Q&A - Running a car with no alternator, just solar panels and erm..fuel

Hello , been a while since ive been on here so thought its time to create a new post, as lame as the topic may seem.

So anyway folks... my wonderance is -

Is it possibly more economical to run a car with no alternator to charge the battery, and rather, have either a single large capacity deep cycle leisure battery, or a bank of 2 or more leisure batteries, being charged by solar panels, say on the roof etc.

It has been on my mind today and ive not found a whole lot of info on the topic, so thought.. hey lets kick it around the ATS community.

I understand that power is needed to run the electrics etc.. hence the battery(s) provide this.
The battery needs to stay charged.. hence the solar panel / array.
The batteries wont charge at night time.. hence the long duration battery / bank of deep cycle leisure battery(s)
Alternator gives out similar voltage to the solar, even more so, using a regulator of some sort.

So there we have it, anyone care to discuss or point the thread in the right direction.

Thanks for looking !!

Im not sure what the percentages of draw from the engine the alternator produces, I doubt its enough to justify re-engineering a system that works.

How ever, in racing application any extra torque off the engine helps, but the added weight of solar might be more than the benefit of the gain of torque from the alternator spinning.

Thats why people buy lighter pulleys and such, but again the weight of panels, and cost of re-engineering probably dont make up from the performance gain.

Not to mention the number of panels need to crank the same as an alternator

reply to post by the2010apprentice


Don't really know what current solar tech is capable of these days.

Your average alternator seems to be in the 100 plus Amp range though.

Car Alternator Current

Remember the car uses the alternator when its running and thats a heavy load. Batteries are primarily used to start the engine.

Of course, you could buy a Tesla. They only burn down on Sundays.

reply to post by the2010apprentice


I have done this and realy was not as much of a savings as I thought, I even hooked the alt to my brake pedal to charge the large deep cycle battery when i Braked.It was not bad on sunny days but cloudy weeks and night driving sucked.I had much better results by cutting off the fuel pump and running the intake through a tank that used only gas fumes.

reply to post by the2010apprentice


Well, considering that when the engine is drawing around 200A from the battery when it is being cranked, and if you have to drive a car with headlamps on like here in Norway, which gives you an additional 20A continuous load on the battery, I cannot see that only solar panels will keep the battery charged.

There maybe some slight fuel saving in theory since the engine will not have to power the alternator but the main thing is that its always topping it up during operation and in theory a solar panel could keep the battery up during long periods of sitting useless but the main problem would be the panels sat on the car would make the car less aerodynamic and thus use up more fuel, and i wonder if a lot of modern cars would flag up the missing alternator on their ECU

I suppose the best way of proving it would be a car in a wind tunnel set to drive at 60mph or something on rollers and see the fuel usage with and without

supergravity
reply to post by the2010apprentice

 

I have done this and realy was not as much of a savings as I thought, I even hooked the alt to my brake pedal to charge the large deep cycle battery when i Braked.It was not bad on sunny days but cloudy weeks and night driving sucked.I had much better results by cutting off the fuel pump and running the intake through a tank that used only gas fumes.

Does vaporized gas fumes really work?

I've researched the carb thing that claimed to do that, and was thinking of with modern tech vaporizing gas to fumes could be done safer and controlled.

Was thinking an Arduno rig with temp controls, only an idea in my mind of course, was thinking of adapting a lawn mower if I ever get around to it.

Night time driving would not be practical with this system over long distances without the use of batteries that are so heavy any savings would disappear in inertia ....

the2010apprentice
Hello , been a while since ive been on here so thought its time to create a new post, as lame as the topic may seem.

So anyway folks... my wonderance is -

Is it possibly more economical to run a car with no alternator to charge the battery, and rather, have either a single large capacity deep cycle leisure battery, or a bank of 2 or more leisure batteries, being charged by solar panels, say on the roof etc.

It has been on my mind today and ive not found a whole lot of info on the topic, so thought.. hey lets kick it around the ATS community.

I understand that power is needed to run the electrics etc.. hence the battery(s) provide this.
The battery needs to stay charged.. hence the solar panel / array.
The batteries wont charge at night time.. hence the long duration battery / bank of deep cycle leisure battery(s)
Alternator gives out similar voltage to the solar, even more so, using a regulator of some sort.

So there we have it, anyone care to discuss or point the thread in the right direction.

Thanks for looking !!

I've been thinking of developing a fan-motor that mounts to the roof of my car to power my audio amp; (wind farm). The thing with alternators/generators in cars has to do with generating more energy than being used, so the battery retains the starting amps for cold-start mornings...I'm guessing. The battery is necessary due to the ignition system; keep the coil energized. Doing away with the normal charging system wouldn't be very beneficial, IMHO. Headlamps use what, 50 amps an hour?

Imagine using an old-school bicycle generator mounted so that it rolls along the drive shaft as it rotates...
DC motors make free energy more possible.

50 amps an hour would take quite an array of panels atop an automobile.

stirling
Night time driving would not be practical with this system over long distances without the use of batteries that are so heavy any savings would disappear in inertia ....

This is right to the point and addresses both main problems with your idea

Insane hyper car from the future, the McLaren P1

You could recharge it with solar panels I guess.

loveguy
Imagine using an old-school bicycle generator mounted so that it rolls along the drive shaft as it rotates...
DC motors make free energy more possible.

Uhhh...what's the difference in that and an alternator (besides recified current)? Still the same power source (engine) using the output to drive it. Still the same internal power source charging the battery.

No free power here I'm afraid. The solar panels at least add to the power used from an external source. That may be something to consider for an electric or hybrid vehicle where battery power could be supplemented for longer daytime range.

DC motors only make it possible to convert one power source (mechanical input) to another power source (electricity output). Now if you want to put in inside the car with a hand crank, or make your kid crank it, with a little extra food input, you can derive cardiovascular benefits while adding power to your vehicle...but your arms will get sore. No free power, and unless you can get free lunches, it will still cost ya.

Moving where the generator (DC) or alternator (AC rectified to DC) gets it's input from the engine is no reduction of overall power needed to drive the car.

reply to post by loveguy


Not to pick on you but you and the OP both have made mention of stuff that is a clear indicator that you have very little understanding of electricity and how to calculate it's consumption.

For example you talked about a consumption of 50 amps an hour... There is no such thing as 50 amps per hour.... there is such a thing as a consumption of 50 amp hours which would be a constant current of 50 amps delivered for the period of 1 hour... or 1 amp of current delivered for 50 hours... etc, but 50 amps an hour just isn't a valid unit of measurement.

The OP themselves talks about solar producing a comparable amount of VOLTS to alternators... This is even more wrong as voltage has NOTHING at all to do with how much energy is being used.

Traditionally you want to measure power consumption by watts or watt/hours. When a system's power consumption is measured in watts what they are saying is if you measured a system at any given moment it would be consuming a constant flow of X watts. Wattage is calculated by measuring how many amps at how many volts a system is drawing power and then multiplying the voltage times the amperage to come up with the amount of watts consumed. (Note this is for a simple DC circuit. Calculating AC power consumption is significantly more involved) Now if that wattage stays constant over a given time period you can then give your power consumption needs in watt hours. What this means is that you need the number of watts listed to be constantly generated for a period of one hour to fulfill the systems need, or if you have something like a battery bank inbetween your load and your generating system you could produce a lower watt hour rating for a larger number of hours to come up with the total watt hours of power your system will consume while running... believe it or not this is already what an alternator does. Your alternator for pretty obvious reasons cannot be used to start the vehicle so the battery provides a very large amount of amperage at 12 volts to crank the engine over. Once the engine is started the alternator provides a constant but lower amperage current back to the battery to replace the large amount of power over a short period of time starting the vehicle took.

Onto the idea of replacing the alternator with solar panels... The reality is alternators are pretty efficient at what they do. Much more efficient than bolting on solar panels would be. Even if you found a way to coat your entire roof in solar cells that were flush mounted you'd be looking at a very substantial cost for something that wouldn't even be able to completely replace your alternator. The only way it could even be moderately effective, and even this way it'd still pretty much be a gimmick not a real fuel saver, is if you found some way to "clutch" the alternator when your panels were providing enough energy to cover system demands that didn't significantly drop the efficiency of the alternator when it was being used.

The better way to do it is to use a flat cogged belt for the alternator/water pump. The reason for the standard V-belt is in space savings and ease of use at the cost of efficiency. Uncovered chains will wear out fast.

The fact is even if you put a wind turbine atop your car....the energy to produce the electricity will be a drag on your engine....
Till zero point energy physics is invented ya don't get something fer nothing...ever....