I think my battery is kaput. So, assuming I need another one (I'm testing it at the moment) is there a recommended brand? Or any to steer clear of?
Is there a real difference between AGM and standard lead acid?
And finally, is it necessary to modify the CSV 409A charger if fitting a lithium?

Picture enclosed of my new low cost favourite device! Battery voltage readout, plus usb charging ports!

Thanks

Peter