F1 Winter Break
Behind Button and Hamilton's winning formula
Behind Button and Hamilton's winning formula
Posted By:   |  18 Jun 2009   |  4:33 pm GMT  |  26 comments

I want to write about something other than the FIA/FOTA war today. There will be plenty of that tomorrow.

It has been well reported that Lewis Hamilton and Jenson Button have exchanged fortunes from last season to this. Button has gone from the back of the grid to the front and Lewis the opposite way.

But there is a common factor in the success of both men and that is the Mercedes engine, which is made in Brixworth, about 20 minutes from Silverstone. Button visited the staff yesterday to say thank you for giving him an engine which has won six of the seven races so far and Hamilton dropped in today to say thanks for the KERS system, without which McLaren would be even further behind!

I also went there today to take a look around and to get a closer look at the only KERS system in F1 which is really working well.

Mercedes High Performance Engines is supplying three teams this year; McLaren, Brawn and Force India. Each team requires 16 engines for the season to cover the race weekends, eight per driver. It’s a far cry from the days when engines were unlimited and before they were homologated, but there is no less effort going on.

As you would expect the place is spotless, I’m tempted to say like a hospital but I’ve never seen a hospital as clean as this. We toured the machine shop and design office and went to the engine build area. There are two men in there who build the engines, using 3,000 components. It takes five days to build one engine and they check each other’s work. Quality control is the name of the game and they haven’t lost an engine yet in a race.

Of the eight engines each of Mercedes’ six drivers will use this season, roughly half of them have already been built. Engine planning is important this year, because you want to try to have a new engine for the real power tracks like Spa and Monza.

The most interesting part of the visit was looking at the KERS system which is the class of the field. The system is used only on the McLaren at the moment and weighs just 24 kilos. Of that the motor is 5 kilos, the converter pack is 3 kilos and the battery pack is 14 kilos. The rest is cabling. The cable, which connects the battery pack to the converter carries 700 volts, which is serious current to have running from one side of a car to another! There are several fail-safes to make sure that the driver doesn’t get electrocuted. The system is 70% efficient, in other words 70% of the energy harvested under braking is available to go back into the system as boost on the straights when the driver wants it. Another thing I had not realised is that Mercedes has the system primed so that it can be used out of the final corner going into a qualifying lap and then reset when the car crosses the start line and then used again immediately.

For Mercedes the whole KERS project has worked out pretty much exactly as the FIA intended it. The F1 division has innovated and come up with a system, which is being used on road cars. So amid the political chaos of the moment is an example of one manufacturer which has worked with an FIA initiative and got something positive out of it.

Despite its success with KERS, however, Mercedes supports FOTA’s position of getting rid of it for next season, to save costs. But it is not a waste for them, because in 2013 F1 will have a new engine, which will be based more on fuel efficiency, rather than capacity and all engineers agree that this engine will have to be based on the hybrid system.

The economic situation at the moment makes throwing cash at KERS difficult to justify but it will the standard in a few years time, with a system like the one Mercedes are running now at the heart of it.

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Hi James,

Do you remember me taking your advice and putting £20 on Brawn to win the Championship? at 15-1? well I got this email from Paddypower this morning:

.....With the British Grand Prix around the corner and Jenson Button and the Brawn team still thrashing allcomers, we've decided to accept reality and settle all bets on Jenson Button to win the World Drivers Championship and Brawn to win the World Constructors Championship as winners!

That's right - given there's no point in making you wait another four months to collect on what is effectively a racing certainty, we've paid you your winnings today....

Cheers James!


Interesting article, and so very refreshing to read about something NOT to do with the FIA/FOTA war! Though I think someone needs to look up his O-level physics notes... "700 volts, which is serious current to have running from one side of a car to another" - err I think you mean serious *voltage* !


James, current is expressed in Amps. 700 volts means nothing without knowing what current the wire is carrying. Also is that 700V DC or AC (in which case divide by 1.242)?

Assuming DC power:
P = VI. (Power (Watts) = Volts x Amps).

If the current is 1mA then its not much to write about, if its 100A, then that is (70KW)

What would be really interesting to know is what the charge capacity is for the battery and how fast that can be discharged and charged.

1 kilowatt = 1.34102209 horsepower

Given that KERS gives a boost of 80HP (or is it BHP?) then that means the battery pack needs to store at least
80 / 1.34 = approx 60KW.

Round it up a bit to allow for losses and the to prevent the battery getting emptied, say they choose to store 100KW in the battery. The more you store, the better the battery you need, which I guess would mean heavier.

Have I got my maths wrong anyone? I don't do electronics for a living so will be rusty on this, having not done any of this for 20 odd years.

Michael Grievson

Its nice to read about something different on F1 for a change


Thank you for writing about F1 rather than the F1 struggles.
'The system is 70% efficient' - that's pretty incredible, especially given that the system hasn't been around long.
I can see many people having fun with an eco friendly nitrous oxide style hit of acceleration if the technology makes it beyond F1...


Aside from the Kers, are the engines Mercedes providing Brawn, McLaren and ForceIndia identical? Curious if there are different specs between them, and if Mercedes is starting to put more or full effort into Brawn.


"... with a system like the one Mercedes are running now at the heart of it."

Maybe, but it will be interesting to see how the development of the flywheel system continues at Williams.



I'd almost forgotten that good, interesting non-political F1 stories existed ;o)

It's pieces like this that I love to read. I am no mechanical engineer, but I like to think I have a good understanding and like to learn more about the technology and the cars themselves.
I can appreciate with the secrecy of F1 tech that it's hard to get much info. But posts like this are great to see.

Maybe you could do another few posts along these lines?


This is very ironic, James, as Hamilton won't be using KERS on Friday.


That's a lot of engine build days. Do they put their names on like Aston Martin do?

Interesting article James, finally some details of KERS. BTW 700Volts is er, mm, Voltage not current, its yer current that will kill you, current comes in Amperes or Amps.
The high voltage is used to cut the cable size (cross section) and internal resistance down. All cables have some resistance even if made of silver, I would guess they would be aluminium cored cables here though for the weight, though with gold plating on the terminals. The power loss is a squared function of the current. eg W=I²R, this is mainly if not entirely given up as heat. So if you use low voltage you need very thick cables and they will get hot. The higher voltage only needs relatively thin cables. There will still be a loss but much less. (Hence our national power grid uses high voltage on the pylon network) The real problem must be on the low voltage side, the cables must get quite hot there. (I did calculate before that they would need water or strong airflow cooling) Hence my hope of seeing this via the infra red cameras, but unfortunately it was only used once by a guy who didn't know where to point it. (BBC please note)

Here is an application for superconductors, which will have next to no resistance and therefore no losses and no heat problems.

Hence also the reason that car manufacturers are now using 36 volt systems, there is a considerable saving in cable weight and cost.


"...I had not realised.. the system [KERS] ..can be used out of the final corner going into a qualifying lap and then reset when the car crosses the start line and then used again immediately."

Are you kidding?!

I think everyone else realised this during the 1st Grand Prix!



good story james, one small point though. Volts inst a measure of current is a measure of potential difference. Amps is the measure of current.



As always, an interesting and insightful article--keep up the great work! I'm glad you've been able to find a direct-to-audience outlet for your musings.


Gavin Pendergrast

Why don't they just put this system in every car as a standard just like the ECU. That would keep costs (and weights) even across all teams and Merc would get a bit of a return on its investment. Raise the min weight by 25kg and you create a level playing field for everyone... and retain the green look MM wants for F1.


I know it's picky, but current is measured in amps, not volts.


Hi James.

I was pondering the Brawn car this morning and was wondering if it would still be the class of the field if it were outfitted with the Honda engine? Or is the Brawn the mightiest car in the pitlane because of Mercedes power?

What are your thoughts on this?




The rules limit the output of KERS to 400kJ/lap. If the Mercedes system can be used twice on one straight in qualifying with no braking to recharge, doesn't that mean the battery can store 800kJ? Is it worthwhile to carry a nearly 7kg heavier battery in the race where your two consecutive KERS boosts would be limited by the rules to every other lap?


Can I just point out that 700 volts isn't current, it is voltage! Current is measured in amps, and the total power of something is the voltage x amps.


James, very interesting article.

Its a shame that such a clever and wonderful piece of technology that Mercedes has designed, will end up being taken off the cars at the end of the season.

I know that changing rules invovles the FOTA and the FIA who probably have bigger problems to sort out at the moment, but, could the FIA allow teams to use the KERS for longer and have more power, thus giving a bigger advantage and mean more teams using and developing KERS?

We see....

Otherwise, I'm really looking forward to Silverstone!


I think we all now know the difference between current & voltage.

"Behind Button & Hamilton's Winning Formula" ,only by where the engine is location, otherwise we would have Hamilton further up the points would we not?


I found this page very useful:

Snail, I guess you are assuming a sine wave, used as a chopper in the voltage converter, but in this case I would expect a square wave to be more efficient.

I know just the man for this, if he is watching, Alan Sykes (Stockport) please put the steam engine down and chip in.

I think the current limiting factors are the 60kW flow rate limit which will be increased next year (Pity no one is going to use KERS next year) and the heat loss in the low voltage side. Copper tube as a stator winding perhaps, then a liquid cooling system. OR maybe a direct High voltage generator with permanent magnet rotor, that would erase the low voltage loss but create other problems.


does anyone know what the efficiency of the energy harvested under braking in a road car like the prius is?


you're so right parrafone and even more so consdiering he was much faster in 1st practice without KERS than Kovi was with it. something like 11 places faster!


It doesnt need 800Kj. The reason being that as soon as the car starts breaking for the first corner it will gain a large percentage of the required power back. The car may break 3 more times before the button is pressed again. Remember the battery icon doesnt show how much energy in in the battery only how much allocated energy is left for a lap. Personally I would love to see them say KERS is unlimited in power and time. That would mean massive investment from the teams but the gains for the motor industry would be worth it once the economy stabalises.


Well I'm glad to have been of service. And glad someone was listening!


Yes but the point is it will be back..

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