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Help! What does my starter motor draw?
I''ve been holding off answering your questions hoping someone with more expertise would provide the information.
Since you haven''t received any info yet, I will attempt to answer some of your questions.
Based upon automotive starters I would say your starter will draw over 200 amps... maybe as much as 350...because of this high current flow, it probably isn''t practical to try to fuse the circuit.
From a practical standpoint, should the starter fail, it likely will be when you are using it. Worst case scenario is the starter is shorted to ground and the starter cable is smoking... maybe on fire. Since you are using the starter and it isn''t responding you will go below to see what''s the problem. Smoke and fire should provide a pretty good clue!
-A good system will have a battery switch to isolate the battery from the short...throw the switch and the problem is solved. (maybe you need to use the fire bottle to put out the fire, but the boat is not likely to go up in flames). So a Battery switch will normally provide reasonable protection from a short...forget the big fuse.
When away from the boat, the battery switch in the ''off'' position will isolate the battery from potential system shorts.
If you plan to use a dedicated starting battery, one with a 1000 amp cranking capacity will do a good job. I have one on my boat and it turns my 4-108 over with much more authority than the deep cycle house batteries I used before.
I don''t consider myself an expert on this but there''s my two cents worth.