Raspberr Pi3 and Arduino questions

**motorolavkg** · 29-08-17, 08:00 PM

Hi all,

I have finally jumped on the bandwagon and order a RP# Model B, but am a bit confused on the power input,
cant seem to find the exact answer on Google.

I just need to know what the MAX power input is, to be considered safe, as 1 of the projects I want to do,
will require a battery pack.

I have been offered a 10000mha power pack, that iirc is 5.5v @ ~3-4A, so will this be safe for the pi, or is it
likely to give me the magic smoke ?

The 3 main projects i want to use the pi for are,
!. kodi - will use my samsung charger for this
2. retropi - - will use my samsung charger for this
3. portable pentest box, hence the battery pack question.

Also on the subject of Arduino`s, can anyone recommend a good AU seller, that sells genuine ones and not knock-off`s?
Am after the UNO, once you dig through EBAY and find the legit ones, they seem to range from about $30-$50.

But the EBAY ones, dont show pics of it with the box, so makes you think it will just come in a anti-static bag.

**shred** · 29-08-17, 08:47 PM

The key to happiness with the Raspberry Pi seems to be to find a good quality USB cable. There are many out there that are absolute rubbish and the price tag is no guide to quality. If you have a decent multimeter, measure the 5v rail on the GPIO connector - make sure it's at least 4.8v and preferably higher. If the voltage dips too low, the RPi will display a little rainbow icon thingy in the top right corner of the display. It also records the low voltage "event" and I have a script somewhere to read this flag. They have a nasty tendency to corrupt the flash memory card if the power supply / cable is not good enough, so pay attention to this.

5.5v sounds a bit too high to me. IIRC, the genuine power supply outputs 5.1v to help overcome the voltage drop in the cable, but 5.5v is probably a bit much.

Current consumed will vary depending on how hard the CPU is running, the brand of flash card and what USB devices you have plugged in. I'd think 750mA is plenty for normal use. If you have a mechanical hard drive attached, it'll be much higher. I run mine with a cheap Plox brand power bank acting as a "UPS". I've also run it from a Xiaomi brand power bank successfully.

**bob_m_54** · 29-08-17, 09:01 PM

Originally Posted by motorolavkg

Hi all,

I have finally jumped on the bandwagon and order a RP# Model B, but am a bit confused on the power input,
cant seem to find the exact answer on Google.

I just need to know what the MAX power input is, to be considered safe, as 1 of the projects I want to do,
will require a battery pack.

I have been offered a 10000mha power pack, that iirc is 5.5v @ ~3-4A, so will this be safe for the pi, or is it
likely to give me the magic smoke ?

The 3 main projects i want to use the pi for are,
!. kodi - will use my samsung charger for this
2. retropi - - will use my samsung charger for this
3. portable pentest box, hence the battery pack question.

Also on the subject of Arduino`s, can anyone recommend a good AU seller, that sells genuine ones and not knock-off`s?
Am after the UNO, once you dig through EBAY and find the legit ones, they seem to range from about $30-$50.

But the EBAY ones, dont show pics of it with the box, so makes you think it will just come in a anti-static bag.

The power pack you're talking about, is it a power bank as used for charging your phone? If so, it should be pretty close to 5V. If it is something else, and you're sure it doesn't go much over 5.5V, I don't think you'll have a problem. I'd be hesitant at running it close to 6V though. As for the current, the Pi will only draw what it needs, plus whatever your USB ports have hanging off it, so no worries having 3A-4A available.

Actually I run mine from a couple of different phone charge power banks.

**motorolavkg** · 29-08-17, 10:16 PM

Originally Posted by bob_m_54

The power pack you're talking about, is it a power bank as used for charging your phone? If so, it should be pretty close to 5V. If it is something else, and you're sure it doesn't go much over 5.5V, I don't think you'll have a problem. I'd be hesitant at running it close to 6V though. As for the current, the Pi will only draw what it needs, plus whatever your USB ports have hanging off it, so no worries having 3A-4A available.

Actually I run mine from a couple of different phone charge power banks.

thanks for that, yes I should have said that it is a phone powerbank, well phone/tablet etc.

bit more info, now that I have double checked.

Brand - OPPO
Model - unknown, im guessing VOOC
mha - forgot to ask this, but think it was 10000 or 12000
standard output - 5V @ 2A
rapid output - 5V @ 3.5A

the other one i was interested in was a sprout one,
24000mha 5V @2.4A

the one that was above 5V is an no name branded one, will have to pop in to cashies in the next day or 2 and re-ask.

**Skepticist** · 29-08-17, 11:55 PM

From memory, the recommended power supply for the Pi3 is rated 5V 2.5A. The main problem is the voltage sagging below 5V on load with cheap lower rated supplies.

As for Arduino UNOs, I've used a few that were under $5 specials on Ebay and yet to have any problem with them (my luck is bound to run out now I've said that)

**motorolavkg** · 30-08-17, 04:18 AM

Originally Posted by Skepticist

From memory, the recommended power supply for the Pi3 is rated 5V 2.5A. The main problem is the voltage sagging below 5V on load with cheap lower rated supplies.

As for Arduino UNOs, I've used a few that were under $5 specials on Ebay and yet to have any problem with them (my luck is bound to run out now I've said that)

yep thats what I`ve read too as a bare minimum for load, if you plan to use power hungry USB devices, a min of 2.5A.

The most i`ll have plugged in most of the time is 2 USB devices

for kali, wifi dongle, and rtl-sdr dongle.

for most other things, kb and mouse combo (like the logitech 2 in 1) and a xbox controller

**bob_m_54** · 30-08-17, 10:01 AM

Originally Posted by motorolavkg

thanks for that, yes I should have said that it is a phone powerbank, well phone/tablet etc.

bit more info, now that I have double checked.

Brand - OPPO
Model - unknown, im guessing VOOC
mha - forgot to ask this, but think it was 10000 or 12000
standard output - 5V @ 2A
rapid output - 5V @ 3.5A

the other one i was interested in was a sprout one,
24000mha 5V @2.4A

the one that was above 5V is an no name branded one, will have to pop in to cashies in the next day or 2 and re-ask.

I'd give the one from cashies a miss personally. It may be there because it's starting to lose capacity. The ones I have been using were both from Kmart. One is a Laser brand (10000mAh 5V@2A), and the other an Audiosonic (11200mAh 5V@1A). Both were cheapies for around $20 on sale, but they will easily run my Pi2B with a IQaudIO DAC+ all day, with plenty left over. I am using a powered HDD into the USB though, so no drain from that.