I’m doing some chillout music at a festival which is in a tent in the middle of a field and I’m pretty certain mains power won’t be available. I already have a battery-powered amp for such occasions, and now I have a sealed lead-acid battery which will provide 12AH at 12v (actually it provides 13.0v currently). If I make up the correct polarity 12v plug to connect to the Dwarf would this be OK (and more importantly, would it work afterwards)???!
I don’t see why the Dwarf would be harmed as it should draw whatever current it needs, but thought I’d better check first before plugging it in.
This is a tough question.
In theory, you are supplying 12V DC, so it would seem straightforward.
If you can use a lithium-ion battery for that, it would certainly be better. They have a more stable discharge and are much less likely to “leak” electrolytes that may damage your electronic equipment. A good laptop battery with a voltage regulator for a steady 12V could do it for you – though for 2 amps you might need more than one in parallel.
If one such option is not available, a Lead acid battery can certainly provide power for longer than others, but voltage floats once it is less than half charged. I would definitely recommend against car/motorbike batteries for electronic applications, choose one suitable for a power backup unit.
For current yes, it will only use what it needs. But voltage only to a certain extent. The regulator at the input can only be pushed so far, though I would think +1V would be within a valid tolerance. The battery’s ability to deliver a steady 12V is what should concern you.
Sorry that I can’t offer a definite answer. This is a thorny topic among DIY electronics folks. Old school types would likely say NO NO NO to using lead acid batteries with digital components. (That’s what my first tutor told me back in the 80s.)
My own choice would be a power station that had AC outs and plug it from there, if you can borrow or acquire one.
Oh thank you – that’s useful. So what you’re saying is that if the voltage starts to drop, the Dwarf internally might struggle. So presumably if I run a mains inverter from the 12 V battery – and I have one of these – then plug the Dwarf power supply into that, there should be no such problem? Is that right? Because presumably the inverter will give a reasonably constant voltage – or presumably will shut down if the battery voltage goes below a certain point. Therefore the Dwarf would be protected in a way that it wouldn’t be if you just simply try to run it directly off a 12 V battery which was slowly losing its charge.
Just thought I would set out my understanding - you can probably tell I’m not an electronics expert! Running it off a regulated mains inverter makes sense to me as it’s more like what it encounters in the real world.
PS just tried with the inverter and it’s great. Draws 1.4A from the battery so in theory could run a few hours from my 12AH battery. So thank you.
There are also different types of Lead-Acid batteries: not all of them support deep discharge. You want one of the type that equips boats or caravans, not the ones used for starting cars which are made for delivering huge current over a short time and are never supposed to be totally discharged.
Good to hear that. If you play your gig with it, please tell us how it went.
Just a sidenote: many of today’s inverters deliver AC power as a real sine wave current. Some still don’t and the “stepped” slope AC flow can mess up digital equipment. (Hospitals for instance need full sine AC power backup units or else some monitoring equipment goes haywire.)
Thank you – yes this one is stepped sinewave, but it seems to work fine. Ideally, when I get to the venue, I will find mains is available, in which case that’s what I’ll use!
Looking forward to using the dwarf. It’s mainly looping, shiroverb and a bit of chorus. Stuff I can switch in and out of and essentially it’s a relatively simple pedalboard I’ve programmed in for this gig. But what I really like about it is that it changes the way you perform. Normally do 17th to 20th century music that’s based on folk – either my own arrangements or other people’s. But for this venue and this crowd the setup I’ve got will be perfect for this ambient stuff I’m doing.
I am really looking forward to using the Dwarf with the rest of my band, as that will replace a bigger pedalboard. That’s for another time though!