I also live in Alaska and have an old-school motorcycle trickle charger under the hood of my snowplow. It's wired in parallel with the block heater and has been working for a decade now without problems. I fully expected to have to replace the battery because of the infrequent use, but it has been starting like a new truck. I use the plow maybe 4 times a winter lately, so it doesn't see much use.
.
.
