MakeShift 01: Analysis, Commentary, and Winners
by William Lidwell
May 13, 2005
The first MakeShift gauntlet was thrown down to take the measure of MAKE readers--an intractable conundrum to separate the intellectual and creative wheat from the chaff: a dead car battery in the middle of nowhere; an eight-hour time limit before deadly weather sets in; nothing but your wits, camping gear, and left-over snacks to solve the problem. The result?
MAKE readers answered the challenge with audacity and vigor. Solutions ranging from rocket-propelled flywheels to potato chip-and-penny voltaic piles were submitted. What follows is an analysis of the "dead car battery" problem peppered by ideas and commentary from the most lucid of reader contributions. In the end, however, there can be only two winners per issue -- readers who submitted the most creative and the most plausible solutions. These MakeShift Masters and their problem-solving booty are announced at the bottom of this page. Since there were so many excellent submissions, I have also taken the liberty of declaring some honorable mentions. No booty for these folks, but some formal acknowledgement for their exceptional work. Winning entries and honorable mentions are presented in their entirety for the edification of all.
For those of you who undertook the MakeShift challenge without success, fret not. Unlike the various forms of IQs, EQs, and GQs that are said to be all but unalterable, the very special brand of genius that I hereby brand MQ (for MakeShift Quotient) is unquestionably advanced through the study of science and engineering and through exercises of creativity and problem solving. You can begin developing your MQ by studying the analysis that follows. Explore and evaluate the highly varied and innovative ideas submitted by MAKE readers. Do this for each issue, and you will soon be thinking like a MakeShift Master.
There are two basic approaches to this challenge: (1) solve the problem in a way that has nothing to do with the obvious parameters of the problem, and (2) start the vehicle by recharging the battery.
A number of readers opted for the non-obvious approach. For example, a contributor on the MAKE: Blog suggested the following:
...review your supplies, take what's needed and get out of there fast, before the snow, a 50-mile walk should take about 4 hours.
No dice. As I replied in the blog, a fast walker can average 3 mph--carrying supplies over rough terrain, maybe 2 mph. Short of being professional athletes, a fit, average couple would be lucky to make it halfway before nightfall (and that's assuming they don't get lost or injured along the way). With bad weather setting in, the decision to hike it out could be their last. People die trying to hike their way out of trouble all the time. A far better plan would be to build a fire and wait for help... or, figure out a way to restart the vehicle.
The survival considerations/tradeoffs of how supplies are used (and possibly wasted) were raised by a number of readers. For example, C. Holdredge offered the following admonishment in this regard (I should note that he then went on to provide a very strong solution to the problem!):
In the scenario presented, spending time trying to start the car is REAL DUMB. The subject has two kinds of shelter, a handy forest for fuel, half a dozen ways to start a fire, and will shortly have a source for extensive fresh water. Anyone qualified to be in the woods at all should be able to survive for weeks under these circumstances, awaiting rescue. In the real world, the subject would be much wiser to spend the time stockpiling dry wood, starting a fire, pitching tent, seeing to their visibility from the air, etc. Fuss with the car to avoid boredom while waiting for the rangers or CAP to find you and haul out.
The general concern is valid. If efforts to restart the car consume precious food and water resources and then fail, you could be in trouble. That said, a large supply of frozen water will be falling from the sky in a few hours. Food is a consideration, but you have plenty and can survive for weeks on light rations. So, while economy of resources should factor in the equation, spending days/weeks in the forest unnecessarily is riskier than not applying yourself and your resources to getting the car restarted--especially if you have the wits and wherewithal to do so.
Last but not least in the non-obvious category are submissions proposing the possibility of push-starting the vehicle. P. Stewart wrote:
You guys stated that "By the way, the car has an automatic transmission--push-starting won't work." This isn't necessarily true. Virtually ALL automatics from the 1930s through the 70s had two oil pumps and could be push started. All that is required for a push start on these older models is a little speed to build up oil pressure. Mercedes-Benz automatics used to have a secondary oil pump driven by the output shaft. I believe they even advertised with this fact into the 70s--you could push start the vehicle when you had a flat battery while this was not possible with most vehicles. Nowadays, with the single pump on the input shaft, there's no pressure to work the clutches unless the engine's turning.
The fact that push starting may well be an option for older vehicles with automatic transmissions is a good MQ point to know. Thanks to Stewart and others for raising it. Unfortunately, the challenge as it appeared on the website did not include the picture of the late-model Volvo SUV that was in the mook, which cannot be push started. What can I say--subscribers have an edge!
So, assuming it is not reasonable to hike your way out or push start the vehicle, and assuming you are comfortable doing something more than collecting wood and waiting for the rangers, let's look at approach #2: starting the vehicle by recharging the battery. Before we begin reviewing reader responses using this approach, it will be useful to briefly review how batteries work. (NOTE: The electrochemistry of lead-acid batteries is complex. What follows is a simplified "need to know" overview for this challenge.)
A battery is created when two different metals or carbon rods (called electrodes) are placed in an electrically conductive medium (called an electrolyte). Stick a penny (copper-plated zinc) and a nickel (nickel/copper alloy) into a lemon, and you have a battery. Put a copper wire and aluminum wire into a jar of urine, and you have a battery. You get the idea.
Different metals react at different rates (i.e., create charged particles) with the electrolyte. This means one electrode will give up electrons at a faster rate than the other, creating an imbalance of the charge distribution in the electrolyte. Bits of charged electrolyte move from one electrode to the other (direction is positive to negative) to eliminate this imbalance. When these charged bits make contact with the negative electrode, they give up their electrons, and electricity is created. As this occurs, the lead electrodes become more chemically alike, the electrolyte becomes less active, and the voltage drops until the battery can no longer deliver the necessary voltage. Stimulating the electrolyte through some form of additive adds chemical energy to the system and may provide a brief energy boost to the battery. Feeding an electrical current back into the battery restores the chemical difference between the electrodes and recharges the battery (this doesn't work for all batteries, but it works for car batteries).
So, recharging the battery involves either finding a way to stimulate the electrolyte, or finding a way to feed electricity back into the battery. Readers had interesting ideas on both counts. J. Russell proposed using the cola to stimulate the electrolyte:
Pour some cola into the battery. Start the car after a few minutes. Of course, you'll have to replace the battery because you've destroyed it, but at least you'll be alive.
G. Fetters proposed a different means of electrolytic stimulation:
- Take the battery out.
- Remove the fluid from the battery.
- Squeeze the dozen limes into the battery.
- Drink the soda and urinate into the battery.
- Fill the remainder of the battery with the water.
- Wait 9 hours and put the battery back in.
Other proposed additives included saliva, potato chip brine, and hydrogen peroxide. Three disadvantages of this basic approach: (1) though the theory is sound, it generally won't work in practice for a variety of reasons (e.g., getting the proportions right), (2) if you try it and it doesn't work, you have likely ruined your battery and eliminated any other opportunity of getting the vehicle started, and (3) several proposed additives run a real risk of blowing up the battery. There is, however, one additive that avoids these disadvantages, as A. Seubert testified:
...Put two tablets [of aspirin] in each battery cell and wait no more than 1 hour (the acetylsalicylic acid combines with the sulfuric acid to get off one more charge.) You can pry the cell covers off with a screwdriver even on most maintenance-free batteries... Then the car will start right up (based on actual experience).
D. Hottle corroborated the soundness of the approach stating:
I know this solution works because I have done it before. To this day, I carry aspirin in my car for just that reason.
As bizarre as this sounds, aspirin will often work depending on the degree of discharge of the battery. It is a reasonably safe approach and usually good for one more engine turn. Be warned that adding aspirin will shorten the battery life, as the aspirin will react with the sulfuric acid to form acetic acid. Good for a boost, but bad for the innards of the battery. Assuming you add no more than a couple of aspirins per cell, it shouldn't cause significant damage nor preclude additional efforts if it fails to work. So there is at least one safe, viable way to have a reasonable shot at getting the vehicle restarted by stimulating the electrolyte. J. O'Brien took this approach further, however, factoring in some key details that could be the difference between success and failure:
Pour the cola on the battery terminals and connectors and wipe any corrosion off using bandages from the first aid kit. Cola is good at removing corrosion and cleaning the contacts will help get more current out of the battery. Reconnect the battery.
Next, crush several aspirin from the first aid kit, put the powder in the battery, and add bottled water to the battery to fill it to the proper level. The acetylsalicylic acid from the aspirin will combine with the battery acid and increase the charge in the battery, and the water will help restore the electrolyte in the battery.
Since it's cold out, the last thing we want to do is get the battery and engine warm and certainly not let it get any cooler. Using the sterno stove, heat water in the empty cola cans and pour warmed water over the battery and engine.
Cola has yielded mixed results removing corrosion from battery terminals, but it is certainly better than nothing. Ensuring clean contacts will maximize energy transfer in the circuit. Topping off the water, if it is low, certainly won't hurt. Warming the battery and engine is a good move if it is very cold. Cold temperatures dramatically reduce the efficiency of the battery, as much as 50% when the ambient temperature is 32 degrees Fahrenheit. Cold temperatures also thicken engine oil, increasing the current required to crank the engine. Carefully pouring warm water over the battery and engine is among the safest ways of warming things up--certainly safer than warming the battery and engine over a fire.
Enough about stimulating electrolytes. In terms of feeding electrical current back into the battery, two basic approaches were offered: (1) create a new battery to trickle charge the car battery, and (2) develop a means of using the vehicle's alternator to charge the battery.
A small digression to set up some of the science. A typical car battery is composed of 6 cells (essentially mini-batteries), each creating about 2 volts for a total of 12 volts. These cells use two different kinds of lead (lead dioxide and sponge lead) as electrodes and a sulfuric acid-water solution as the electrolyte. The cells are connected to one another and to two terminals, one positive and one negative. To start a vehicle under normal conditions, a battery needs to be able to discharge around 12 volts at 200 amps.
In case you don't know, voltage (measured in volts) is the force that pushes electrons from one electrode to the other. Current (measured in amps) is the rate of flow of electrons between the electrodes. By way of analogy, imagine you are at a batting cage. The force the pitching machine uses to pitch the ball is like the force pushing electrons (voltage). The number of balls pitched per unit time is like the number of electrons moving between two points per unit time (current). The force pushing electrons is a function of the different reactivities of the electrodes in the electrolyte. The current is a function of this reactivity and the surface area of the electrodes. Since a lot of current is required to start an engine, the electrodes are made into thin plates to maximize the surface area available to donate and receive electrons. The more surface area, the more current.
One last tidbit. Connect multiple batteries in series (i.e., connect the terminals of one battery to terminals of opposite charge on another) and the voltage adds up as the current remains constant. Connect multiple batteries in parallel (i.e., connect the terminals of one battery to terminals of the same charge on another) and the current adds up as the voltage remains constant.
With this out of the way, let's look at some of the battery ideas submitted. M. DuPont proposed creating a battery using a potato chip/lime/soda electrolyte and electrodes made of aluminum cans and the copper clips from the jumper cables. Her diagram is as colorful as the procedure proposed to create it:
- Swig eight fluid ounces of water. Gotta stay hydrated.
- Use the knife to carefully cut the top of water bottle off, so that the top is just wide enough to slide in two soda cans, standing side by side. Make sure you keep as much water in the container as you can.
- Eat two potato chips for luck.
- Finely crush up the remaining potato chips in their bag, and dump them into the water bottle. Stir with a screwdriver.
- Eat the banana. No sense letting your blood sugar dip, if it's gonna be cold.
- Squeeze the juice of a dozen limes into the water bottle.
- Drink one can of cola, and pour a second can of cola into the water bottle. Don't mind if it overflows. Then use the knife (or its file, or a rock) to scrape at least half the paint off the two cans.
- Carefully widen the openings on the tops of the two empty soda cans, so that the cans can be firmly clipped together, back to back, with the jumper cable. Clip 'em together with the BLACK jumper cable.
- Bite an apple. Mmm. Chew and swallow.
- Go into the car and turn off or unplug every accessory: radio, fan, heater, headlights (duh), interior lights, and anything plugged in to charge (cell phone, for example). Also, turn the ignition to OFF and pocket the keys. This is so nothing sucks up the power when you try to start 'er later.
- Disconnect the car battery terminals from the car's cabling.
- Using the knife (or file, or rock), scrape any gunk/corrosion off the car battery terminals. Do NOT touch any part of the car while doing this, and, stand on two folded-over, DRY sleeping bags to further insulate yourself from accidentally grounding out the car battery and jolting yourself. Just because it can't start your car DOES NOT MEAN it can't stop your heart. Be careful.
- Clip the free end of the black jumper cable to the positive ("in") terminal of the car battery.
- Clip the nearest end of the red jumper cable to the negative ("out") terminal of the car battery.
- Dip the other end of the red jumper cable into the water bottle. Position it so that it is dipped into the bottle, fully submerged, but not going very far below the surface of the water. You can notch the water bottle to accept the cable, if that helps keep it hanging in place.
Figure 1. M. DuPont's Salt-Lime Battery
The idea of creating a battery like this to recharge the car battery is sound enough (and if this battery didn't work, you could always drink the electrolyte!). The question is whether a makeshift battery can generate sufficient voltage and current to trickle charge the car battery in eight hours? Voltage--no doubt. Current--questionable. S. Cahill addressed the current issue in his wet cell solution:
The  wet cells themselves will not deliver enough instantaneous current to start the car, so they must be used to recharge the car battery over several hours. The car battery can then be used to deliver the "cold cranking" amps to start the car (hopefully) for a few seconds. We must develop enough potential to "reduce" lead sulfate back into lead and lead peroxide, which is the reaction that powers the car battery. The six cells of the lead-acid cell need a total potential in excess of 6*2.12 V, or 12.72 V in order to recharge.
These types of batteries could only generate milliamps of current. However, if they can generate sufficient voltage over a long enough period of time, the battery will recharge. As Cahill notes, it will take about 13 volts to overcome the internal resistance of the battery. So, the viability of this approach really depends on the level of discharge of the battery and the amount of time you have to recharge the battery. If the car battery is not too discharged, the ambient temperature is not too cold, and the makeshift battery is able to generate 13+ volts for 8+ hours--could work! A different battery configuration worth considering--known as a voltaic pile--was proposed by N. Kondrick:
...Get your water and cut a corner off the jug and trim it down so it's big enough to fit all your copper [from jumper cables], aluminum [from cola cans], and cloth as well as some liquid and still be able to hold some liquid.
Now stack all the copper, aluminum, and cloth together in a copper/cloth/aluminum pattern--make sure there is no bridging of metals across the cloth and no bridging of the cloth.
Use a couple of adhesive bandages to attach one end of each wire to the ends of the stack (red wire to the copper end, black wire to the aluminum end).
Stick the whole stack into your plastic container (the corner from the water jug). You'll probably want to do it sideways so you can more easily cover it all with liquid.
Squeeze the lemons into your plastic container until the juices cover your whole stack.
In this voltaic pile, each aluminum/cloth/copper layer forms a cell. The proposed voltaic pile is essentially eight cells in series. The copper and aluminum layers are the electrodes, and the juice-soaked cloth is the electrolyte. Since these cells are in a series configuration, their voltage adds up and their current is constant. It is doubtful that a voltaic pile of this length could generate the required voltage, though the pile could be extended using different coins and other materials scavenged from the supplies. Current would be nominal, but you should be able to get a few volts out of it. Hook enough of them together and you have a shot, assuming you have enough time.
Creating batteries to recharge the car battery makes use of chemical energy. Another approach would be to use mechanical energy to recharge the battery. P. Salkie summarized the "eureka moment" and the problem of this approach nicely:
...let's think of one of the most reliable, efficient, proven, general-purpose converters of chemical energy to electrical energy ever to exist on this planet--the internal combustion engine attached to some sort of generator! And you were even smart enough to bring an internal combustion engine along _with_ you! Total Genius!
Oh yeah. That's the problem, isn't it--can't start the damned thing. So, let's think of one of the other most reliable, efficient, yadayada converters--you. Yes, you (and the person who's looking daggers at you) are reliable, efficient converters of organic food compounds to mechanical energy. So, eat that fruit, drink some cola, and let's get down to work! First, we'll need to come up with some way of generating electricity from mechanical energy. Fortunately, you packed along a generator system with you on the trip! What? Didn't see that on the equipment list? Well, it's there all right--the car is guaranteed to have an alternator. It is conveniently attached to a voltage regulation system (which ensures we don't overcook the battery or blow up the radio) and it's even already wired in for us! All we have to do is turn it. A lot. A whole hell of a lot. Just an amazing amount of lot.
As Salkie points out, the alternator is sitting right there waiting to be used. The key problem in using the alternator is figuring out a way to spin it fast enough to generate the energy required to recharge the battery. A little bit about modern alternators: alternators generate electricity by spinning one charged copper coil (called a "rotor" or "field coil") inside another stationary copper coil (called a "stator"). The electromagnetic field created by the spinning field coil extends to the stator, and pulls electrons around the stator coil--voilá: electricity. Since there are no magnets in an alternator, you need some starting current to generate an initial magnetic field in the field coil. This starting current can come from the car battery or some other external power source. Once the field coil is generating a magnetic field, you then need to spin it at a minimum rate of around 1,000+ RPM or nada--2,000 RPM to recharge at the optimal 14 volts. The total voltage coming out of the alternator is a function of the strength of the magnetic field and the speed of rotation. A variety of solutions were proposed to make this happen. R. Bohn offered one innovative way of addressing this problem:
- Make sure the parking lights are turned off.
- Eat the banana (will need the energy!)
- Remove the alternator from the car using the tools.
- Mount the alternator on the bumper.
- Replace the small belt wheel on the alternator with the larger belt wheel from the engine.
- Connect the spare tire to the larger belt wheel (we're building a flywheel here).
- Connect the alternator to the battery using the jumper cables (POLARITY MATTERS!).
- Take a break. Drink a cola with some lime juice...
- Start spinning the spare tire. This should turn the alternator and charge the battery.
- After several hours check the battery by turning on the headlights. They should shine brightly when the battery is charged. Turn them back off!
- Remove the spare tire and return it to the car.
- Re-attach the small belt wheel to the alternator. Return the alternator, the large belt wheel and the belt to the engine.
- Have another cola and cross your fingers.
- Start the car and head for home.
P.S. My wife insists that a proper solution must include the banana.
Using the spare tire as a flywheel is an excellent way of getting the most turns per unit time for the least amount of energy. If you could maintain a spin rate of one revolution per second (i.e., 60 RPM) with a 30" spare tire, you could roughly generate 1,800 RPMs. Impressive. Unfortunately, the field coil was never charged in this solution, so no electricity would be generated. No comment regarding the banana! J. Gasbarro caught the field coil detail and even made plans for a backup power source:
Apply field current. Connect the free wire from the lamp [extracted from the trunk and connected to the alternator] to the battery. If you're lucky, the lamp will light, indicating that you have current in the field coil of the alternator. Lead acid batteries will often recover some of their charge after they have been deeply discharged if they are just left to sit for a while. Warming them helps. If the lamp does not light, then you have to go to your backup field current source, which is the depleted cellphone battery. The cellphone is smart enough that it will not discharge the battery below about 3V. So there should be enough charge left to power the alternator field current for a few seconds (see About the Alternator section). Use the adhesive bandages to tape wires onto the cellphone battery as necessary.
Finally, S. Curl proposed a way of getting to the core of the alternator RPM problem that would make MacGyver proud:
Using the provided tools, I remove the car's alternator and wedge it into the side of the bumper where the shaft can protrude....If the wires won't reach, I extend them with the jumpers. I then mount the spare onto the alternator with a combination of wire lashes from the jumper cables and a clever adhesive paste of mashed fruit supplemented with adhesive bandages. More of this paste and the bandages are employed to affix the two road flares to the tire. My mate, meanwhile, has been carving the apples to create rocket nozzles which are now crammed onto the flares and lengths of gauze "fuse" attached. By hand, the wheel is spun as quickly as possible, and at that moment of peak velocity, the fuses are lit and the rockets fire. The added boost offers peak generation of energy, which is then applied to starting the car, and away we go!! And that's why I'm a sculptor and not a mechanic!
Since this entry is such a tough act to follow, I'll take it as my cue to close. Here are my summary thoughts on the challenge. Aspirin is the simplest solution. If it works, you are out of the jam in 30 minutes, no muss no fuss. If it doesn't work, then Plan B. I am skeptical about the feasibility of creating a battery to trickle charge the car battery given the time and conditions. Even if you have an uncanny grasp of electrochemistry (which some of you clearly do!), getting the electrolytic proportions right and everything hooked up in a rough environment is no trivial task. A lot can go wrong, and there just isn't a lot of time to tinker. Therefore, the best Plan B is the alternator. Turn the alternator fast enough and it will recharge the battery. If the car doesn't start, turn it some more. Relatively simple and reliable. The only risk of this approach is accidentally damaging the alternator or belts in the process--so be careful! General factors to consider for all solutions: effects of temperature on the battery and engine, quality of the connections in the car battery circuit, water levels in the battery, acidic strength of electrolyte, minimum RPMs required to generate V/C from alternator, implementation time required by the approach, ability to test progress and tune your approach, simplicity, ability to back-out or try alternative approaches if you fail, consumption of resources needed for survival, contingency plans, and safety.
I would like to thank everyone who submitted solutions to the MakeShift 01 challenge. There were many excellent submissions, and selecting two winners from the batch was no easy task. For future reference, the level of detail provided in the submissions played a major role in the selection process. So, as your high school teacher used to say, "Show your work!"
Winners receive a one-of-a-kind Make t-shirt to celebrate and show off your unique brand of genius; and the ultimate MakeShift Master tool--the SWISSMEMORY USB Victorinox 512MB--equally useful for hiking and hacking. With these awards and your frighteningly high MQs, we at Make expect great things. Go forth and solve the world's problems!
Without further ado, the winners of the inaugural MakeShift 01 challenge are:
- "Alessandro Volta" Honorable Mention: Sean Cahill
- "No Stone Left Unturned" Honorable Mention: Melanie DuPont
- "Rube Goldberg" Honorable Mention: Phil Salkie
Congratulations to the two inaugural MakeShift Masters and the Honorable Mentions (applause...accolades...bowing). All showed an impressive ability to think creatively, apply both theoretical and practical knowledge, and communicate their solutions in a fun and effective manner. I encourage all readers to study these winning entries; it will improve your respective MQs and prepare you for the next MakeShift challenge. Until then, happy making!
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i wish i had seen this challange before, I managed to pull start a 4cyl 1979 datsun engine,
put it in park or neutral, turn the car on, wrap a peice of rope around the fan or other engine pully, and make a stick handle on the rope, brace yourself and pull.. just like pull starting a mower, only alot more force is required!
only took me 2 tries, and that's because my rope slipped.. (Be careful dont knot or anything the rope onto the car because it will wind up and possibly hurt you or something!)
Posted by adricm on May 13, 2005 at 01:24:34 Pacific Time
- Weak analysis
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I think the analysis of some of these entries is weak.
Despite noting that ~13V is required to charge the battery [actually close to 14V is required to fully charge a lead acid battery], no mention is made that none of the single cell battery solutions will generate anything like enough voltage, for example a copper-aluminium battery with coke electrolyte will give you 0.946 volts. You'll need a series string of about 15 of these to charge a car battery.
Warming the battery is a good idea, but a lead acid battery has massive thermal inertia, as well as being encased in insulating plastic. Pouring warm water over it will achieve little. Best bet would be to use a container large enough to hold the battery [if you have one]. Make a large fire and boil water, then put the battery in the container and pour hot water around it [don't immerse the battery completely of course]. You might need to iterate a few times to get the battery warm.
Similarly the engine is too massive to warm by pouring a small quantity of warm water on it. Best options would be either a) Remove the engine coolant and heat it over a fire, then replace it [assumes you have a container large enough], or b) make a large fire with some rocks in it, and when the fire burns down, push embers and hot rocks underneath the engine sump.
Something nobody addressed with any of the battery charging ideas was that without a meter, you have no idea if your solution is actually charging the battery, which means you could be wasting time and/or energy. If you have a compass and some fine insulated wire, wrap as many turns of wire as possible around the compass to make a galvanometer. Test by connecting in series with the battery and a low wattage bulb. You should see the compass needle deflect when you complete the circuit. Now wire the galvanometer in series with your charging arrangement, and if you are in fact charging, you should see the galvanometer deflect in the opposite direction.
Posted by HiroProtagonist on May 15, 2005 at 17:01:51 Pacific Time
- Voltaic pile
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One other comment about the battery solutions.
The voltaic pile is the only homebrew battery mentioned that has a hope of generating sufficient voltage. Unfortunately it is unlikely to generate enough current to be useful.
There is a serious flaw in this solution though: "Squeeze the lemons into your plastic container until the juices cover your whole stack".
You cannot make a multiple cell battery that shares a common electolyte. In order to work properly, the electrolyte of each cell must be separated. This battery would work if the metal plates were separated by cloth moistened with acid, but sitting in an acid bath, adjacent cells are effectively short circuited by the electrolyte.
Posted by HiroProtagonist on May 15, 2005 at 17:13:27 Pacific Time
- Supplement to lower required voltage/current
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No one mentioned running the engine on just 1 cylinder to reduce required current/voltage. This was mentioned on a car talk episode a long time ago, that to save energy on a dead battery you remove all spark plugs except for 1, or just unplug all but 1 from the distributer cap (if you have one).
Just a new persoective.
Posted by enigmae on June 06, 2005 at 15:10:50 Pacific Time
- Use the alternator
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Has anyone actually made one of the options above and determined the voltage and ampage generated. Personally I doubt that they would either generate enough voltage to overcome the internal resistance of the battery and if they could, that they would generate a current for sufficient time. I think the solution is in using the Alternator.
All that needs to be done is determine a way of spinning the alternator for long enough to charge the battery. I suppose that it could be left on the car and some way determined to either spin the alternator directly ( as in using the pulley on the alternator) or alternatively spinning the whole engine. To eliminate (or decrease ) compression, the plugs could be removed.
The best option would be to remove the alternator and the battery, hook them up so that they are in charge mode (i'm thinking this would be + to +) and here is the crux. Jack up the front left of the car so that the wheel is off the ground and can spin freely. Put the pulley on the wheel and start spinning the wheel. I would use the wrench to latch on to one of the wheel nuts and start cranking (literally as some of those wrenches have crank shaft like shapes).
I reckon that 15 minutes at good rate would be enough and probably not that tiring and the ratios of wheel to pulley would be sufficient.
My wheels are 60 cm diameter. Maybe I would have to run it on the walls rather than the threads. So maybe 45 cm giving 275 mm radius. Gives 1727 mm circumference. I don't know how big American alternator pulleys are so I'll give a range
radius circ ratio
10 62.8 27.5
20 125.6 13.75
30 188.4 9.17
40 251.2 6.88
50 314 5.5
Assuming that you could spin the wheel at 2 or 3 revs a second, then that should give you sufficient revs, but probably at a low ampage. I am assuming that the voltage generated is independent of revs. Is that true.
Depending on the revs, then you might have to go a bit longer.
The only bit I am not sure would be available is wire to connect the alternator leads to the battery. If there was enough available then the battery could be left in place and the wire ends squashed between the terminals and teh high amps lead clips. I suppose that wire from the jump leads could be used (The whole leads would have too much resistance). They would have to be insulated from each other and the car. Or if things were desperate, you could rip out some wiring from the interiors lamps, brake lights, trailer connector, etc)
This married with the common sense steps above would get you out (assuming you have a vice grips!!! to get the alternator off.
Diarmuid (Fremantle, Australia)
Posted by dwrenne on June 17, 2005 at 17:40:28 Pacific Time
- Getting that automobile going again
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The objective =was= to charge the battery.
But, if the battery is a gonner anyway, attempts at using other sources to charge it will likely be a waste of time.
But, let's look at the other possibilities.
(A) If the battery is =really= dead, then the recommended option of charging it simply won't work. And, attempts at push-starting won't work either, because alternators need to have a voltage source for the field winding, in order to set up the necessary magnetic field that required to produce a current.
I don't know of any modern vehicle that uses a generator (which uses residual magnetism to set up the initial field).
(B) But, on the other hand, let's say that all of the necessary ingredients called for in the various scenarios used to produce an EMF, aren't available. What then?
And, how many people actually carry all that stuff around with them anyway?
For my money, I'd simply carry a spare battery, and be done with it!
But, neglecting that?
I'll suggest the more labor intensive solution that'll at least give you the ability to move the vehicle without resorting to pushing it especially if you happen to not be in the greatest physical shape, and one that gets it moving with more velocity than with pushing.
This solution works best with vehicles having manual transmissions. I wouldn't have anything else!
Most automobiles have jacks which are used to raise the vehicle to replace flat tires, and for other purposes. If you are astute enough, you'll elevate the rear or the front of the vehicle (as suits the problem, since you can start a vehicle in either direction depending upon the gear the transmission is in), and build a ramp of rocks or other solid woodland debris.
With enough elevation having the proper slope of the ramp, and having a battery with just the minimum energy left to power the ignition system, you'll be going again.
But, of course, if you happen to drive a vehicle outfitted with a magneto ignition? Then push-starting is a 'no-brainer!'
And, if you happen to be the proud owner of an IH ScoutII with a Nissan Diesel? You don't even need a battery period!
Then there's that problem with most 'modern' automobiles: Electrical/Electronic nightmares. The entire vehicle requires some kind of EMF to make it work. If you don't watch what you do to minimize the drain upon the battery, you'll actually be working against yourself by disabling the control system which manages engine functions, and defeating your efforts in the process.
Remember: In modern vehicles, simply switching on the ignition applies power to a host electrical/electronic items, and =even if= the battery charging scenarios were an option (you had all the ingredients called for), you'd still be between a rock and a hard place if you didn't know your vehicle's systems well enough to make the decision to disable those which weren't absolutely necessary for it's basic operation.
A modern standard Lead-acid battery not of the deep-cycle design, doesn't take kindly to being discharged almost all the way. In fact, they are almost impossible to recharge decently, and even when that can occur, they are essentially 'wasted.'
If the batter is really dead, then you're wasting your time trying to charge it. Since you're on a road anyway, the travel is the easiest. Stick to the road, and don't resort to using shortcuts over rough terrain unless it's not that far to another road providing closer access to help. Also, you might encounter another vehicle on that road.
The key here: Stick to the road. You'll at least have the visibility needed if there are others around traveling about in vehicles
If you have a modern 'nightmare' vehicle, and you don't know its electrical system, then you're playing with fate. Hike out now, with the least load needed to survive the walk. Remember: You =are= on a road, and it's the fastest easiest way to travel on foot.
And, as for the comment about getting lost in the dark? Well, if you =are= on a road, how can you get lost in the dark?! If there's only one way out ...
If you are driving an older vehicle with a manual transmission, then you have a better chance to play the game with Mr. Battery if he's still alive.
But in any case, I'll salute the over-the-top innovative suggestions put forth. Who knows? Maybe they would work in many situations!
Posted by ScotsHighlander on June 18, 2005 at 10:21:41 Pacific Time
- Another approach that needs brainstorming
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Along the lines of pull starting the engine, let's use the engine to do that. We have gas in the tank. We need to collect a small amount of that somehow. We need to know which cylinder is at the right point for a power stroke. We need to remove each spark plug in turn to figure this out. Put a tablespoon of gas into each cylinder and put the spark plugs back on. Remove the spark plug wire from the cylinder we chose above. Now we need to get a spark to that plug. Unless the disconnected spark plug wire will work for this, we have to scavenge for some wire as others have suggested and run that to our plug. Static electricity may be a good source of spark. http://home.earthlink.net/~lenyr/stat-gen.htm has a good method that might be possible in some fashion with the items on hand. I have built one of these PVC pipe static generators before, and they are quite a lot of fun. I suppose we should probably test our ability to make the spark at the spark plug before we replaced our plug back into the engine earlier. The key should be in the on position with all power draining accessories turned off or disconnected by fuse. Make your spark and start the engine. Once the engine is running, put the spark plug wire back onto the plug.
We need further refinement of the static spark machine made with items on hand. A Leyden Jar can be made with a soda bottle and pieces of aluminum can. We don't want the capacitance to be too large, because we want to build up a voltage large enough for the spark gap.
For building our static, maybe we can use paper rubbed against the rubber of our front tire. We can jack the tire up off the ground so we can rotate and keep our contraption still.
Posted by gearspring on June 21, 2005 at 10:16:19 Pacific Time
- The starter is the key
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One thing people seemed to miss is that with all their battery making skills they could've just hooked the leads up to the starter itself. This is much more plausible than trying to recharge the battery. Once the engine got going it would recharge the battery. This also eliminates waiting 8 hours to recharge it.
Posted by praufet on June 25, 2005 at 13:19:58 Pacific Time
- 2CV6 -> No Problem
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I do not get the problem. ;-)
I drive a 1989 Citroen 2CV6. It has this crank. Normaly you use it to change the tire, but just in case: There is a crank-case in front. I plug it in there and tell my sturdy friend to turn it, while I sit inside ready to act the moment the engine catches on.
I hope, you get what I am saying. My english has rusted some what.
Posted by Arne_Hofmann on July 22, 2005 at 08:48:45 Pacific Time
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