Came acrossed this mad man

[arber333]

... by using lead-acid batteries.

That's his innovation. He has a 400-mile range, lead-acid powered car, he thinks will last 30 years.

Well now I don't know what to think.

He forgot the Peukert effect where high power drain causes massive degradation of available charge in the Pb battery. I predict that those 130kWh AGM will only give like 60kWh of true energy. Rest is lost when idiot (me) stomps on the pedal. I mean even Lions have P effect, its only a lot less pronounced.

[MattsAwesomeStuff]

He forgot the Peukert effect where high power drain causes massive degradation of available charge in the Pb battery.

Probably not a big deal on batteries with 400 mile range. That's a 6 hour drive. Draining the cells at 1/6C isn't going to take too huge of a Peukert hit.

...

...

Except that he is also designing it with SOMETHING NO OTHER EV ON THE MARKET HAS... a switch. A switch that breaks the battery pack up into 3 packs.

Why?

Because range anxiety is the biggest problem with EVs you see. And his logic is that you can't have range anxiety if you have multiple packs, because you'll know exactly how far you just got draining the first pack completely empty.

So, umm, I think range anxiety is 98% "What if I need to travel further and I can't stop at a gas station?" and maybe 2% "Oh it's so hard to guess the exact precise range on an EV". But, anyway, that's his solution.

Which is going to undo any of the benefits of having a gigantic lead acid pack.

...

Y'know, I don't care. I don't think it's a great design, I don't think it's a good product to sell, but I don't care. The world is better off if every beer is not a Budweiser. If he's passionate about this and his logic is bizarre to me, oh well, I'm still glad to see him build his little oddball mishmash lead sled.

[collin80]

It's painful to hear of someone like this. I believe he means well but... this isn't a good plan and he is likely to waste a lot of time and money figuring that out. It's like all the perpetual motion people. They SWEAR that their design is finally the one that will change everything. But, it's not. And, this won't work either. But, you often can't convince people that they're driving off into the weeds.

[jon volk]

Whelp, that devolved quickly.

[arber333]

He forgot the Peukert effect where high power drain causes massive degradation of available charge in the Pb battery.

Probably not a big deal on batteries with 400 mile range. That's a 6 hour drive. Draining the cells at 1/6C isn't going to take too huge of a Peukert hit.

Except that he is also designing it with SOMETHING NO OTHER EV ON THE MARKET HAS... a switch. A switch that breaks the battery pack up into 3 packs.

Let us see what happens. I would like to see how a 4t car moves along.
I can judge by my own mishaps and lately i moved my Kokam pack from MX3 to Pug 406. This is like 400kg heavier car. And it shows. I have like 5% less range in identical conditions. I think this is due to increased weight they have to lug around. Also there are two large hills on my route and at highway speeds...

Didnt he say his packs can run in paralell as well? So you can have them all ON at the same time which is what i would do anyways...

Also in case of high battery capacity and lower drain Iam allready at that. I charge to 4V per cell and drain not less than 3V per cell, ever. And even that comes to a couple instances per year.

[dougyip]

Jon:

AN fitting on front cover was used for injection. It is aligned with air gap. Sight plugs on right were used to see inside during testing

Drain plug at back of rotor cavity. Silicone sealant around bus bars to prevent fluid intrusion into inverter area.

[bobwind]

Doug when I read of your idea to use oil injection to cool the drive on the other forum, I suspected friction was going to be a issue. You are nuts to have tried water! I would not have had the stones for it. My bet for success is a mist of a low billing novec fluid. Maybe a 45 or 55 c. Spray in a mist, it boils, and you remove the gas, condense and return it. Co2 or n2 might so work, hell just a tank of compressed air might work, I think you need about 500x the flow of water for air cooling to provide equle heat removal.

How did you remove condensate from the drive? Did you ever think of pulling a vacuum on the drive? A lot of that heat generation might be from friction heating of the air. Centrifuges pull vaccume on the rotor to keep Temps down.

So you have any numbers on what the water injection was able to do?

Bob

[muehlpower]

Has anyone ever tried to use an air conditioning compressor to cool directly into the gap between the rotor and stator. For this, the interior would have to be sealed to withstand a pressure of 5 bar. The water cooling of the rotor could then perhaps be omitted to save a sealing point.

[MattsAwesomeStuff]

Carry on, but, I'm confused how this thread came to be about extreme bleeding edge cooling methodologies, rather than this guy building a lead sled that's Tesla powered. Is he really going to need the absolute upmost racing-edge cooling ability?

[dougyip]

The spray water injection testing was only moderately successful. We were able to slow down the rate of overheating, but not stop it. We tested on the dyno and were somewhat limited by the dyno overheating. If I remember right, in our test run the stator might have reached 85 degC with the spray water off, and 65 degC with the water on.

We were spraying a finely atomized mist into the rotor gap. The water would flash to steam and exit the vent at atmospheric pressure. We did not need any vacuum assist.

[SciroccoEV]

As someone who has wasted far too many hours of my life capacity testing Lead acid batteries for EV racing. This guy does not even remotely grasp the limitations of Lead Acid batteries.

[collin80]

As someone who has wasted far too many hours of my life capacity testing Lead acid batteries for EV racing. This guy does not even remotely grasp the limitations of Lead Acid batteries.

I suspect that, yes. He seems OK with electronics but seems to have never even heard of the concepts of physics or chemistry. Lead acid cells are not a good match for EVs and the only reason anyone ever used them is because there was nothing else. For a long time lithium cells didn't really exist and NIMH batteries were patent encumbered. So, lead acid it was. Now there is no excuse.

Also, FWIW, AGM cells are the Devil. They are intentionally acid starved and that quickly causes trouble for EV use. I've been there and gotten the t-shirt. He's going to ruin those batteries. It won't take 30 years either. I give him about 2-3 and he's done.

[bobwind]

On the batteries he is using, to me that is the least interesting of his projects. I ran the numbers and I don't see the advantage on cost or range. My lipo pouch battery I am building seems to beat it on everything but total Kwh, but maybe he sees something I don't.

The external igbt bank that let's you drive the motor to slag is interesting. I know people in the ev drag racing community that might really be able to use this concept. Being able to put 50% more kw into these things might really change things.

Doug. Those are really interesting results. I may bench test my novec fluid idea. It basically is the same but if the fluid accumulates in the drive nothing goes smoke. The vaccume is to remove the air, not the water vapor. The air causes friction with the spinning rotor, and can heat the rotor significantly. Think skin of Lockheed blackbird a Mach 3. Evacuating the chamber might just do the trick.