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can i set up a capacitor bank to start up my car if the battery is dead? Answered

a huge advantage to capacitors is low leakage (for some types) and i want to know, first of all, how much energy a starter motor needs to start the engine? one of my constraints is money (>$200) so if it works, but i can't afford the capacitors, then oh well. also, i want to know if i can make a simple circuit that would sense if the battery is dead and then switch to using the capacitors and also be able to recharge the capacitors. im also worried about the amount of leakage of capacitors with such high capacity (which might defeat the purpose of this idea), and where i could actually put the rig that would be safe from heat, and still have access to the starter motor. if this is feasable, i just might make my first instructable out of it: the invincible starting car


i bet that this would do the trick,


No! (like other comments) You could just carry a spare battery? L

Nope. Fergitit.

Be better to invest in a second battery and maybe a higher capacity alternator.

Basically, a second battery _is_ the "capacitor bank" you're looking for, or the closest thing to it. And, yes, there are several ways of setting up a car to charge a small backup battery and then switch to that (usually manually) when needed. Sears used to actually sell a battery which had a backup battery built into it, with a switch on the top of the battery case; that had the advantages of not needing alterations to the car's wiring and not forcing you to deal with finding somewhere to put the second battery.

. It can take 250-300A to crank a small-block V-8. Times 9V (approx volts when cranking) = 2250-2700W. Smaller engines will require less, but I have no idea how much less.