tag:blogger.com,1999:blog-6676835811534572362.post9122775189656505575..comments2024-02-06T10:02:20.731-06:00Comments on EVTV.ME: Regenerative Braking - Entirely a Myth?Jack Rickardhttp://www.blogger.com/profile/15936311474215791697noreply@blogger.comBlogger120125tag:blogger.com,1999:blog-6676835811534572362.post-8012330670190987532010-08-29T16:45:05.265-05:002010-08-29T16:45:05.265-05:00I'm sure you read it, but no, there is absolut...I'm sure you read it, but no, there is absolutely no problem with THundersky's accepting charge before, during, or after charge. They accept regen quite readily and there is no need of supercapacitors. Supercapacitors can accept all the charge very quickly and without the losses of a chemical conversion, and they can also make that charge available for acceleration very quickly.<br /><br />Reduced brake plads? Common. This is a $5000 drive train and a $3000 transmission and we want to save wear and tear on a $18 pair of brake pads???<br /><br />Jack RickardJack Rickardhttps://www.blogger.com/profile/15936311474215791697noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-10591480439748486242010-08-29T08:34:55.061-05:002010-08-29T08:34:55.061-05:00Hello Jack and greetings from England. :)
I've...Hello Jack and greetings from England. :)<br />I've attempted to run through these posts looking for comments on charge/discharge charactoristics of Thundersky type batteries.<br /><br />I might be wrong but read somewhere LiFePo4's don't accept a charge immediately after discharge. It is why PML Flightlinks Mini project was fitted out with 4 Farad's of supercapacitors to soley take the regen charge. Big enough to accept 70-0mph against its mass.<br /><br />After all, batteries are a chemical process, not a capacitive one. Have you done any experiments on this?<br /><br />I'm definitely a backer for all wheel regen braking into a dummy load even if it only means reduced service/replacement costs of brake pads and discs!<br /><br />All the best Jack, (Brian& co.). Your show is a revelation to me.Unknownhttps://www.blogger.com/profile/09138234430078775883noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-75986776634051582742010-07-11T16:35:56.947-05:002010-07-11T16:35:56.947-05:00There is certainly some losses through the motor a...There is certainly some losses through the motor and controller and indeed some heat. But it is like the wH, it would not account for any of this.<br /><br />To my way of thinking, there IS a cost to regen and that is mechanical strain on drive train components and the inadvisability of braking on two wheels vice 4. Well worth it for even 6-8% gain. We have no gain. That's what started all this. That's why the testing.<br /><br />The testing puts more definitive numbers to it. It no longer "seems" like we're not getting anything looking at a couple of drive logs and some calculations. We're now not getting it to a tenth of an amp hour.<br /><br />So you're point as to heat is technically correct, but I don't think signficant in magnitude. It doesn't explain this situation.<br /><br />Jack RickardJack Rickardhttps://www.blogger.com/profile/15936311474215791697noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-64606210927848949342010-07-11T16:29:54.668-05:002010-07-11T16:29:54.668-05:00Found it.
"You see, wire telegraph is a ki...Found it. <br /><br />"You see, wire telegraph is a kind of a very, very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? And radio operates exactly the same way: you send signals here, they receive them there. The only difference is that there is no cat."<br />A. EinsteinJack Rickardhttps://www.blogger.com/profile/15936311474215791697noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-57485217745410851742010-07-11T16:25:35.152-05:002010-07-11T16:25:35.152-05:00This conversation reminds me of a famous descripti...This conversation reminds me of a famous description by Albert Einstein that I will paraphrase probably so badly that it won't work.<br /><br />"You see my dear, the telephone operates like a cat that stretches from New York, to Los Angeles. You pull the tail in New York, and the cat lets out a yowl in Los Angeles.<br /><br />Now wireless is exactly the same thing - but without the cat."Jack Rickardhttps://www.blogger.com/profile/15936311474215791697noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-37219283844061194102010-07-11T16:23:15.857-05:002010-07-11T16:23:15.857-05:00Most of all I argue that there is no way to get le...Most of all I argue that there is no way to get less efficiency than friction brakes.<br /><br />And I've demonstrated that you can five times and over nearly 250 miles of urban driving.<br /><br />You wll NOT let go of the concept that the only drive that matters is the one with regen, despite the fact that you never did drive it. It was only theoretical.<br /><br />And if you compare it to ANOTHER drive that is NOT theoretical you will find that it nets out to near zero, and if NOT zero , on the wrong side of it.<br /><br />You have simplified this to "Does the act of braking using regen produce current." Of course it does. So does sunshine. But I can't use it in my car. The difference is I probably COULD use sunshine....<br /><br />Jack RIckardJack Rickardhttps://www.blogger.com/profile/15936311474215791697noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-43016975741905634872010-07-11T16:17:40.541-05:002010-07-11T16:17:40.541-05:00"Why do you completely ignore what I am sayin..."Why do you completely ignore what I am saying is possibly the real culprit; namely AH vs WH? Do you have a technical argument that says WH is not relevant, or do you believe it is so trivial an argument that it isn't worth addressing directly? I gave you a cogent explanation of what might be happening with your AH measurement during regen and you ignore it completely. If it turns out that this is THE issue and you completely ignore it you will never find the truth. If its not the issue then give me an argument that proves it or at least provides some support for your assumption that it isn't important. I am genuinely interested!"<br /><br />Dan:<br />I believe it is so trivial an argument that it is not worth addressing directly. I tried not to address JRP holding zero regen with his trigger finger and failed, but I do insist that I will not address this. It is entirely too trivial and leads to goofy discussions of things that cannot possibly matter to this topic.<br /><br />The results might indeed be different. On the order of milliamps.<br /><br />I've posted a continuation of all this on a new topic. This page scrolls forever. Please do view the latest video and I will be happy to resume the discussion on that page.<br /><br />Jack RickardJack Rickardhttps://www.blogger.com/profile/15936311474215791697noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-89933780282395823882010-07-11T16:04:41.231-05:002010-07-11T16:04:41.231-05:00PMD,
I'm not sure where the 15% comes from an...PMD,<br /><br />I'm not sure where the 15% comes from and for my argument I don't claim any particular gain; just that there must be some gain with regen if you drive a route with significant braking. If you drive an identical route with an identical car you will use an identical amount of energy. The question is, when you get to the end of the route do you have more energy in your battery on the run with regen than the one with friction brakes. Jack proposes he has the same or less energy in the battery using regen, and I am saying I think he has more energy in the battery than he realizes. The reason he has more energy than he thinks is that when he is regening the voltage rises and pumps more energy into the battery than he accounts for since he is monitoring amps only. Amps is only half of the power calculation. If he could set up an experiment to measure Watt Hours instead of Amp Hours I think his results would be different. My argument is only that there should be SOME energy recovered during regen, not how much or if it is worth the money or the hassle or anything else. Most of all I argue that there is no way to get less efficiency than friction brakes.<br /><br />Respectfully,<br /><br />DanAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-44609221331966120762010-07-11T15:20:54.797-05:002010-07-11T15:20:54.797-05:00You guy's are missing something, and it is the...You guy's are missing something, and it is the same thing that has Jack and I scratching our heads. I may be way off in this thought experiment, but lets give it a go anyway.<br /><br />The car without regen took 78AH to go around the circuit. For conversation purposes say the car averaged 120v on the pack.<br /><br />Now you guys all assume that the car got a 15% gain in wH due to regen on the second run.<br /><br />The original run was 78*120=9360wH. If the second run had a 15% increase then you are saying that the car actually took only 7956wH. If this is true then the car would have to had an average pack voltage over the course of the trip of 102v (78AH*102=7956). There is just no way that was true. This is the crux of the problem.<br /><br />I do like the thought above regarding heat into the motor and controller. Regen is recovering 15% of the power, but maybe 7.5% is going into heating the motor and controller, and running a hot motor and controller gives 7.5% less efficiency so you end up with a zero difference.<br /><br />Is there a way to test for this? Or am I way off base.palmer_mdnoreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-80319204812251198272010-07-11T14:05:19.485-05:002010-07-11T14:05:19.485-05:00"Regen causes all the drivetrain components t..."Regen causes all the drivetrain components to be less efficinet due to heat."<br /><br />With a professional life as a R&D engineer at company doing lots of 4Q 3-phase inverters I tend to disagree with you on that statement. Our inverters are used for UPS's and not automotive, but that is, from a topological point of view, inconsequntial. The AC to DC effinciency is above 98% for a modern 4Q inverter. So the main losses are in the batteries and motor.<br /><br />Martin.Martin Zachohttp://www.citystromer.dknoreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-45991822507153542442010-07-11T13:50:48.233-05:002010-07-11T13:50:48.233-05:00Let's be clear. The heat is not the cause of t...Let's be clear. The heat is not the cause of the inefficiency, it IS the inefficiency. And while I agree that not all of the regen energy makes it to the battery, SOME does. With regular brakes, NONE does. That's the point. Don't make it more complicated than that.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-90341185064750152612010-07-11T13:33:16.526-05:002010-07-11T13:33:16.526-05:00Theory: "Where does the energy go?". Hea...Theory: "Where does the energy go?". Heat. Either the brake pads and rotor (no regen), or the motor/controller/batteries(regen). Some of the energy gets into the batteries, but most of regen transfers to heat in the electric components, thereby reducing efficiency and causing more Ah to be consumed overall the more it is used. Since heat in the brake pads and rotor doesn't affect drivetrain efficiency, you need less amp hours overall. Regen causes all the drivetrain components to be less efficinet due to heat.vpoppvhttps://www.blogger.com/profile/10485365382600002638noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-86977489763907641002010-07-11T12:23:45.217-05:002010-07-11T12:23:45.217-05:00The first law of scientific endeavor is:
1) Do n...The first law of scientific endeavor is:<br /><br /><br />1) Do not deceive yourself.<br /><br />I hearby add the second LAw<br /><br />2) focaults' razor says: see above<br /><br />I have been an electrician for 25+ years and I always used WATTs not AMPs to determine what work is being done, then of course divide by Volts to find AMPs. <br /><br />Jack please explain why we should not use KWHRs.<br /><br />Regards, JMSJMSnoreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-40040514755735198352010-07-11T11:38:41.920-05:002010-07-11T11:38:41.920-05:00"Hmmmm, to hold a steady speed you are still ..."Hmmmm, to hold a steady speed you are still "accelerating" against friction and wind, so the throttle must be constantly in a positive position"<br />Nope. Your are applying work in order to MAINTAIN a constant speed.<br /><br />Let us please keep the term as correct as possible - otherwise we will just confuse each other to an even higher level ;-)<br /><br />Martin.<br /><br />Martin.Martin Zachohttp://www.citystromer.dknoreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-19166804519984950782010-07-11T11:31:58.600-05:002010-07-11T11:31:58.600-05:00"And I've compared it and found it doesn&..."And I've compared it and found it doesn't do what you report."<br /><br />I don't doubt that your data as you gather it exists and is accurate for what it is. By replicating the test with multiple runs and vehicles with good repeatability you can have confidence in your numbers being accurate for what they are. I question if you are measuring the right parameters and interpreting correctly.<br /><br />"Your stuck on "Where does it go?". It never was there in the first place."<br /><br />Of course it was there, "it" being energy. There can't be any debate on this! When you are driving down the road the energy is there in the kinetic form. It can't be destroyed so it has to go somewhere.<br /><br />"I think the regen induces oscillations in the driving speed." <br /><br />If you have regen on the brake pedal and you are not touching the brake pedal, how can it possibly induce an oscillation? Steady state driving has no dog in the fight, nor does acceleration. Only deceleration at a rate that exceeds the decel rate provided by the other drag losses (wind, rolling)is even in the equation. I will agree to these points:<br />1) There is no regen available during accel<br />2) There is no regen available during steady state<br />3) There is no regen available during coasting decel<br />But not this:<br />4) There is no regen available during braking at a rate that exceeds coasting decel <br />I say "available" because being there doesn't mean it is captured. It might have been available but lost due to the design of the capturing circuit.<br /><br />Why do you completely ignore what I am saying is possibly the real culprit; namely AH vs WH? Do you have a technical argument that says WH is not relevant, or do you believe it is so trivial an argument that it isn't worth addressing directly? I gave you a cogent explanation of what might be happening with your AH measurement during regen and you ignore it completely. If it turns out that this is THE issue and you completely ignore it you will never find the truth. If its not the issue then give me an argument that proves it or at least provides some support for your assumption that it isn't important. I am genuinely interested!<br /><br />DanAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-56825843448631508572010-07-11T11:15:06.615-05:002010-07-11T11:15:06.615-05:00"My "theory" to explain these resul..."My "theory" to explain these results is that regen tends to induce these accel/decel oscillations around the steady state speed. I can readily OBSERVE this effect with the throttle based regen and in fact it is quite pronounced."<br /><br />Hmmmm, to hold a steady speed you are still "accelerating" against friction and wind, so the throttle must be constantly in a positive position and you must constantly be drawing amperage from the pack. I've never seen regen appear while holding steady speed on the flat. At 45 mph on the flat I use about 50-60 amps, I've never seen that go negative in those situations, nor have I noticed oscillations. <br /><br /> Are you saying that since even steady state driving has minuscule fluctuations in load that the motor is having microsecond events between power and regen as you travel, too small to show up in the gauge, but over time would show up in more energy used to travel?<br />JRP3Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-83985110248983170452010-07-11T10:41:17.195-05:002010-07-11T10:41:17.195-05:00"According to you, simply driving a vehicle t..."According to you, simply driving a vehicle that has regen wastes energy even before you start to slow down with regen. This is because even when trying to coast you will probably be either using some current or some regen, which is less efficient than coasting, and that any braking energy that can be had will not overcome that inefficiency?"<br /><br />I would suggest you mentally modify the concept of "coasting" and replace it with the concept of "maintaining a steady speed".<br /><br />As you go down the road at a steady 45 mph, you are NOT coasting if we stay focused on our flat ground 5 mile drive. You are driving and you are using energy. You must do this to overcome the effects of rolling and wind resistance. But you do not have to overcome the inertia of the entire vehicle mass which you DO have to do to accelerate. That same inertia is what you are "recapturing" with the regen.<br /><br />My "theory" to explain these results is that regen tends to induce these accel/decel oscillations around the steady state speed. I can readily OBSERVE this effect with the throttle based regen and in fact it is quite pronounced. <br /><br />Somewhat less obvious is that regen on the braking side does the same thing, in much the way power brakes would over manual brakes. It would be a lesser effect, but still there.<br /><br />This would account for the almost linear lineup of our results. Least efficient was with regen on both brake and throttle. Next most efficient was brake regen only. Most efficient was no regen. That lineup poses some problems in theory. This explanation would account for that.<br /><br />That doesn't mean it is correct. It means it would account for that.<br /><br />Jack RickardJack Rickardhttps://www.blogger.com/profile/15936311474215791697noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-74520187826953752122010-07-11T10:39:25.218-05:002010-07-11T10:39:25.218-05:00"Martin - then you are suggesting that I have..."Martin - then you are suggesting that I have derived some very erroneous data basically because I don't know how to drive a car properly or correctly. Well, that may be true. It's certainly a possibility."<br /><br />I am unable to detect if you are being ironic, sarcastic or honest here... Please excuse if the finer aspects of the American language passes me by.<br /><br />But to my experience if there is something that seems to be incorrect, the data (or formulation of the test) is wrong in most cases. In some rare instances people might stumble upon new knowledge, but that is rare.<br /><br />"It might be worth pursuing the earlier suggestion of doing the test with another driver. Perhaps one that is better at operating these here electric vehicles."<br /><br />I am only trying to say that the driver normally have a very great influence on the efficiency of the drive - and to make a setup that will prove or reject your thesis, may be very hard in a real life environment.<br /><br />Martin.Martin Zachohttp://www.citystromer.dknoreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-17603372173295510402010-07-11T10:32:28.357-05:002010-07-11T10:32:28.357-05:00"Let me pose this question to you. If I wrote..."Let me pose this question to you. If I wrote in that I mounted a wind mill on top of my car and that I am now getting 10% better gas mileage and I have a lot of data to prove it, would you feel comfortable refuting this based on science or would you feel the need to duplicate my setup and gather data to refute it? I hope you would feel it to be legitimate to point out the fallacy of my invention and suggest that whatever test I used to gather my "convincing data" must have a flaw. Not because you ran the same experiment but that the fundamental laws as we know them (1st law) don't allow for my results."<br /><br />Dan:<br /><br />First, what data? And second, how did you collect it. Assuming that it defies the fundamental laws of physics is the usual response to new reports.<br /><br />But this is comical. YOU are the one with the perpetual motion machine in presuming that you can put energy back with the regenerative braking. I'm reporting it didn't work. So you have your analogy badly out of kilter by about 180 degrees. Regen is your wind sail. And I've compared it and found it doesn't do what you report.<br /><br />Your stuck on "Where does it go?". It never was there in the first place. When you decel, you have to accel, and that takes more energy round trip than just maintaining a steady speed. The regen influences you to do this as you drive, and it is cummulative across a significant drive.<br /><br />If you want to go up a hill and down a hill you will show a gain. But if you do it across a longer drive, you wind up with lots of unnecessary accels and decels. They don't have to be extreme. As I said, you can reduce it to 47 and 43 around 45 and wind up with the same disparity, but to a lesser degree more commensurate with what we are measuring.<br /><br />I don't entirely agree that it takes the same energy to accelerate quickly as to accelerate slowly, but for the purposes of this discussion I'll allow it. It is essentially true. And it is probably at the heart of this.<br /><br />Maintaining a steady speed simply does not require the energy that it does to accelerate. And you don't get all of it back when you decelerate. I think the regen induces oscillations in the driving speed. Actually I know it does. I think that's where the disparity comes from.<br /><br />Again, and again, you are stuck on looking for the lost energy of the braking segment. But you are still looking at the drive you made, not the drive you didn't make (with no regen).<br /><br />Jack RickardJack Rickardhttps://www.blogger.com/profile/15936311474215791697noreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-842104713754934712010-07-11T09:59:00.691-05:002010-07-11T09:59:00.691-05:00Sorry for the duplicate post above... I got an err...Sorry for the duplicate post above... I got an error message and thought it didn't post the first time. Please delete one of them.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-36547972161547842682010-07-11T09:56:20.605-05:002010-07-11T09:56:20.605-05:00If we are to solve this debate, we must focus on t...If we are to solve this debate, we must focus on the energy and where it goes. Draw a free body diagram around the car and account for all of the energy going in and out. It's easy to get lost in the weeds if we try to talk about complicated driving scenarios. Let's keep a focus on where does the energy go when we slow the vehicle down using brakes. We agree that if we use pads, all of it goes up in heat dissipated by the rotors. Where does it go if we use regen?<br /><br />Here is an interesting aside regarding power and energy. It is counterintuitive but nonetheless true that it takes a lot more POWER to accelerate a mass quickly (than slowly), but no more ENERGY (assuming no losses in the power delivery system). I know in the real world there would be some losses, but when we do calculations in physics using "frictionless planes" or "ignoring wind resistance" we don't imply the conditions exist. Rather, they serve to illustrate the principles.<br /><br />I look forward to your thoughts.<br /><br />Regards,<br /><br />DanAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-4706960005748990462010-07-11T09:52:49.107-05:002010-07-11T09:52:49.107-05:00Jack,
This is getting fun, isn't it? No comme...Jack,<br /><br />This is getting fun, isn't it? No comments on my last post? <br /><br />Let me pose this question to you. If I wrote in that I mounted a wind mill on top of my car and that I am now getting 10% better gas mileage and I have a lot of data to prove it, would you feel comfortable refuting this based on science or would you feel the need to duplicate my setup and gather data to refute it? I hope you would feel it to be legitimate to point out the fallacy of my invention and suggest that whatever test I used to gather my "convincing data" must have a flaw. Not because you ran the same experiment but that the fundamental laws as we know them (1st law) don't allow for my results.<br /><br />It looks to me that your thought experiment for the aggressive accel/decel drive has a problem on the comparison side. It sounds like you are comparing this aggressive drive using regen to a "normal" drive not using it. In other words, do you really believe that if you drove the aggressive drive with standard brakes you would be better off than with regen? You show how the inefficiencies of the regen don't recapture ALL of the energy of slowing down which is spot on. But you must realize that mechanical brakes don't capture ANY of the energy of slowing down. Which is better, "doesn't capture all", or "doesn't capture any"? This is precisely the type of drive that shows regen to be useful!<br /><br />I think you need to look carefully at your data collection and analysis to see if there could possibly be a fallacy. This is not a personal attack; its just an objective challenge. You have run the experiment with multiple passes with multiple vehicles, but with the same drive and the same instruments. My suspicion is that the instruments are not lying to you, they are misleading you.<br /><br />I continue to think the problem lies here;<br /><br /> "wH introduces a whole series of things I DON'T want to get into"<br /><br />I'm not sure what you mean by that, but as I pointed out in my last post, energy is what we are talking about, and that is WH, NOT AH. Think about this. If your electric motor is drawing 50 amps at 100 volts, you are using 5000 watts of power. You do this for 1 hour and you have used 5000 watt/hours of energy. If you run the same 50 amps but this time at 95 volts, you use 4750 watt/hours of energy. This 5% difference resulted from a change in voltage that I would think can and does happen in the real world. In the case of regen, the voltage MUST go up to drive current into the battery (against the battery voltage) yet you only measure amps and assume the voltage is constant. The result in an understatement of the energy recaptured to the battery. I think you need to employ a WH meter connected between your motor and controller. I don't know if a conventional home WH meter would respond to the frequency and waveform of the AC motor you are using, but it is that type of meter that will give you true energy usage. In fact, I suppose the power companies use WH meters rather than current meters for this same reason.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-59363782341458441542010-07-11T09:50:53.993-05:002010-07-11T09:50:53.993-05:00Jack,
This is getting fun, isn't it? No comme...Jack,<br /><br />This is getting fun, isn't it? No comments on my last post? <br /><br />Let me pose this question to you. If I wrote in that I mounted a wind mill on top of my car and that I am now getting 10% better gas mileage and I have a lot of data to prove it, would you feel comfortable refuting this based on science or would you feel the need to duplicate my setup and gather data to refute it? I hope you would feel it to be legitimate to point out the fallacy of my invention and suggest that whatever test I used to gather my "convincing data" must have a flaw. Not because you ran the same experiment but that the fundamental laws as we know them (1st law) don't allow for my results.<br /><br />It looks to me that your thought experiment for the aggressive accel/decel drive has a problem on the comparison side. It sounds like you are comparing this aggressive drive using regen to a "normal" drive not using it. In other words, do you really believe that if you drove the aggressive drive with standard brakes you would be better off than with regen? You show how the inefficiencies of the regen don't recapture ALL of the energy of slowing down which is spot on. But you must realize that mechanical brakes don't capture ANY of the energy of slowing down. Which is better, "doesn't capture all", or "doesn't capture any"? This is precisely the type of drive that shows regen to be useful!<br /><br />I think you need to look carefully at your data collection and analysis to see if there could possibly be a fallacy. This is not a personal attack; its just an objective challenge. You have run the experiment with multiple passes with multiple vehicles, but with the same drive and the same instruments. My suspicion is that the instruments are not lying to you, they are misleading you.<br /><br />I continue to think the problem lies here;<br /><br /> "wH introduces a whole series of things I DON'T want to get into"<br /><br />I'm not sure what you mean by that, but as I pointed out in my last post, energy is what we are talking about, and that is WH, NOT AH. Think about this. If your electric motor is drawing 50 amps at 100 volts, you are using 5000 watts of power. You do this for 1 hour and you have used 5000 watt/hours of energy. If you run the same 50 amps but this time at 95 volts, you use 4750 watt/hours of energy. This 5% difference resulted from a change in voltage that I would think can and does happen in the real world. In the case of regen, the voltage MUST go up to drive current into the battery (against the battery voltage) yet you only measure amps and assume the voltage is constant. The result in an understatement of the energy recaptured to the battery. I think you need to employ a WH meter connected between your motor and controller. I don't know if a conventional home WH meter would respond to the frequency and waveform of the AC motor you are using, but it is that type of meter that will give you true energy usage. In fact, I suppose the power companies use WH meters rather than current meters for this same reason.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-41648408594240783542010-07-11T09:34:14.175-05:002010-07-11T09:34:14.175-05:00My point is for a test to be valid the driving mus...My point is for a test to be valid the driving must be the same up until it's time to slow down. You seem to be saying that the driving cannot be the same with and without regen, and that you cannot drive a regen vehicle in such a way as to meaningfully recover any braking energy. According to you, simply driving a vehicle that has regen wastes energy even before you start to slow down with regen. This is because even when trying to coast you will probably be either using some current or some regen, which is less efficient than coasting, and that any braking energy that can be had will not overcome that inefficiency?<br /><br />JRP3Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6676835811534572362.post-44833442205263082452010-07-11T08:59:46.092-05:002010-07-11T08:59:46.092-05:00Jack
I went back over the original post and want...Jack<br /><br /><br />I went back over the original post and wanted to know how you determined the amp hours used in the original tests?<br /><br />You said:<br /><br /> "And we ignored how much was coming out and going back in, and looked for the TOTAL AH consumed on the 76.6 mile drive"<br /><br />Did you look for this using the zantrax?<br />Did you look for this by recharging the batteries and reading KWHR in?<br /><br />I don't like using the word assume. It seems to me you are measuring the amount needed to "fill'er up" since you ignore AMP HRS in and AMP HRS out.<br /> <br />Also,<br />I read through the comments and I hear some people asking for you to take the readings in KWHs not AHRs.<br /><br />I also am wondering why.<br />Although if you fill up at the wall I don't think it matters.<br /><br />Regards, JMSJMSnoreply@blogger.com