Powering my house with the MB - Page 2 - PeachParts Mercedes-Benz Forum

chasinthesun · #16 12-14-2008, 10:52 AM

Would 3 gallons a day be a good guess on usage for your 240d to run the load needed ? Ive heard of the old single cylinder Lister diesels get great efficiency while running off grid homes ,sounds like the 240 is doing the job. During Hurricane Ike I had my 300d charge 2 extra car batteries I had for tv and small frig usage off an inverter, 5 hrs at night and 5 hrs in the morning was the regular routine for 2 weeks .I know after a few days some comforts are greatly missed .Its a bit weird when power does finally come back on ,you really get a sense of relief for the small things like power to your home.
Their are some guys that travel the states just for selling generators in times like these .The sell off back of semi s was popular here in Houston for 3 straight weeks during that time ,at a 30 to 50% mark up no less .Mostly Chinese knock offs .The first news story broke about them selling for $1300 plus ,real crooks.

pizzachef · #17 12-14-2008, 11:11 AM

My wagon supposedly had been upgraded to a 115 amp alternator. Is there a way I can verify this from somewhere on the alternator? I'd like to be able to have a similar setup.

Squiggle Dog · #18 12-14-2008, 11:30 AM

I'd like to be able to do the same as well. The only thing I worry about is, isn't letting a diesel engine idle that long bad for it? Wouldn't it build up carbon deposits that would cause the engine to smoke, run poorly, enter the oil and cause the engine to wear? I'm no expert, that's just what I've been told.

a2t · #19 12-14-2008, 11:32 AM

I did this with my 300D back in March when we had the tornado here in Atlanta. Ran my fridge and TV, on waste veg oil

Off the grid altogether! Took a long time (like 12 hrs) to burn off 1/4 tank wvo at idle.

Yeah these cars are definitely work horses. Mine was sitting out in the driveway in 70 mph winds getting hailed on, powering my house, while running on WVO.

I should call mercedes and offer to let them film a commercial

Bio300TDTdriver · #20 12-14-2008, 11:38 AM

That would be my concern as well. That's why I asked earlier what RPM the car was running at. It might be OK if it were for a day or two and you gave it a few Italian tuneups the next time your drove it.

Quote:

Originally Posted by Squiggle Dog

I'd like to be able to do the same as well. The only thing I worry about is, isn't letting a diesel engine idle that long bad for it? Wouldn't it build up carbon deposits that would cause the engine to smoke, run poorly, enter the oil and cause the engine to wear? I'm no expert, that's just what I've been told.

Graminal95 · #21 12-14-2008, 12:19 PM

Well I think about it this way, a diesel runs with an air fuel ratio of what ever to make the power it needs to turn a certain rpm. So for my application its putting in just enough fuel with a huge excess of air to make the engine idle and power the house. The combustion temp is going to be very low because of the huge excess of air but at the same time there is so little fuel being burned that I don;t think its going to make everything carbon up, as excess air also means very complete combustion. But we'll see in a few days. I just put new nozzles in an it smokes so little I can't believe its the same engine in the car.

So after 30hrs its used just over a 1/4 tank or ~ 4 gallons, that's ~ 35 cents an hour....not to bad.

coonerboy · #22 12-14-2008, 12:36 PM

You have had it running for 30 straight hours!! Cool!! It might not hurt to shut it down once in a while to check your oil level. I know alot of generators have low oil shutdowns..... These cars don't!!

WhoWhat · #23 12-14-2008, 08:30 PM

Quote:

Originally Posted by Bio300TDTdriver

It says; "3 FT Battery Cables Included" in the description.

So I would venture a guess that it attaches to your battery.

Alright, alright...so I didn't scroll down far enough.

Stevo · #24 12-14-2008, 08:59 PM

Quote:

Originally Posted by chasinthesun

Ive heard of the old single cylinder Lister diesels get great efficiency while running off grid homes

My little one "lunger" Lister runs about 6 hours on a gallon of fuel but thats only 2Kw through a six current transfer switch. Its enough to run the house, if more is needed (shop or deep well pump) I fire up the diesel Yanmar 5 Kw.

spark3542 · #25 12-14-2008, 09:49 PM

Quote:

Originally Posted by babymog

I had a large diesel generator for a back-up genset at my house, started to realize that at 3GPH x $3/gallon, I'm looking at $9/hour in fuel, x 24hours = $216/day. I could stay in a nice hotel room, order room service, and let insurance pay for the lost food.

Anyway, with a stock alternator on a 240D, 45a, which is more like a 1200rpm output, not idle, you're putting out 45v x 13vdc = 585watts. Most of my inverters are high-end sine-wave units, IIRC around 95% efficient, the cheaper ones are typically less (some much less, and if a square-wave it will lose a great deal more efficiency running an inductive motor like a refrigerator). So, lets figure 80% efficiency from the 585watts = 468watts which is 4amps load at 117vac. It will likely have enough surge capacity from what's in your battery to start the load, but unless your total combined loads are less than 4amps continuous/average, you will drain the car battery until the inverter drops out on low voltage. The current drawn will also increase as the voltage drops so that even a 3a or 3.5a load will be greater than the output of your car's alternator, and the alternator will lose output as it heats up, and we're assuming the alternator is capable of its original rated output even though most aren't after some miles/years of use.

A lot of fuel and car use for a little output, but better than nothing I guess.

You're off by a decimal. Your house genset would use more like 0.3 GPH, and that's even a a good load.

Run your genset on a WVO/RUG blend for about $0.16 per gallon and your cheaper than the grid.

Graminal95 · #26 12-14-2008, 10:29 PM

Well its time for bed, and shes been running for over 42 hours now....I think I'll unplug her, take her for a short drive and then plug her back in for the night.

TheDon · #27 12-14-2008, 10:42 PM

Quote:

Originally Posted by lutzTD

I was thinking the same thing. why buy a diesel genset for hurricane season, theres always the coupe

I like that Graminal95 has the heater and the computer powered during this emergency, we need updates

I kinda like this idea, I think I will invest in a big inverter for my car and a male-male plug..

some of the other home owners in the neighborhood bought generators, guess I'll get some spare diesel.

all you have to do is watch temps and make sure no one steals the car.

zsmith29 · #28 12-14-2008, 10:47 PM

To make sure that no one steals the car all you have to do is unplug a vac line and then there is no power steering and I think the wheen might actually lock.

katja · #29 12-14-2008, 10:49 PM

Cool! I had thought of this idea a while back but haven't tested it yet (I only have a 750w inverter) and it's great to see that it actually works!

I'd think the 240D or early 300D's are ideal to run as generators as they have the fast idle control. It's just like the ambulances that are run on high idle for long periods to keep all the life support equipment going.

Jeremy5848 · #30 12-14-2008, 11:03 PM

Quote:

Originally Posted by TheDon

. . . all you have to do is watch temps and make sure no one steals the car.

And remember to throw the main house breaker so you're not energizing the utility lines. It would be a shame to hurt an electric repairman trying to fix the down lines.