WHICH BATTERY TO USE

[aguy]

hello guys
my qustion is which battery do u think i need to put in the car?
we use suzuki gsx r-600 engine 96 modle with carburetor we conver it to injection feul system
with a ECU -( megasquirt) but that's the only change so is it mater?
the original battery of this motobike is 12v/8ah
what more exploter the battery in the car ?

[BStoney]

Please utilize the "FIND" feature on these forums. There are at least two threads out there talking about Batteries and their applications...

Thanks...

[ben]

We need a sticky thread telling people that unsolicited "What ****** should I use..." will be ignored until the search command has been used and the questioned is re-phrased along the lines of; "I've read thread A and thread B and I've understood that these are the options, but I think this. What do you think...?"

The Matlab user group has a very similar problem.

BTW as a design judge I do keep an eye on which Unis are asking lots of people to do their work for them.

Also (bearing in mind I'm not an Electrical guy) shouldn't you work out what systems you have on the car, what the power requirements are, what the charging rate of the alternator is, calculate what battery you need and add a contingency if you keep stalling and need to restart? Can't be that difficult right?

Ben

[pengulns2001]

actually being that the stock bikes these days have about the smallest/lightest batterys you can find and use far more power than our fsae cars you might as well use whatever comes stock on the bike that your motor came out of we dont have

headlights
blinkers
brake lights
misc sensors etc

[PatClarke]

And remember, despite the rumours, Ohm's Law has NOT been repealed ;-)

Nothing is more gutting than having a flat battery at driver change in the Enduro, and there are many who live here who can attest to that!

Regards
Pat

[drivetrainUW-Platt]

about that, do they allow cars to be started externally, I have seen many teams carrying around portable battery jumper boxes as seen here:

http://search.ebay.com/jump-starter_W0QQfromZR8QQfsooZ1...pZ1QQssPageNameZWLRS (http://search.ebay.com/jump-starter_W0QQfromZR8QQfsooZ1QQfsopZ1QQssPageNameZWL RS)

are these allowed at the start of an event/driver change for endurance?

[BeaverGuy]

I know that external batteries have been allowed to start the car at the beginning of an event. I don't know about during driver change though as our car didn't make it that far the last two years.

[PatClarke]

Hi all,
external batteries are NOT permitted to be used to restart the car at the endurance run driver changeover.
Regards
Pat Clarke

[absolutepressure]

What about restarting by mechanical means? i.e. having 2+ team members push the car and having the driver engage the clutch. I know this works in fully functioning cars (w/ working batteries) but don't know if the alternator would create enough energy while just being pushed to start it.

Or, (forgive me for not reading this section of the rules and being electrically incompetent) what if you had a big capacitor instead of a battery? You could start the engine with the external battery and have the alternator charge the capacitor while it's running and doing laps. Then, use the capacitor to start the engine at the driver change. Capacitors won't die, batteries will.

[Drewbe]

That would be a monster capacitor though. Just doing some quick math i picked up in my circuits class you, assuming a BEST case senario you need one shot of 60 amps for 1 second and you need a minimum drive voltage of 8 volts for the starter, you would have to have a 15 Farad capacitor. A 1 Farad capacitor is a slug a metal that you could almost practice curls with. A capacitor big enough to ensure ignition would almost match the weight and volume of the engine.

I suppose that a smart ass could design a voltage amplifier and rectifier circuit to run off your engine's alternator and parallel the charger circuit of the battery. However the circuit design would have to bump the DC output up to some thing rediculous like 300 volts to get comfortable margin to start the engine with just one farad. Then you have to be able to protect the car if that thing shorts out because of crappy electrical work.

You dont want to go down that road. Just build your engine, test its reliability, be confident in you're fuel tuning, and take GOOD care of the battery you choose. Dont ever let it just charge on 50 amps car chargers. It will be fried.

[absolutepressure]

Hmm, that sucks. But on the topic of size, I've seen 6 farad (I think...It was 6 something) capacitors at a high end audio equipment store that were about 9" high and 3" in diameter. Price was ~$60. All I know about electical stuff is when you crank up the voltage on a DC output, shit starts to burn...and it's cool http://fsae.com/groupee_common/emoticons/icon_smile.gif


Addition-Here you go http://www.stingerelectronics.com/web/prods/capacitors.asp Pick one you like.

P.S. I dare you to touch it.

[BStoney]

Originally posted by absolutepressure:
What about restarting by mechanical means? i.e. having 2+ team members push the car and having the driver engage the clutch. I know this works in fully functioning cars (w/ working batteries) but don't know if the alternator would create enough energy while just being pushed to start it.

This is not allowed anywhere at competition. Period.... For safety reasons of course.