DC battery charger?

[hyperope]

I have a Yachtthruster bow thruster on my boat. Is is an external model. Above the thruster, under the forward bunk, resides the batteries- 24 volt. Those batteries are charged by a DC battery charger located in the engine room which uses 12V from the house bank to charge the 24V thruster batteries. I believe my charger has failed as there have not been any lights illuminated on the unit for a while and the thruster has finally stopped working. Engage the control and just a bunch of clicking under the bunk. I have yet to check the batteries, but I'm sure they are dead, which would make sense if the charger is toast. Company said they'd sell me a new charger for $500. It is a 12 to 24 volt charger running 10 amps. I have found another model 12 to 24 with 20 amps for $200.Would there be any contraindication to using a charger with more amps, if the charger also has a float feature, like the previous one? Any chance increased amperage would harm the batteries?