ROLANDRechargeable Amp Power Pack (BTY-NIMH/A) – Official Rechargeable Battery Pack for Select Roland Amplifiers including CUBE Street EX, AC-33, KC-220 and BA-330. Longer Runtime – More Output Power

To quote the manual"In the event that you leave the amp on after use and the battery keeps discharging, the battery mayover-discharge, causing the safety protection circuit to activate. The battery cannot recharge in this case."I tried, "Try unplugging and plugging the adaptor into the DC IN jack several times." again, as per the manual, 20 times, no joy, still dead. I'm thinking that I should have bought Duracells.When I plug it in, 2 LED flashes, then dead. When I unplug it, 1 LED flash after 2 seconds then dead. Unplugged and then plugged in again, quickly, BEFORE the single flash...it started charging. £99 battery...relief!.I really struggle to believe that this design got through any kind of project review, at any stage.Yeah, it works as a battery. It lasts quite a long time. If I forget to turn the amp off next time, will it still recover?I have a bit of Roland/Boss kit. I had an unqualified high opinion of Roland/Boss up until this point.If you never, ever, forget to turn your gear off, this is for you..If your battery won't charge, I hope that this works for you.

Very useful accessory - really adds to flexibility of Boss Katona Air Ex. Allows unit to be used anywhere when main’s unavailable.

The battery was completely flat on arrival. It would only charge for 2-3 minutes before the 'fail' light illuminated. Repeated attempts didn't improve things.

I’ve had two now , both have not worked despite following the trouble shooting procedures to the TI thought I’d cracked it but went in to play live and it went dead after 5 seconds.The second battery lasted 1 hourIt took 50 to 60 pluging in and plugging outs to get them to even charge and then they would charge the around 10 mins and then stop chargingThese things are hit or missIf you like to gamble ; buy this battery

Great idea it would save messing about with batteries. But it is very overpriced. At the end of the day it is just a power bank.

top kit

These work fine but it is best removed when not used. They're pretty expensive for what they are. If it does go completely flat try putting a small DC voltage from another battery across the contacts of the battery pack. Give it a few seconds to equalise the voltage then if you're lucky it will then charge.Managed to save mine luckily. Big loss at £100 if you can't. I contacted Boss and they had not heard of this at the time. No plans for a lithium battery version at the time, this being Nimh.

Read the reviews, some were saying it simply does not work. I decided to take a chance for my AC 33, because its Roland, but yeah this thing didnt even charge. A completely useless product and a waste of £105. Its amazing to me that this got past quality control at Roland. Roland, why are you still selling these!!!