Portable Power Supply

Does anyone have any recommendations for a portable power supply I could take with me for a robot, or if I take the Jetson with me on the go, mainly I need to find a new power supply that could last me a few hours running the jetson or at least 30-45 minutes when its at full throttle and using something like ROS.

I used to have a Anker battery for the Tx2 but I would like to possibly power it from USB C so I don’t have to strip any cables. Also that battery is under powered and old now anyways.

Hi, there should be a lot of portable power banks on market which support USB-C 5V/12V/20V output, you can search it online, Amazon or others.

I use a 5 Ah 4S LiPo battery, connected to the barrel power connector. At 4S (about 15V) it doesn’t draw more than 2A tops, so it’ll last for at least two hours.

I use a small microcontroller and a P-channel MOSFET to monitor the voltage and turn off the power if the battery goes too low (12.8V cut-off) to save the LiPo when I walk away.

Btw, the same LiPo also powers my motors and actuators, so the whole robot, when moving, doesn’t have 2h runtime. On the other hand, the Xavier, when idling, draws much less than 2A. My entire bot, when idling, draws about 1.4A at 15V.

If you’re not designing protection for a soft battery into your robot, a hard-case battery is probably better; something like this: https://hobbyking.com/en_us/turnigy-5000mah-4s1p-14-8v-20c-hardcase-pack-1.html
You’ll also need a LiPo balance charger to keep it charged and in good shape.

According to Themal Design Guide (5.1 POWER SUPPLY), Xavier DC supports 9V-19V.
Xavier’s maximum power consumption is 30W, so you can choose a battery that can output 9V/3.34A, 12V/2.5A, 19V/1.58A or more amperes.
Also, the discharge voltage of the lithium ion battery is 3.7V, so the capacity of the battery that can be used for 1h is
30Wh/3.7V*1000=8109mAh

Therefore,
DC OUTPUT 19V/1.58A/8109mAh battery can run Xavier for 1h at full power.
However, in consideration of deterioration of the battery,
DC OUTPUT 19V/2.5A/12000mAh or higher battery is better. (Adapter is 19V/3.42A)

It will be a category of mobile batteries for laptops.

@naisy Each LiPo cell is nominal 3.7V, that’s true, but a battery suitable for powering the Jetson has 3 or 4 cells, thus you can divide the mAh capacity by 3 or 4 based on how many cells in series you put.

Or to put another way, a 19V battery with 8109 mAh capacity has 198.1 VAh == Wh capacity, or about 154 Wh, which divided by 30W draw equals about five hours or run time.

Note: The “power bank” batteries may output different voltages, and what matters is the watt hours, not the amp-hours, because X amp-hours at 19V equals X*2 amp-hours at 9.5V. Thus, those power banks are typically rated in watt-hours. Batteries with defined cell counts/voltages (not using built-in boost/buck converters) will be rated in (milli)amp-hours.

I feel very enlightened

Hi @snarky,

I’m using a Li-ion mobile battery for laptop. (It is like a USB mobile battery.)

I was wondering if one could have PSU + a battery power-bank connected at the same time.

If you use a ready-made “power bank” with built-in charge control and step-up voltage regulator, then that depends on the design of your power bank. Hook the bank to the load, and hook up the charging cable to the bank, and see what happens.

If you’re using a plain battery (3S or 4S LiPo, or 4S or 5S LiFePo, typically) then you can parallel a DC voltage with the battery, assuming the DC voltage is reasonable for the battery. This will create a “float” on the battery, which for LiPo batteries is not great; you should not float LiPo batteries at their full charging voltage, because this will significantly degrade the life time of the battery. I’ve successfully floated LiPo batteries at lower voltages, such as 3.9-4.0 volts per cell, but I haven’t measured the amount of lifetime degradation; theory says there should be some but not as bad as for the top voltage. The other benefit of “floating” a battery like this is that when there are temporary large power draws (such as if you have motors involved,) the battery serves as a buffer, and dampens back EMF and voltage swings. I’ve blown out electronics before by feeding a switch-mode power supply straight into a motor without buffering, and the power supply swinging the voltage way too high when starting/stopping the motor.

If you’re using a power bank with voltage converter, OR if you don’t want to float the battery, then you need to create a cable that connects each of the power and battery through a diode; typically a forward-biased low-loss Schottky type to avoid losing too much power. At 19V, you may see up to 2A (3.5A if you have additional external devices plugged in) so make sure the diode is rated at twice the expected current to avoid overheating it. If the battery voltage is higher than the power supply voltage, and the power supply isn’t designed to be safe against back-feed, you’d also want a diode on that input, so the safest thing is a cable with two inputs, both of which are diode protected, merging to one output going to the barrel connector on the Jetson.

Is there a specific name for the connector used to power the Jetson?I would like to power my Jetson with a cable thats not stripped and taped together haha.

It’s a 2.5mm x 5.5mm barrel connector.

I’m using one of these: https://www.jameco.com/z/CD018-1-Velleman-2-5mm-x-5-5mm-Female-DC-Plug-to-Screw-Terminal-Single-_2227233.html

If that’s still too lab-prototype for you, there’s various cables terminated in that kind of connector available all over the internets. Make sure you get the “female” plug (the jack on the Xavier is a “male.”)

Or you can go with USB-C, assuming you have a power source with sufficient voltage/power capability and smarts to tell the Xavier what it has.

I use a 6S and one of these. Its worked fine on TX1 TX2 and now Xavier. http://www.mini-box.com/DCDC-USB-200. It has usb connection so you can set output voltage that way or via jumpers. Also monitor the input voltage so you will know when its time to shut it down to keep from hurting the battery.

Hello,

I bought https://www.amazon.ca/Energizer-Reliable-Charging-Capacity-Universal/dp/B07MXNZDGB/ref=sr_1_3?s=electronics&ie=UTF8&qid=1550702437&sr=1-3&keywords=energizer+external+portable+battery for my Jetson TX2 and it is not working.

Do you guys recommend something like this… https://www.amazon.com/POWEROAK-External-capacity-50000mAh-Portable/dp/B073R6NKLW/ref=asc_df_B073R6NKLW/?tag=hyprod-20&linkCode=df0&hvadid=312097415645&hvpos=1o2&hvnetw=g&hvrand=197434375640415609&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9030533&hvtargid=pla-569720266000&psc=1&tag=&ref=&adgrpid=64832514209&hvpone=&hvptwo=&hvadid=312097415645&hvpos=1o2&hvnetw=g&hvrand=197434375640415609&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9030533&hvtargid=pla-569720266000 ?

I am looking for a turnkey solution to have my robot up and running asap.

Tyagi

Krisdonia Portable Laptop Charger (TSA-Approved) 92.5Wh/25000mAh Travel Laptop Power Bank External Battery Bank for HP, Dell, Lenovo and Other laptops https://www.amazon.com/dp/B076GYGR6M/ref=cm_sw_r_cp_apa_i_wC3QCb122GNTJ

I use this with the Xavier and Tx2, it comes with connectors and the cable is the same as for the Jetson from both sides.

Thanks a lot! There is not much information for a good battery out there for the Jetson. I really appreciate it.

Yea no problem, let me know if you have any other questions. I have another smaller battery but I forgot the name but it also works. Its an Anker battery but I don’t know the model. I’ll link it later.

My design has no weight constraints. The larger the battery capacity the better. Thank you!

92 Wh isn’t that much. Try a 6S LiPo for large RC trucks or airplanes, and a 5A buck controller.
And note that “25000mAh” is for the 4V cells if they were hooked in parallel, but they’re hooked in series to get to the “laptop” voltage, so that’s a really misleading statistic.
Something like https://hobbyking.com/en_us/multistar-high-capacity-6s-20000mah-multi-rotor-lipo-pack.html
That’s 20000mAh for the full 6 cells, so about 400 Wh. Put more in parallel if you need more runtime.
Here’s a buck converter that would work: https://amzn.to/2UIHNLK (there are tons of other options, this one just had a nice metal case and a low price.)
Note that you’ll want some kind of under-voltage warning, else you run the risk of draining the battery to the point of damage.

Thanks for the suggestion for the larger battery pack. I think I will use the larger battery pack for version 2. I just need to prove my concept at this stage so that we can proceed to beefier product design. I will use the 92Wh to get things moving for now.

Thanks a lot for the help guys!!

Hi,

I’m trying to power my jetson xavier off 12v using a barrel connector, the light comes on briefly but does not boot up. It works fine off 19v. Is there anything I need to do to get it to run using 12v?

Thanks in advance