UBEC voltage

[pcorbett]

I have an UBEC: I'm pretty sure it is one of these: http://www.hobbyking.com/hobbyking/stor ... ction.html - from ebay: http://www.ebay.co.uk/itm/180773848790? ... 1497.l2649

At first I powered it was 4 alkaline AAs. My multimeter recorded 5v across the output. Good! However the pi kept resetting itself. So I tried 6 alkaline AAs. The multimeter said 5.3V. I was suspicious but tried it anyway. It worked!

A few days later I was doing some robot-building, and tried powering my pi using the UBEC and 6 (cheap, pre-charged) NiMH AAs. This didn't seem to get a result. On some examination, I found that the pi wouldn't boot properly at all after that - not from one of those USB phone chargers either, not even from my normal power source. The red PWR led would light but not the green ACT led. I checked the voltage across TP1 and TP2 - 4.5v, which I remember reading was a bit low. Measuring the resistance across the polyfuse F3 was a bit tricky - I think 0.8 ohms. It doesn't seem to have recovered in the last couple of days.

I'm currently powering the UBEC (but nothing beyond that) off the 6 NiMH batteries - my multimeter says 5.15V.

As a stop-gap I got myself a new pi, and I'm reluctant to try unusual ways of powering it until I know what's going on.

Is it usual for UBECs to be 0.3 or so V above the stated 5V? Could this problem have fried my pi? Is the damage likely to be permanent or is it likely the polyfuse will recover?

[joan]

I've been using these http://www.ebay.co.uk/itm/270740352010 for 8 months (powered from a 12V laptop PSU). Not noticed any problems. Just measured the powered up voltage at 5.4 volts.

[Dilligaf]

5.3 volts if fine and shouldn't cause any problems. Sounds like you may have a bad polyfuse on the PI, you can power the PI from the gpio pins bypassing the input fuse, the included connector on the UBEC will work, you may need to relocate a wire in the connector. Pin 2 or 4 for 5V and pin 6 for ground, see here http://elinux.org/Rpi_Low-level_peripherals

[pcorbett]

Alas, waiting a week to see if the pi would recover didn't work.

Likewise, powering the pi via the ground and 5v pins didn't work either - same symptoms (PWR LED on, ACT LED not on)...

[MaxK1]

Are you sure the SD card has not been corrupted? Can you check on another system if the fat32 partition is still OK?

[pcorbett]

I've got a spare pi, and the SD card works fine with that.

[rpdom]

The other thing to check is that the card is making proper contact with the socket.

One of my Pi 'A's recently started to fail to boot and after a brief investigation (card worked fine in other Pi 'A'), I found it wasn't always making contact with the pins. Pressing the card against the Pi helped, or putting it in at a slightly different angle. Next step is to try and lift the connectors slightly with a sewing needle.

[hobbyguys]

I am not using a pi, but a 5v ubec on my quadcopter, here is the one I got from amazon.com

https://www.amazon.com/HOBBYMATE-Switch ... ds=ubec+5v