Jim wrote:
I have a Lenovo ThinkPad A475 and want to buy a Type c usb hub, but i'm
a little unsure how the power side of things come in.
Of course if i want to run say 3 HDD off the hub i suspect (correct me
if i'm wrong) I will need to provide it with more power than the laptops
bus can provide on it's own.
So this being the case are there any good quality (live in uk and don't
want to spend over £50 if poss) hubs that come with a psu, if not what
kind of PSU do i uy i don't want to buy some junk from the far east that
goes bang at the drop of a hat.
Any other help or advice would be more than welcome.
Jim
It's too bad articles like this weren't written in a way
so that a user could understand what the equipment in
hand is doing.
https://en.wikipedia.org/wiki/USB_hardware#Power
5V @ 3A would come close to running three 2.5" HDD in
compact USB enclosures. With the right brand of SSD,
you could get away with 5V @ 1.5A for three SSDs (Samsung,
not a Kingston with a Sandforce controller). I measure my
SSDs with my ammeter, before tethering them off USB ports,
so there won't be an overload.
*******
Now, this thing has two USB-C connectors, and three blue USB3 connectors.
https://www.diamondmm.com/product/di...pe-3-port-hub/
The laptop side connector, carries data from laptop to three ports.
It also allows charging current to flow upwards to the laptop.
The second type-C port is for connecting a charger. I presume
this can power the downstream ports, but can't be sure of it.
This item can negotiate USB-c power and has a 5V @ 3A option
which might be enough to run the three USB3 ports. While it is
doing its thing, the laptop should be disconnecting its VBUS
power.
https://www.newegg.com/Product/Produ...82E16812923003
The history on USB-C cabling is not good - an engineer at Google
went out of his way to test cables from Amazon and found non-compliant
ones. I think his laptop got damaged while doing the testing. Smart
cables are supposed to have a comms chip in the cable, to carry out
the negotiation. I have no idea how each device knows its role, and
knows what the user is trying to do.
Summary:
I wouldn't touch your idea with a barge pole!
Not your fault. Just a failure of the USB PD spec to
offer the "reassurances necessary to buy stuff". I can't
tell what I'm getting, can't do basic re-engineering of
the products I'm seeing. Can't tease out a spec I can trust.
I would connect *one* drive, do my thing, do a Safely
Remove, or whatever. I have one USB3 "item", where when you
do a Safely Remove, followed by unplugging it, the "dirty shutdown
indicator" increments by 1, meaning the device really wasn't
happy, even though it was "told" what was about to happen.
And this is the kind of behavior I *don't* need. Then when
the thing breaks later, I'll be going "hmmm - my fault or
their fault".
I can't meet your price target. Seems like "Apple pricing" abounds.
Nobody wants to bundle the adapter with the hub, because then
their tier pricing would be too high, and they'd sell zero of them.
This seems to be the nature of whizzy/bloated specs.
I can envision marketing people doing lines of coke off
a coffee table while writing this one up.
It's all very clever, but as I've explained before, people
buy "garbage" based on price. If you can't hit decent pricing
targets, your product will be a flop. You can tell from the
number of products with zero reviews, how well this is working.
What I'm seeing so far, seems to be 2x to 3x too expensive,
and part of the root cause, is it's taking more than one
silicon chip to build it. The integration level isn't there
to make the price drop lower. Two devices (hub and AC adapter)
will each have "negotiation chips" to "talk" over the cable.
And that's a waste.
I understand Bill Gates wants to buy this setup, but has
to wait for his allowance next month.
A question for you. Does Lenovo offer a dock for that laptop ?
Would a NAS work for you ? Say, a NAS with multiple drives
(over Ethernet) plus *one* drive at a time connected to the
laptop for portability.
Paul