Tired of the block heater plug hanging down from the front bumper? - PeachParts Mercedes-Benz Forum

Jadavis · #1 12-01-2006, 03:33 PM

I'm looking for ideas on how to clean up the plug hanging out from under the front bumper. I'm thinking about this:
http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10001&langId=-1&catalogId=10001&classNum=311&subdeptNum=310&storeNum=9&productId=14773

Even cheaper here:
http://www.overtons.com/modperl/overtons/detail/pdetail2.cgi?r=detail_view&item_num=34531

I was thinking of wiring in my block heater and a trickle charger on my battery to the socket. Maybe with a blocking diode on the charger so that it will not reverse power when not plugged in. That way you just remove the cover, plug in the end of the extension cord and set the timer.

Any thoughts?

-Jim

babymog · #2 12-01-2006, 03:41 PM

Chargers have diodes already, it's how it changes AC to DC.

Jadavis · #3 12-01-2006, 03:47 PM

So why is it that if you leave a charger attached to the battery and don't plug it in you will completely drain the battery, most likely killing it?

On another note, a reviewer recommended this attachment:
http://www.marinco.com/scpt/ProdPage.php?loadItem=101A_Marinco%20Shore%20Power

Jeremy5848 · #4 12-01-2006, 03:50 PM

...I may shamelessly steal it from you.

A blocking diode should not be necessary; the charger should not draw any current from the battery when it is not working.

You might want to put in some kind of a switch so you can have (for example) the trickle charger on without the block heater. Ideally, the trickle charger should be on all night while the block heater comes on for a few hours in the early morning, just before you need the car.

The factory block heater draws about 400 Watts while the aftermarket radiator hose versions draw about 600 Watts. That's a lot of power to be adding to your electric bill all night.

The decision should be based on how often you expect to need the block heater. The trickle charger (1-2 Amps) could run every night all night and do no harm to an otherwise healthy battery.

#5 12-01-2006, 03:52 PM

Quote:

Originally Posted by Jadavis

So why is it that if you leave a charger attached to the battery and don't plug it in you will completely drain the battery, most likely killing it?

I have a tender charger installed on my battery and it doesn't drain. I have a short extension cord with 3 sockets installed to feed my block heater, battery heater, and charger. I have the male plug tucked under the rubber trim piece below the right headlight where it doesn't show.

Biodiesel300TD · #6 12-01-2006, 03:54 PM

On my wagon I have the plug for the glow plugs comming out from under the grill. It's zip tied to the cross brace behind the grill. It gets tucked in at the base of the grill and is easily pulled out when needed. I can also tuck it behind the grill during the warm months, and it's not visable.

You can barely see the plug in this PICTURE.
Its on the passenger side just below the grill, it looks like a little light spot.
It's also not dragging the ground in the snow or getting as much road grime there.

#7 12-01-2006, 03:57 PM

Quote:

Originally Posted by Jeremy5848

The factory block heater draws about 400 Watts while the aftermarket radiator hose versions draw about 600 Watts. That's a lot of power to be adding to your electric bill all night.

Assuming $0.10 per kW-hour, 600W for 8 hours = $0.48 per night.

Jadavis · #8 12-01-2006, 04:10 PM

Quote:

Originally Posted by Craig

I have a tender charger installed on my battery and it doesn't drain.

My experience with this came from a boat battery that I had hooked up on a charger. At the time I was in the navy. I pulled the battery out of my fishing boat and charged it up. In all that goes into getting ready to go on a 6 month deployment I forgot to unhook it. I remembered once we got underway. I emailed my wife and asked her to unhook it for me. When I got back 6 months later I found out that she unplugged it but did not unhook it. The terminals were completely covered in corrosion, the clamps were 1/2 eaten away, and the battery was ruined.

I know, 6 months is a long time, but it still concerns me a bit.

-Jim

Jeremy5848 · #9 12-01-2006, 04:15 PM

Quote:

Originally Posted by Jadavis

... the battery was ruined. -Jim

That's interesting. I suppose it depends on the battery charger. Some may have components that do draw a little current from the battery when unpowered. The single worst thing you can do to a battery is to draw a very small amount of current from it for a very long time. Even a few milliamps will eventually drain the battery and ruin it.

PaulH · #10 12-01-2006, 04:28 PM

Concerning the plug. On my '87 I have the plug to my block heater tucked up behind my lower trim under the front bumper, thus it can't be seen, yet is easy to get to. However, if you want to put an external plug on your car, then go to a commercial truck dealership (I suggest an International rather than a Pete dealership - the part will be cheaper!) to buy a nice chrome one with a spring loaded chrome cover.

JimmyL · #11 12-01-2006, 04:32 PM

Boy, I have bigger fish to fry than if I have a plug hanging out a little.
My charger has a light for the display, and if not plugged in the battery powers the light. So that would draw current from the battery....

Jadavis · #12 12-01-2006, 04:37 PM

Quote:

Originally Posted by JimmyL

Boy, I have bigger fish to fry than if I have a plug hanging out a little.

I do too, but it is scratching at the back of my mind. I think the real reason I want to add it is so that I can tie in the charger and everything into one plug.

As to cost for heating, 50 cents a night isn't that much but it adds up. That also assumes that you plug it in just before you go to bed. Not likely for me! Maybe I'll see if I can fit a timer under there also.

Maybe I'll just not worry about it!

-Jim

aceofspd · #13 12-01-2006, 04:45 PM

I have looked at that plug and also wiring in a charger. I am thinking of a larger charger as I would like to power the 12 volt water pump to get everything toasty after I do the SVO conversion.

Has anyone tried to use that water pump?

Greg

Jadavis · #14 12-01-2006, 04:56 PM

Yep, I've been thinking about it...

I just looked over my diagram again. You can delete the check valve right after pump #2. The one going back to the block has to be there and will do the job of the one right after pump #2.

-Jim

84300DT · #15 12-01-2006, 08:29 PM

Quote:

Originally Posted by Craig

Assuming $0.10 per kW-hour, 600W for 8 hours = $0.48 per night.

you only need to heat the block heater for about 3 hours before starting the engine in sub freezing ambient temps.
no need to leave it on all night...
waste of electricity.