KERS overcharge

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Jabberwocky
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KERS overcharge

Postby Jabberwocky »

I was reading something a while ago that I had not thought of before. As part of the KERS harvesting system, teams have now started to use heat sinks to disapate energy that it harvests that is not needed for the batteries. I assume this is so that the power being drawn is kept constant on the generator so that its physical resistance is more linear under braking.
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Re: KERS overcharge

Postby What's Burning? »

Jabberwocky wrote:I was reading something a while ago that I had not thought of before. As part of the KERS harvesting system, teams have now started to use heat sinks to dissipate energy that it harvests that is not needed for the batteries. I assume this is so that the power being drawn is kept constant on the generator so that its physical resistance is more linear under braking.

You're right because we've had instances of drivers being told to change settings on their KERS in order to optimize braking characteristics.

That being said, how do you dissipate energy through heatsinks? They'd have to discharge the unused electricity into some type of coil or transformer that would release it as heat. Given the weight constraints and extreme heat in an F1 car, I'd think there would be a more elegant way to dissipate large amounts of current quickly that wouldn't have the same physical penalties.
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Re: KERS overcharge

Postby darwin dali »

What's Burning? wrote:
Jabberwocky wrote:I was reading something a while ago that I had not thought of before. As part of the KERS harvesting system, teams have now started to use heat sinks to dissipate energy that it harvests that is not needed for the batteries. I assume this is so that the power being drawn is kept constant on the generator so that its physical resistance is more linear under braking.

You're right because we've had instances of drivers being told to change settings on their KERS in order to optimize braking characteristics.

That being said, how do you dissipate energy through heatsinks? They'd have to discharge the unused electricity into some type of coil or transformer that would release it as heat. Given the weight constraints and extreme heat in an F1 car, I'd think there would be a more elegant way to dissipate large amounts of current quickly that wouldn't have the same physical penalties.

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Re: KERS overcharge

Postby Jabberwocky »

What's Burning? wrote:
Jabberwocky wrote:I was reading something a while ago that I had not thought of before. As part of the KERS harvesting system, teams have now started to use heat sinks to dissipate energy that it harvests that is not needed for the batteries. I assume this is so that the power being drawn is kept constant on the generator so that its physical resistance is more linear under braking.

You're right because we've had instances of drivers being told to change settings on their KERS in order to optimize braking characteristics.

That being said, how do you dissipate energy through heatsinks? They'd have to discharge the unused electricity into some type of coil or transformer that would release it as heat. Given the weight constraints and extreme heat in an F1 car, I'd think there would be a more elegant way to dissipate large amounts of current quickly that wouldn't have the same physical penalties.


I would imagine that it is some sort of "variable resister", so as to have a constant draw.
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Re: KERS overcharge

Postby stonemonkey »

Jabberwocky wrote:
What's Burning? wrote:
Jabberwocky wrote:I was reading something a while ago that I had not thought of before. As part of the KERS harvesting system, teams have now started to use heat sinks to dissipate energy that it harvests that is not needed for the batteries. I assume this is so that the power being drawn is kept constant on the generator so that its physical resistance is more linear under braking.

You're right because we've had instances of drivers being told to change settings on their KERS in order to optimize braking characteristics.

That being said, how do you dissipate energy through heatsinks? They'd have to discharge the unused electricity into some type of coil or transformer that would release it as heat. Given the weight constraints and extreme heat in an F1 car, I'd think there would be a more elegant way to dissipate large amounts of current quickly that wouldn't have the same physical penalties.


I would imagine that it is some sort of "variable resister", so as to have a constant draw.


I dunno, I would lean towards some sort of pulse mode to control the generator load and the battery charging.

Not so sure the cars should be generating microwaves DD.
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Re: KERS overcharge

Postby darwin dali »

stonemonkey wrote:
Jabberwocky wrote:
What's Burning? wrote:
Jabberwocky wrote:I was reading something a while ago that I had not thought of before. As part of the KERS harvesting system, teams have now started to use heat sinks to dissipate energy that it harvests that is not needed for the batteries. I assume this is so that the power being drawn is kept constant on the generator so that its physical resistance is more linear under braking.

You're right because we've had instances of drivers being told to change settings on their KERS in order to optimize braking characteristics.

That being said, how do you dissipate energy through heatsinks? They'd have to discharge the unused electricity into some type of coil or transformer that would release it as heat. Given the weight constraints and extreme heat in an F1 car, I'd think there would be a more elegant way to dissipate large amounts of current quickly that wouldn't have the same physical penalties.


I would imagine that it is some sort of "variable resister", so as to have a constant draw.


I dunno, I would lean towards some sort of pulse mode to control the generator load and the battery charging.

Not so sure the cars should be generating microwaves DD.

I was thinking more of a lightning ball to discharge electricity - wouldn't that be cool to watch? Especially during the SIngapore night GP!
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Re: KERS overcharge

Postby stonemonkey »

darwin dali wrote:
stonemonkey wrote:
Jabberwocky wrote:
What's Burning? wrote:
Jabberwocky wrote:I was reading something a while ago that I had not thought of before. As part of the KERS harvesting system, teams have now started to use heat sinks to dissipate energy that it harvests that is not needed for the batteries. I assume this is so that the power being drawn is kept constant on the generator so that its physical resistance is more linear under braking.

You're right because we've had instances of drivers being told to change settings on their KERS in order to optimize braking characteristics.

That being said, how do you dissipate energy through heatsinks? They'd have to discharge the unused electricity into some type of coil or transformer that would release it as heat. Given the weight constraints and extreme heat in an F1 car, I'd think there would be a more elegant way to dissipate large amounts of current quickly that wouldn't have the same physical penalties.


I would imagine that it is some sort of "variable resister", so as to have a constant draw.


I dunno, I would lean towards some sort of pulse mode to control the generator load and the battery charging.

Not so sure the cars should be generating microwaves DD.

I was thinking more of a lightning ball to discharge electricity - wouldn't that be cool to watch? Especially during the SIngapore night GP!


Tesla coils ftw.
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Re: KERS overcharge

Postby Jabberwocky »

stonemonkey wrote:
Jabberwocky wrote:
What's Burning? wrote:
Jabberwocky wrote:I was reading something a while ago that I had not thought of before. As part of the KERS harvesting system, teams have now started to use heat sinks to dissipate energy that it harvests that is not needed for the batteries. I assume this is so that the power being drawn is kept constant on the generator so that its physical resistance is more linear under braking.

You're right because we've had instances of drivers being told to change settings on their KERS in order to optimize braking characteristics.

That being said, how do you dissipate energy through heatsinks? They'd have to discharge the unused electricity into some type of coil or transformer that would release it as heat. Given the weight constraints and extreme heat in an F1 car, I'd think there would be a more elegant way to dissipate large amounts of current quickly that wouldn't have the same physical penalties.


I would imagine that it is some sort of "variable resister", so as to have a constant draw.


I dunno, I would lean towards some sort of pulse mode to control the generator load and the battery charging.

Not so sure the cars should be generating microwaves DD.


I don't think batteries cope well with pulse charging, well I suppose it depends on battery memory etc.

On the Battery side of things, I wonder what batteries are used As the think how much they get charged and discharged through a race.
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Re: KERS overcharge

Postby What's Burning? »

They probably get a new battery every race.
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Re: KERS overcharge

Postby stonemonkey »

What's Burning? wrote:They probably get a new battery every race.


How green would that be?
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Re: KERS overcharge

Postby What's Burning? »

stonemonkey wrote:
What's Burning? wrote:They probably get a new battery every race.


How green would that be?

Don't look behind the curtain.
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Re: KERS overcharge

Postby Jabberwocky »

wouldn't a capacitor be a better option?
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Re: KERS overcharge

Postby stonemonkey »

Jabberwocky wrote:wouldn't a capacitor be a better option?


Faster to charge/discharge and lasts a lot more cycles but can't store anywhere near the amount of energy of a battery.
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Re: KERS overcharge

Postby Jabberwocky »

I suppose it depends on the CR time.

5.2.3 The maximum power, in or out, of any KERS must not exceed 60kW.
Energy released from the KERS may not exceed 400kJ in any one lap.
Measurements will be taken at the connection to the rear wheel drivetrain.


OK, as they seem to say they are using high voltage (I will say that, that is 1KV for ease of the maths) which means that to get the maximum of 60kW out of the system the resistance on the motor must be 16.6 ohms, (I don't know of that is the sort of resistance/impedance that an electric motor under load would cause) however it seems reasonable.

So to get a CR time of 6.6 seconds, you would need a capacitor of 400mF.

It has been a few years since I did CR calculations so they might need to be checked.
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Re: KERS overcharge

Postby stonemonkey »

I'm not sure about your calculations, also you wouldn't want to be discharging to 0.

But I stand corrected, in recent times the capacitors have been improving
The amount of energy stored per unit weight is generally lower than that of an electrochemical battery (3–5 W·h/kg for a standard ultracapacitor, although 85 W.h/kg has been achieved in the lab[4] as of 2010[update] compared to 30–40 W·h/kg for a lead acid battery, 100-250 W·h/kg for a lithium-ion battery

Still lower density than chemical batteries but have been used successfully in racing.
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