Author Topic: DC-DC Power supply recommendation  (Read 627 times)

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Offline allencTopic starter

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DC-DC Power supply recommendation
« on: September 17, 2023, 08:41:39 pm »
I'm searching for a DC-DC step up power supply.  The application is simultaneously driving up to 3 NEMA 17 steppers drawing ~1A each at 28-36V using DM542T drivers.  I want to use a common 18V tool battery, which typically start out in the 21V-ish range.  The application has a low duty cycle; the motors will move infrequently (couple times a minute) and briefly (2-10 seconds.)

There are a lot of small, cheap DC-DC SMPSs around.  I've found they can't deliver the current even unloaded.  I'm thinking I need something in the 120-150W range.

The budget is not super tight: anything around $200 or less is fine.  Nice to haves would be a control line to startup/shutdown the PS and an enclosure.  The closest I've found is the Meanwell DDR-120B line.  They've got 24V and 48V output versions.  The former is a bit too low voltage and the later is too high...  The 24V can supposedly be cranked to 28V but I'm hoping to not have to play such games and I'd rather operate at higher voltage for better torque and lower current.  I don't actually *know* that I couldn't use 24V (which is right at the low end of the DM542T driver specification,) but I'd like to just avoid the guesswork and buy something that solves it.
« Last Edit: September 17, 2023, 08:46:08 pm by allenc »
 

Offline soldar

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Re: DC-DC Power supply recommendation
« Reply #1 on: September 17, 2023, 09:24:04 pm »
You might consider using two batteries in series and dropping a few volts if necessary. Probably more efficient.
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Offline allencTopic starter

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Re: DC-DC Power supply recommendation
« Reply #2 on: September 17, 2023, 09:37:13 pm »
I have considered that.  Do you have any converter in mind?  42V to 36V or less?
 

Offline soldar

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Re: DC-DC Power supply recommendation
« Reply #3 on: September 17, 2023, 10:43:15 pm »
I have considered that.  Do you have any converter in mind?  42V to 36V or less?
Dropping very few volts should raise efficiency. Stepdown modules seem to be more common, more efficient and cheaper than boost step-up modules.

I am using several of these and they work well:
https://www.ebay.com/itm/404206822347
DC CC 9A 300W Step Down Buck Converter 5-40V To 1.2-35V Power module

They are nominally limited to 40 V input. It may be that
(1) you could find one with a higher input or
(2) you could measure and find the batteries do not go up that high or,
(3) the device will accept a few more volts for a while without problem.

They are cheap enough that you can test them. I bought a bunch of them and have them around for whenever I need one. I have one right next to me feeding a printer that requires two different voltages and I do not have the original PSU. Rather than providing the two voltages I just supply the higher one and step down from there.
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Offline Someone

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Re: DC-DC Power supply recommendation
« Reply #4 on: September 17, 2023, 11:53:20 pm »
Change to lower voltage motors, its the easiest parameter to change.
 


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