
Last edited:
Joined
Jul 10, 2015
Messages
9,799
Points
113
Yes with 36v at 2.5a we got cheated, they are only taking 90W in, no way they put more than 30w out LOL

Yea, some are real and some are China rated, I bought some outdoor LED lights that were way under spec, but I have some good ones now, they are intense, but my security cameras see just as well in the dark with their onboard IR emitters, I look at the monitor and it's like daytime only in black and white, the consumer grade technology has become quite good and affordable too.


Have you seen this crazy thing >>> https://www.ebay.com/itm/RGB-Full-C...077680?hash=item3d4f65d0b0:g:NroAAOSwSutaDAaL

https://www.ebay.com/p/1840mw-Wide-...itm=222445477826&_trksid=p2047675.c100623.m-1
 
Last edited:
Joined
Jul 10, 2015
Messages
9,799
Points
113
Hell the RGB engine is worth the 100 bucks, well just about.

https://www.ebay.com/itm/SUNY-DMX-4...243355&hash=item35c67db239:g:jrYAAOSwbl5ZftQd


-----------------------------------------------------------------------------------------------------------



These DC to DC LED drivers wouldn't work or could they, some people use led drivers.

https://www.ebay.com/itm/Power-Supp...hash=item1c886004be:m:mnj1ZT3pZgJhXljPOVQhg7g



------------------------------------------------------------------------------------------------------------
 
Last edited:
Joined
Sep 20, 2013
Messages
17,254
Points
113
I could be wrong, but the way OP is trying to miniaturize this, I believe he wants it in a HH. My point was this is not a good idea.
 
Joined
Jul 3, 2015
Messages
500
Points
43
I'm looking for a 22A 4V driver. (2 26650s as power source)

A small driver with the ability to use an external adjustable pot (as blackbuck M8) would be great.

Any designs for such a driver would also be useful.

22 amps! What are you building, a portable electric chair :eek:
 
Joined
Jul 10, 2015
Messages
9,799
Points
113
Going to be a lot of waste heat me thinks...but why 22a at only 4 volts?
 




Top