Comments on: Ditch Gasoline?! http://twoguysrally.com/2008/04/14/ditch-gasoline/ Two guys on a journey into the Rally Racing world Tue, 07 Feb 2012 14:07:59 +0000 http://wordpress.org/?v=2.5 By: Mark Ozimek http://twoguysrally.com/2008/04/14/ditch-gasoline/#comment-27 Mark Ozimek Fri, 18 Apr 2008 17:26:24 +0000 http://twoguysrally.com/?p=26#comment-27 It kinda depends on the battery technology used. Lithium Ion batteries is one of the better commercially available types, but has a tendency to go into thermal run away and explode. Remember all the worry like a year or two ago regarding laptop batteries? That's why. Just use cooling solutions similar to current cars: lots of surface area and fans for when you're not moving fast enough. The amount of waste heat created from batteries and electric motors is pretty small compared to what an ICE dumps through the radiator and out the exhaust pipe :P It kinda depends on the battery technology used. Lithium Ion batteries is one of the better commercially available types, but has a tendency to go into thermal run away and explode. Remember all the worry like a year or two ago regarding laptop batteries? That’s why. Just use cooling solutions similar to current cars: lots of surface area and fans for when you’re not moving fast enough. The amount of waste heat created from batteries and electric motors is pretty small compared to what an ICE dumps through the radiator and out the exhaust pipe :P

]]> By: Idiot Cyvant http://twoguysrally.com/2008/04/14/ditch-gasoline/#comment-26 Idiot Cyvant Fri, 18 Apr 2008 16:28:39 +0000 http://twoguysrally.com/?p=26#comment-26 Is there an issue with managing the heat from batteries? Is there an issue with managing the heat from batteries?

]]> By: Mark Ozimek http://twoguysrally.com/2008/04/14/ditch-gasoline/#comment-22 Mark Ozimek Tue, 15 Apr 2008 22:25:38 +0000 http://twoguysrally.com/?p=26#comment-22 Most batteries are good for >500 cycles before the capacity decreases significantly if properly cared for. There are several factors in this though, such as charging voltage, operating temperature, discharge current, and a few others. The discharge current is really the sticky point here. Keep in mind that one horsepower is 745.7 watts. So to supply an electric motor in a rally car with power, a battery pack is going to have to be able to put out >150 kilowatts. Let's say for the sake of argument that we design a battery pack to put out 250 volts. Power is equal to voltage * current, so 150,000 watts / 250 volts = 600 amps. Just.. wow. That power level has to be sustainable too, not a peak value, or else we're gonna blow stuff up from overloading the batteries. Most batteries are good for >500 cycles before the capacity decreases significantly if properly cared for. There are several factors in this though, such as charging voltage, operating temperature, discharge current, and a few others. The discharge current is really the sticky point here. Keep in mind that one horsepower is 745.7 watts. So to supply an electric motor in a rally car with power, a battery pack is going to have to be able to put out >150 kilowatts. Let’s say for the sake of argument that we design a battery pack to put out 250 volts. Power is equal to voltage * current, so 150,000 watts / 250 volts = 600 amps.

Just.. wow. That power level has to be sustainable too, not a peak value, or else we’re gonna blow stuff up from overloading the batteries.

]]> By: Charles Smith http://twoguysrally.com/2008/04/14/ditch-gasoline/#comment-21 Charles Smith Tue, 15 Apr 2008 20:18:13 +0000 http://twoguysrally.com/?p=26#comment-21 You sir, have touched on the issue Mark and I were stumbling on. The batteries just aren't there yet, and we guess you'd have to change all the batteries out every service (because charging is too slow). Although you could probably reuse the batteries every other set of stages. You sir, have touched on the issue Mark and I were stumbling on. The batteries just aren’t there yet, and we guess you’d have to change all the batteries out every service (because charging is too slow). Although you could probably reuse the batteries every other set of stages.

]]> By: Idiot Cyvant http://twoguysrally.com/2008/04/14/ditch-gasoline/#comment-19 Idiot Cyvant Tue, 15 Apr 2008 15:36:41 +0000 http://twoguysrally.com/?p=26#comment-19 What about the long term lifespan of the batteries? How frequently would they have to be replaced? What about the long term lifespan of the batteries? How frequently would they have to be replaced?

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