I am having issues with a Raspberry reporting undervoltage. They apparently kick out this error at anything under 4.65 volts. This is plugged into a 4 way extension, which is chained off another.
I'm wondering if this is similar to when I plug in a part charged iPod into an extension, and it doesn't seem to realise it's been plugged in, but works fine from a wall socket.
Does voltage (or something) get reduced by use of extension leads? I've not got a lot of choice really as my office is actually the third bedroom and only has 1 wall socket, but probably 15 or more (very low load) things running from it on chained extensions.
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The voltage will drop a bit, but unless they are very long it will be a small drop, probably not enough in itself. Changing the 'vampire' might fix it, or even wiggling the plugs to improve the connection.
Not that I have any special expertise in this, it's just another internet opinion!
I'd suggest measuring the drop but you need some proper kit to measure AC voltage with any accuracy.
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I remembered after posting I have a mains measurer, no idea how accurate, what would one expect for a tenner? :-)
I'm coming to the conclusion that my problem may be caused by a combo of cheap plugs and some new cables, which seemed pretty good for fast charging phones but maybe not providing the full voltage for the Pi.
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In order of most likely cause:
1) USB power cable to Pi. Try a shorter, heavier gauge cable.
2) USB power supply at it's limit. Pi 4 needs ~3A under heavy load.
3) Combination of 1) and 2).
4) Poor quality extension leads. (Fire risk!)
I have a Pi4B running fine off a 15W P/S with 2 x 2TB USB drives attached.
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I wonder if it's more to do with the 'chained extensions'? There might be sufficient impedance in the length of them and the connections between to cause a voltage drop. Have you checked the total current draw from everything connected? does anything get warm?
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The USB charger is probably designed to accept anything between 110 and 240V.
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>> The USB charger is probably designed to accept anything between 110 and 240V.
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Good point. Also that it might not be man enough especially if it wasn't supplied for the Pi. And cables seem very variable in performance. I have a right selection, and some will charge one thing and not another.
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Thanks all. I've spent most of the afternoon until now trying to sort this out and I am pretty sure it was the plugs. I hadn't changed anything recently except the power cables, for short ones which do the rapid charging OK. The devices ran (mostly) OK but booting etc was problematic.
I've now done a fair bit of swapping and testing, ending up with using an Anker 5 port USB charger, originally bought for use with phones, supplying both PIs, with the new power cables. So I probably still have an underlying problem with teh cables, now being masked by the much better "plug".
The Pi which was being most troublesome now fires up every time ( - it was looping on boot and never quote getting there, although once in about 40 tries it would boot then be OK) with no under power message (because I've been able to hook my spare screen to it so I can see what's going on). It's also taken a core system upgrade, which it had gone through the motions of many times but on reboot it was not upgraded.
So it feels like another afternoon wasted but I was unlucky (or maybe a bit daft) to have not blamed the wiring/plugs till I'd done a raft of researching the (spurious, as it seems to have turned out) errors. But I didn't have anything else to do.
Had a drive in an MG4 EV this morning so it wasn't so bad a day :-)
Thanks again.
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Are all the ports the same rating? What usb are we talking about, b or c, because different cables can have different ratings, with in-built chips setting the actual performance?
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The Raspberries take USB C. The 5 port charger I'm now using has five equal ports (but I'm only using 2), it doesn't do fast charging (pre-dates it I think), but it seems to provide a more compatible amount of power. It's a well old version of this tinyurl.com/yzyzcp36
I'm pretty sure the cables are OK as neither Pi has errored tonight.
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So referring to Kevin's point 2, the 5 port charger is not up to the job.
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Maybe not in theory but it isn't throwing errors anymore, so it's less bad than the previous one :-)
It's actually a Lumsing 40W 5 port charger (so it says on the outside), with only 2 ports in use.
I don't operate the Pi's on heavy load, they actually do very little. The errors were only seen at boot time, when they probably are being worked a bit.
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>> drive in an MG4 EV this morning
How did you find it. I just got the long range version the other day. Didn't like the spoiler on the Trophy model and the extra bits seemed rather a lot for the money given it is a budget car.
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I was quite impressed. It was an orange trophy stickered all over with sales patter. I was invited along to see the facelift of the one I have, the MG5, but it didn't seem worth driving as the differences from what I've got don't affect the drive much, so I asked if I could try the 4. I think the in-car tech and toys are similar, and are a definite advance on my MG5, whether they are worth the extra I'm not so sure.
I quite enjoyed the MG4 to drive. Like you, not wild about eh plastics around the back, but it's a lot of car at a good price. It was physically a bit small for me (maybe I am too big for it!) but tbh I rarely do long journeys so I'm not sure that should bother me. Having said the, the additional 30ish miles range over the MG5 is good.
I paid £24.5k for mine a year ago and I got a quote from one of the online people of £27k ish the other week. Leaves me with a cost to change of about £4.3k which i don't really think I want to start to justify.
Though one feature is that because of the improved software I reckon it is likely to be included in Octopus's Intelligent tariff, for which I'd need to buy about £1000 worth of OHME to get the existing car onto.
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What on Earth are you all talking about ?
Asking for a friend.
Ted
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Haha... and I'm no expert, obviously!! :-)
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Yes, hopefully they will come out with an integration for it. I could do with another couple of hours at the cheaper rate.
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Voltages and extension cables - Manatee
