Raspberry Pi Forums

I took delivery of a case and battery pack today, this one in fact:

http://www.amazon.co.uk/Raspberry-Power ... Y9EVZ2LQ75

I have just the power cable and a LAN cable plugged into the Raspi and the raspi is not booting up.

What I see is the red light on and the OK/ACT greed LED flashing every second. I have checked the wiki to see what that means but can't find an explanation. The LED isn't flashing a set number of times or in any repeating pattern. It's just flashing on and off every second.

The battery pack has two power options, a 500mA one and a 1A one. Both have the same effect.

If I plug the same power cable into my usb power socket the Raspi boots up fine.

The battery has a series of LEDs that show that it is fully charged.

Has anyone else seen these symptoms or know a fix for them?

The Raspi is a model BH1208

cdilla wrote: ...
I have just the power cable and a LAN cable plugged into the Raspi and the raspi is not booting up.

What I see is the red light on and the OK/ACT greed LED flashing every second. I have checked the wiki to see what that means but can't find an explanation. The LED isn't flashing a set number of times or in any repeating pattern. It's just flashing on and off every second.

The battery pack has two power options, a 500mA one and a 1A one. Both have the same effect.

If I plug the same power cable into my usb power socket the Raspi boots up fine.

The battery has a series of LEDs that show that it is fully charged.
...

What voltage appears accross the Pi's testpoints (http://elinux.org/R-Pi_Troubleshooting# ... r_problems) in each case?
What voltage appears on the battery pack terminals when it's NOT connected to the Pi?
Trev.

Thanks for the pointer Trevor.
The battery pack is outputting 3.87V on both the 500mA and 1A outputs.
Methinks 'tis not enough

I'll see what the vendor says. Maybe it's a duff battery.

cdilla wrote:Thanks for the pointer Trevor.
The battery pack is outputting 3.87V on both the 500mA and 1A outputs.
Methinks 'tis not enough

I'll see what the vendor says. Maybe it's a duff battery.

Just wondering - what type of battery pack is it? eg. 4 x NiCd or NimH cells or a Li ion (mobile 'phone) pack. I'd expect (at least) 4.8V "off load" for the first two types, not sure about the Li ion. In any case the Pi needs 4.7V min. Your 3.87V does seem low but if it was a Li ion pack IIRC they take several intial charge/discharge cycles before they can be charged fully, but often "arrive" partially charged - hence many 'phone, netbooks etc. have to be charged for several hours "before first use".
Trev.

A Li-ion battery by itself will never power a RPi. The voltage from a single cell is too low and the voltage from two in series is too high. It must have a DC-DC converter to deliver 5volts to the RPi.

Can you give a URL to details of the battery pack?

Thanks for the further input.
The battery pack came with the case (url in original post) and the bundle is advertised as being suitable for the raspi- it comes with a raspi case too.
There is no actual name on the battery, just a logo of three Ss arranged around a T.

The battery pack itself does have its input/output specs written on it and they say
INPUT DC 5.0V
OUTPUT1 DC 5.0V 1A
OUTPUT2 DC 5.0V 500mA

When I was looking for a battery pack I saw a very similar unit for sale (without the acrylic case) which had a link to the manufacturers page and that also said 5v output. It looks identical apart from being white and having a different logo. Here is a link

http://www.amazon.co.uk/TeckNet%C2%AE-D ... _sbs_ce_14

The battery has three LED bars that indicate its charge level marked with 1/4, 1/2, FULL icons. The 1/4 and 1/2 were fully lit when I got it and the FULL one half lit. I charged it for an hour or so and it showed fully charged.

I've stuck it back on charge now and will leave it for a few hours and see if that makes any difference.

cdilla wrote: ...
When I was looking for a battery pack I saw a very similar unit for sale (without the acrylic case) which had a link to the manufacturers page and that also said 5v output. It looks identical apart from being white and having a different logo. Here is a link

http://www.amazon.co.uk/TeckNet%C2%AE-D ... _sbs_ce_14
...

Hmmm... having taken a quick look at your (second) link (above) it appears that one is a "Lithium Polymer" battery. I'm not sure how different (if at all) that is to a Li(thium) ion cell but, having checked the "power management" page of my eelo eReader, which, I think, uses a similar power source, charged from a "standard" USB 'phone charger, it's charge/discharge graphic display only goes up to 4.5V on the voltage axis. Also, IIRC, the maximum I've seen, so far, is ~4.3V, but it's only on around its fifth charge/discharge cycle. This ties in with drgeoff's comments.
Trev.

I've had some success.
When I had looked into the battery type before I bought it, as mentioned above, I found a youtube review of it and one of the things the reviewer said, and showed, was that the button was only for lighting up the power storate LEDs on the battery and not an on/off switch. So he showed the pack working (charging a phone) with the LEDs off.

What I have discovered this morning is that when the LEDs on the battery are switched off the voltage of the battery outputs is 3.87V. But when the LEDs are switched on the outputs both read 5.0V !

So, yesterday I was using it always with the LEDs off and it had the problem described above.
Now I am using it with the LEDs switched on and the Raspi is up and running. It's been running now, connected to the 500mA output, for four hours so far and the battery says it is at half charge.

Assuming the battery pack switch is working as intended the problem lies with the lack of documentation that came with it. I'm still not sure why the switch both illuminates the LEDs and raises the voltage to 5V, or why, if the switch is an on/off switch the battery still outputs 3.87v when "off".

Anyway, for now I have a functioning battery powered RasPI. Thanks again for your interest and help.