Of course, with a lot of those devices, you can just cut out the middleman and use a DC to DC converter that steps the 12V DC from your truck's electrical system either up or down without first converting it to AC before converting it back to DC.
N'ezie, na ọtụtụ ngwaọrụ ndị a, ịnwere ike bechapụ onye na-etiti na iji DC na DC mgbagharị nke na-eme 12V DC site na igwe eletriki nke ụgbọala gị ma ọ bụ ala ma ọ bụrụ na ọ naghị agbanwe ya na AC tupu ịgbanweghachi ya na DC. .