Warning about cheap leads - Printable Version +- Forum (http://forum.xbian.org) +-- Forum: Software (/forum-6.html) +--- Forum: Installation (/forum-16.html) +--- Thread: Warning about cheap leads (/thread-1727.html) |
Warning about cheap leads - IriDium - 5th Nov, 2013 02:02 AM The other day I used my USB lead from my Rpi to charge my phone at work. Unfortunately I left it at work. I knew I had a spare lead, routed in my lead drawer and found a cheap (Ebay job) USB to micro USB lead. That will do I thought. I checked the voltage 5.15v - Ok and plugged in the Rpi. The PSU is 5v 3.8amp and powers the RPi and the hub. The RPi connection has seen 756ma so will draw what it needs. It worked....... almost. The ethernet sometimes worked, and then the screen started going black and then back to XBMC. The KB and mouse failed to function. Puzzled, I plugged in a spare 1amp PSU and all worked fine. I stripped the lead, and at 10cm it was only supplying 465ma, at it's full length - 1m - it was only drawing 265ma. No wonder I was having problems, I'm surprised the RPi even booted. Morel of story: Don't buy cheap, and check more than just the PSU if your RPi displays strange behaviour. RE: Warning about cheap leads - rikardo1979 - 5th Nov, 2013 03:50 AM I have posted few months, or more than few months and few times about this pretty much same issues, LAN connection drops etc, etc... RE: Warning about cheap leads - IriDium - 5th Nov, 2013 03:54 AM Glad someone else is as ignorant as I in the RPi power issues. A word to all gals and guys out there who answers problems. The RPi is cheap, so users will buy cheap peripherals, leads etc. Always ask about PSU, connectors, HUBS, leads etc - in most cases "strange" circumstances, are not Xbian! I fell foul of it, others will also. Thanks Rico, for making me feel normal - ish RE: Warning about cheap leads - IriDium - 5th Nov, 2013 07:04 PM I did a little test today, to see what amperage the RPi needs. Below are my results. What you should gain with this, is the importance of a good power supply - 1 amp at least and a powered hub, especially if you have more than a coupe of USB devices. The devices were attached and the system rebooted. The devices are cumulative. At rest (Red light on) = 0.11ma Figures in ma. Devices attached -> Peak amperage -> At rest amperage Nothing - 410 - 330 Wireless KB - 430 - 350 Ethernet - 510 - 450 Hub no power - 620 - 540 Hub powered - 510 - 460 Wifi – no hub - 600 - 510 Wifi – hub no power - 760 - 650 Wifi – hub powered - 510 - 460 USB speakers no power - 750 - 650 UBS speakers powered - 520 - 460 Pwd HDD no power hub - 520 - 460 Flash drive unpowered hub - 890 - 810 Re: Warning about cheap leads - rikardo1979 - 5th Nov, 2013 08:32 PM nice one m8 I would like to see like when u stream full hd video like 20gb of size with dts sound RE: Warning about cheap leads - IriDium - 6th Nov, 2013 12:11 AM Didn't really make a lot of difference: 1080p 10G DTS .mkv file played over SMB. Static 610 -> Playing video 680ma. Interestingly, moving the mouse needed 30ma!! Mind you, this is on Beta 2 - I wonder what it would be like on earlier releases! |