Parallel BattBorgs?


Hopefully a simple question. I am powering an official RPi 7" screen and a RPi 2B (with CSI camera) from a pack of 8 x 1.2v 2500 mah rechargeable batteries with a single BattBorg. This setup struggles a bit with only 1.5 amps from the BattBorg. My question is, if I connect 2 BattBorgs in parallel, using the single battery pack, will I get 3 amps and banish the little square rainbow?

piborg's picture

Yes you can use more than one BattBorg together like that.
We have also used one BattBorg to power the sreen and a second to power the Raspberry Pi and bits in the past.

Is the square rainbow on constantly, or does it flicker?

No, the rainbow is not on all the time, it appears for a while after boot up and then occasionally it fades in and out.
I like the idea of powering the screen and Pi with separate BattBorgs, I will probably put in an order for another one soon.

piborg's picture

That is good, it points to the 1.5 A limit being the problem.
As it indicates that the 5 V rail is too low it would suggest a different problem if it was on constantly.

What will be happening is that occasionally the BattBorg cannot keep up with the demand, so it "stumbles" a bit and delivers a slightly lower voltage.
Bootup consumes a fair amount of power, so it would make sense that it is on around or just after the boot sequence.

As suggested by piborg I am now running the screen and the Pi from separate BattBorgs connected to a single battery park. Works a treat, no rainbow any more.

Following on from my original thread above I have been trying to run Diddy with two cameras, the official rpi camera connected to the CSI slot as normal and an old USB webcam. I intend to mount the webcam on a servo so that 'he' can look around.
Initially I have had a problem with both cameras hanging after about a minute of running. After much trial and error I have concluded that it is a lack of amps that is the problem. (As Diddy is run headless I don't get the rainbow square on my VNC display.)

By using both battery power (via the BattBorg) and the normal Pi micro USB power input I can successfully run both cameras continuously but Diddy is like a dog on a chain, restricted to the length of the USB lead!
Would a second BattBorg wired in parallel solve this?

My current set up is:

Rpi 3
UltraBorg - for ultrasonics and servo (currently powered by the Pi but will revert to batteries when servo fitted)
XLoBorg - for compass heading
Gertboard - using the open collector chip to switch headlights (torches) but not powered from Pi
Cameras driven by V4L2 and Opencv

piborg's picture

From the sounds of it a second BattBorg in parallel to the first would likely solve the problem.

I would guess the webcam is trying to draw a fair amount of current from the USB, pushing it over the edge.
I imagine you would be seeing the rainbow square if there was a monitor attached like you suspect.

Out of curiosity how well does the webcam work when everything is happy?
It would be good to get more than one camera on some robots here ^_^

Thanks PiBorg. Another BattBorg ordered.
The webcam is a Logitech Quickcam Chat which I bought about ten years ago. Resolution is only 320 x 240 so the quality is not as good as the Pi camera but as I'm running them both at 160 x 120 in the interest of processing speed it's quite acceptable.
I haven't yet tried any cv2 symbol recognition with the webcam as I've only recently got it working. I've amended the cv2 video processing thread to accept "0" and "1" camera indices and can therefore run an instance of the processing thread for each camera and display both images side by side on the VNC desktop.

Second BattBorg added, I'm pleased to report that both cameras now run continuously from the battery pack. I wonder if there's a market for an upgraded BattBorg giving more amps from a single board?

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