I am about to get a new battery for my Speedster Turbo.
The following two should fit size wise:
Varta Blue Dynamic 544 402 44
Varta Silver Dynamic 552 401 052
First one has rated 440A cold start current, and the second has 520A.
I am pretty sure the first one has plenty strength to crank the engine, but will I put starter relay/starter in danger with the more powerful one?
The starter motor acts nearly as a short circuit with its low impedance, but whether it is effectively lower than 250mohm with cabling, fuse and relay is questionable.
Pretty funny (well, not really funny) is that I have start issues when the car has been resting in the sun (not correlated to hot/cold weather temperature), sounds like the starter engages for a fraction of a second, and then... silence. After some attempts it gets going. I measured the battery voltage to 12.06V (about 4degC), and with the engine running a little over 14V.