My car is strangely not charging correctly. Anyone got some ideas? Scenario: 94 V8 SS running fine for about 450km's of 500km trip. Stop in to visit people about 30km from home. Upon departing their home, notice my battery warning light is on (after traveling a few km's with everything electrical on). Also notice that the voltage read out on my head unit is down around 2Volt from where it normally sits. (11.8 down from 13.8-14.2). I checked I hadn't thrown an alternator belt, and then continued on home. Testing: checked all fuses (fine), removed battery, checked water level of every cell (maintenance free but had caps??), cleaned terminals, refitted battery (trickle charged for 30min), checked alternator belt deflection (approx 12mm), removed alternator plug (it was clean) electrical lubed and refitted. Started and was charging fine. 14.6volt output at alternator power lead, 14-14.2 on head unit display, 14.4ish across battery. Drove to servo for some gas (fine), 400m to the supermarket (fine), start up to drive home - issue rears it's ugly head again. Got home, checked alt power wire, and output is at 12.2volt, so is battery and head unit display. Car is now on trickle charger and I will pull down and examine my spare alternator before putting that in (condition unknown). If any one has had a similar issue, or can recommend something to check please let me know.
Checked specific gravity of each cell? Maybe a diode has failed in the rectifier bridge, reducing alternator charge output. How hot does the alternator get? Checked the B+ terminal tightness?
Checked specific gravity of each cell? Maybe a diode has failed in the rectifier bridge, reducing alternator charge output. How hot does the alternator get? Checked the B+ terminal tightness?
Haven't checked gravity, but quite confident the battery is not the issue (only 13months old and a good brand) Yeah I thought the diode bridge may have been at fault, so was going to chuck my spare alternator on if it appears all good. The alternator did not seem excessively warm compared to other components of the engine bay. ahh good thinking, I will check that.
The problem could be the voltage regulator in your alternator. The bushes wear out over time and you can start getting the battery light coming on intermittently or full on. Easy and (relatively) cheap to replace - $35 for a new Bosch unit on eBay.
Update: wire brushed, sanded, lubed and refitted B+ terminal (It was done up, but not super tight) also done the same on D+ terminal. refitted battery negative terminal and found that when fully tightened - it could still slightly rotate on negative post. Modified terminal and refitted so it holds tight. I'll give the battery a little longer to trickle up and then see if that has made any difference. Also: V/R brushes on spare alternator look close to the end of there service life, so it will get any parts before I look at fitting it.
Started it up and now have 14.4 @ B+, 14.3 across battery, and 14.2 (maximum) at head unit. It seems all is fixed for now. although, may hurray with my spare alternator rebuild just in case. thanks for the ideas guys. (i'll keep you posted if the issue comes up again)
main charging cable from alternator to battery, common issue is for the insulation to get brittle and break away leaving the cable exposed. When the cable heats up from the engine and heat from resistance in the cabling, the main charge cable can break contact and fail to feed power from teh alternator to the battery. Run a new cable or add in an extra one in parallel to the original one.
as BlackVXGTS said, i had same problem recently, bought new voltage regulator think was bout $40, thought worth a shot being alot cheaper then alternator new or reco, installed it and all good
Drove to work fine today, started car to come home and . . . . the issue is back!! got home, and took out the V/R from Alternator Left is from spare Alt, and right is what was in the car. I have put the V/R from the spare alternator in to the car and will see if it fixes the issue.
Update; It seems that the brushes were the issue, as 3 trips today have not shown any charging issues. The current ones should last me awhile; until I rebuild my spare alt with new bearings/bushes etc. Thanks for the ideas all
