Please help me identify this burnt piece

[Zip112]

The DC heaters page I found (http://dcthermal.com/catalog/sa12-2000) also says this about their smallest 220 watt heater:
"This is our smallest 12 volt heater. Designed for very small equipment or systems that can not handle over 20 amps on the electrical system."

Does anyone know if a tractor battery is usually a "system that can not handle over 20 amps on the electrical system"?

 

[Tha fios agaibh]

Sears riding lawn tractor, or an AllisChalmers combine.

I think it depends on your charging system.

 

[Tha fios agaibh]

The 12-3000 is 360w
The 12-4000 is 480w
The 12-5000 is 600w

So deductive math tells me that the 12-2500 is 300watts