# Question about jetson nano powered by exeternal power source

Hello,

I have installed the YOLO algorithm in the jetson and I want to install the jetson in my car (plus a camera and 7 inch lcd screen) for live car recognition. Currently my power supply can provide up to 4.5A .
I saw the waveshare for batteries case but it outputs max 2.5A.
I want to ask if I put 6x18650, my topology will be the following:
seriesPair1(bat1+bat2) // seriesPair2(bat3+bat4) // SeriesPair(bat5+bat6)
so the voltage output will be around 3.6*3 = 10.8V and afterwards with one stepdown converter I will stepped it down to 5V, I want to ask if this topology will be enough to provide the jetson around 4A?
my budget is around 70 \$, if someones has other alternative.

thank you in advance

this is the step down which I will buy:

Two supplies rated at 2.5A max, when in series, still won’t put out more than 2.5A. I’d look for something else, but consider this: A “buck” converter or regulator only cuts to a lower voltage, while a “boost” converter or regulator can also increase voltage. Some are of course buck/boost and can do both. In theory, a pair of 2.5A 3.6V batteries, in parallel, could put out 3.6V at 5A. If your converter is 100% efficient (and it won’t be), and your goal is output of 5.2V, then 3.6*1.45 would get you to 5.2V; 5A divided by 1.45 would give you 3.45A. Not as much as you have currently, but better than the series model. Three in parallel would probably do the job with a good boost converter; then again, three in series with some models of buck converter could also do the job. However, most regulators you find for DC from higher voltage to lower voltage are linear or otherwise designed such that they cannot increase the output current. I’d be skeptical that it would work with that particular battery, especially given the Jetsons’ need for a very well regulated power source.

If you had three of those batteries in parallel, another three in parallel, and then the pairs of three in series, it could work. On the other hand, this would tend to die rather fast if one battery was slightly higher quality than another (the internal resistance has to match for it to work well; as batteries age their internal resistance tends to go up at an unpredictable rate).

Your best bet would be a battery capable of putting out slightly higher than 5.2V at the full current, combined with a low dropout (LDO) regulator (a quality one). I don’t know of anything in budget, but maybe someone else has suggestions. Or if you know of a regulator which is not a linear regulator (the design which cannot provide increased current at lower voltage…perhaps some switching regulator will work).

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thanks for the advice,
as I told I am planning to mount the jetson in a car, and I found of waveshare but provides only 2.5A, it would be ideally if will be a ready kit to support up to 4A. or even some power bank which will provide abou 3A.
I found this power bank which I will plug it through the barrel jack,
any suggestions if this will work ?
https://www.skroutz.gr/s/23704130/NiteCore-NB10000-Power-Bank-10000mAh-με-Θύρα-USB-A-και-Θύρα-USB-C-Μαύρο.html

We don’t have suggestion on not validated devices. But for nano itself, 5V, 4A should be enough. You can choose power supply based on that.

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I couldn’t tell you if that would work or not (part of the problem is that I can’t read the language, the other part is that even if I could, then I wouldn’t know how good the regulation is; regulation quality is critical on a Jetson).

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