Thinking of adding a 12 volt battery warmer to warm up the Shorai on cold starts. Below freezing starts are really difficult. Even turning on the key with all of the lights on and waiting 5 minutes does not seem to help. It takes three tries at a minimum, and sometimes many more. I thought that adding battery warmer would both warm the battery and act as a drain to help warm the battery thorugh use. Here's the only battery warmer/blanket I can find that is DC powered: http://gateopenerking.com/store/dc-battery-heater-kit-not-solar-compatible-for-dc-operators.html Any thoughts?