Power Supply Issues

The Beagle Bone doesn’t work with some power supplies. It appears that it is not tolerant of inexpensive power supplies (such as the DLInk). We are sure this is not due to lack of amperage as the Beagle Bone draws about 350 mA from our lab supply and the power supplies that fail are each rated at 1A and 2A. I think it has to do with inexpensive switching supplies which are inherently noisy.

Here’s where it get’s interesting… We found a supply that works in the lab, but when installed in the field it the Beagle Bone’s power light was on, but the heartbeat lights didn’t blink and the unit would not operate. We thought the supply went bad in the field, so we took the Beagle Bone to our local Radio Shack, tried a supply that worked in the store and then installed them both back in the field. The new supply did not work in the field.

The AC power in the field is supplied by Solar Power and I figured this might be the issue. We plugged the new supply and Beagle Bone into a commercial (non solar) outlet and it worked fine.

I have to think that the inverter on the Solar Power is injecting similar noise as the cheap switching supplies.

Two questions…

  1. Has anyone had issues with the Beagle Bone operating with cheap switching supplies or from Solar Power?

  2. If so, any ideas on solutions to clean up the Solar Power source?

Thanks in advance,

Jeremy

DLink supplied have a slow ramp. They have never worked that I have ever found with any of the boards. Cheap power supplies are cheap power supplies. You need to use a cheap power supply plus a little more money. There is a list of power supplies that work on the support Wiki. USB is particularly sensitive to this and as the supply supplies the voltage to the USB, you need to keep that in mind.

Rule #1. Measure your voltage and see exactly what it is. If it is out of spec, then you need to fix the issue. You need a good ground.

To clean up the solar voltage put a good 5V regulator in front and a battery would not hurt either. A switcher should do the trick for the regulator. Lot’s of those out there. Varying voltages is not something processor look kindly on, especially when the voltage drops below the operating specification like when the sun goes down.

Gerald

another interesting isue.
when i turn on my bbb i must unplug hub usb (for mouse, keyboard, usb
wifi, ...). i can just plug hub usb after a boot started.. if i turn
on bbb with hub usb the hub usb will not work. after the 10first
seconds that i had turn on bbb i can plug hub usb. when a plug hub usb
to the bbb and to the power,bbb will power from hub usb. (sorry for
bad english, it get worst every day :D)

I run my BBB using a 4 dollar chinese power supply 5v 1amp and works
like a charm
i also run my design lab and whole house from solar power and only ever
have issues
when the transfer switch gets switched slowly and the power does a mild
brownout
then the power supply/BBB needs a quick plug/unplug and all is well

i would suspect you are having some grounding issues

just a guess

Solar inverters are generally “modified sine wave” which is only slightly better than a square wave. The RMS voltage will be 120, but the peak voltage will be lower, and lower-cost switching supplies that depend on peak voltage may have a problem.

If the solar power charges a battery, you should be able to get a switching “buck” converter that will drop the DC down to 5v fairly efficiently (as Gerald mentioned).

We’re using modified sine here. Granted I personally power my bbb via USB 3.0 from a laptop. So perhaps some extra filtering on the input cable into the laptop. However this modified sine system is the same system evilwulfie is on as well. I only power via USB as an easy means to avoid the short brown outs evilwulfie mentioned above( as I require long uptimes to test software that I am writing ).

Adding filtering kind of makes sense to me, as i do know that that we do have excessive line noise on our system. But perhaps if you measured the actual AC output from the wall, and check the specs on the “wal-wart” you’re using, perhaps you’ll find that it may not be enough. But this is just a guess.