which external HDD for backup

Hi all,
back to the gurus!
It's time for another complete backup, (I use Acronis 2017) so I'm going to buy another external HDD to use as my others are getting like me on a Saturday night....a bit full
I like WD's as I've never had a problem with them but my questions:
Will a 2Tb 2.5 portable without AC power, just USB3 connectivity, be OK?
I mean is there enough power through the USB port for reasonably quick transfer?
Any disadvantages or advantages to have an AC powered HDD?
Ta

Hi,
I wouldn't get a portable personally just a simple enclosure
I'd stick with a 3.5" blue series as well but as you wanted a 2tb
http://www.amazon.com/Sabrent-ECS-ST.../dp/B00095OAQG

Western Digital WD Blue Hard Drive 1TB WD10EZEX 7200 RPM 64MB Cache SATA 6.0Gb Internal Hard Drive-Newegg.com

I tend to go the same way as ThrashZone.
Many portable ext backup drives have the following restrictions:
- HDD that cannot be connected to a standard sata connection if the usb3 to sata electronics interface fails.
- some portables from WD (eg. MyBook essentials) used to hardware encrypt the data on the drive so when the interface fails the drive is useless.
- micro usb interface connections that can cause problems.
- come with backup bloat software.

I recently bought a backup system for someones PC from Australian supplier MSY
- WD 2TB Blue - Au$94
- Unitek Y-1091 usb3 docking station - Au$17
works fine.

You can get low cost enclosures if you want. Simplecom seem to work ok. Just like portables they restrict ventilation.

Hi,
Yeah the other one is unavailable but here's a bundle of another one with a blue series 1tb hdd
https://www.amazon.com/ORICO-Toolfre...BXGSTZ7APEEXM9

I got this one locally for about 50.us at Fry's
http://www.amazon.com/Hornettek-Ente.../dp/B00CYFM520

Thanks guys for your input. As luck would have it a mate of mine lent me a 1 Tb WD Passport ultra, (USB powered), to try.
Plugged it in, did a backup of both OS and data HDD's in less than an hour, created a boot disc in five minutes and all good.
Swayed me in as much as I'll hopefully never need to use it anyway, so went and bought a 2Tb of the same model.
$100 well spent......I think!