"on the run" battery charging

[Red-Rover]

Just bought a new Lund fishing boat with a 2012 Mercury 60, 4 stroke. This boat has one starter battery and one deep cycle battery for trolling. These batteries are currently not connected in any way.
My question is about "Charge on the run" battery chargers that use the motors alternator to provide some charging capacity. Do these chargers cause damage to the outboard motor charging system? Do they provide enough charging capacity to be worthwhile? Really interested in experiences that you folks have had.
Thanks in advance for any replies.

 

[Faztbullet]

Re: "on the run" battery charging

I sell them and they work really well on the bigger motors, do not expect it to recharge much if you fish 2 hrs and run 15min to next spot. The tourney guys use them as they make 3-8 mile runs between spots.