Thought I have a hunch the ChargeTech would meet my power requirements, the stuff I am coming across about the damage that these modified sine waves, which are more like square waves, can do to PSUs is troubling.
It would seem that the only battery packs with true sine waves are rather large and clunky.
I think I’ll just have to give up my dreams of making elektronic music away from an outlet. 
there’s always the op-1 and circuit for nice outdoor composition!
OK, so just to clarify:
I am in the UK, I wish to power an A4 (with an EU plug) and an OT (with a UK plug)
Is the only currently available option the xtrom AL390? with some plug adapters involved?
There seem to be no RAVPower ones available I the UK with anything over than USB ports.
I cant seem to find the XORO one either.
Anyone in the UK having any luck?
Thanks
One more reason for 
to make at least one portable device.
Or provide elektron endorsed portable battery power banks.
Im thinking of buying three of these xtorms to run three units at once.
nachtaktiv above seemed to be powering 3 off the one pack
Yer but it will draw power faster and his description of weird crackling noises discussed on facebook did not inspire confidence. Better to have direct line in. I found this for 150 so might buy one to try out then decide from there.
Ah ok. I’m not on the facebook elektronauts group… didn’t know about that.
Might start with one and work my way up from there.
It was discussed on dawless jammin group.
So i got a xtorm and it so far has been working great. Using it to only power 1 Elektron at a time mainly as I’m still learning my OT. Used it about 4 hours and it still says 75% charged.
Gonna try and power them both tonight and if needed buy a second one.
Poweradd Pilot Pro2 23000mAh Multi-Voltage works a treat with RYTM
Do you just plug it straight into the RYTM? How many hours of play time do you get?
With the xtrom you plug in the usual plug adapter straight into the battery bank
I’ll let you know later, just got it, but it seems like quite a beast. Does take ages to charge, but such is the nature of Lithium batteries apparently (http://www.bbc.co.uk/news/technology-37255127).
"Quick charge
If the battery charges too fast, generating heat, lithium plates form around the anode which can create a short circuit.
“Normally you would have a battery management system that controls the rate at which you charge,” said Prof Grey.
“Batteries are optimised so that you don’t charge too fast - if you do that you will plate the lithium.”
This is also why battery charging can be a frustratingly slow experience, she added."
There is a dc out (switchable via the button on the top between the different voltages it does) with an included cable and adaptor. They’re going for 70 bones on uk amazon at the moment.
Hmmm not a bad option for a second battery. the Xtrom is pretty nippy on the charge in comparison but does cost double the money…
I live on a boat so my entire life is DC battery powered. the more options the merrier really especially as I keep cruising further away from my studio and miss my synths…
After 4 hours contstant use and playback, it’s about 47%, so not as good as the xtorm.
Still that’s not bad especially for the price.
My thoughts exactly, and for my train commute it’s perfect. I shall keep the xtorm in mind for other things; like possibly for powering a custom stereo for my bike; boom2 is hardly loud enough. Want my bike to have a stereo as loud as a car lol
Hmm yeah I see I made a mistake there but when I use it on 9V it works… probably shouldn’t do that tho but it does!
Yeah the first time I plugged the Poweradd Pilot Pro2 in I used the wrong adaptor and it didn’t work so I thought I had wasted £80 but tried a different one and it worked fine! I tried the octatrack on it at 9V and it works but I’m unsure how safe that is and to be honest the Rytm is less menu-ey and more fun especially on a train journey! It lasts about 10-12 hours use on the Rytm which is fine for me!