12 volt blanket

[southpennrailroad]

Just purchased the Walmart bed warmer. I think it works great. However I was wondering if it would drain the battery if left on the converter all night. I asked if I could return it as I was thinking maybe the 12 volt one mentioned above would be more kinder to the battery with a more shut off after warming up after getting into bed and the turning it on just before getting out of bed in the am. I usually get up about 04:00.