On Tuesday, 22 February 2022 at 20:37:20 UTC, John Larkin wrote:> >> Some "USB" (irony emphasis on the U) cables are specifically > >> resistive, to limit current. > > > >examples? > > > >can't see any reason to a USB cable being resistive other and as > >a side effect of trying save money on copper > I've seen gadgets that come with a specifically resistive USB power > cable and warnings to use only that one. I don't have a link.In that case it isn't a USB cable. Its something else with USB-style connectors. John
Wires overheated while charging iPad with ATX PSU
Started by ●February 21, 2022
Reply by ●February 22, 20222022-02-22
Reply by ●February 22, 20222022-02-22
On Tue, 22 Feb 2022 12:58:07 -0800 (PST), John Walliker <jrwalliker@gmail.com> wrote:>On Tuesday, 22 February 2022 at 20:37:20 UTC, John Larkin wrote: > >> >> Some "USB" (irony emphasis on the U) cables are specifically >> >> resistive, to limit current. >> > >> >examples? >> > >> >can't see any reason to a USB cable being resistive other and as >> >a side effect of trying save money on copper >> I've seen gadgets that come with a specifically resistive USB power >> cable and warnings to use only that one. I don't have a link. > >In that case it isn't a USB cable. Its something else with USB-style connectors. > >JohnAren't they all? USB is a mess. -- If a man will begin with certainties, he shall end with doubts, but if he will be content to begin with doubts he shall end in certainties. Francis Bacon
Reply by ●February 22, 20222022-02-22
tirsdag den 22. februar 2022 kl. 22.36.05 UTC+1 skrev John Larkin:> On Tue, 22 Feb 2022 12:58:07 -0800 (PST), John Walliker > <jrwal...@gmail.com> wrote: > > >On Tuesday, 22 February 2022 at 20:37:20 UTC, John Larkin wrote: > > > >> >> Some "USB" (irony emphasis on the U) cables are specifically > >> >> resistive, to limit current. > >> > > >> >examples? > >> > > >> >can't see any reason to a USB cable being resistive other and as > >> >a side effect of trying save money on copper > >> I've seen gadgets that come with a specifically resistive USB power > >> cable and warnings to use only that one. I don't have a link. > > > >In that case it isn't a USB cable. Its something else with USB-style connectors. > > > >John > Aren't they all?no, random Chinese dothats convinnietly powered by the 5V from a USB port is not USB> USB is a mess.how so?
Reply by ●February 22, 20222022-02-22
On Tuesday, February 22, 2022 at 2:30:01 PM UTC-5, John Larkin wrote:> On Tue, 22 Feb 2022 19:43:32 +1100, Sylvia Else <syl...@email.invalid> > wrote: > > >On 22-Feb-22 3:04 pm, jla...@highlandsniptechnology.com wrote: > >> On Tue, 22 Feb 2022 14:30:00 +1100, Sylvia Else <syl...@email.invalid> > >> wrote: > >> > >>> On 22-Feb-22 12:31 pm, s7382 wrote: > >>>> https://i.stack.imgur.com/YaRcd.png > >>>> How it's wired. With my wiring, the USB wires are heating up to around 200-300F. > >>>> Am I using the right voltage? > >>>> Is the iPad demanding too much power? The PSU worked fine after the incident. > >>> > >>> I expect the iPad can draw a fair amount of current, and the ATX PS > >>> could certainly supply it. How thick are the conductors? > >>> > >>> Sylvia. > >> > >> I wonder what the actual voltage is. > >> > >> > >> > > > >Presumably 5V, unless you're thinking that it's drawing too little > >current for the ATX PS to be stable. > > > >Sylvia. > Some "USB" (irony emphasis on the U) cables are specifically > resistive, to limit current. > > I'd expect that an ATX switching supply might make a lot of voltage > with a light load. > > OP could measure both.I don't think computer supplies work that way. They either regulate or shut down. The problem is keeping it working while running a relatively light load. However, 3 amps is not a uniquely light load for a PC supply. I don't think that is the problem. Much more likely is the supply is providing all the power the iPad is asking for and the wires are too small. Or maybe the connector contacts are bad and the OP is feeling the heat there. -- Rick C. - Get 1,000 miles of free Supercharging - Tesla referral code - https://ts.la/richard11209
Reply by ●February 22, 20222022-02-22
On 23-Feb-22 9:21 am, Rick C wrote:> On Tuesday, February 22, 2022 at 2:30:01 PM UTC-5, John Larkin wrote: >> On Tue, 22 Feb 2022 19:43:32 +1100, Sylvia Else <syl...@email.invalid> >> wrote: >> >>> On 22-Feb-22 3:04 pm, jla...@highlandsniptechnology.com wrote: >>>> On Tue, 22 Feb 2022 14:30:00 +1100, Sylvia Else <syl...@email.invalid> >>>> wrote: >>>> >>>>> On 22-Feb-22 12:31 pm, s7382 wrote: >>>>>> https://i.stack.imgur.com/YaRcd.png >>>>>> How it's wired. With my wiring, the USB wires are heating up to around 200-300F. >>>>>> Am I using the right voltage? >>>>>> Is the iPad demanding too much power? The PSU worked fine after the incident. >>>>> >>>>> I expect the iPad can draw a fair amount of current, and the ATX PS >>>>> could certainly supply it. How thick are the conductors? >>>>> >>>>> Sylvia. >>>> >>>> I wonder what the actual voltage is. >>>> >>>> >>>> >>> >>> Presumably 5V, unless you're thinking that it's drawing too little >>> current for the ATX PS to be stable. >>> >>> Sylvia. >> Some "USB" (irony emphasis on the U) cables are specifically >> resistive, to limit current. >> >> I'd expect that an ATX switching supply might make a lot of voltage >> with a light load. >> >> OP could measure both. > > I don't think computer supplies work that way. They either regulate or shut down.In an ideal world, certainly. But who knows what some cheap PS from China might do? Not that I'm saying that the OP has such a PS, but anything is possible. Sylvia.
Reply by ●February 22, 20222022-02-22
On Tuesday, February 22, 2022 at 6:01:13 PM UTC-5, Sylvia Else wrote:> On 23-Feb-22 9:21 am, Rick C wrote: > > On Tuesday, February 22, 2022 at 2:30:01 PM UTC-5, John Larkin wrote: > >> On Tue, 22 Feb 2022 19:43:32 +1100, Sylvia Else <syl...@email.invalid> > >> wrote: > >> > >>> On 22-Feb-22 3:04 pm, jla...@highlandsniptechnology.com wrote: > >>>> On Tue, 22 Feb 2022 14:30:00 +1100, Sylvia Else <syl...@email.invalid> > >>>> wrote: > >>>> > >>>>> On 22-Feb-22 12:31 pm, s7382 wrote: > >>>>>> https://i.stack.imgur.com/YaRcd.png > >>>>>> How it's wired. With my wiring, the USB wires are heating up to around 200-300F. > >>>>>> Am I using the right voltage? > >>>>>> Is the iPad demanding too much power? The PSU worked fine after the incident. > >>>>> > >>>>> I expect the iPad can draw a fair amount of current, and the ATX PS > >>>>> could certainly supply it. How thick are the conductors? > >>>>> > >>>>> Sylvia. > >>>> > >>>> I wonder what the actual voltage is. > >>>> > >>>> > >>>> > >>> > >>> Presumably 5V, unless you're thinking that it's drawing too little > >>> current for the ATX PS to be stable. > >>> > >>> Sylvia. > >> Some "USB" (irony emphasis on the U) cables are specifically > >> resistive, to limit current. > >> > >> I'd expect that an ATX switching supply might make a lot of voltage > >> with a light load. > >> > >> OP could measure both. > > > > I don't think computer supplies work that way. They either regulate or shut down. > In an ideal world, certainly. > > But who knows what some cheap PS from China might do? Not that I'm > saying that the OP has such a PS, but anything is possible.Of course, everyone leaves out unneeded parts, so the design that suits PCs is a circuit that requires a minimum load (not sure from which voltage). The supply does not go out of regulation in the sense of overvoltage. It does not output current on all outputs. There is no reason why it would overvoltage because of a light load. But, as I've mentioned, the iPad is not going to draw a light load and obviously *is* drawing a heavy load, at least for the wires being used. 20 years ago PC supplies powered the CPU through the 5 volt rail. But the current go so excessive they bumped it up to the 12 volt rail. Now the 5 volt rail powers a lot less of a PC and so, not as much current. -- Rick C. + Get 1,000 miles of free Supercharging + Tesla referral code - https://ts.la/richard11209
Reply by ●February 22, 20222022-02-22
On Tue, 22 Feb 2022 13:42:06 -0800 (PST), Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:>tirsdag den 22. februar 2022 kl. 22.36.05 UTC+1 skrev John Larkin: >> On Tue, 22 Feb 2022 12:58:07 -0800 (PST), John Walliker >> <jrwal...@gmail.com> wrote: >> >> >On Tuesday, 22 February 2022 at 20:37:20 UTC, John Larkin wrote: >> > >> >> >> Some "USB" (irony emphasis on the U) cables are specifically >> >> >> resistive, to limit current. >> >> > >> >> >examples? >> >> > >> >> >can't see any reason to a USB cable being resistive other and as >> >> >a side effect of trying save money on copper >> >> I've seen gadgets that come with a specifically resistive USB power >> >> cable and warnings to use only that one. I don't have a link. >> > >> >In that case it isn't a USB cable. Its something else with USB-style connectors. >> > >> >John >> Aren't they all? > >no, random Chinese dothats convinnietly powered by the 5V from a USB port is not USB > >> USB is a mess. > >how so?There are a zillion barely-different but incompatible connectors, nearly all with non-obvious polarization. The C connector scheme is pretty good... decades late. -- If a man will begin with certainties, he shall end with doubts, but if he will be content to begin with doubts he shall end in certainties. Francis Bacon
Reply by ●February 23, 20222022-02-23
On Tuesday, February 22, 2022 at 3:21:04 PM UTC-5, Don Y wrote:> On 2/21/2022 6:31 PM, s7382 wrote: > > https://i.stack.imgur.com/YaRcd.png > > How it's wired. With my wiring, the USB wires are heating up to around 200-300F. > > Am I using the right voltage? > A VOM seems like the easiest way to VERIFY that. > > You may find the PSU requires a heavier load on the supply than you are > providing. > > Putting an ammeter in series with the load to give you a rough idea of > the amount of current flowing would be a good idea. Likewise, the voltage > DROP across the cable's length. > > Is the iPad demanding too much power? The PSU worked fine after the incident. > iPad get warm (battery)? > > If you disconnect iPad from your "adapter", there should be NO current flowing > and no "heat", right? (i.e., wiring error)iPad battery is OK, it's the USB wire that gets hot,
Reply by ●February 23, 20222022-02-23
On 2/23/2022 12:11 PM, s7382 wrote:> On Tuesday, February 22, 2022 at 3:21:04 PM UTC-5, Don Y wrote: >> On 2/21/2022 6:31 PM, s7382 wrote: >>> https://i.stack.imgur.com/YaRcd.png >>> How it's wired. With my wiring, the USB wires are heating up to around 200-300F. >>> Am I using the right voltage? >> A VOM seems like the easiest way to VERIFY that. >> >> You may find the PSU requires a heavier load on the supply than you are >> providing. >> >> Putting an ammeter in series with the load to give you a rough idea of >> the amount of current flowing would be a good idea. Likewise, the voltage >> DROP across the cable's length. >>> Is the iPad demanding too much power? The PSU worked fine after the incident. >> iPad get warm (battery)? >> >> If you disconnect iPad from your "adapter", there should be NO current flowing >> and no "heat", right? (i.e., wiring error) > iPad battery is OK, it's the USB wire that gets hot,But, with the iPad electrically NOT connected to the "adapter" that you've made, do the wires get hot? I.e., if you've accidentally miswired/shorted the adapter in your construction attempt, then the "fault" may be independent of the iPad's presence. (actually having *numbers* for V and I would *really* help you!)
Reply by ●February 23, 20222022-02-23
On Wed, 23 Feb 2022 11:11:09 -0800 (PST), s7382 <s35587079@gmail.com> wrote:>On Tuesday, February 22, 2022 at 3:21:04 PM UTC-5, Don Y wrote: >> On 2/21/2022 6:31 PM, s7382 wrote: >> > https://i.stack.imgur.com/YaRcd.png >> > How it's wired. With my wiring, the USB wires are heating up to around 200-300F. >> > Am I using the right voltage? >> A VOM seems like the easiest way to VERIFY that. >> >> You may find the PSU requires a heavier load on the supply than you are >> providing. >> >> Putting an ammeter in series with the load to give you a rough idea of >> the amount of current flowing would be a good idea. Likewise, the voltage >> DROP across the cable's length. >> > Is the iPad demanding too much power? The PSU worked fine after the incident. >> iPad get warm (battery)? >> >> If you disconnect iPad from your "adapter", there should be NO current flowing >> and no "heat", right? (i.e., wiring error) >iPad battery is OK, it's the USB wire that gets hot,The battery may not be OK for long! Why not use the right iPad charger? -- If a man will begin with certainties, he shall end with doubts, but if he will be content to begin with doubts he shall end in certainties. Francis Bacon
