Onboard starters

[ChrisB]

I believe Pook has said he wants an on-board starter for the '05 car... and after seeing the few stalls yesterday, it's probably about time.

Anyone have any thougths on this?

Any guesses as to how much additional weight the extra motor + battery would weigh?


Here's another thought... how much does the on-board airjack system weigh? Could it be discarded to somewhat offset the weight of an onboard starter system? (F1 does just fine w/o airjacks in the car)

[RacinM3]

I like the onboard starter idea. Use a battery that's good for maybe 2 starts. Maybe like a motorcycle battery? I don't like the idea of eliminating the air jacks, plus, I don't think the air jack system weighs anywhere near what a starter/battery system would. There are already enough people in jeopardy in pit lane during a round of stops.

I wonder how much weight teams are adding to make minimum weight with driver this year. I wonder how that compares with the weight of a battery/starter.

[datachicane]

They'll almost certainly be compressed air systems rather than electric. There's already ballast in the cars, so any weight difference is bound to be minimal.

[Hink]

Another possibility is a capacitor rather than a battery. It could be a lot lighter, but only good for one start. OTOH you may have to worry about what happens if it discharges in an accident.

[RARules]

Originally posted by Hink
Another possibility is a capacitor rather than a battery. It could be a lot lighter, but only good for one start. OTOH you may have to worry about what happens if it discharges in an accident.
No, a capacitor wouldn't do very well. When it comes to capacity (stored energy), even the biggest electrolytics pale in comparison to a regular battery.

Plain capacitors work by putting opposite charges across a non-polarizing dielectric like a vacuum, air, ceramic, mica, etc.

Electrolytic capacitors have a liquid dielectric that has a dipole moment (per molecule) that get oriented in the direction of the field being applied. Much bigger energy storage, but it can't be delivered quite as quickly.

Batteries are the ultimate capacitor in terms of capacity because they store energy electrochemically. But when used heavily, the chemistry gets all fouled-up (figuratively and literally), leading to resuced sevice life.

A super electrolytic (there are some odd ones these days at about a Farad (that's a million microfarads) at 5 volts) I suspect it's somewhere between a traditional electrolytic and a battery in characteristics. These are sometimes used to keep volitile memory alive in consumer electronic devices when the power is cut for several miniutes. These are on the order of a thick quarter - not heavy-duty devices. Frankly, I don't know their discharge characteristics.

Anyway, even though an electrolytic capacitor can probably deliver charge more quickly than a battery (peak current = 1/ internal resistance), their capacity really sucks. you'd need a HUGE capacitor to deliver enough energy to start an engine.

Even the motorcycle battery suggestion also posted is marginal because even though it's a battery, they can't deliver much current since their plate area is small (high internal resistance).

The optimal battery for this kind of application would be very wide (in both directions) but thin. Perfect shape to replace a ballast plate (but keep it from scraping the pavement...).

So, even not knowing much about compressed air starters, they sound a lot more promising than batteries or capacitors.

[ChrisB]

The optimal battery for this kind of application would be very wide (in both directions) but thin. Perfect shape to replace a ballast plate (but keep it from scraping the pavement...).

Good idea!

(and keep the airjacks.. I forgot that it would require another crew-member over the wall)

[RichK]

RARules, I have personally built a capacitor the size of a motorcycle battery, that started an Army 2-1/2 truck. It can be done!

I imagine that compressed air would be cheaper, lighter and more effective, though.

[Hink]

Originally posted by RichK
RARules, I have personally built a capacitor the size of a motorcycle battery, that started an Army 2-1/2 truck. It can be done!

I imagine that compressed air would be cheaper, lighter and more effective, though.

I've seen a cap capable of putting put 1/4 MV (that's Mega Volts) in one shot that fits in a bucket. The energy in a cap is (C^3 V^2)/2. Now I wouldn't want that thing to discharge in a car wreck, but it's a lot lighter than batteries I'm familiar with for a given power output. I don't know much about lithium batteries except they have a lot of power in a small package. Their downside is volatility.

I would like to know more about how the compressed air system works. You wouldn't run a compressor off the engine because that takes power off the ground so I'm guessing a cannister.

[Napoleon]

Originally posted by Hink
so I'm guessing a cannister.

Thats how I always assumed it would work. A cannister the crew fills with air prior to the race.

I suppose an alternative would be some kind of small canister with the chemicals that create the gas that blows up air bags found in cars that you could set off if you stall.

[Hink]

Originally posted by Napoleon
Thats how I always assumed it would work. A cannister the crew fills with air prior to the race.

I suppose an alternative would be some kind of small canister with the chemicals that create the gas that blows up air bags found in cars that you could set off if you stall.

I wouldn't doubt if your alternative is right. Small package, quick punch, and crash safe.