Block Heater Current Draw - PeachParts Mercedes-Benz Forum

RML · #1 12-18-2007, 01:12 AM

I have an 84 300D, am in western PA and have started to use my block heater. I can plug it in at work to an outlet on a light pole in the parking lot. I was wondering how much current it draws so I can estimate the cost of running it over an 8 hour day. No one is asking me to pay for using the outlet but I would like to know what kind of dollar volume I am dealing with in case anyone asks.

Richard

#2 12-18-2007, 01:14 AM

It is 400w so I believe the total cost is less than a dollar/day.

RML · #3 12-18-2007, 01:31 AM

The wattage is really helpful to know. I am paying 11.405 cents per kWh so if my math is right, at 400w, I am using 4/10 of a kWh or 4.562 cents per hour. In 8 hours that figures out to 36.5 cents. $1.825 per 5 day week. It seems well worth the cost to have it plugged in.

Do you know if it runs constantly or does it shut off and on with a thermostat. If there is a thermostat, I guess it all depends on the outside temperature as to what percentage of the time it is running.

#4 12-18-2007, 01:35 AM

Constant.

RML · #5 12-18-2007, 01:42 AM

Thanks, Forced. That sums it up quite easily. I appreciate the help.

pawoSD · #6 12-18-2007, 02:01 AM

I think the in-block heaters are actually even a little less than that. Like 325 watt or so. My external hose heater uses about 380ish. All in all, they don't cost much to run. I haven't needed mine yet this winter.

Coldest its gotten so far has been about 17-18F. I only use mine if its below 15F.

All my extension cords are messed up....I need to get a good short one so I am prepared....*note to self

Bio300TDTdriver · #7 12-18-2007, 11:36 PM

Plug it into a timer. Have it come on 2-3 hours before you need to start it. That will save you .66 a day. You should have the timer paid for after 3 weeks.

nhdoc · #8 12-19-2007, 07:03 AM

Quote:

Originally Posted by Bio300TDTdriver

Plug it into a timer. Have it come on 2-3 hours before you need to start it. That will save you .66 a day. You should have the timer paid for after 3 weeks.

Excellent idea. Just be sure the timer is rated to handle at least the power draw of the heater...some are just designed for light duty. You definietly don't need it on for 8 hours to pre-warm it, 2-3 hours would be plenty. The fact that you are using it at work also means it is warm when you park it. It probably stays above ambient temp for at least 2-3 hours after you shut down so to plug it in when the engine is already warm is a waste of energy anyway.

Shawn D. · #9 12-19-2007, 09:15 AM

Quote:

Originally Posted by pawoSD

I think the in-block heaters are actually even a little less than that. Like 325 watt or so.

I measured mine at 430 watts using a La Crosse Technology 3362U watt-meter.

The cost and wattage has been discussed before: 300D - cost of electricity for block heater.

#10 12-19-2007, 09:47 AM

Quote:

Originally Posted by pawoSD

I think the in-block heaters are actually even a little less than that. Like 325 watt or so. My external hose heater uses about 380ish.

Mine measures about 35 ohms, which comes out to about 411W at a full 120V.

Whiskeydan · #11 12-19-2007, 11:56 AM

Quote:

Originally Posted by Craig

Mine measures about 35 ohms, which comes out to about 411W at a full 120V.

The resistance will go up as it gets hot. Should be under 400 watts when warm.

The timer is an excellent idea.

#12 12-19-2007, 11:59 AM

Quote:

Originally Posted by Whiskeydan

The resistance will go up as it gets hot. Should be under 400 watts when warm.

The timer is an excellent idea.

Probably true, I'll try to measure the resistance after it's been plugged in for a while.

I've never bothered with a timer, the power usage is to low to worry about the cost.