Laptop outlet in a 24VDC panel

[jtn]

I have begun using 480VAC power supplies in my panels to keep heat from a transformer out of the panel. This works great if the panel is mounted inside a building and there are outlets available. Does anyone know of an economical way of supplying 120VAC power for a laptop in a panel that does not have a 120VAC xfmr in it? I would would love to find an outlet that has a 24VDC to 120VAC inverter in it with just enough power to run a laptop. All the inverters I have found provide way more power than that and cost $1000. Thanks for any leads!

 

[the_msp]

Industrial, probably going to be rare.

Domestic, something that a truck (24V) battery etc, maybe:
https://www.amazon.co.uk/Power-Inverter-Outlets-Truck-System/dp/B09FXV57FF

Whether that passes UL etc, I don't know

 

[Lare]

Car DC outlet port and car laptop charger is economical.

 

[Ken Roach]

Because more boats run on 24V than cars/trucks, a marine purpose inverter might be appropriate.

I would reach for a Mastervolt or Xantrex because that's what I use on my boats. Maybe a GoPower, since they're part of Dometic now.

Their GP-ISW-200-24 has a different part number for the 24V unit than the 12V unit, so be sure you order the right one. That's got hefty lugs instead of a cigarette lighter plug and provides 200W on a GFCI outlet.

Or, get yourself an in-panel industrial unit: https://mou.sr/3M4CAYP

 

[BryanG]

Going from 24v d.c to 110/220V a.c, just so that the laptop power brick can convert it back to 12-18V d.c. seems a bit wonky. Can't you just get a DC/DC converter to change the 24V d.c. in to whatever your laptop needs.

 

[I_Automation]

I have a car laptop charger rated for 12 to 24 volts. I also carry in the car a 125 watt AC power inverter.


But consider the wattage the converter and the laptop will use, it might be enough to require a larger DC power supply.


EDIT: you can also specify an external 120V power source along with the 480V


Also for a transformer that doesn't heat up the enclosure put an enclosed dry transformer on the outside of the enclosure - like this but take gravity into consideration and lower it:

 

[JesperMP]

I have had the same thoughts.
Historically we always had a power outlet in the cabinet, no matter big or small.
But then we switched to direct 3-phase to 24V psu's with no single phase stage, whereby a transformer for only the PC power outlet became a luxury.
1. Laptops have better batteries and/or are more power frugal. The batteries used to last a few hours at most, now they last at least half a day.
2. Every control panel is networked. Instead of hooking up at the panel, you can do so from a control room with plenty of power outlets.
3. As an alternative for installing a 24V to AC in every panel, get a 24V-to-laptop power supply for the occasional need. Like has already been suggested, you can get one that has a 12V/24V supply intended for car or truck use.
Because of 1 and 2 it has turned out to be a non-issue that there is no power outlet in the panel.

If the above is not good enough reasoning, and you must have a permanently installed power outlet for the laptop, consider this:
Instead of going over the bridge with a 24VDC to AC converter, have a small transformer for the laptop outlet only. And then have a circuit breaker for the transformer and label it "turn off when laptop is not plugged to outlet". edit: A transformer generates the most heat when it is NOT under load.

 

[KuulKuum]

2. Every control panel is networked.

"Every" is subjective, where I work about 50% of the systems are only locally networked with its local devices and the access to the network is within the panel itself.

 

[arpus4KM]

you could go the compact route and get one of the Milwaukee Top Off charger adapters.

It's just a converter that uses 18v L-ion batteries and has an output rated at 175watts, which should be enough to charge any laptop.


slap a 24v to 18v buck converter on it and as long as you have the appropriate size fusing on that 24v line, then you've got a nice 24v powered 110v ac outlet that is meant to charge a newer laptop (180w standard on the new laptops that I've seen).



Or.... you just buy a combo of the Milwaukee 18v 6.0 AH batteries and the AC adapter for 279 and you'll have two batteries (plus the laptops power) that will last more than a days worth of work.

 

[theColonel26]

Like others have said

Just keep a little Marine Inverter in your back pack and stick the wires in a spare terminal block space.... Don't need to have it be permanent.

1. Laptops have better batteries and/or are more power frugal. The batteries used to last a few hours at most, now they last at least half a day.

IDK what laptop you have but my ThinkPad P15 Gen 1 sucks battery like crazy. I am lucky if I get 90 minutes, and that was when it was new in 2020.

2. Every control panel is networked. Instead of hooking up at the panel, you can do so from a control room with plenty of power outlets.

This is not always true sadly though it should be since it is 2023.

I carry around a Mobile Wifi AP/Router and just plug it in to the machine network if it is isolated and I don't want to me out on the floor by the panel... Only has so much range though especially in plants.

3. As an alternative for installing a 24V to AC in every panel, get a 24V-to-laptop power supply for the occasional need. Like has already been suggested, you can get one that has a 12V/24V supply intended for car or truck use.
Because of 1 and 2 it has turned out to be a non-issue that there is no power outlet in the panel.

"Car Chargers" for laptops are not nearly as common as they used to be. but it is your best option if you can find one for your laptop model.

 

[I_Automation]

"Car Chargers" for laptops are not nearly as common as they used to be. but it is your best option if you can find one for your laptop model.

The charger I bought was a travel airplane kit sort of like this but this is only for Dell and only 12V.



The charger has the cigarette lighter plug plus it came with an adapter for a special 12V plug on airlines that I have never seen on all the planes I have been on - half of which were international flights on foreign airlines.


Also the charger has a slide switch for a variety of output voltages and an assortment of plugs for various laptops.

 

[jtn]

Pretty much my thoughts on a small transformer at this point. The panel will be outdoors remote from other outlets, and multiple people will be using it over time so it needs to ha place to plug in multiple styles of chargers. I would love to find someone that sells a little 2A outlet with a small inverter built into it!

 

[James Mcquade]

jtn,

what is your controls voltage in the panel?
120 ac, 24 vdc?
Unless they changed the rule, NFPA 79 states that control panel voltages above 120 volts is not allowed. I do not have my manual with me at present.
the 480 volt power supply will need to have finger safe terminals and take NEC 70E - arc flash into consideration. if i am incorrect, some one please correct me.
james

 

[lfe]

If your laptop's power connector is USB C, you can use this, which can also charge the mobile phone.

https://www.amazon.com/Charger-HKY-12V-24V-Adapter-Replacement/dp/B08MQ7HMPY/

And this: https://www.amazon.com/SMAKN-Cigarette-Lighter-Connector-Adapter/dp/B074CT5CSN/

 

[jtn]

jtn,

what is your controls voltage in the panel?
120 ac, 24 vdc?
Unless they changed the rule, NFPA 79 states that control panel voltages above 120 volts is not allowed. I do not have my manual with me at present.
the 480 volt power supply will need to have finger safe terminals and take NEC 70E - arc flash into consideration. if i am incorrect, some one please correct me.
james

There are motor starters in the panel, so 480VAC is coming in. It is a UL rated panel, and whatever I come up with for the outlet will need to keep that UL. As of now I am looking at a small xfmr just for the outlet. Would love to get rid of the 120VAC in the panel so it is closer to what is our standard panel now as if it is in a building there will be outlets in the building to connect a laptop to.