How small battery can I charge with a Tystor charger?

For valve-controlled batteries, the battery manufacturer usually indicates maximum charge current.
Mostly in A or part of C (C = Battery Ah).
If you do not find any information, you should use C / 4, ie 25% of the Ah’s.
Example: 40Ah C / 4 = 25% of 40Ah i.e. max 10A charger

How big battery can I charge with a Tystor charger?