alternater test ???
my car just died before, i jump started and no problems for about 5 k's.
so i went and got a new battery.
want to know how to tell if the alternater is stuffed before i go out and by a new one.
dont want to lash out for one if there is nothing wrong with the one i already have.
car starts now with new battery, but not game to drive it any where until i can find a way to test alternator
any information be greatly appreciated.
Banned
Have you got a digitial multimeter. $10-15 will get you one and you can make some measurements that will give you a good idea.
With the engine idling, measure the voltage across the battery. If it is 14-14.5V, good
Turn on every electrical load possible, lights fans demister etc. remeasure voltage across battery....it if drops below 13V, then alternator is possible not doing to well at idle.
With all the electrical loads still going, raise rpm to 2000. If alternator rises to 14V+ good. Exceeding 15V is not so good.
If it fails here, problem may also be due to the regulator, which can be replaced separately to the alternator.
Banned
if the charge light on the dash is on, then chances are the alternator isn't working. haha
NEEDS MORE POWER!
simple test
start your car and remove your battery terminal clamps (CAUTIONdo not arc your spanner or the battery clamps on any metal) if the engine stalls your alternator is stuffed
WARNING! do not try this unless you believe in luck!
Last edited by jatsvl; 02-07-2008 at 09:27 AM. Reason: backlash warning!
Nobody wants to play with me
The Wagon on Wheels..
You should see about 12-13volts on a good charged battery with engine off. When you start the engine you should see about a 2 volt rise, so 14-15volts. Also check your dash battery globe is not blown, if alternator dies this should come on too.
Originally Posted by Blown V6 Hatch
It's cheap and half arsed - perfect fit for a Commodore
Reaper
IMO under no circumstanses should you remove the battery terminals while ya have the engine running,you can spike your computer or ya sound system.
Phillip
NEEDS MORE POWER!
Hence the CAUTION!IMO under no circumstanses should you remove the battery terminals while ya have the engine running,you can spike your computer or ya sound system.
Phillip
done this test many times on many vehicles, no arc no problems!
Nobody wants to play with me
Banned
I believe your caution referred to not accidentally shorting the +ve lead that would go to the battery to ground.Hence the CAUTION!
done this test many times on many vehicles, no arc no problems!
Removing the battery from the charging system allows high voltage spikes from the alternator to reach all the delicate componentry, the battery normally acts as an electrical sink for these.
It is perhaps only good luck that you havent fried anything yet.
NEEDS MORE POWER!
how lucky am I? i have driven vehicles without a battery in them!
Nobody wants to play with me
Banned
You doubt what i wrote?, fine, but instead of making fallacious comments why not read up on the phenonmen instead of providing potentially damaging info to everyone:how lucky am I? i have driven vehicles without a battery in them!
Try:Car and Deep Cycle Battery FAQ
Well jatsvl,as i said you can do some serious damage i dont know what your qualifications are but i am a qualified auto electrician by trade,i have seen a vehicle driven without a battery in it ,in his case it cost him around $1800 to replace the computer,cd player,instrument cluster and climate controls,i have seen a 24 volt truck with a blown alt fusible link and the voltage at the alt was 178 volts,hmmmmmmm imagine if ya had ya cd player hooked up to the alt,all i can say is ya been lucky.
Phillip
NEEDS MORE POWER!
DOUBT? I accepted your comment and added a warning to my original post, the fact remains that I must have been lucky, ACCEPTED!
I thought the point of a forum was for everyone to share their experiences and knowledge and to accept advice from ALL who have something to contribute then decide which of this knowledge is best for you.
I have no intent to cause damage to anybodies vehicle simply added my experience to an OPEN forum.
comsirac & prh's comments are duly noted!
Nobody wants to play with me
Banned
A good alternator shouldn't have a problem with removing the battery...
a commodore alternator probably would...
we like the bun
the way to test an alternator is to load the electrical system, switch on heater to max blast, radio etc. give it some revs and measure the voltage across the battery - if it drops from 13.8 or so when you do that stuff then the alternator is failing to provide sufficient charge.
actually that's a charging system test, the alternator is not the only possible cause - regulator etc. although i think sometimes they're integrated.
Banned
Jules, ^ already covered in thread.
Possibly an alternator could be designed with this in mind. Care to suggest any alternator that is currently produced and used on any car where this could be done without problems?
crappy ol' VN driver
it's obvious that you shouldn't own a commodore, it may kill you one day
this is gold. just as a note of interest, a guy i use to work with had his alternator in his race car rigged up in such a way that he could switch it off.
Body by Holden, Soul by Brock
the Legend will live forever
VN exec T5: 15.1sec @92.2mph 1/4 mile, 9.7sec @ 74.6mph 1/8mile, 2.3sec 60ft, 0-60mph 6.827sec 22/11/07 Gtech competition
we like the bun
the alternator won't necessarily have a problem - but where is the charge the alternator produces going to be fed, if not into the battery?
the answer is into other electrical components, damaging them.
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