Hi Svbravo . Thanks for your interest.
I found a 200w 12v DC
heater on amazon.ca. A12v thermostat, on amazon.com (I bought two. One for the
batteries, and one for the fridge, to control a spillover fan from
freezer to fridge).
My
battery compartment is only about 1.5 cubic meters. And the cells are in a box, raised off the floor by about 12cm. So some holes on the bottom of the box, and near the top.
There's a nice bulkhead mounted, dual, 12v fan I may get, to encourage flow into the
battery box. I could heat under the box and let convection do the
work, but I want to get a feel for how hot the
heater will get. The elements are surrounded by
aluminum, so no fire risk, but the box is
epoxy over honeycomb, and I don't want any part of it to reach above 60 Celsius, or it'll soften, as that was my post cure temp.
200 watts is a lot, but it'll cycle, and the compartment is all insulated with the foam
core. If it's too much, I'll just heat under the box (with the thermostat in the box, )with a couple incandescent bulbs, At about 30 watts, and let convection do the
work for me.
When I'm aboard, and
heating the
cabin to 20C, even at minus 19 C outside, the compartment is at plus 15 with the door cracked open. But when I'm not aboard, I want some heat in that compartment. The two Esparza heaters take about 40w each at minus 19C. So 200 watts cycling at 30 to 50% won't be too bad, if we are not running the espars.
I'm out of country right now and
posting with android. So please ignore choppy sentence structure... Let me know if you'd like me to post the links to the
gear.
Cheers.
Paul.