Conventional Ignition Fed Relays

120A - 200A relays (12V or 24V)

where cost is the overriding factor then simply fit a relay with a direct ignition feed, no frills.

Part Number                            R12120           R24120           R12200          R24200
Coil nominal V                              12                   24                     12                  24
Contact current rating A              120                 120                   200                200
Active switching current A           120                 120                   200                200
Active switching power W         1400               1400                 2800              2800                                   
Coil rating  continuous W             2.4                  2.4                    2.4                 2.4

Ignition Voltage required       8.0V - 15.5V  |  16.0V - 31.0V | 8.0V - 15.5V | 16.0V - 31.0V
Ambient rating deg C                                               -40 - + 85
Relative humidity                                                 85% at 40 deg C
weight                                                                       90 grams