Generating Power to Charge Battery Pack

Hello, It might be easier to use a van, install solar panels on the roof, use the motor and tranny area for extra 500 lbs of batteries. I would install an electric start generator set (honda motor), pull fuel from vehicle tank, maybe tap into vehicle exhaust. Much easier to wire, no power loss with belts an pulleys. Lots of room underneath to mount drive motor. This way the gen / set could easily change to a larger or smaller, even diesel if wanted. Keep in mind that everything not fastened down very well behind you will come up and visit in an accident. Some batteries give off a fine acid mist, or vapor when charging, along with explosive hydrogen gas. Some thought will be needed to protect the passenger compartment. Maybe you have newer, better style batteries. Your trailer idea reminds me of my uncle that built a water wheel, that would turn a generator, this would power an electric pump to move the water back up above the water wheel. He never would tell me if it worked. best wishes, bill P.S. , most car alternators produce three phase ac, that can be pulled off the three leads off of the windings. disconnect the diodes, or remove. Or leave as is, and pull three seperate ac sources between the leads. the voltage regulator will keep it at about 14 volts. you can easily get 200 volts with a little tinkering.have fun !

A van is out,my car is a clone of a lotus 7,runs on 72 volts. The battery pack in the car is capable of sustaining my drive motor for arround two hours. With one generator at twelve volts I wouldn't be able to keep up with the chargeing needs,hence 6 alternators 6 batteries. Connect the two packs together. The first pack drives the car, the second pack recharges the first pack and the alternators recharge the second pack. Run 2 cables to the car from the trailer,a whole lot easier than running wires from the alternators to each battery in the car,lots fewer connectors. If a drivetrain from the trailer wheels won't work,then maybe I will have to figure out how to seperate hydrogen from water and run a small engine on that to pull the alternators. The object of this whole thing is to have mobility and not feed the fuel companies. By tinkering with the internals of an alternator I may be able to get 72 volts but nowhere near 300 amps. 6 65 amp alternators will net me 390 amps at 72 volts. The large auto manufacturers refuse to put electric cars out to the public because of their ties to big oil and they are all screwing all of us. If that last statement gets me kicked out of here then I am sorry,but I'm not retracting it.

Let's assume your batteries are 80 amp hour or so. That, times 72 volts, would yield 5.76 KWh. If you can currently go for two hours of routine use, then running a 3 KW generator continuously would keep the batteries charged. Of course if you run that generator on gas, you've defeated your purpose, but you could run a gasoline generator on alcohol or propane (or hydrogen), and you could run a diesel generator on biodiesel (or hydrogen or other gases -- but the cost of conversion would be very high).

I'm afraid you'll find generating and storing hydrogen to be a problem. There is a thread here entitled "The Hydrogen Hoax" (http://cr4.globalspec.com/comment/36976/Re-The-Hydrogen-Hoax) . That thread discusses some of the hurdles to using hydrogen as a fuel for vehicles. The main hurdle is that is takes more energy to create the hydrogen from water than you get back out of it. (So you end up paying the power company instead of the oil companies.) But if you have the time, you can certainly experiment. However, biodiesel (which you can make yourself with a tiny fraction of the effort to create and store hydrogen) would have the advantage of enriching neither the power company nor the oil companies.

Sorry to be a wet blanket but 6, 65A alternators won't get you 390 amps at 72 volts. If you put them in parallel you'll get 390 amps at 12 volts or if you put them in series you'll get 65 amps at 72 volts. Usually safer when considering this sort of project to multiply your volts by amps and think in watts. Volts and amps can be shuffled around but the watts remain constant (actually they diminish alarmingly quickly but that's another story!) In rough terms your alternator is putting out about 780 watts or about one horse power. Thing is, that's output. Power in will be higher due to inefficiencies. Those inefficiencies translate to heat and then you discover that car alternators were never designed to supply 780 watts continuously.

I would suggest getting your hands on a proper generator. They're usually easy to find. I picked up a 6kva one a few years ago for nix due to a conrod sticking out the side of the engine. Generator was fine. Point is I could hardly lift that generator, weighed a whole lot more than a box of car alternators because it was built to work continuously.

I'm still puzzled as to how your system of charging a battery via a trailer that's being towed by an electric vehicle works but I'm assuming you live at the top of a mountain or something.

Hilltopper,

Your words:

"If a drivetrain from the trailer wheels won't work,then maybe I will have to figure out how to seperate hydrogen from water and run a small engine on that to pull the alternators.The object of this whole thing is to have mobility and not feed the fuel companies. "

If it looks like a duck, walks like a duck, quacks like a duck, it's probably a duck.

"The large auto manufacturers refuse to put electric cars out to the public because of their ties to big oil and they are all screwing all of us."

The public hasn't wanted electric cars in any numbers, for the very same reasons you are unhappy with yours.

"If that last statement gets me kicked out of here then I am sorry,but I'm not retracting it."

Believe me no one will kick you out for saying that about the "evil conspiracies" that keep ideas like yours from being a reality.

People regularly make the very same claims here on a regular basis.

What keeps these types of ideas from being realized is that they very simply violate the laws of physics. We do not have to look to any external forces when the "free energy", "something for nothing", "not PPM, just extend the range (for nothing)" ideas fall flat from their own scientific impossibility and wishful thinking. You cannot recharge a car while driving because you will have taken more extra energy from the driving batteries with the load from the alternators, than you can possibly put into the charging ones, and by a factor of at least 2! As for hydrogen, it takes more energy to separate it than you get from burning it, so that will also drain your batteries much quicker. Either way, after all your efforts you will end up with a lot less range than you started with. Charging extra batteries at home, however you want to, would extend the range somewhat, but as pointed out, towing a trailer imposes extra friction and wind resistance, not to mention weight.

The difference with you, is that you are not trying to "sell" your impossible schemes like many, but to merely use them for your own purpose, otherwise "rude" would be a gross understatement for the comments you would get here, but because you seem sincere in your lack of understanding people are not going out of their way to be rude.

You might want to take a look at this thread, rdavm's posts, and the replies it provoked:

ttp://cr4.globalspec.com/comment/38382

Please understand this is an engineering site and we approach things in that way and judge things on their technical merits, or lack thereof. We have had several "Free Energy" schemes here lately, and that has created (speaking only for myself) a certain "lack of patience" regarding hearing them repeated yet again.

In any case, whatever you want to think about the auto companies and oil companies etc has nothing to do with the unworkability of what you are trying to do. Perhaps you could replace the batteries in the car with new ones of higher capacity, or add extra ones somewhere in the vehicle.

Regards, Greg

Let me guess.

You have a vehicle powered by an electric motor which takes its power from batteries. Unfortunately, a battery has only so much storage so you add more batteries to increase the range. You're probably thinking of switching batteries so that when one is drained the next one is connected. Then, to increase range a little further, you want to recharge your drained batteries so that you can reuse them. You also thought that running the alternators with the electric motor will add to its load and shorten your battery's running hours. Therefore, the solution is to connect a trailer to the vehicle and run the alternators from the trailer's drive train and use one alternator for each battery.

You didn't say so much, I know. But this arrangement is actually worse than having the alternator running off the electric motor. The trailer will be an added weight. Add the batteries and the alternators (six!) and you have a vehicle that can carry the weight of the driver, the chassis, the trailer, batteries, alternators and...nothing else.

Personally, I rather like the idea of switching batteries. If it were up to me, I'd still run the alternator off the motor and electronically switch the batteries. The circuit will take care of which battery to charge and which to use.

Another perpetual motion machine!!

The energy to charge the batteries is still going to come from the first set of batteries. It might be converted to kenetic and potential energy first but it still ultimately comes from the original charge. In fact, it's not even a very good perpetual motion imitator as there will be so much loss in converting the potential energy in the first set of batteries to potential energy in the second set of batteries that it will be practically useless. A lot of work for nothing!

Sorry; grow up, get an education and get a job.

Another anonymous ****!

You're basic idea has a number of flaws in it. The first being that you can create a net positive amount of electricity by converting the movement of your electric vehicle to electricity.

You can recover some of the energy from your vehicle - for instance using regenerative braking, but ultimately the idea of adding an alternator that adds drag to the vehicle will just end up using more power than it generates.

The second problem is the "6 alternators" idea. If you want to charge a variety of batteries, you just need one alternator. Switch the alternator from battery to battery to charge the string of six, or charge all six at once from one alternator. Adding extra alternators just adds weight and additional drag. But, like I said, adding an alternator at all will cost you more in power than it will gain you, unless it's part of a regenerative braking system.

The third problem is the trailer - there's no advantage to pulling your equipment behind the car as opposed to having it in the car, and the trailer just adds additional weight.

In an electric vehicle, the maximum amount of energy is present when you have fully charged the batteries and start off. You can never accumulate more energy in your batteries than what you start off with - this is just a constant of the universe, due to the laws of thermodynamics. You can't change that fact. (The exception to this rule is if you start off on top of a mountain and coast down the mountain and use regenerative braking to charge your batteries, or if you use solar cells to gain energy from the environment.)

So, if you want to build an electric car, investigate regenerative braking, and look for the most efficient drive train, and batteries that will give you the best power/weight ratio.

At 65 I refuse to grow up. Have been educating myself and others for years(just in different fields) and am retired now and am letting the kids work. No more jobs for me.

"Have been educating myself and others for years(just in different fields)."

Well, I just hope it wasn't science, or engineering, or auto mechanics, or economics, because, if so, it appears that you have done a lousy job!

Kind of reminds me of the terrible singers who appear on "American Idol" auditions, are obviously very bad singers, and then it comes out that they have several degrees in music or voice and have in fact been teaching others how to sing for years!

I really hope your forte is in history, English, art, or some other non-technical subject!

I won't go back over the obvious flaws in your plan. Others have already done that well enough. Here's a thought, at least as good as any of your others: Instead of more batteries and alternators and other gizmos on your trailer, how about a really, really, really, long extension cord and a power inverter? Better yet, find Tesla's secret designs for sending AC power through the air and capturing it to power his automobile on the fly!

One of the recent electric cars (not the Tesla, but another sporty looking one, if I recall) offers a trailer to tow behind for charging the batteries. The trailer houses a gas or diesel generator. If you bought a small diesel generator and rectified the 120 VAC output to 120 VDC, when you connected that to your batteries (72 volts, I am assuming) (stand back: do this with a contactor, not by hand) the generator output would sag under the load, possibly enough that, if you carefully watched the battery voltage, you could cut off the generator before the batteries were overcharged (and before the generator begins to smoke!). If you found that the charge rate was too fast for the batteries or generator, you could reset the generator's governor and regulator to a more appropriate level.

Then, if you ran this generator on biodiesel, you'd be green and fairly efficient. (Not quite as efficient as getting power off the grid, but at least you'd be carbon neutral -- which power plants are not.) If you were industrious, and did your own gathering of biodiesel (used french fry grease) your charging costs could be very low.

If you simply towed a trailer which drives alternators from the trailer's wheels, then, as others have said (some rather rudely), you have a net loss: the energy that is driving the alternators has to come from the vehicle batteries -- but you've added weight and friction that wouldn't be there without the trailer.

Are we talking a perpetual motion machine here or are we being unkind. This sounds like a drop on regenerative braking unit to me.

I suspect though that the sums won't add up. By the time you haul the trailer up the hill, bowl down the other side, happily charging your batteries, you'll probably be worse off than if you'd left the trailer at home. Friction is so greedy!

NO perpetual motion. I just want to extend my range. And some of the replys sound like they were comming right out of oil central. Kill the fool that wants to try something different and not buy our oil. Enough of that but that is the way I felt when I read some of the replys. The bulk of my chargeing will be done at home with chargers in the shop. This was just to try to extend my range.

By range extension I guess you mean a better MPG.

Within the available technology the IC engine still is the best (in terms of power output to prime-mover system weight and stored fuel weight to effective range) way to generate mechanical power to drive a personal vehicle.

However if you want to improve MPG you must think of:

1. Regenerative Braking.

2. Using battery power to inch your vehicle when in heavy traffic start stop situation thus cutting on engine idle time. Similarly starting off from traffic lights on battery and bringing in IC engine power when you have sufficient speed - this also to cut engine idle time.

3. Lighter vehicle components.

4. Better aerodynamics.

5. Competing with the likes of Toyota and Honda who are already selling HYBRID cars around these concepts.

Anyway good luck to your courage.

Hilltopper,

You don't call it perpetual motion, but what you want to do is charging the spare batteries while driving. Correct me is I'm wrong.

The energy to charge is extracted from the rotation of the wheels.

Just make a trailer that does this, install a kind of force sensor on the car connection. An try to measure the force needed to pull the trailer with the charging active and not.

Nobody is willing to force you to buy oil. You are free to charge your batteries with what you want but you must add energy from a source.

Well, you did say "comments and questions will be appreciated". I guess some took your word for it.

I'm all for using electric cars though I haven't the economic ability to build (much less buy) one. A two hour run time is terrible so I can understand your desire to extend your range. I don't think adding a spare battery pack is going to give you a significant increase. The added weight of the pack will slow you down and drain your battery faster. Add the weight of the alternator (even just one) will worsen the situation. You might get a small increase in range but not significantly so. Certainly not twice your present range.

I would suggest that you try something else like lightening your car. If you have a metal bodied car, try using fiberglass. Maybe you could get rid of the differential or change the material to a lighter type. See if you could improve streamlining, and taking out the non-essentials like the radio or air-conditioning (that's a big maybe). If you're the only one who's going to use the car, take out the extra seats.

These are just some suggestions. I think others can offer more, maybe better. A kilogram saved might improve your range better than an additional battery pack for all we know.

Even when you get your prime mover problem solved, wouldn't it be

a lot simpler to rig a 72V. generator from a DC motor than to set up

all the switching & relays for separately charging all those separate

12V. batteries? - Less failure points = less problems, & probably a

smaller lighter system overall.

One stuck relay could trash the whole system with the scheme you propose.

IIRC, surplus airforce DC generators & motors are availible that might be

modified to serve.

Pragmatist,

How do you propose to power the DC motor?

Are you suggesting that the generator so driven will produce more power than the motor consumes?

Because that's the way your post reads, unless I am missing something.

Regards, Greg

I think the law of conservation is on stack. Please ensure that the energy required for charging the batteries obtained from trailer will not be supplied by the batteries driving the vehicle!

TAre

< Law of conservation(of Energy) is on stack.>

But I think he is not bothered!

He is having Fun.

That's what matters most to him--in his golden retirement.

If all you wish to do is extend your range, then a second (identical) bank of batteries in the trailer - recharged at home - would instantly double the range.

"If all you wish to do is extend your range, then a second (identical) bank of batteries in the trailer - recharged at home - would instantly double the range."

NOT quite! you still have to drag around that second set of batteries while using the first, and carry the first while using the second. There is a lot of tire and other friction eating up energy all the way, so the increase in range would be considerably less than double.

Whether we like it or not, and whether we are kind or rude, this is indeed another futile attempt at perpetual motion: There must be a source of energy to drive any machine, and any machine that rolls on wheels must get that energy from a source outside the machine, not from its own motion.

Regarding the 6 alternators, if equally well designed (matched to the assigned task)and fabricated, one large one is always going to be more efficient than 6 small ones.

Dick

While I appreciate that the "double" is not quite right, the main point I was making was that a second set of batteries would not need charged enroute, while still allowing a considerable increase in range.

Slightly off subject: I have had cars where the addition of the full 1/2 tonne payload has led to a 50% rise in fuel consumption, but also one which could carry a full tonne payload with little difference to the performance.

The increase in range will depend on how able the motor is to carry the extra load - perhaps the first test which needs to be done is to find out what range the car will have with a trailer loaded with the same weight as a set of batteries, then double that and see if the investment would be worthwhile.

Whether we like it or not, and whether we are kind or rude, this is indeed another futile attempt at perpetual motion:

No, hilltopper is aware that this is not a perpetual motion machine (PMM). He's only concerned with increasing the range of his electric car. It's only the fact that he's planning to recharge his inactive batteries using power from his active batteries, is what makes it look like a PMM. Since recharging is slower than discharging, there's no way to keep the car going indefinitely.

In a way, a normal car does that same thing. It uses the battery to start the engine and, once it's running, the engine drives the alternator to recharge the battery. Yet, we all agree that this is not a PMM, right? The only difference here is that the battery doesn't provide power to run the car but only to start it.

Granted that hilltopper's idea isn't feasible. However, since he's submitted it for scrutiny, we've already come up with several possible alternatives for him. I'd say that this thread was worth the ridicule from some of the others.

how about a fresh volume of electrolite nd an electrolite pump to recharge the batteries instead of bringing a second set of batteries?

OK for recharging the electrolyte, but how do you recharge the plates??????

Greg

When ya connect the discharged batteries to the alternator that "load" will almost stop your forward momentum even with your accelerator petal "floored" !

better to install a 6 ~ 10 kW photovoltaic system on your roof, feed power back into the power company grid during the day at the high rate of $0.50 / kW and recharge an electric car off the power company grid at the low rate of $0.02 / kW...this setup also eliminates your utility bill as well. this is what I did ...RS

It sounds like what you really need is more power. Your lead acid batteries are to heavy and bulky. I have been reading about a different kind of battery. It is a flow battery. What it is is a single cell. with vertually unlimited capacity. This is possiible because it is a single cell with the solution being cirrculated through the cell. The capaicty is only limited by the size of the storage tank. From what I have been reading they are using this battery as a load shedding system on the grid. But I can't imagine why you couldn't use it in an electric car. It would be perfect as the power to weight density is very high. There are several types that I have read about but the one that they seem to be using is a zinc/bromine flow battery. From what I understand the materials are both cheap and plentiful. I would like to find the time to experiment with one, beause is sounds like it is something that the home builder can work with.

Interesting. I'll have to read more about them.

I'm afraid I can't help. But here is an interesting site concerning home builtds. This guy is in England but you could probably substitute parts with the same or better ratings and come out with good results. http://www.electric-cars-plans.com/ The body is made of fiberglass by the builder and would be light. Anyone know anything about his company? The idea of doing a conversion using a small stick shift junk yard car with no motor has crossed my mind. My question is, How many years would could batteries last if you used a good quality battery and used the vehicle conservatively? Don