With over night temps of 0 degs, both of our cars have been very stubborn to start in the mornings. Here is the question, can I plug-in both cars from the same outlet (15amp)? I would use 2 seperate extension cords.

__________________
1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member

generally yes. A typical power use is about 350 watts which draws about 3 amps @ 120 VAC.

__________________
'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

The block heater seems to be able to maintain a temperature of 40 F regardless of how long you leave it plugged in, well at least with temps not exceeding 40 F from my experience. Why didn't they design one that can maintain the coolant at a temperature closer to the optimum operating temperature (80 F)? I mean, I know it will draw more current, but I just think that engine wear would be reduced even much more if the engine and coolant (and oil) were closer to operating temperature when you start the car. Afterall, isn't the expansion of the cylinder walls and other engine components during cold starts the greatest source of engine wear?

__________________
1999 Mercedes-Benz S600, 103K miles - garage queen
1988 Mercedes-Benz 560SEL, 89K miles - daily driver
2007 Hyundai Sonata Limited, 31K - daily driver

Maybe, with the higher temp. the heating element probably would not last as long.

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )

The block heater I ordered for my 126 had a rating of 400 watts - about 3.5 amps. Two would be no problem, even on the same extension cord, assuming no other major loads on the circuit.

The radiator hose heater I'm using seems to get the coolant up to about 40 degrees and it draws 600 watts. I imagine it would take a pile of amps to get an entire engine up to 80 degrees.

__________________
1984 300Sd 210k

Former cars:
1984 300D 445k (!!) (Strider) Original (and not rebuilt) engine and transmission. Currently running on V80 ( 80% vegetable oil, 20% petroleum products). Actually not, taking a WVO break.
1993 300d 2.5 275k. Current 120/day commuter
1981 300SD 188k (Hans) Killed by a deer

If they can make those M-B diesel starters with all that compression last for over 20 years and over 200,000 miles, I'm sure they can make heater elements that could last as long as the ones we have now. Hey, all it will do is cost more, but then what is cheap about these cars?

It would take a whole lot of wattage to get the entire engine up to 80 C, but I think 60 C wouldn't be too bad.

__________________
1999 Mercedes-Benz S600, 103K miles - garage queen
1988 Mercedes-Benz 560SEL, 89K miles - daily driver
2007 Hyundai Sonata Limited, 31K - daily driver

Thanks for the info. If 3.5 amps is all one heater draws, then I'll rig up a way to have both run on one cord. I guess what I can do is get a 2 into 1 adapter and use my other extension cord to plug into the one that I'll have the first car plugged into.

__________________
1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member