Gon5~SPARTA~ Posted May 23, 2015 Share Posted May 23, 2015 Link to comment Share on other sites More sharing options...
Donziboy2 Posted May 23, 2015 Share Posted May 23, 2015 EE rant system activated. That looks cool..... Sadly I went to school for electronics so its actually not so cool...... Pros. Will outlast a normal car battery (provided he adds atleast 1 more cap in series since they are rated for 15V total and a car can actually exceed that in some cases) If he removes the stupid sock he put on them later in the video they will also last much longer..... Much lower Internal Series Resistance vs Lead acid batteries (meaning more instantaneous power... also bad in some ways) Cons. Most caps are rated at 80C for a few thousand hours.... Most cars can get hotter then that under the hood, way to go sock man..... Based on bar napkin math you will get about the same amount of power as a small 12V 4A SLA battery, but you can get it all almost instantly. So don't forget to turn your clock off........ Since they have really low ISR you can damage a normal battery charger trying to charge them, damage your alternator trying to charge them, damage some poor sods battery trying to jump start one and last but not least burn out your starter much faster then with a normal car battery along with wearing it out alot faster every time you start the car. You can do much the same thing with a 3Cell lipo battery out of an electric car, you can also cause them to burst into flames if you leave them connected to your car to long while it is running....... EE rant system off. Its a cool idea and I may play with it for my electric gocart but for the average consumer it will cause more issues then it will solve. Link to comment Share on other sites More sharing options...
Athlon64~SPARTA~ Posted May 24, 2015 Share Posted May 24, 2015 (edited) That must be the Same hack that did the A/C repair guide a wile back. A starter requires 225 to 300 cca to start, much less counting the ecm draw fireing the injectors at the same time. This must be the same fella that claims he has a perpetual motion machine as well, a altenatior running a motor, running the altenatior. I don't think those little capastiors can discharge that amount of currant for that amount of time to start that cat. It would go click and dead. Edited May 24, 2015 by Athlon64~SPARTA~ Link to comment Share on other sites More sharing options...
Donziboy2 Posted May 24, 2015 Share Posted May 24, 2015 (edited) That must be the Same hack that did the A/C repair guide a wile back. A starter requires 225 to 300 cca to start, much less counting the ecm draw fireing the injectors at the same time. This must be the same fella that claims he has a perpetual motion machine as well, a altenatior running a motor, running the altenatior. I don't think those little capastiors can discharge that amount of currant for that amount of time to start that cat. It would go click and dead. Actually you can, its more to do with it not being a practical thing to do. Just using the CCA you gave, you need roughly 1 watt per second at 300A to start a car. Those small caps can hold over 30 watts of usable power before the voltage goes to low. The small blue caps he showed are actually capable of a short circuit discharge in the 1000A range. That larger bank he showed would probably work better for most people, but regardless of which caps are used some form of charging/maintaining would be required. Like a small solar panel. Edited May 24, 2015 by Donziboy2 Link to comment Share on other sites More sharing options...
Zathrus~SPARTA~ Posted May 24, 2015 Share Posted May 24, 2015 (edited) yeah.... like you said, nice idea, but he does have some things very wrong. If it were me, and I wanted an emergency capacitor starting system, I think I would figure out how mount them behind the grille in front of the radiator to keep them much cooler. The engine compartment is pretty hot... especially where I live where ambient air temps can hit 107 degrees F. A fairly large bank of capacitors would actually mount nicely to the front of the lower main radiator support. Obviously keeping them from discharging by getting wet might be a problem there so one would have to figure out how to protect them from getting too wet. Personally, I am thinking of mounting a second battery. My truck has a reinforced battery mount on top of the passenger side wheel well in addition to the main battery that is mounted on the drivers side. While capacitors are attractive in many ways, I am not sure they are quite ready yet for these kinds of applications yet. But they are quickly approaching that level. Ideally you would want a capacitor bank that could at least duplicate the starting amps (with significant duration of those amps) of your main battery. Edited May 24, 2015 by Zathrus~SPARTA~ Link to comment Share on other sites More sharing options...
Donziboy2 Posted May 25, 2015 Share Posted May 25, 2015 Speaking of cramming batteries..... I should have this monster running in a few months Link to comment Share on other sites More sharing options...
Athlon64~SPARTA~ Posted May 25, 2015 Share Posted May 25, 2015 It don't sound right http://rapidtables.com/calc/electric/Watt_to_Amp_Calculator.htm Link to comment Share on other sites More sharing options...
Donziboy2 Posted May 25, 2015 Share Posted May 25, 2015 (edited) It don't sound right http://rapidtables.com/calc/electric/Watt_to_Amp_Calculator.htm That is not the best tool for this.... Since it does not deal with capacitors. First its not the total storage(in watts for this case) but how fast you can dish it out and how long its actually needed. Lets do some math first, lets go with a starter that needs 300A(actually pretty high for a small car) to start a car. That's 300A x 12V = 3600Watts, but that's 3600 watts in an hour. So divide that by 3600 seconds in an hour you get 1 watt per second. If it takes 3 seconds to start the car then you only consume 3 watts from the battery or capacitor. Now for the capacitor, lets go with the 350Farad/2.5V caps. Now the math for this is different and it gives you watt per second. And capacitors in series dont stack like batteries would, instead they are added the same way resistors are in parallel. So for 6 series capacitors at 350Farad and 2.5V you end up with a 58.334Farad capacitor good for 15V. 3600 Joules = 1 watt/hour energy(joules) = 1/2 * c * v^2 0.5 * 58.334 * 15^2 = 6562.575 watt/seconds 6562.575 / 3600 = 1.823watt/hour , that damn napkin was drunk I tell ya! That's a little short for 3 seconds, but if you need 300A to start a small car then you need a new starter/engine anyway. One thing to remember is that with a Lead acid battery, pulling 300Ahour will drain the battery exponentially faster then a 20Ahour rate or 100Ahour for that matter. The capacitors wont care since there internal resistance is massively smaller then the battery. But you waste more energy charging capacitors vs batteries. Edit, just found this nice little calculator. http://www.calctool.org/CALC/eng/electronics/capacitor_energy Edited May 25, 2015 by Donziboy2 Link to comment Share on other sites More sharing options...
Athlon64~SPARTA~ Posted May 25, 2015 Share Posted May 25, 2015 Ohms law is ohms law, but ok. Link to comment Share on other sites More sharing options...
Donziboy2 Posted May 25, 2015 Share Posted May 25, 2015 Ohms law is ohms law, but ok. And what part of Ohms law are you confused on? Link to comment Share on other sites More sharing options...
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