Dab of oppo, Atalante,which Varta did you choose? There are two mentioned, 30a ( 530 030 030) and 40a (540 126 033).
They both seem to have the same dimensions (same footprint as the Banner but taller) so I can't see a reason not to go for the 40. Cold cranking amps are 330, vs 300 for the original Banner (I can't find this anywhere though so basing myself on a comment on the other thread). The Varta 30a is rated at 180 CCA so sounds low.
Did you fix a higher battery clamp and replace the round terminals?
Click on image in my post above for all details.
