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Need help powering a 12V vehicle video monitor from 5V

Old Steve

Jul 23, 2015
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Here are some more clues that may help. On the battery it says-

Input 5V/1A Max
Output 5V/1A Max
Capacity: 8.14Wh(2200mAh)

http://www.amazon.com/Color-Cube-Portable-Power-Black/dp/B00KPXZPWA/ref=pd_sim_sbs_86_1?ie=UTF8&refRID=08ET99PWMG20WT1BC56B&dpSrc=sims&dpST=_AC_UL160_SR160,160_
I just spotted your post with the battery specs. Way too small. To get 12VDC, 0.5A (6W), to allow for the wrong ratings on that monitor, the DC-DC converter will need to pull in excess of 7W at 5V, about 1.5A, at 85% efficiency.
To run for 1 hour, with a current drain of 1.5A, it would require a battery of over 15Wh, (3000mAh), and probably nearer to 20Wh, (4000mAh).

Those battery specs that you posted don't add up, either. 8.14Wh at 5V is 1628mAh.

So, you'll need a much larger 5V battery and a larger DC-DC converter.
 

Old Steve

Jul 23, 2015
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Jul 23, 2015
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Hi Steve,

I have had the lower powered units for a little while now. A friend of mine had a 12V power source he used to power one of the monitors and that is how I was able to check that it works.

Can you recommend a specific DC-DC converter and power supply I can purchase off of Amazon or another site? I am so new to this, and still a little confused, I just want to make sure I purchase the right thing.

Thanks for for breaking it down and explaining it all to me Steve. Hopefully this will all get it to work :)
We were typing at the same time. Read my last post as well before making any decisions.

I can't point you to a specific DC-DC converter or battery. I'd need to spend a fair bit of time searching, and it's already way past my bed-time. (1:50am here)

Look for a converter capable of providing at least 0.5A at 12VDC, and 1A would give you an even better chance of success, and a 5V battery with a capacity of 4000mAh to 8000mAh, if you want to be assured of getting 1 hour out of it. You'll need to go even bigger with the battery to get longer. 4000mAh, (4Ah), capacity doesn't mean that you can pull 4A for 1 hour. Batteries don't work that way. ie A 160mA 9V NiCd battery that I have here only lasts for 2 hours if I drain the current at 40mA, an effective 80mAh. It would only truly give me anywhere near 160mAh if I drained it at a much slower rate. The faster you drain a battery, the less of it's rated capacity is actually available.
 

jasongitar

Sep 4, 2015
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Sep 4, 2015
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Hi Steve, thank you for all of your help. I found a 10000mAh 5V battery pack already, now just need to find a converter, I'll keep you posted. Have a good night and thank you again :) Hopefully this will do the trick :)
 

Old Steve

Jul 23, 2015
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Jul 23, 2015
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Hi Steve, thank you for all of your help. I found a 10000mAh 5V battery pack already, now just need to find a converter, I'll keep you posted. Have a good night and thank you again :) Hopefully this will do the trick :)
A quick point on charging the 10000mAh, (10Ah), battery. To fully charge it from flat at a normal C/10 rate, you'll need a 1A charger and a 14 hour charge. You can charge it more quickly at a higher current rate, but check it's specs for more info.
 
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