I have been trying to figure out a way to run the BBB off cheap rechargeable batteries, either 9V or 6 to 8 AAs. I have been successful in running the BBB off a 3-cell Lipo with a 7805 5V regulator circuit. However, when I use the same design with cheaper batteries the board continuously reset. My suspicion is that the batteries can not provide the necessary current.
Does anybody know of the BBB working with cheap rechargeable batteries? And if so, what is the power supply circuit design that is used?
I do a lot of BBB work with 1S, 2S, and 3S LiPo packs. Remember, the lower the voltage the higher the current requirements are going to be on the batteries. Pretty sure that I’ve run from a 2xAA alkaline pack but I know that the LiPos can easily supply the current. During boot I’ve seen spikes up to 1A at 3V - which is typically where you’ll see the brown outs. I’m using a buck/boost regulator that allows for a large input voltage range (3-14V).
Ron is perfectly right!
And where do you get cheap rechargeable batteries?
LIPO prices are going down
alcaline prices are going up
Do you really want to invest time and money in last millennium
alcaline technology?
7805? If you connect 9v to an 7805 about 40% of the power is converted
to heat. There are much better solutions available.
BTW @Ron: What buck/boost regulators are you using. Maybe you can
provide some hints to the community... I have the ADP1111 sitting on
my Desktop, but I did not find the time to solder something
together.....
Dieter, you’re right, linear regulators do waste a bunch of power. Just FYI, I took a quick look at the ADP1111 and it doesn’t look to me like it’s going to have enough power for the BB.
I’m using the TPS63061. It’s a great part but the footprint isn’t exactly prototype friendly. If you’re interested, I have a small write-up and pic of my board here.
Your PowerBar and PowerCape are great. PowerBar is quite interesting for Automotive applications where you got 12-14V power.
I’m really looking for a UPS like cape which can give me backup power via a LiPo/LiIon in case main power goes out and re-charge the battery. Maybe is a good feature for next version of PowerCape
Currently we can only have 1 LiPo/Ion backup with the included TPS but just limit us to 3.3V rail of the BBB and not the 5V rail which usually supply extra capes and USB.
Dave, I will be making schematics available for all of my projects as they get finalized. The schematic and layout for the TPS63061 is actually pretty straight-forward. The only tricky part is the size of the footprint (3mm x 3mm). If you only need a buck regulator, there are other options in friendlier footprints (like SO-8). For example, I’m considering something like the TPS5430 for the BeagleDrone project where the power source will be 3S or 4S LiPoly packs.
Thanks, Juanjo. One of my requirements for those boards was to be able to power a BB from vehicle power. I do have another board planned which is almost exactly what you’ve described: PowerCape + battery charger. It will automatically switch to battery power on DC loss, and charge the battery on DC restore.
He starts with a 3.6V LiPo battery, and uses the BBB on-board regulator to create 3.3V. Unfortunately, this leaves out the USB circuits that want 5V.
The article in the link includes a booster circuit, to generate the 5V for USB
I agreed there are better solutions available and that is really what I am asking… what are those better solutions? For what I am looking to do is having everything needed to run the BBB off battery for as cheap as possible. We are designing a hardware setup for students to use and they have to be able to buy all the components for as cheap as possible. The problem with Lipo (from what I have seen) is that the chargers are the expensive part.
Here is where I am at right now. Need at least 9V for running motors as well as the BBB.
3-cell Lipo = $9 from HobbyKing
Lipo charger = $12 from HobbyKing
Lipo charger power supply = $8 from Amazon
Voltage Reg, diode, caps, wires etc. = $3 from DigitKey
This might be the best solution. But my thought was students might already have AA battery chargers at home.
Thoughts?
Also, can you point me to a better circuit design that doesn’t use the 7805?
Search ebay for “LM2596 buck converter”. Variable output up to 3A, 10 for $10 from China. I’m running my setup from a 12V car battery through these. There are buck/boost converters to be had on ebay too, they’re a bit more expensive but still probably cheaper than you can make them yourself.
Hi Rowland
Up to now you did not tell us that you use 9V for motors that consume
maybe much more power than a BBB. If you Project is a little Segway or
robot car where it is okay when the battery is down after 20 Minutes
or so, then go ahead with the 7805. You can solder this together even
without PCB.
And, because it's a students project it's maybe safer not to use
lipo's..... they tend to explode if not charged correctly:-(
We power the Beaglebone and the motors off 6 NiMH AA rechargeable batteries and the robot lasts for about 4 hours. I have a circuit board layout with a toggle switch that I could share if you wanted it, but it is fairly straightforward and you could wire it up without a PCB easily.