Author Topic: Looking for a high temperature plug pack (wall wart)  (Read 545 times)

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Offline aargee

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Looking for a high temperature plug pack (wall wart)
« on: March 06, 2019, 01:31:20 pm »
Most plug pack type supplies don’t seem to come with a temperature operating range, I’m looking for an Australian one that will withstand roof cavity temperatures of 40-50 degrees centigrade and supply 5VDC @2A, any clues where to get one? Or should I just look for a quality unit and hope for the best?
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Offline Gyro

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Re: Looking for a high temperature plug pack (wall wart)
« Reply #1 on: March 06, 2019, 02:00:25 pm »
I may be over cautious but I don't think I would ever trust a wall wart in a roof cavity, it sounds like too much of a fire risk.

I'd either look for something a bit more 'industrial' (metal cased) or feed the 5V supply up from below.
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Offline mariush

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Re: Looking for a high temperature plug pack (wall wart)
« Reply #2 on: March 06, 2019, 02:04:55 pm »
5v at 2A is pretty much most USB phone chargers can manage.
You could buy a cheap one and just open it up and transplant the contents into an aluminum project box or something, making sure you insulate it from the metal.
For example : https://uk.farnell.com/hammond/1550q/enclosure-diecast-30-1x55x60mm/dp/1823045
Just drill two holes for the cables and you're done... if you're paranoid, maybe flood it in epoxy or flame retardant foam or whatever.

If price is not a big deal, maybe get a 20-25va toroidal transformer, a bridge rectifier, a capacitor and a cheap 1$ dc-dc converter from eBay (or use linear regulator if the transformer output is low enough) and then again, insulate it in a metal box.
« Last Edit: March 06, 2019, 02:07:11 pm by mariush »
 

Offline deadlylover

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Re: Looking for a high temperature plug pack (wall wart)
« Reply #3 on: March 06, 2019, 02:11:21 pm »
Meanwell make some, I think you'll have to get the interchangeable plug type ones so you can fit the Aussie plug on it if you have a strict requirement for the wall-mounted style (unless you're ok with a 'desktop' style one like a laptop charger, in which case there's lots of options).
 

Offline NiHaoMike

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Re: Looking for a high temperature plug pack (wall wart)
« Reply #4 on: March 06, 2019, 02:52:56 pm »
Just oversize it i.e. use a 4A module. It's not unusual at all for those wall warts to get above 50C on the outside at full load, so oversizing gives more room for a higher ambient.
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Offline aargee

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Re: Looking for a high temperature plug pack (wall wart)
« Reply #5 on: March 07, 2019, 03:24:12 am »
Thanks all, I am following the path of over-sizing the specs and see how that goes.
Next step may be the Al chassis version with suitable plug, as suggested.
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Online David Hess

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Re: Looking for a high temperature plug pack (wall wart)
« Reply #6 on: March 07, 2019, 04:06:59 pm »
Just oversize it i.e. use a 4A module. It's not unusual at all for those wall warts to get above 50C on the outside at full load, so oversizing gives more room for a higher ambient.

Exactly, if you cannot find something more suitable, then power derate one.
 

Offline Zero999

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Re: Looking for a high temperature plug pack (wall wart)
« Reply #7 on: March 08, 2019, 04:17:07 pm »
Just oversize it i.e. use a 4A module. It's not unusual at all for those wall warts to get above 50C on the outside at full load, so oversizing gives more room for a higher ambient.

Exactly, if you cannot find something more suitable, then power derate one.
Yes, to help matters, the over-current protection normally has a negative temperature coefficient, which also provides some thermal protection by default.
 


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