Here are 12 volt DC fuses that can handle up to 750 amps.
http://www.bluesea.com/product.asp?Product_Id=23472&d_Id=6623&l1=6607&l2=6623
The reason to fuse the connecting cable between the batteries would be to provide fire protection from short circuits that could occur due to chafing or front end collision.
Toyota uses fusible links (except for starter). Most owners never have a problem that results in the fusible link blowing, but the need is still there. I expect if compact high amperage dc fuses were commonly available in the past that the factory starting circuits would already be fused.
http://www.bluesea.com/product.asp?Product_Id=23472&d_Id=6623&l1=6607&l2=6623
The reason to fuse the connecting cable between the batteries would be to provide fire protection from short circuits that could occur due to chafing or front end collision.
Toyota uses fusible links (except for starter). Most owners never have a problem that results in the fusible link blowing, but the need is still there. I expect if compact high amperage dc fuses were commonly available in the past that the factory starting circuits would already be fused.