Kers on outlap

[dave34m]

During the Turkey GP, Lewis Hamilton just came out of the pits and into a battle with Piquet. Martin Bundle commented that he was surprised LH didnt pull away easliy after turn 8 by hitting the kers button (he described it as the happy green button).

Are the cars loaded with kers when they leave the pits, I would have thought that they would have to be discharged for saftey in the pits and wouldnt have any kers havrvested for the first lap back on track.

Very interested to hear your comments.

[tommylommykins]

Where would they discharge it to?

If the drivers are only allowed to use KERS for 6.6 seconds per lap, and the batteries can store more than 6.6 seconds worth of energy, how would they dischahrge the energy? They couldn't legally put it through the wheels... is there a radiator for this purpose or something?

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Also, if KERS is safe enough that the drivers can charge and discharge it while moving at 180mph, would it then be deemed unsafe for the pit cerw to work on the car with KERS charged while it is stopped an inactive?

[Slife]

Could they ground the car, when it is at the pits ?

[Conceptual]

Could they ground the car, when it is at the pits ?

While refueling, I think that the chance of sparks from a KERS discharge through the strips would be inherently unsafe.

Unless it is 100% non-sparking, I would think that it may add undue risk.

The best place for the KERS energy IMHO is inside its designed and tested container on the car!

[flynfrog]

the kers weather charged fully or discharged is still going to be at a high voltage. think of your car battery fully charged is 14.4 volts fully dishcharged is 10 volts. so the potential is still there to arc just not much current. when they make it safe for the crew I am guessing they have a relay on the back and the change it to the open position. the pack is sitll live but its not connected to any of the batteries.

[Ian P.]

Just to make it VERY clear that a car battery is NOT discharged at 10 Volts. It still holds an amazing amount of energy. The concept of fully charged at 14 volts is correct. It is just that with most chemical storage batteries the working range is only about 10 to 25% of the total capacity. A battery may be considered discharged at 10 V, but don't think for a second there is ....only a small charge left......the energy is significant and will still melt a wrench dropped across the terminals. If it doesn't explode all over you first.
Just a little warning there.
Discharging a KERs system is not going to be trivial. There is a geat deal of energy there and the pit grounding straps can not handle that amount of current. They are there for static charge disipation only.
Hamilton had probably used his available working charge on the previous lap.

[flynfrog]

Just to make it VERY clear that a car battery is NOT discharged at 10 Volts. It still holds an amazing amount of energy. The concept of fully charged at 14 volts is correct. It is just that with most chemical storage batteries the working range is only about 10 to 25% of the total capacity. A battery may be considered discharged at 10 V, but don't think for a second there is ....only a small charge left......the energy is significant and will still melt a wrench dropped across the terminals. If it doesn't explode all over you first.
Just a little warning there.
Discharging a KERs system is not going to be trivial. There is a geat deal of energy there and the pit grounding straps can not handle that amount of current. They are there for static charge disipation only.
Hamilton had probably used his available working charge on the previous lap.

Yes my example was a car battery a kers system is in the 100s of volts my point being even in its discharged state it has a lot of potential.

[bhall]

There's a video somewhere around here about the McLaren KERS in which a team engineer states that their KERS completely charges itself under braking in half a second. With that in mind, even if the car came into the pits with no charge remaining, I see no reason why it couldn't be used on an out-lap since it's so easy to recover.

[dave34m]

Fully charged in half a second, is that what they said. I think Lewis Hamilton has said that they will struggle to charge the kers system in Silverstone because of the lack of heavy braking areas.

[DaveKillens]

The regulations define how KERS is used. It can be "shut down" for pitting.

9.9.2 The system will be considered shut down when all energy is contained within the KERS modules and no high voltage is present on any external or accessible part of any KERS module.
The shutdown process must take no longer than two seconds from activation.

So when pitting, the KERS system shuts down, and is returned to running order on leaving pits. The batteries or energy storage system can be at a highly energized state, but it would have all it's energy contained and not present or accessable.

The regulations state how much energy can be stored, how quickly and how much may be discharged each lap. The KERS management module can ration that out automatically. But as for charging, it can be done anywhere. So a car could easily regain KERS energy very quickly, to be made available for discharge the next corner.