Battery Power for xu4?

by **jl303** » Sun Jul 19, 2015 10:28 am

Hi,

Is there any battery that could power xu4?
A lot of portable battery packs I found for smartphones are 5v/2a.
Thanks,

JL

by **phaseshifter** » Sun Jul 19, 2015 11:55 am

5v 2a it may run it with just browsing and no peripherals for 15 min`s ...learn ohms law and do the math you could parallel a few of them you may get an hour out of 4 of them depending on what you are doing with the Xu4

by **odroid** » Sun Jul 19, 2015 8:34 pm

I could see 2.5~3Amp of peak current in the booting process.
So the 5V/2A battery pack will cause instability seriously.

by **jl303** » Mon Jul 20, 2015 1:16 pm

So I guess no luck...

I found some battery pack that delivers 4a total, but that's total ports combined, not through a single usb port.

by **PennState_UAS** » Wed Jul 22, 2015 10:45 am

I wrote a post on how we powered our xu3 computers from a lipo battery. Here it is: viewtopic.php?f=97&t=14807

Pretty similar power requirements, we haven't tried it on an xu4 yet but our solution should work.

by **jl303** » Thu Jul 30, 2015 5:49 am

I also found a portable battery that delivers 5v/4a through one usb port. It's called Anker 2nd Gen Astro3.
http://www.ianker.com/product/79AN7904S-B2A
I exchanged with Anker support, and they said it can deliver up to 4a through one usb port or combined. They sell many different batteries but they said this is the only battery that can do it so far.
I just received the battery and a usb to 5.5mm cable.
I just plugged it in with no soldering and no modification, and it seems working fine.
Anker 2nd Gen Astro3 12800mAh 3-Port 4A Portable Charger External Battery Power Bank with PowerIQ Technology
http://www.amazon.com/Anker-12800mAh-Po ... B00CEZBKTO
StarTech USB2TYPEM 3 Feet USB to Type M Barrel 5V DC Power Cable
http://www.amazon.com/gp/product/B003MQO96U

by **arich57** » Wed Aug 05, 2015 12:47 am

jl303 wrote:I also found a portable battery that delivers 5v/4a through one usb port. It's called Anker 2nd Gen Astro3.
http://www.ianker.com/product/79AN7904S-B2A
I exchanged with Anker support, and they said it can deliver up to 4a through one usb port or combined. They sell many different batteries but they said this is the only battery that can do it so far.
I just received the battery and a usb to 5.5mm cable.
I just plugged it in with no soldering and no modification, and it seems working fine.
Anker 2nd Gen Astro3 12800mAh 3-Port 4A Portable Charger External Battery Power Bank with PowerIQ Technology
http://www.amazon.com/Anker-12800mAh-Po ... B00CEZBKTO
StarTech USB2TYPEM 3 Feet USB to Type M Barrel 5V DC Power Cable
http://www.amazon.com/gp/product/B003MQO96U

Have you had enough time to play with this to have an idea of how long you can run the xu4 on this battery? I was looking for something similiar and curious what type of run times you are getting.

Thanks.

by **chrisjx** » Thu Aug 06, 2015 9:54 am

We used the UPS-2 with the U3 and it worked for at least 4 hours on batteries. Great balance of performance and power requirements.

I would say the XU4 is not a replacement but a different device. Different footprint (I have to design new 3D bracket), different bulky HDMI, no micro usb, no I/O port to UPS, double power requirement, no UPS...

Not a replacement. Different footprint and double power might make it unusable for us. We might have to go to lower performance device of the C1. It still has a UPS.

Curious to know how much warning there was of the impending cutoff of the U3? Did I miss the warnings that production would end? Seems like it was 6 days ago; it was announced July 30th. Done. We would have bought 20 sets, maybe more if we had known they we going to disappear.

Very sad.

by **phaseshifter** » Thu Aug 06, 2015 9:58 am

check with other suppliers there may be stock with some of the internet sellers...

by **chrisjx** » Thu Aug 06, 2015 12:54 pm

Thanks, phaseshifter. I wil do that.

by **arich57** » Sun Aug 09, 2015 10:56 pm

I measured amperage during start up with a smart-power to be a max of 2.2 between several boot ups. That was with nothing plugged into UX4 other than sd card.

Just wanted to let people know who are looking for battery solutions, you definitely need at least a 3amp source to be safe.

by **buba013** » Tue Oct 27, 2015 4:58 am

This seems to work http://www.amazon.com/Kingneonlux-QIDIA ... B00U12OG9S ( use the m port)

I have cloud-shell running so lcd powered up my wifi hostspot works and my now portable Plex server for the kids is working .

by **emanpuedam** » Wed Dec 16, 2015 7:06 am

Battery Power for the XU4 Solved! I am Powering my XU4 with a Small Li-Ion Battery Pack
Instructions and Links to Required Parts Listed Below:

It is possible to power an XU4 with a battery system. It took me a few weeks and a lot of trial and error, but I am now powering a XU4 running Ubuntu 15.04 with a battery. All of the components were purchased on Amazon and the entire system should only cost +/- $50. Some basic electronics skills are required to connect the components. If there is anyone who is determined to complete this project in spite of being a complete noob when it comes to electronics. Contact me and I will take the time to write up a step by step, foolproof guide to building a replica of my system.

The Problem:
The XU4 requires 5 volts (power supplied from a USB) however it also requires up to 4 amps. USB ports only provide 2 amps and the most you can hope for from a USB battery charger is 3 amps from a single port. Therefore, none of the USB battery power supplies are an option. There are now battery power packs that provide an AC outlet, however they are bulky, expensive and it would be inefficient to use the XU4's wall transformer.

The Solution.
Since no USB battery power pack will provide sufficient amps, you will need to use a voltage transformer and a battery power pack that can supply it's required input voltage.

I purchased all of the components I used on Amazon (links included).

First you will need to find a voltage transformer. I picked the DROK 12v/24v to 5v/5a 25w Converter. This item is cheap, well reviewed, water proof and has a 90% conversion efficiency rate. It also accepts 12v to 24v as input, allowing a wide range of sources to be used as power sources. It may turn out you already have a device you can utilize and save some money.

If you don't already have a suitable battery power pack, my I recommend the unit i finally settled on TalentCell Rechargeable Li-Ion Battery Pack. This unit utilizes a Li-Ion battery pack, making it lightweight and small enough for easy transport. It should provide power to the XU4 for multiple hours when fully charged. It also has a USB power output that can be used at the same time as the 12v output. If you plan to run a lot of peripheral devices with your XU4, this outlet can be used to power some of the devices, relieving the strain on the main power source.

Once you have these two units, it is a relatively simple matter of connecting the 12v output of the TalentCell (a 5.5mm barrel plug) to the DROK's input and then attaching a second 5.5mm barrel plug to the DROK's output so it can be plugged into the XU4.

That is all it takes to provide battery power to your XU4.

If you have absolutely no experience working with electronics, I urge you to seek out someone who does. A simple mistake such as reversing the polarity of a plug (switching pos. and neg.) could cause irreparable damage to the converter and or your XU4! I would recommend that you own and are comfortable with a soldering iron and a test meter before undertaking this project.

I am more than happy to help in any way I can. If enough people express interest, I would be willing to construct and sell at cost + S/H a pre-fabed kit (including DROK coverter) that would connect the TalentCell directly to an XU4. Please let me know if you are interested. vectorfield@worker.com

by **jacky** » Sun Jan 10, 2016 1:18 am

Hey,

Think that by using these cables:
http://www.amazon.com/Power-Enhancer-Fe ... le+femelle
http://www.amazon.com/niceeshop-Barrel- ... +%2F+2.1mm

And connect 2 usb on this battery
http://www.amazon.com/Upgraded-Capacity ... r+16750mAh
on 2.1A and 2.4A.

It should also work?

by **phaseshifter** » Sun Jan 10, 2016 2:25 am

16,75 a/h battery will run it u will need the barrel to usb cable
so battery ==>usb to barrell connector==>xu4..
http://www.amazon.com/niceeshop-Barrel- ... +%2F+2.1mm............use this cable for the powering of the xu4
should run it for a few hours how long will depend on load and remember you can really only use 75% of the battery capacity..or you will destroy it rapidly.
.so good for approx 3-4 hours i would think..maybe more..its hard to determine exactly..

by **vanja** » Sun Jan 24, 2016 2:02 am

jacky wrote:Hey,

Think that by using these cables:
http://www.amazon.com/Power-Enhancer-Fe ... le+femelle
http://www.amazon.com/niceeshop-Barrel- ... +%2F+2.1mm

And connect 2 usb on this battery
http://www.amazon.com/Upgraded-Capacity ... r+16750mAh
on 2.1A and 2.4A.

It should also work?

hi jacky,

is this a solution you are using or just plan to use?

cause it is most simple+cheap ($32, 11.3oz, featuring a 4.5A total output capable of simultaneously charging 2 tablets)

another candidates from amazon
* http://www.amazon.com/Upgraded-Capacity ... B00M3073L4 ($50, 15.8oz, 3 amps per port or 4 amps through three ports)
* http://www.amazon.com/EasyAcc-20000mAh- ... B01422TC14 ($35, 16 oz, up to 2.4A per port, 4.8A Output)

please share any experience with power banks for xu-4

regards,
Vanja

by **jacky** » Mon Feb 01, 2016 11:19 pm

vanja wrote:
jacky wrote:Hey,

Think that by using these cables:
http://www.amazon.com/Power-Enhancer-Fe ... le+femelle
http://www.amazon.com/niceeshop-Barrel- ... +%2F+2.1mm

And connect 2 usb on this battery
http://www.amazon.com/Upgraded-Capacity ... r+16750mAh
on 2.1A and 2.4A.

It should also work?

hi jacky,

is this a solution you are using or just plan to use?

cause it is most simple+cheap ($32, 11.3oz, featuring a 4.5A total output capable of simultaneously charging 2 tablets)

another candidates from amazon
* http://www.amazon.com/Upgraded-Capacity ... B00M3073L4 ($50, 15.8oz, 3 amps per port or 4 amps through three ports)
* http://www.amazon.com/EasyAcc-20000mAh- ... B01422TC14 ($35, 16 oz, up to 2.4A per port, 4.8A Output)

please share any experience with power banks for xu-4

regards,
Vanja

Hi vanja ,

I just received the battery but my Odroid won't boot while the battery is plugged to it.

Everything works fine with my Raspberry for 8 hours.

I'm waiting for this : http://www.amazon.fr/gp/product/B019IL6 ... TE_3p_dp_1
to try and understand what's wrong.

Does anybody know what could be wrong ?

by **odroid** » Tue Feb 02, 2016 9:33 am

Need to measure the output voltage of the battery when you turn on the XU4 with a DMM.
I think the In-rush current of XU4 could be 2~3 times higher than RPI.

by **Respectech** » Wed Feb 03, 2016 5:44 am

I was hoping to find a good solution from the suggestions above, but most of the links above are either 404 or not in stock. There are a couple that seem to be promising, but kind of expensive.

ameriDroid has a DC-DC converter with more than enough capacity at http://ameridroid.com/products/dc-dc-12 ... -converter on sale for $9.22! So you can use any rechargeable battery pack at any voltage between 5VDC and 30VDC to power your XU4. Great for using the XU4 as a car-puter.

by **venkatbo** » Wed Feb 03, 2016 7:50 am

Respectech wrote:... ameriDroid has a DC-DC converter with more than enough capacity at http://ameridroid.com/products/dc-dc-12 ... -converter on sale for $9.22! So you can use any rechargeable battery pack at any voltage between 5VDC and 30VDC to power your XU4. Great for using the XU4 as a car-puter.

Nice accessory @Respectech.
Have a question for you. I have 3 XU4's in my lab and I was wondering if it would be safe (over-current usage protection, etc) to use one of these to provide 5V/4A for each of the 3 XU4's. If that is safe to do so, do you have any recommendations for a psu whose output can be used for the input side of this accessory ?

thanks.

by **Cancerian** » Thu Feb 04, 2016 4:21 am

jl303 wrote:I also found a portable battery that delivers 5v/4a through one usb port. It's called Anker 2nd Gen Astro3.
http://www.ianker.com/product/79AN7904S-B2A
I exchanged with Anker support, and they said it can deliver up to 4a through one usb port or combined. They sell many different batteries but they said this is the only battery that can do it so far.
I just received the battery and a usb to 5.5mm cable.
I just plugged it in with no soldering and no modification, and it seems working fine.

I just found the Anker PowerCore 20100, which says that it can deliver 5v/4.8a through any combination of ports, but one of Anker's support representatives indicated that they have no battery that can deliver 4a through a single port, and that even the Astro3 only delivers up to 2.4a through each port, or 3a in the case of USB type C ports. After speaking with the representative, I came away with the feeling that I would burn out some of the electronics or hit an overload protection feature of the battery if I made the attempt to connect any of their batteries to an XU4 and experienced high load conditions or had peripherals connected to the XU4's USB ports. @jl303, have you experienced any issues with the Astro3, and if not, do you think the newer PowerCore 20100 would also work under similar conditions? I really like this battery if it can work with the USB to type M barrel above, as it has a battery capacity of 20100 mAH, which is much higher than the 12800 mAH capacity of the Astro3, and the current price of the PowerCore 20100 is lower than the price I see on Amazon for the Astro3 by $40 USD. Has anyone else used either of these battery systems to power an XU4, and if so, what problems did you face while using it?

by **Respectech** » Thu Feb 04, 2016 9:43 am

venkatbo wrote:Nice accessory @Respectech.
Have a question for you. I have 3 XU4's in my lab and I was wondering if it would be safe (over-current usage protection, etc) to use one of these to provide 5V/4A for each of the 3 XU4's. If that is safe to do so, do you have any recommendations for a psu whose output can be used for the input side of this accessory ?

thanks.

Let's see if the converter can do the trick via some math. The specs state it is 95% efficient, and can supply up to 12A on the output, so that should be able to power 3 XU4's at full utilization (4A * 3). If you were using a 12VDC input power supply, this means that the 12VDC power supply would need to be able to supply 12A * (5VDC / 12VDC) / .95 = 5.27A@12VDC. I did a quick search in my PSU drawer and found a couple of 12VDC/3.3A power supplies, so those would be a bit too small. The 12VDC/3.3A PSU would be enough to run 2 XU4's almost certainly, or 3 at an average of 2.5A being pulled at any one time by all 3. I think that's reasonable, but it sounds like an experiment would be needed to verify.

I hope this helps!

by **dronus** » Fri Apr 29, 2016 3:25 am

As for many applications that are mostly idling, the largest power draw will be while booting.
Maybe it's possible to have a reduced clocking early, or delay the activation off some devices to later, to reduce the peak draw on bootup?
For example, if the cpu clock would be lowered from the beginning, PHY and HDMI stay disabled until the end off the boot when they could be activated if the desktop is already up and idling.

by **DarkBahamut** » Sat Apr 30, 2016 8:15 pm

I'm not sure about disabling other devices, but limiting the booting clockspeeds should be possible.

You need to compile a kernel with the following change.

File in question is drivers/cpufreq/exynos5422-eagle-cpufreq.c

Lines 661 and 662 set the A15 booting frequency.

Code: Select all: info->boot_cpu_min_qos = exynos5422_freq_table_CA15[L9].frequency; info->boot_cpu_max_qos = exynos5422_freq_table_CA15[L9].frequency;

L9 = 1.5GHz. You could try L15 maybe (900MHz) and see if that helps. I've not tried it so no promises though. Should look like this after.

Code: Select all: info->boot_cpu_min_qos = exynos5422_freq_table_CA15[L15].frequency; info->boot_cpu_max_qos = exynos5422_freq_table_CA15[L15].frequency;

by **dronus** » Tue May 03, 2016 9:20 am

I found an easy solution not requiring kernel changes: Just adding maxcpus=2 to the kernel command line in boot.ini drops the bootup power usage to 4W.

Individual CPUs can later be reenabled according to the available power by writing 1 to the /sys/devices/system/cpu/cpuX/online files.

This way the XU4 can boot and run stable from an 2A power bank.

by **mad_ady** » Tue May 03, 2016 4:35 pm

This information needs to make its way on a wiki page

by **odroid** » Tue May 03, 2016 4:54 pm

mad_ady wrote:This information needs to make its way on a wiki page

Good idea. I added a link with a credit to dronus

http://odroid.com/dokuwiki/doku.php?id= ... eripherals

by **dronus** » Fri May 13, 2016 7:39 pm

You may drop the credit, but maybe do a real wiki page or section instead :-)

Clicking the link is confusing, as there are several other working solutions here.

The page may mention the hardware (eg. selfmade Li-Ion circuits) and software solutions (like mine, using a power bank and adjusting the software).

by **odroid** » Mon May 16, 2016 9:46 pm

@dronus,

Can you show us the result of below commands when "maxcpus=2" was added in the kernel parameter?
One user reported the "maxcpus=2" didn't work well.

Code: Select all: cat /sys/devices/system/cpu/cpu0/online cat /sys/devices/system/cpu/cpu1/online cat /sys/devices/system/cpu/cpu2/online cat /sys/devices/system/cpu/cpu3/online cat /sys/devices/system/cpu/cpu4/online cat /sys/devices/system/cpu/cpu5/online cat /sys/devices/system/cpu/cpu6/online cat /sys/devices/system/cpu/cpu7/online

by **ard** » Fri May 20, 2016 9:48 pm

I just compile the kernel with the powersafe governer. Once the boot reaches X11 I put in the right frequencies and switch to performance governer.
I normally use 1.4GHz for the cpu's as that limits it's peaks to 7W or less.
I've tried turning off cpu's and later turn them on again, but you have to reroute irq's when you turn on cpu's. But I will definetely try that.
As for power usage: https://www.youtube.com/watch?v=SVSActfqXlQ shows quake2webgl on chromium and the last few seconds show the smart psu, with lower than 1A power usage.

by **odroid** » Sat May 21, 2016 10:26 am

Thank you for the detail explanation as well as the video.
Quite impressive the low power consumption while running the webgl application.

by **ronaldlees** » Fri Jul 08, 2016 12:02 am

Respectech wrote:I was hoping to find a good solution from the suggestions above, but most of the links above are either 404 or not in stock. There are a couple that seem to be promising, but kind of expensive.

ameriDroid has a DC-DC converter with more than enough capacity at http://ameridroid.com/products/dc-dc-12 ... -converter on sale for $9.22! So you can use any rechargeable battery pack at any voltage between 5VDC and 30VDC to power your XU4. Great for using the XU4 as a car-puter.

That price is a couple dollars cheaper than I've seen for similar supplies on Amazon, so thanks for the link!

I learned to love this type of supply because I needed to use large LCD screens with SBC boards. One thing I found about these types of supplies is that I needed to exercise the potentiometer before first use. Without any load attached, I take a screwdriver and turn it through most of its travel, one way then the other, while staying within the voltage specs (using a voltmeter to monitor). Probably, it wouldn't hurt to spin the pot a few times before anything is attached, remembering the number of turns, and returning to the original position (which should be, but may not be, minimum voltage level). After exercising the pot, I just set it to the desired voltage (usually 5 VDC). This is not advice, but it works for me! Caveat Emptor! I have found that the position of the potentiometer (initial setting), out of the box, is pretty random. Most of these supplies are "counter-clockwise = lower voltage," but that's not true of all of them.

If I don't "exercise" the potentiometer, it can have little burs inside of it, or "filiments" - which can cause erratic output. It's only my guess that there are filiments inside new pots, because I'm certainly no potentiometer expert. IMO, the exercising, by turning it a few times, helps to minimize this problem, but probably it could still happen. This would seem to be true of any potentiometer controlled supply. So, AFAIK such supplies need a certain "burn-in" procedure. Probably, the exercise should be done with a dummy load of the same current draw as the intended target, prior to actual use. I blew up a nice VU screen because the supply went berserk and put over 12 VDC to it! It wasn't the Ameridroid supply, but another brand of the same general build. Better safe than sorry!

by **ronaldlees** » Fri Jul 08, 2016 12:40 am

The whole potentiometer problem would seem to say it's better to have a fixed output supply, if one can live with the non-flexibility.

by **Rushlight** » Wed Aug 10, 2016 6:03 pm

for 60-100$ Bestbuy sells battery packs that can output 3.0-4.5A though 1-2 USB ports,some are over 10000mA. it's not super powerful, however, if you're shrewd you can find a really cheap one, buy a few, and hook the batteries up in series off one board :3

by **nmshaikh** » Thu Dec 22, 2016 6:46 pm

Respectech wrote: ...ameriDroid has a DC-DC converter with more than enough capacity at http://ameridroid.com/products/dc-dc-12 ... -converter on sale for $9.22! So you can use any rechargeable battery pack at any voltage between 5VDC and 30VDC to power your XU4. Great for using the XU4 as a car-puter.

Hi guys, this is my first time posting on this forum. I bought my Odroid XU-4 board in mid November this year and I am using it for a robotics project to control a small autonomous car. I needed to power my board while it is on the car and I have developed a solution similar to the one mentioned by Respectech by using a cheap adjustable output voltage regulator that regulates the input voltage from the car battery from 7.2 volts to the 5 volts needed by the XU-4.

All you need is a voltage regulator, a couple of capacitors, and a couple of resistors to solder the circuit yourself. The particular voltage regulator I have used is the LD1084v by ST Microelectronics. This is a low dropout voltage regulator that can take between 6.5 VDC to 30 VDC as input to give an output of 5 VDC at 5 Amps. I have attached the circuit schematics for the regulator. All you need is 2 capacitors at 10 uF, 1 resistor at 120 ohms, and 1 resistor at 365 ohms to complete the circuit (I have also used a metal heatsink just in case. I am not sure how heated up the voltage regulator will get). I have attached another image showing the XU-4 board hooked up to the car battery and my laptop screen after the voltage is regulated. The cost of all the components was around 15 Malaysian Ringgits (about 3.5 US dollars!)

Feel free to ask me about any additional information. I am happy to help

Circuit Schematics.JPG: Schematics for voltage regulator circuit; (33.11 KiB) Downloaded 3772 times

15696703_10211728347829787_1027034741_o.jpg: XU-4 powered by a 7.2 volts 2000mAh battery; (179.12 KiB) Downloaded 3772 times

by **hommsy** » Fri Feb 10, 2017 12:30 am

Does anyone have the issue where the XU4 keeps restarting at boot when connected to battery?

It seems to me that when the current draw reaches around 3A, the XU4 reboots (or maybe loses power and starts up again)

Anyone faced this issue? Anyone has a fix?

setup:
2 LiPo batteries 4S 14.8V 6.6Ah connected in parallel
1 Turnigy SBEC step down converter (step down to 5V and max 5A)

by **mad_ady** » Fri Feb 10, 2017 5:01 am

To reduce startup current demands you can boot with only the little cores and manually switch on the big cores as needed. Add numcpus=2 (or 4) to bootargs in boot.ini

by **Zeroth** » Fri Feb 10, 2017 8:33 am

Hi everyone,

Is the conclusion to this thread that there is no easy way to power the XU4 by battery? By "easy" I guess I mean... No way without soldering stuff together? (I'm not very good at that and tend to break things when I try). I was hoping for a set-up with some kind of battery pack / power bank and some adapter cables but it looks like that may not be possible?

Cheers,

Jonty

by **rooted** » Fri Feb 10, 2017 8:41 am

Zeroth wrote:Hi everyone,

Is the conclusion to this thread that there is no easy way to power the XU4 by battery? By "easy" I guess I mean... No way without soldering stuff together? (I'm not very good at that and tend to break things when I try). I was hoping for a set-up with some kind of battery pack / power bank and some adapter cables but it looks like that may not be possible?

Cheers,

Jonty

A power bank would be okay if it has 4A USB output.

by **Zeroth** » Fri Feb 10, 2017 7:26 pm

rooted wrote:A power bank would be okay if it has 4A USB output.

Hi, thanks for the help. I read that each USB port only goes up to around 2A? So do I have to combine the output from multiple USB ports somehow?

by **hommsy** » Fri Feb 10, 2017 8:55 pm

Zeroth wrote:
rooted wrote:A power bank would be okay if it has 4A USB output.

Hi, thanks for the help. I read that each USB port only goes up to around 2A? So do I have to combine the output from multiple USB ports somehow?

Yea you could combine batteries. What im doing now is connecting 2 LiPo batteries in parallel, the oputput of those goes to a step dpwn converter which then goes to the xu4. This should work (will confirm this method by tomorrow)

battery: https://hobbyking.com/en_us/multistar-h ... -pack.html
converter: https://hobbyking.com/en_us/turnigy-5a- ... -lipo.html

by **Zeroth** » Sat Feb 11, 2017 12:10 am

Thanks hommsy. I'm not to good with electronics so sorry for any stupid questions... How have you attached this set-up to the correct 5.5mm power input? Also how long battery life do you expect and is there enough current to support an external hard drive connected to the XU4?

by **hommsy** » Sat Feb 11, 2017 7:44 pm

mad_ady wrote:To reduce startup current demands you can boot with only the little cores and manually switch on the big cores as needed. Add numcpus=2 (or 4) to bootargs in boot.ini

and sounds like a good plan for booting but what happens after that? in other words, when switch back to all cores after boot, wont the xu4 disconnect again because of insufficient power? have you tried this?

by **hommsy** » Sat Feb 11, 2017 8:51 pm

mad_ady wrote:To reduce startup current demands you can boot with only the little cores and manually switch on the big cores as needed. Add numcpus=2 (or 4) to bootargs in boot.ini

just a small correction for future reference, its maxcpus=2 not numcpus=2

by **mad_ady** » Sun Feb 12, 2017 2:05 pm

Right, sorry for my mistake. The point is that on boot all cores will be busy and the startup current exceeds 2A. After startup is done you can enable all cores and the system should be stable as long as the load is light and doesn't exceed 2A. It will crash if you go above 2A though.

by **Zeroth** » Mon Feb 13, 2017 8:52 pm

Hi hommsy, did you manage to get that set-up working?

by **hommsy** » Wed Feb 15, 2017 7:06 pm

Zeroth wrote:Hi hommsy, did you manage to get that set-up working?

Yea it finally works. No need to reduce the number of CPU's either.

You will need a battery, something like this https://www.amazon.com/Floureon-Battery ... tery&psc=1
[in battery choosing, make sure its not rated as 10C and make sure the mAh is enough for your application]

and then you will need a step-down DC-DC converter (or BEC), something like this https://www.amazon.com/FVT-Adjustable-U ... ds=ubec+6a
[make sure that the output is 5v and the current is at least 5A ]

and thats it..well of course you will need some connectors, plugs and soldering..

by **Zeroth** » Fri Feb 17, 2017 6:49 am

Great, thanks for the help

by **cdhinrichs** » Sun Mar 26, 2017 5:02 pm

Hi Everyone,

This has been a very helpful thread for me. Thanks to many of the contributions here, I've gotten my XU4 to:
- run from battery for over 3 hours, with the batteries claiming they're nowhere near spent, (as judged by the 4 blue LED indicators,)
- record H.264 video on *two* cameras simultaneously at 640x480 on a high quality setting the whole time, (although one camera seems to have dropped out after about 27 minutes for what appear to be software (ffmpeg) underflow reasons).

There were many obstacles to overcome, and several of the posts here have been instrumental in overcoming them. But first, the proof:
https://www.youtube.com/watch?v=osY7ODJco5Q

My ultimate aim is to do some kind of AR/stereomorphic projection / flow-field mapping in real time while riding a bicycle, (DON'T try this at home - *I'm* not even there yet.) As a first step, I needed to get the odroid to run on battery for a prolonged period, and do some non-trivial work. And, acquiring video data will be useful for later stages. So, I set the first milestone to be acquiring video from 2 cameras on a long bike ride. Later, I want to do real-time processing and display on, e.g., something like this: https://store.vufine.com/collections/all.

or this
https://www.amazon.com/Gender-ACCUPiX-G ... B00AXVWNGA
(much riskier, not recommended, but cyber-punk as ****.)

As far as applications, I think a visual speedometer overlay would be pretty rad. Or something that overlays your planned route so you don't have to stop to check your google maps or strava route along the way. Or something that shows points of interest, places to eat, or bike routes. Or it could display low optical flow areas in high color saturation (low optical flow means the object is moving right at you,) so you can see oncoming collisions before they hit you. But mainly, I just want to get something to work in real time from battery, preferably using the GPU.

My batteries:
Some people suggested getting a 12V battery + voltage converter + soldering, but I am not a soldering enthusiast, and would rather throw $$ at the problem so I got 2 of these:
https://www.amazon.com/gp/product/B012N ... UTF8&psc=1

and then for good measure I threw in one of these:
https://www.amazon.com/gp/product/B01G1 ... UTF8&psc=1

They look like a lot of money, but if you check https://slickdeals.net/ 2-3 times a week you'll see a deal on them. You could get the three for < $100 that way.

In theory, this combination should deliver ~12 amps, but I had my odroid spontaneously reboot on me several times, so probably the "smart" electronics were making them deliver less current than they're rated for, probably since lithium battery fires are more of a liability than underperforming batteries used for bobby projects. The upside is, they last longer. It's also possible that the massive USB daisy chain I used had something to do with it. *shrug*.

Thanks go to:
-jacky for this (I needed 5):
https://www.amazon.com/Power-Enhancer-F ... le+femelle
and this (I needed 1):
https://www.amazon.com/niceeshop-Barrel ... +%2F+2.1mm

-jl303 mentioned the Anker batteries, but they were even more $$, and I couldn't find that exact one.

-dronus for the -maxcpus=2 tip (I got mine to run with maxcpus=4 just as well. Maypbe the "cpus" are just threads, and the cores are what counts. Occasionally I've noticed things tend to break down when you cross from the 4th cpu to the 5th. YMMV, though.)

- The question then is, if you boot with 2 or 4 cpus online, how do you re-enable them? Elsewhere on the odroid forums I found this trick:

sudo -i
echo 1 > /sys/devices/system/cpu/cpu[0:7]/online

That's it, you can re-enable the cpus one at a time. BUT! what if you re-enable them all at the same time? You'll crash. So, what I did is, I created a script that does this:

echo 1 > /sys/devices/system/cpu/cpu4/online
sleep 1
echo 1 > /sys/devices/system/cpu/cpu5/online
sleep 1
echo 1 > /sys/devices/system/cpu/cpu6/online
sleep 1
echo 1 > /sys/devices/system/cpu/cpu7/online
sleep 1

and it works! The limitation is not how much total amperage the batteries can support - it's how *sudden* of an amperage demand they can support.

Likewise, I set the governor to "conservative" since that's designed to ramp up the cpus more slowly. I'm experimenting with mixing performance and conservative governors to get the best cpu utilization without maxing out the batteries. I believe the package you want is called "cpufrequtils". The command you want is "cpufreq-set", which allows you to set the governor and the max clock frequency for each cpu. The video you see above was set using 1600M as the max frequency for each core, (although the first 4 cores really wanted to run at 1400M for some reason.)

I also needed to figure out how to disable X11 on startup, but that information was elsewhere. Sorry, I don't have the link where I found that information, but it wasn't a major obstacle. You can google it.

This page on FFMPEG was useful:
https://trac.ffmpeg.org/wiki/Encode/H.264

The command I use to start the capture is:
ffmpeg -s 640x480 -i /dev/video0 -c:v libx264 -preset ultrafast -crf 17 cam0.mpg -y
ffmpeg -s 640x480 -i /dev/video1 -c:v libx264 -preset ultrafast -crf 17 cam1.mpg -y

The -crf argument is important. It tells ffmpeg what quality you want. Lower is better, and I think 0 is lossless. People say that 18 is the threshold for subjectively seeing compression artifacts, and I agree after having tried several settings. So I set it to 17. With the 2 batteries, though, the best I could get was 19 without crashing. (That's why I got the third.)

I find it convenient to start each from a different tty. Then I unplug from the monitor, and go on a bikeride.

Good luck!

EDIT:
I looked up the answer to how to how to disable the GUI, and it turns out I didn't just google it, I got it from the odroid user in this thread:
viewtopic.php?f=112&t=9722#p167971
Thanks, odroid.

The command is
sudo systemctl disable lightdm.service

Restarting the GUI can be done with the command
sudo service lightdm start

by **mad_ady** » Sun Mar 26, 2017 6:55 pm

This sounds like a great project and will probably make for an interesting read in Odroid Magazine. You should start a new thread under projects so that your post is easy to find. Now for some tips:
* the first 4 cpus are the little cores and only go up to 1.4GHz. They are also low performance and power efficient.
* Your ffmpeg encoding is done in software and this limits your resolution and compression quality. It might also explain the lost frames you get sometimes. You should get kernel 4.9 from HK and the ffmpeg branch that supports hw encoding for better efficiency (you wouldn't need the big cores with it). Search for the HW encoding howto on the forum to get you started.
* If you search in my "XU4 as a NAS" howto, I have some tricks using cgroups to force the system to run on the big or little cores and have specific processes attached to the big cores for efficiency. HMP is probably not what you need in your case.