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Author Topic:   Which one?
Speedway65
Dirt Freak

Total posts: 344
posted July 28, 2004 08:40 PM  
Had a problem with our battery and alternator this past week,I was just wondering whats better to use a voltmeter or a ammeter?

STREET16
Dirt Maniac

Total posts: 158
posted July 28, 2004 09:33 PM  
Personally, I say a voltmeter, but it depends on what you want to know. An ampmeter will tell you if your battery is charging or not, but if it stops charging it doesn't give you any indication of how much juice you have left in the battery. But if your system stops charging it will be obvious at a glance. A voltmeter tells you how much voltage is in the system - with the engine off it will show battery voltage, with the engine running it will show either battery voltage or alternator output voltage - which ever is greater. If the alternator stops charging the voltage level will start dropping (which may not be obvious), giving you an indication of a problem and letting you know how much juice you have left in the battery. And a voltmeter is a lot easier to hook up. A meter will not fix a problem, and since both will let you know if you have a problem the real question is "is it worth the extra work to know at a glance?"

Speedway65
Dirt Freak

Total posts: 344
posted July 28, 2004 10:05 PM  
We know what the problem is.Alt went south and battery went flat.Got the unit fixed and put a brand new battery in.Don't care whether the driver sees the gauge it for us the pitcrew!Got ran into in the feature tire went flat ,when he came in to change it car slipped out of netural into reverse needless to say with the rearend spinning it was hard to change.So not expecting a problem we had him kill the motor.Changed the tire and also had to run out on track to get left rear spring back to put back in.Get all that done in time and guess what?**** thing wouldn't turn over.So thats why i am asking the question.LOL

racer17j
Dirt Forum Champ
Total posts: 5390
posted July 28, 2004 11:26 PM  
well why don't any of you just tell the guy you can tell the alternator is charging with a volt meter duh any alternator should put out 13.2 to 15.2 that would tell if the alternator is charging but it don't tell you if the alt. is converting ac to dc voltage to charge the battery (bad diodes) come on guys help the guys that need it stop beating around the bush and answer the question

WesternAuto17
Dirt Forum Champ
Total posts: 569
posted July 29, 2004 07:24 AM  
I run a voltmeter so I know if there's trouble with the alternator. On my car, the voltmeter runs at 14.5 while the car is running and around 12 when its not. So if its running and the meter is reading 12 and dropping, than I know I have an alternator problem.

Like street said, both let you know if there's a problem, but the volt meter is a lot easier to hook up. I just wired mine into the gauge light circuit. As a driver, I couldn't care less about it, but the mechanic (also me) likes the quick assurance that all is well with the charging system.

Lets go ahead and NOT debate the merits of running an alternator or not for the 964th time.

stic8
Dirt Full Roller

Total posts: 69
posted July 29, 2004 02:47 PM  
speedway about the spring coming out put about3 zip ties around spring and where it sits on axle it will help hold it in place when car get upset iowa he said unit was fixed so the diode probally was checked or replace

Speedway65
Dirt Freak

Total posts: 344
posted July 30, 2004 09:59 AM  
Already had 2 zipties and it still managed to come out.

iowatoolman
Dirt Freak

Total posts: 369
posted July 30, 2004 05:42 PM  
use a peice of 1/8 inch aircraft cable and a crimp to hold the spring in that works way better than zip ties

Ego Racing
Dirt Forum Champ
Total posts: 724
posted July 30, 2004 06:49 PM  
If the car was running and he killed it and the battery was to flat to start it back up it probably would have went dead before the end of the race, unless the battery went flat and the Alt was keeping it running, then when you killed it it would be daed without a chance of starting.

JohnG
Dirt Maniac

Total posts: 137
posted July 30, 2004 07:08 PM  
I would use a hose clamp for the spring.

and I do run a voltmeter.

BUT just so you know a voltmeter and ammeter are both dead shorts that you put in your system. So if you run either make sure you allways turn of your master battery disconnect during the week.

I do run a alternator and the appropriate 4 post shut of for it.

stormy
Dirt Full Roller

Total posts: 49
posted July 30, 2004 07:23 PM  
throw the alternator in the s**** pile and charge ur battery before u run. Ive never had a problem running this way.

iowatoolman
Dirt Freak

Total posts: 369
posted July 31, 2004 12:37 AM  
hey stormy it is worth a 1 to 2 hp loss running an alt. because a gm hei ingition needs more than 12.6 volts to get the most spark out of the coil
if your not getting the most spark you probably are loosing more than 1 to 2 hp think about that

Ego Racing
Dirt Forum Champ
Total posts: 724
posted July 31, 2004 10:11 AM  
In a 50 lap modified race our battery would be about 10 volts and 1/2 the amperage of a charged battery. We started running an alternator and just hooking it up to charge the battery and our lap times were almost 1/2 a second faster at the end of a 75 lap race than they were at the end of the 50 lap race. I have seen several racers loose a 100 lap race because the battery went dead.

waltonjr1
Dirt Forum Champ
Total posts: 516
posted July 31, 2004 11:56 AM  
With all these altenator disputes i think its safe to say that it probally doesen't make much of a difference either way, so do whatever floats your boat. An altenator will not make you win or lose a race. Ive won many w/o one.


stormy
Dirt Full Roller

Total posts: 49
posted July 31, 2004 05:13 PM  
what about the 1 or 2 hp loss running the alt. pulley, plus added front end weight. I've not seen one person at our track run an alternator. When u run a 12-15 lap feature battery drain doesn't seem to be a problem with a healthy, fully charged battery. But, like waltonjr1 says- whatever floats ur boat.

I-B-RACIN
Dirt Maniac

Total posts: 132
posted August 01, 2004 04:45 PM  
I'd agree with stormy. throw the alternater out thats weight, power and one more thing to go wrong. Get a good gel cell battery charge it before you go to the track.We can pack track, run warmups, heat and feature without chargin. You can get an orbital at NAPA for about 100$ MSD say there hei works better below 12.5 volts.

[This message has been edited by I-B-RACIN (edited August 01, 2004).]

Speedway65
Dirt Freak

Total posts: 344
posted August 04, 2004 08:05 AM  
alt only weighs about 7 pounds.This is the first problem in 3 yrs running it.Turns out field coil was fried,all fixed and ready to go!Put a voltmeter in just for peace of mind.

[This message has been edited by Speedway65 (edited August 04, 2004).]

WesternAuto17
Dirt Forum Champ
Total posts: 569
posted August 04, 2004 08:30 AM  
I think, as a driver, if I got hit so hard it flattened a tire and knocked the spring out, I might be happy the car wouldn't re-fire. I'd like to take a good look at everything before I raced again. That's a solid hit.


littlesister
Dirt Full Roller

Total posts: 48
posted August 04, 2004 08:52 PM  
You don't need the alternator, it just takes away horsepower.

[This message has been edited by littlesister (edited August 04, 2004).]

Speedway65
Dirt Freak

Total posts: 344
posted August 05, 2004 05:53 AM  
Both upper control arms were messed up other than that everything else was ok.We already ran on Friday and everything worked great.Besides we are top 3 in points. Really didn't need that 18th place finish,seeing the points leader failed to start the feature.

[This message has been edited by Speedway65 (edited August 05, 2004).]

    

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