Planning on converting my 32' sailboat to electric and have done a lot of reading, including a lot of threads here.
What I am trying to figure out is whether there is any way to build LiFePO4 batteries that could power an electric sailboat, but also work as starter batteries for a diesel engine until I can save for and buy all the parts for the conversion. I'm trying to avoid buying another lead acid battery that will only last a year or two. Most of the cells I have looked at have 1C rating, which doesn't seem like enough. However, it isn't clear to me how much current is required to start the engine. It's a >50yr old Volvo MD2 and has a dynastarter=starter/generator instead of a starter motor and alternator. I have several tricks for starting it with dying lead acid batteries and can even start it by hand when warm (there is a detachable hand crank) so I know I don't need a lot of power. The dynastarter is basically a 12v DC motor that I think is less powerful than the one I plan to power the sailboat with (10kw Etek 48v motor 150A continuous 330A max).
So although lots of cranking amps would be helpful, they are not necessarily required. Is there a way to limit the current output to the dynastarter? Could I just use a motor controller? I'm not sure, but I think both the Dynastarter and the Etek are both brushed DC motors.
Also, although it looks like 200Ahr or bigger cells would be a good match for the Etek, I see more deals and other advantages to 100Ahr cells. I know it is better to start with a bank of matched large capacity cells, but how much worse is it to build up a bank of 100Ahr cells over time?
What I am trying to figure out is whether there is any way to build LiFePO4 batteries that could power an electric sailboat, but also work as starter batteries for a diesel engine until I can save for and buy all the parts for the conversion. I'm trying to avoid buying another lead acid battery that will only last a year or two. Most of the cells I have looked at have 1C rating, which doesn't seem like enough. However, it isn't clear to me how much current is required to start the engine. It's a >50yr old Volvo MD2 and has a dynastarter=starter/generator instead of a starter motor and alternator. I have several tricks for starting it with dying lead acid batteries and can even start it by hand when warm (there is a detachable hand crank) so I know I don't need a lot of power. The dynastarter is basically a 12v DC motor that I think is less powerful than the one I plan to power the sailboat with (10kw Etek 48v motor 150A continuous 330A max).
So although lots of cranking amps would be helpful, they are not necessarily required. Is there a way to limit the current output to the dynastarter? Could I just use a motor controller? I'm not sure, but I think both the Dynastarter and the Etek are both brushed DC motors.
Also, although it looks like 200Ahr or bigger cells would be a good match for the Etek, I see more deals and other advantages to 100Ahr cells. I know it is better to start with a bank of matched large capacity cells, but how much worse is it to build up a bank of 100Ahr cells over time?
