16.75 VDC output needed @3.5A

[john61ct]

Need a power supply with the above output, producing resistive heat, actually first feeding into a variable power control

I assume some wiggle room on the voltage but dunno, prefer as close as possible. Same with the current spec the control may not be current limiting, rely on the PSU for that?

Does not need to be a charger, no auto termination but overheat and other basic protections would be nice.

Any input power spec at this point would be great but ideal would be either DC at 12 or 24V,

or AC house current 120V USA or Euro 240V

TIA

 

[nicobie]

Pretty specific specs. What are you building? Couldn't you use a regular 24V meanwell with a dc to dc converter?

I must be missing something as you are way better at electronics than I am.

 

[john61ct]

LOL we all have our gaps.

Yes as mentioned a DC-DC unit would be fine, don't really care what is upstream.

Looks like that 16.75V is a rare voltage, only see Dyson wallwarts dual output with 24V as well.

But something reliable that is ADJUSTABLE ideally volts and amps limiting, would be just the ticket.

If it took 20VDC input, would let me use USB PD now THAT would be sweet!

Calling @method...

 

[methods]

I use TRC
https://www.trcelectronics.com/mean-well

Most-All Meanwell will do at least +/- 10%, but remember to pick only those that can drop into true CV/CC. No hiccup etc. Remember that some require a fan.

Generally speaking the potted Meanwell power supplies are super-hero's. I use them in every major project.

16.75*3.5= ~60W
So you can drop anything producing LESS than that, but of course consider others producing more (or far more).

The voltage you propose is going to be a "15V Power Supply"
Like these: https://www.trcelectronics.com/mean-well-open-frame-power-supply-epp-100

That list is already sorted down, so those are just what are available in that particular flavor (for example). There are M A N Y flavors so we will search differently in a moment.

SO you pick one, and get its data sheet
https://www.trcelectronics.com/View/Mean-Well/EPP-100-15.shtml



so you move on

-methods

 

[methods]

This type is FAR better, but obviously more expensive.

https://www.trcelectronics.com/View/Mean-Well/HEP-100-15A.shtml

All of them will be 120/240V compatible, 50/60hz. Most of them will run off of 60V or more DC as well.



Now see how that meets requirements? You can always go over (and should go over) with your current, UNLESS... you are trying to do a CC application, like charging batteries that can not take more than X.XX

Anyway
Bask in the glory of those particular Power Supplies and others like them. Read the datasheet and think about things like IP68. That means you can piss on the thing in a wind storm and it will just magically work forever. You could drop it in the bath tub for a while.

Anyway
Purchase Link: https://www.trcelectronics.com/View/Mean-Well/HEP-100-15A.shtml

Best $90 + Shipping you ever spent. That Power Supply is ready to be strapped to the frame of your bike and ridden off into the sunset.

SO
Start there and work backwards. For every $10 you save, figure out why. For every hour you waste, CHARGE YOURSELF $20. After you waste 3 hours then buy some piece of CRAP off Amazon for $30 that just blows up and sucks

Well
Then come back and tell uncle methods about it.

MOST IMPORTANT IDEA: "If you cant include hourly on your time searching, than change something"

Cuz
Literally you could go dig holes for the next door neighbor, make $60, and get the better supply.

out

-methods

 

[lnanek]

Isn't that essentially 4*4.2v so just a 4S LiIon charger in CV mode? I have several wall warts that are that spec dug out of the cardboard e-waste bins at work. Several 4S RC chargers too since I like to bid $10 on those on eBay and take whatever no one else bids up. I think my XTAR Dragon VP4 has a 4S connector too, actually.

 

[john61ct]

Isn't that essentially 4*4.2v so just a 4S LiIon charger in CV mode? I have several wall warts that are that spec dug out of the cardboard e-waste bins at work. Several 4S RC chargers too since I like to bid $10 on those on eBay and take whatever no one else bids up. I think my XTAR Dragon VP4 has a 4S connector too, actually.

Ooh yes great observation, definitely an easy approach for off grid use.

Being able to control (limit) amps a big plus

 

[john61ct]

Thanks methods, yes pricier than I was hoping but you are right of course.

You can always go over (and should go over) with your current, UNLESS... you are trying to do a CC application, like charging batteries that can not take more than X.XX

See that's where I want to be cautious.

Resistive heat production is the use case, and the manufacturer has closed no more being produced.

Different model units, different power output by the same manufacturer, are supplied with different bricks, not only different Vdc but different amps spec'd.

So I figure maybe the load can pull unsafe current levels and the PSU requires true limiting there to a maximum as a safety feature, not starting fires.

There is also an 11-level User Control dial for heat level, no idea if it is varying the voltage or the current.

Now that my head is a bit clearer, I see the cost of good stuff and you reminding me my time has (some) value

probably best off just chasing down spare NOS units to keep on hand.

But I will keep this open in case I do delve deeper one day, thanks for those detailed inputs!