OM617 Block heater question for electrical gurus - PeachParts Mercedes-Benz Forum

Stretch · #1 12-02-2010, 01:51 PM

Dear All,

The sudden rush on block heater threads has got me thinking about installing one in my OM617 whilst I'm rebuilding it. I can source one locally from a USA specification car but it of course runs off 110 volts not the 220 volts we get here...

If I remember correctly the amount of energy supplied at 220V 50Hz is about the same as 110V 60Hz - something to do with the number of cycles in a given time and the area under a graph (an integration problem) - so would there be any problem in directly hooking up something simple like a (110V 60Hz) block heater to a 220V 50Hz supply?

Any electrical engineers in the house?

I've just revised my opinion on this and I don't think the energy is the same - perhaps I'm getting confused with the reason why the 110V 60Hz and 220V 50Hz were chosen - that's something to do with lethal voltages I think...

lupin..the..3rd · #2 12-02-2010, 01:53 PM

Don't plug your 110v heater into a 220v outlet unless you're looking to collect the insurance money.

You need a step-down transformer to change your 220v into 110v. But a block heater draws a pretty significant current, so you'd need a fairly large transformer.

It would be cheaper and easier to replace your 110v heater with the correct 220v one.

Stretch · #3 12-02-2010, 02:08 PM

Quote:

Originally Posted by lupin..the..3rd

Don't plug your 110v heater into a 220v outlet unless you're looking to collect the insurance money.

You need a step-down transformer to change your 220v into 110v. But a block heater draws a pretty significant current, so you'd need a fairly large transformer.

It would be cheaper and easier to replace your 110v heater with the correct 220v one.

I haven't checked to see if there is a correct 220V one - but I have a sneaky suspicion that it would be the same anyway as it is probably only a coil set in some insulation... I'm guessing a block heater is a simple thing

Carpenterman · #4 12-02-2010, 08:57 PM

How is the 220V delivered there? Is it like the U.S. where there are two-110V sides? The socket would have 3 prongs (hot 1, hot 2, common/ground) or possibly 4 prongs (hot 1, hot 2, common, ground).

It's relatively easy to rewire a 220V outlet into a 110V one by using a 110V outlet and leaving one of the hot leads free with a wire nut over the exposed end. I doubt the difference in frequency would matter to a dumb device like a block heater.

It works, but it would not meet code. DYODD.

vstech · #5 12-02-2010, 09:04 PM

nope. europe 200v is to neutral... and it's 50 hz too... there is no 110 side... the block heater is only 400watts, so any decent step down inverter would be fine. a hair dryer is 1500 watts by comparison...

nazrat · #6 12-02-2010, 09:36 PM

For reference my 220V heater worked fine on 110V. It just provided half the watts.

It's pure speculation but MB could have only built 220V heaters. Supply 110V cords to the states and 220V cords elsewhere.

-Tad

funola · #7 12-02-2010, 09:55 PM

Do not plug a 110 v block heater into 220. It will likely burn out very quickly. You should be able to find a 220 V W123 block heater from Sweden or Finland.

Stretch · #8 12-03-2010, 05:28 AM

Thanks I'll have a chat with a man with a dog!

funola · #9 12-03-2010, 09:22 AM

Quote:

Originally Posted by nazrat

For reference my 220V heater worked fine on 110V. It just provided half the watts.

It's pure speculation but MB could have only built 220V heaters. Supply 110V cords to the states and 220V cords elsewhere.

-Tad

That is incorrect. Your 220V heater worked on 110 but put out only 1/4 the watts, not half. If you run a 400 watt 110 V heater on 220 it will put out 1600 watts for a brief period then BURN OUT!

vstech · #10 12-03-2010, 09:37 AM

keep in mind that most euro power is more like 190, but it's still too much for the heater designed for max of 130...

dieseldan44 · #11 12-03-2010, 10:08 AM

Power=Voltage^2/Resistance

So as funola said, dont use the US block heater. You'll be powering it with 4x the power by doubling the voltage it wants to use. Use a Euro one, and when you get back to the states, replace it with a US one.

I think the main trouble in installing the block heater is breaking the freeze plug or old block heater loose at 20+ years. So if you recently installed it the R and R shouldn't be bad.

Or you can use a step down transformer arrangement rated for 1000W or more as vstech suggested. Be conservative with something thats going to consume power constantly (like a heating element) and unattended.

Im an EE for my job...thats why I drive a car with virtually no electronics :-)

Jeremy5848 · #12 12-03-2010, 01:02 PM

Mercedes had to have made block heaters in 220V . . . Germany uses 220VAC power after all. Dieseldan makes the important comment when he notes the potential difficulty of extracting the existing plug afte 20+ years. I would advise draining the coolant (including the block), cleaning the oil/grease/dirt from around the plug, using a torch to warm the block around the plug, and finding a snug-fitting wrench or socket with a long handle.

Stretch · #13 12-03-2010, 01:04 PM

Quote:

Originally Posted by dieseldan44

Power=Voltage^2/Resistance

So as funola said, dont use the US block heater. You'll be powering it with 4x the power by doubling the voltage it wants to use. Use a Euro one, and when you get back to the states, replace it with a US one.

I think the main trouble in installing the block heater is breaking the freeze plug or old block heater loose at 20+ years. So if you recently installed it the R and R shouldn't be bad.

Or you can use a step down transformer arrangement rated for 1000W or more as vstech suggested. Be conservative with something thats going to consume power constantly (like a heating element) and unattended.

Im an EE for my job...thats why I drive a car with virtually no electronics :-)

Thank you very much - I'll see if I can find a European version - funny to read about your opinion on electronics. Working on modern cars would indeed be like a bus man's holiday... variation is the key.

nazrat · #14 12-03-2010, 05:32 PM

If someone really wants one, I have a 220V block heater I removed from a 1980 om617. It just needs the AC plug. Unlike our US block heaters, this plug threads onto the block heater and it is armored cable.

-Tad

funola · #15 12-03-2010, 06:05 PM

Quote:

Originally Posted by nazrat

If someone really wants one, I have a 220V block heater I removed from a 1980 om617. It just needs the AC plug. Unlike our US block heaters, this plug threads onto the block heater and it is armored cable.

-Tad

How do you know it's a 220V heater? Do the person you're selling it to a favor by measuring the resistance first so you don't waste their time and money. It should be around 120 ohms for a 400 watt 220 V heater. If it measures 30 ohms, it's a 110 V heater.