When I first started running the Wally battery for my UA5, I had another second dongle for my ODL276. I lasted one show - I plugged into the battery and went to plug into my UA5, but the 2 ends had touch, shorting out the battery.
Remember that UA5 is reverse polarity, so it + is on the outside. Where are the polarity of everything else is normal, so - is on the outside. It might be the other way, but irregardlsss, touch these 2 and you've just shorted your battery.
It will reset when you plug in to charge.
Terry