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Please Help replacing 2 power adapters with 1 battery or power bank.

Manuel Medeiros

Jul 5, 2017
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Jul 5, 2017
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Hi everyone,

I have a controller board for a lcd screen powered by a 12v 3A adapter.
This LCD screen belonged to a Sony Vayo and it's battery power is 11.1V 5200Mah.

This lcd screen now works with a raspberry PI for which I need a 5v adapter.

I would like a power bank to power both items but i don't know if it is possible...Does it exist?

Thanks
 

kellys_eye

Jun 25, 2010
5,511
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Jun 25, 2010
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Yes. There are power banks that are supplied for use with HDD readers - I have two. The come with the conventional molex connector to power the HDD but that can be easily removed. IIRC it was capable of delivering 2A at 12V and 3A at 5V but if you search around you might find one with a higher output.

Indeed, there should be lots of small PC power packs that provide 12/5V - I've seen many over the years.

Alternatively you could get a 12V adapter with (say) 4 or 5A output and use a small regulator to drop to a 5V output as well.
 

dave9

Mar 5, 2017
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Mar 5, 2017
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Doesn't a PI use a small current, something like 200mA peak? I'd just throw an LM7805 regulator and capacitor between the 12V adapter and it. Put a modest heatsink on the regulator.
 

Robert_fay

Jun 15, 2017
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Jun 15, 2017
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Depending on what all you want to use it for. pi actually recommends a supply that will do 2A for full functionality. If you are not using it to power anything just to control the screen you can probably get by with much, much less.
 

dave9

Mar 5, 2017
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^ Even then, there are ~ $1USD delivered buck switching regulator boards on eBay, barely larger than a LM7805 with a heatsink on it, could possibly be stuffed into the housing already being planned for the project. Examples:

https://www.ebay.com/sch/i.html?_from=R40&_sacat=0&LH_BIN=1&_nkw=buck+regulator&_sop=15

Considering the low cost and size, they may be a better option than an LM7805 linear regulator, except i mentioned the 7805 first because many people have some of those already, instead of waiting a month for something to ship from China, maybe receiving the order or maybe a month goes by and no package so you have to reorder and wait another month, etc.

I've had that situation happen more and more in the past couple years. Fortunately it has been easy to get a refund... so far.
 
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