Charging trolling motor battery

[pbyrne]

What's a good way to charge a trolling motor battery (we use the trolling motor for the dinghy) using the boats electrical system?

There is a 400w inverter but that seems odd to use considering its 12v to 12 v.

Suggestions for battery size and charge would be good too.

[Jim Hardesty]

google    battery combiner

Think that's what you want.
Jim

[waughoo]

I would suggest a victron orion tr smart dc to dc charger.  This senses battery charge power on the house bank and then turns that into charge current as an output.  Being a propper battery charger, it has charge profiles you can set based on the battery chemestry.  This is what I am planning to use for my dedicated start battery.