Full throttle Electric Supercharger Build Thread

[Margovincent_22x]

Originally Posted by Gary in NJ

While it has been said may times throughout this thread, I guess it still needs to be repeated every few pages:

The eCharger is for those who are interested in momentary boost and it will not compete head-to-head with full-time high output solutions (turbocharger or supercharger). The laws of physics can not be changed, even with a massive alternator and super capacitors. You can't get more then you put in. Further, even if this system ran at an unrealistic 99% efficiency, that still leaves a 1% drain on the charging system.

This is an "inexpensive" low-boost alternative. Adding super capacitors puts the system into a price range where a turbocharger or supercharger make a lot more sense.

Thanks for the info.. wasn't back reading with this..

[nonicname]

they need to get these batteries going already so we can use them on our ESC!
[ame="http://vimeo.com/51873011"]The Super Supercapacitor | Brian Golden Davis on Vimeo[/ame]

[Bu-Tang]

Originally Posted by nonicname

they need to get these batteries going already so we can use them on our ESC!

Very cool indeed, srill don't need it for this setup, maybe for a full out hybrid like Tesla lol

Sent from my SGH-I337M using Tapatalk 4

[bfrank1972]

Originally Posted by Gary in NJ

While it has been said may times throughout this thread, I guess it still needs to be repeated every few pages:

The eCharger is for those who are interested in momentary boost and it will not compete head-to-head with full-time high output solutions (turbocharger or supercharger). The laws of physics can not be changed, even with a massive alternator and super capacitors. You can't get more then you put in. Further, even if this system ran at an unrealistic 99% efficiency, that still leaves a 1% drain on the charging system.

This is an "inexpensive" low-boost alternative. Adding super capacitors puts the system into a price range where a turbocharger or supercharger make a lot more sense.

I'm not sure I understand "laws of physics can not be changed" and "you can't get more than you put in". True, it seems initially that the target use for this is short bursts of power, but even early results are showing that extended street use is possible without battery depletion. Given that motor drive power is 3500 watts, wouldn't it be conceivable that a big 300 amp alternator could sustain the motor for very long periods of time? Keep in mind the system works only under full throttle, and even on high speed race tracks you're on full throttle only part of the time. Part/no throttle situations would be charging the system again. I'm not sure if there are thermal limits to running the motor at full capacity for extended period of time, but I imagine that could be dealt with as well. This system certainly can't compete with the 'big power' of a turbo or belt driven S/C, but I don't think it's unfathomable that this system could be developed for track usage given enough time and interest.

[industrial]

Originally Posted by bfrank1972

I'm not sure I understand "laws of physics can not be changed" and "you can't get more than you put in". True, it seems initially that the target use for this is short bursts of power, but even early results are showing that extended street use is possible without battery depletion. Given that motor drive power is 3500 watts, wouldn't it be conceivable that a big 300 amp alternator could sustain the motor for very long periods of time? Keep in mind the system works only under full throttle, and even on high speed race tracks you're on full throttle only part of the time. Part/no throttle situations would be charging the system again. I'm not sure if there are thermal limits to running the motor at full capacity for extended period of time, but I imagine that could be dealt with as well. This system certainly can't compete with the 'big power' of a turbo or belt driven S/C, but I don't think it's unfathomable that this system could be developed for track usage given enough time and interest.

What you are describing would be better solved by deploying an exhaust turbine generator which the OEMs are busy developing as we speak. Hopefully we can easily retrofit these systems into our cars in the future.

A larger alternator should work to keep the system running all the time for track use too. There is no law of physics that restricts the amount of power you make from ramming more air and fuel into a motor. Remember guys, you are using engine power to cram more air into the motor which combines with more fuel to make more power. It's not something from nothing...you are adding more fuel or running a leaner mixture.

[SloS14]

Originally Posted by bfrank1972

This system certainly can't compete with the 'big power' of a turbo or belt driven S/C, but I don't think it's unfathomable that this system could be developed for track usage given enough time and interest.

Although this is a bit of a thread side-track you are correct. There's no reason this couldn't be done. As long as the alternator can output at least nearly-enough to maintain the battery(s) this shouldn't be a problem.

[Robftss]

Presently:

Nominal power ~3000 Watts, recharge 350 Watts, ~8:1

With Aux charger in parallel, recharge 700 watts, ~4:1

So max duty cycle 25%.

Depending on roadcourse +70% required for full lap continuous usage.

KERS type logic required to manage deployment for post apex torque burst, F1 styles

[Calum]

Originally Posted by Robftss

Presently:

Nominal power ~3000 Watts, recharge 350 Watts, ~8:1

With Aux charger in parallel, recharge 700 watts, ~4:1

So max duty cycle 25%.

Depending on roadcourse +70% required for full lap continuous usage.

KERS type logic required to manage deployment for post apex torque burst, F1 styles

700 watts at 14v is about a 50 amp draw. I wouldn't want to run any more, and I'd be careful to not run things like the rear defrost at the same time, but that should be doable with our 120 amp alternators.

Is there anything in there to ensure the draw increases slowly? Even just a slight delay on. The second charger?

[Grantmac]

Hello all,

I registered here specifically because of this and the open source thread, the thread popped-up over on miata.net. I drive an MX-5 which I dual purpose as a DD and STR car. I'd love some more power on the street but don't want to add a full-time SC and end-up in SSM class. Being able to revert to NA in 10 minutes is a huge draw for me.

I also like the idea of storing potential energy over a fairly long period of time and then releasing it over a short period of time. I think if I datalogged my average spirited drive I'd be at full throttle for less than 5% of the time, even less on the daily commute.

As I understand it: right now the system uses cascade charging from the 12v system to charge the 24v SC batteries and keeps the systems separate.
Why not do a Series/Parallel system like this:
http://www.the12volt.com/installbay/forum_posts.asp~TID~128392~PN~1

It would eliminate one of the batteries, or allow you to run a 36 system with the same number of batteries currently used and retain the 12v charging system. Your recharge time would also be reduced because you wouldn't be limited by the cascade charger but rather the alternator and battery itself.
Of course you'd want to isolate the batteries with the key off, but if you ran them parallel with the key on that would allow for twice the starting battery amperage. Which is something you lose going to a smaller starting battery. Then run series when the SC kicks in and completely isolated from the alternator (which would run the onboard electronics).

As for the bigger battery/alternator/road racing question:
This idea is actually pretty good, but not in the way that many people are considering. In the current scheme the alternator doesn't power the SC at all, it only charges the battery when the SC is NOT engaged. That is why people are getting such good numbers at low boost. It also means the engine is actually under less load for a given output with the SC engaged, which is good for the engine. Going to a larger alternator to try and drive the SC directly would result in much lower peak HP numbers for a given level of boost.
Where a bigger alternator comes in would be in getting the batteries charged faster when off the SC. For street driving the system is currently capable of doing this, maybe even for AutoX or time-attack as well.
Ideally the batteries would be sized to use 50% of their capacity during the longest time of full-throttle on the track. The alternator would be sized to recharge 50% of the batteries capacity in the braking and partial-throttle zone after that straight. This would likely require a 24v alternator to keep things efficient, maybe even a completely separate charging system.
Think of it as regenerative braking but instead of storing efficiency (like a hybrid), you are storing HP.

I don’t think this will compete with traditional forms of FI for maximum power applications in a race environment.
But a race environment which they are ideally suited for is certain classes where the cars are classed by HP and weight. This system produces massive low-end torque with moderate HP gains, basically ideal.

I’ve got some ideas for an improved control system but I’ll save that for another post.

-Grant

[Bu-Tang]

There are sooooooooooo many ppl with soooooooo many ideas........ lol

[mid_life_crisis]

Originally Posted by Bu-Tang

There are sooooooooooo many ppl with soooooooo many ideas........ lol

That last one scares me. I have visions of relays sticking and alternators burning up trying to charge 24 volts instead of 12.

[HunterGreene]

Originally Posted by mid_life_crisis

That last one scares me. I have visions of relays sticking and alternators burning up trying to charge 24 volts instead of 12.

And then the flux capacitor surges and suddenly you are driving a twin in 1955 where they haven't even heard of Premium grades of fuel. Good Lord.

[Grantmac]

Originally Posted by mid_life_crisis

That last one scares me. I have visions of relays sticking and alternators burning up trying to charge 24 volts instead of 12.

Alternator would have no connection when batteries were in series, worst case senario you just aren't charging. If you read through that thread there are some pretty simple circuit breaker set-ups that would keep thing safe.
Of course a similar set-up was commonly used starting large trucks for years and relays have gotten a bit more reliable since then.

My main concern would be the speed which the relays engaged, that may limit the usefulness of such a system.

Either way it seems like Rob has got something figured out which will increase duty cycle to 25% and that is very exciting. In my application the 24v system is likely to produce as much power as I'd be comfortable with stock internals (200hp), so 36v is academic at this point. Although I'd still like to see a slightly different control scheme (details later).

-Grant

[bfrank1972]

Originally Posted by Robftss

Presently:

Nominal power ~3000 Watts, recharge 350 Watts, ~8:1

With Aux charger in parallel, recharge 700 watts, ~4:1

So max duty cycle 25%.

Depending on roadcourse +70% required for full lap continuous usage.

KERS type logic required to manage deployment for post apex torque burst, F1 styles

Curious, what are the limitations for recharge rate other than alternator capacity? # of battery packs and chargers in parallel? Also I was thinking a bit less that 70% duty cycle for full road course, but then again that's me driving

I guess this starts boiling down into an exercise of balancing cost with performance - the whole system could be priced with 'upgrade' options.