Glen - The amp meter will show like that because it's showing the charge it's putting back in the battery that the starter robbed cranking over.
If the wire is getting hot make sure you have good clean connections on every thing and might be that you need a larger wire , 10ga. at least.
If the wire is getting hot make sure you have good clean connections on every thing and might be that you need a larger wire , 10ga. at least.