Solar powered 300d - PeachParts Mercedes-Benz Forum

123mike · #1 11-26-2015, 12:15 PM

I,m going green diesel. If it works like I plan. 5 more hp from not running alternator. Mike

Stretch · #2 11-26-2015, 12:55 PM

Well - ummmm - good luck

vstech · #3 11-26-2015, 01:13 PM

Quote:

Originally Posted by 123mike

I,m going green diesel. If it works like I plan. 5 more hp from not running alternator. Mike

So... You are thinking a 15 watt panel will maintain a diesel battery... I hope you park for extended times... Like a week between starts...

vstech · #4 11-26-2015, 01:14 PM

On extended trips, if you don't run anything but the radio, and you don't run the heat... It's possible the alt won't draw juice...

leathermang · #5 11-26-2015, 01:22 PM

Good Luck...
lots of things you could be doing which would make a positive difference instead of playing with this concept..... more HP without a change in gearing...which would be silly given the small size of the HP increase..... will not change your mileage....
What are you trying to accomplish ? A topic of conversation some will fall for ? That is fine and has no downside that I can think of.... except the wasted time....
When you wake up...I mean finish.... be sure to share your conclusions...

MBeige · #6 11-26-2015, 01:30 PM

Here is a green diesel, that does not require any alterations...

ah-kay · #7 11-26-2015, 01:31 PM

There may be some truth in it, but realistically it won't give you 5HP. 1HP = 745.7 watt. 5HP will be 3.7KW. I don't think your solar panel will be dishing out 3.7KW any time soon. A panel like that would give 15-20W max. You will gain some HP for not running the alt but it would be in the order of 0.1HP or less.

Good idea and have fun.

leathermang · #8 11-26-2015, 01:36 PM

Quote:

Originally Posted by MBeige

Here is a green diesel, that does not require any alterations...

LOL, cute...
it fits with what I have suggested for years about choosing a color to paint a car.... the early 1970's MG's had what was called ' Snowberry white' ... Snowberry is an actual berry grown in the UK ... it is very slightly green in tint...
I painted a VW that color and regularly had people stop and ask me about the color.... in a parking lot it looked white...
but if you got it anywhere close to green grass... or trees......as you can see in one of those pictures..... it picked up that green and really looked nice...

sloride · #9 11-26-2015, 01:47 PM

Quote:

Originally Posted by ah-kay

There may be some truth in it, but realistically it won't give you 5HP. 1HP = 745.7 watt. 5HP will be 3.7KW. I don't think your solar panel will be dishing out 3.7KW any time soon. A panel like that would give 15-20W max. You will gain some HP for not running the alt but it would be in the order of 0.1HP or less.

Good idea and have fun.

X2 when HP is advertised by the manufacturer it is at the fly wheel. There will be no difference in HP just slightly less parasitic drag from flywheel HP. That would be great if that did work, that would mean a close to 7% increase if used on a 240D as advertised 70 or so HP.

Stretch · #10 11-26-2015, 01:53 PM

@123mike

I do honestly wish you luck with your project.

Let us know how you get on.

(Though night time driving might be a bit of problem)

tjts1 · #11 11-26-2015, 03:00 PM

A modern NCB2 microprocessor controlled alternator that can shut off the field during acceleration will give you more peak power without any downside. You'll also drop a few LB for the same output vs your stock antique alternator and the internal fan will reduce parasic drag.

sloride · #12 11-26-2015, 03:14 PM

Quote:

Originally Posted by tjts1

A modern NCB2 microprocessor controlled alternator that can shut off the field during acceleration will give you more peak power without any downside. You'll also drop a few LB for the same output vs your stock antique alternator and the internal fan will reduce parasic drag.

Good information, I will look into it as I was determining what will total my 300d. It won't be an alternator failure now

123mike · #13 11-26-2015, 03:59 PM

This worked well on my 94o Volvo. I had a switch to the energizer wire to the alternator, if the battery voltage fell below 12 v, I would flick on the alt.. Each evening I would plug in the battery to a charger. The Volvo was about silent at idle due to no alt load. Had a 49 mile range before volt fell below 12, ADiesel may work better sine no spark plugs. Mk

Graham · #14 11-26-2015, 05:03 PM

Some sailboats use this sort of technique. Engines are often quite low HP (for example 15HP on a 32footer) and alternators quite large (120amp). When motoring in a strong tidal or river current, you sometimes want the full engine output. A switch can be installed to stop the alternator from charging and give you a few extra HP.

As a rule of thumb, 12-volt alternators use one horsepower for every 25 amps of output. A special marine alternator may actually put out 120amps and impose a load of 5HP which is significant on a 15HP engine! But can't see how you would get a 5HP load on a 300D.

The original 300D 55A alternator might actually put out 25A, so load would only be 1HP. And it only puts out that many amps when bringing battery back up to full charge after starting or if you have another large load, such as lights at night.

For daytime driving, I would guess that load is probably about 1amp or 1/25HP. The solar panel will cope with that, but not much point really.

97 SL320 · #15 11-26-2015, 05:35 PM

Nice attempt but there are many engineering realities that come into play here.

As others stated, 5 HP is 3,700 W , this would be 274 Amps @ 13.5 V. ( I'm ignoring alternator losses ) I don't see the electrical loads on your car being anywhere near that.

If we assume a 55 A alt, that would be 742 W, about 1 HP ignoring losses.

Alternators rarely are called on to put out max current for any length of time

The suns rays are very weak and require a lot of solar cell surface area to do much. Liquid fuels have an incredible amount of energy per weight / volume. Hang around the electric car sites to get some sense of what it takes to dive a car down the road.

Deep cycling a cranking battery is a bad thing and it will fail earlier. Cranking batteries have thin plates to promote high ion flow ( to generate high current in short bursts ) These thin plates are susceptible to damage from a deep discharge. Deep cycle batteries have thick plates to allow low current over a long period of time.

You really need to install an amp meter to determine actual vehicle loads when the alternator is off. Better yet, look towards the electric car guys for a power out / power in battery monitor to get a true sense of what is going on.

Amp meters are typically installed between the battery and accessory loads, this serves to monitor if the battery is being charged of called upon to make up for a alternator that can't keep up ( like at idle ). You will need to put one on the alternator output wire to get a true sense of loads.

Given you are charging the battery at night ( one can assume TN isn't like North Pole with 6 months of sun light ) your energy is coming from a power plant somewhere.

And, if you really want to be green, find nearly any properly operating car from 99 and up, it can even be gasoline as it will have worlds better emission controls than an uncontrolled diesel. Calling this green is kind of like a non emission controlled 63 VW bus with "Save the planet" painted on the side rolling down the road.