Alternator readings flagged on tester
 

Hey,

So recently I tested my alternator at Halfords and they used a GS Yuasa battery tester which also tests alternators.

It tests the battery in 3 stages - loaded (lower voltage), unloaded (upper voltage) and diode ripple.

My 2001 S60 failed in the loaded stage with AC, rear defrosters and high beams on (1.5k to 2k revs). The GS Yuasa battery tester flags an issue when the max voltage in the loaded test is less than 13.8V. Mine was 13.42V. Could I get an idea of what could cause this issue? I know the alternator is one, I was wondering if there are any other components that could?

I have attached an image of the test.

Hi When the battery was loaded, what revs was the engine doing, when loaded Test you want to run the car at least 2000 rpm, your rippel is a bit hi,
it should be under 200mV , it may get better with new brushes,
When i had low voltage loaded or unloaded i found that the alternator bushes had worn out, i changed the REG unit, did it in still in engine bay mine is a 2002 s60, i would say that your reading is not bad, when mine was bad it was only just over 13V with no load,
Dave

Google suggests anything north of 13.2 volts under load is ok, and don't forget that it is the Halfords employees job to sell you a battery at a very inflated price.

The car was doing around 1800 rpms during the loaded test im pretty sure. I tried keeping it in the 1,500 to 2,000 range.

I actually used to work there and left last week, thats the only way I know my ex-colleague isn't trying to upsell me. We don't actually get much training on our alternator tests, all it is is 'red X bad alternator/check again at garage'.