neilt1978 Posted December 9, 2019 Author Share Posted December 9, 2019 Sounds like the alternator isn't giving it the juice it should be,it's only new around six months ago, I've taken the Battery off and gonna check the voltage tomorrow to see if it's dropped ,its currently on 13v, if it's still around that tomorrow I'm gonna connect it to the car and leave it another day then check the voltage again and see if anything is draining it when it's connected to the car if it's still charged then it must be when I'm driving the car around the fact that the alternator isn't 100% then the Battery is dropping. Quote Link to comment Share on other sites More sharing options...
Mr B Posted December 9, 2019 Share Posted December 9, 2019 regulated voltage (running) seems low, normally at 13.7 to 14.2 even at idle, did you increase revs to see if voltage increased . I would be suspicious of your charging system and suggest either read up on doing some further test yourself or get it checked out, the dealer who fitted that alternator may do some quick tests free if you think alternator/charge output an issue . a poor new alternator or a poor connection voltage drop that present before the alternator swap could still be present perhaps . I would test your running voltage again at Battery posts and at 2000rpm and then also test at the alternator large cable output stud (+ multimeter lead right on the alternator stud) and if voltage at alternator much higher than at Battery post you got connection issue causing voltage drop . If voltage at alternator and Battery same and as low as your first test results then that alternator looks likely an issue. If it aftermaket or reman it not uncommon as lot of pretty junk parts hardly fit for purpose in the market these days . Quote Link to comment Share on other sites More sharing options...
neilt1978 Posted December 9, 2019 Author Share Posted December 9, 2019 Thanks a lot ,it's a shame your not nearby you seem more clued up than most around here! Quote Link to comment Share on other sites More sharing options...
Mr B Posted December 9, 2019 Share Posted December 9, 2019 The subaru charging that simple just about anyone can get some diagnosis results on basics of if or how well it appears be working . If you googled few pages on testing alternators/charging and watched a youtube video or 2 you could be fairly competent yourself for basic checks and be able spot the obvious or have good idea on direction of issue . amount of garages that just fits parts or tell you it possibly this or maybe that is ridiculous on simple issues such as a charging system . See how you get on and keep us updated . 1 Quote Link to comment Share on other sites More sharing options...
neilt1978 Posted December 11, 2019 Author Share Posted December 11, 2019 Checked once more the voltage,,with nothing switched on and car running the Battery is reading 13.01v, the alternator when tested directly is reading 13.04v, now when I turn everything on, lights etc the Battery is reading 12.36v and the alternator is 12.40 I've also noticed that with the AC on and everything that the fan cuts in every thirty seconds or so for about five seconds then stops, is that normal. Thanks Quote Link to comment Share on other sites More sharing options...
Siluro Posted December 11, 2019 Share Posted December 11, 2019 1 hour ago, neilt1978 said: Checked once more the voltage,,with nothing switched on and car running the battery is reading 13.01v, the alternator when tested directly is reading 13.04v, now when I turn everything on, lights etc the battery is reading 12.36v and the alternator is 12.40 I've also noticed that with the AC on and everything that the fan cuts in every thirty seconds or so for about five seconds then stops, is that normal. Thanks The connections are good as the voltage drop is low. Based on these facts I would suspect the Alternator. The fans for the AIrcon sounds normal to me. Quote Link to comment Share on other sites More sharing options...
Mr B Posted December 11, 2019 Share Posted December 11, 2019 Did you increase rpm or that at idle ? even at idle I expect see over 13.7 . Does look likely alternator output issue so best speak with garage that fitted it. they'll be able test and have warranty on that part if they smart and no additional charges for you if it recently done . A plus is alternator easy accessed and replaced on these cars . I had lot of issues with starters and alternators reman and pattern part over the years to point we only got 1 reman company we willing use and prefer used genuine over anything pattern part new . Need be very fussy with parts used these days (it not always cost related either) ... Quote Link to comment Share on other sites More sharing options...
neilt1978 Posted December 11, 2019 Author Share Posted December 11, 2019 Yeah I increased the revs, it increased slightly but not much, I got in touch with the garage they gonna replace it on Friday if it's faulty, God knows where they even got it from so hopefully it'll be sorted. Quote Link to comment Share on other sites More sharing options...
neilt1978 Posted December 13, 2019 Author Share Posted December 13, 2019 Well here we go again,took the car to the garage who put the alternator on, who turned round and said to me"the alternators fine it's kicking out 13.1v under heavy load"and then proceeded to say the Battery is at fault not kicking out the right amps ,,I give in ☹️ Quote Link to comment Share on other sites More sharing options...
Mr B Posted December 13, 2019 Share Posted December 13, 2019 13.1 ain't good . The voltage only half the story from alternator , what amps it kicking out and what ripple it show on a scope . What make alternator is it, can you see a label on it ? I would proceed push them harder, if they can't check amp output or ripple just push HARD get it swapped. I been in the auto repair game over 30 years and dealt with subarus close to 25yrs and a charge voltage as low as 13.1 is suspect, I class anything under 13.7 suspect and generally it always be over 14 on oem alternator as they that good and regulate voltage to a tight range . Junky aftermarket and refurbs can be problematic . standard test range is 13.5 to 14.4 An AGM Battery for example would not charge at 13.1 . Quote Link to comment Share on other sites More sharing options...
neilt1978 Posted December 13, 2019 Author Share Posted December 13, 2019 Well yeah as you say it seems low but hey ho he's the mechanic,he's replaced the Battery with a Bosch Battery ,he said the Battery was short of a few Amps(he did say the figure but I can't remember),it hasn't cost me anything but no doubt in a week or so I'll be back to a flat Battery. Quote Link to comment Share on other sites More sharing options...
Mr B Posted December 13, 2019 Share Posted December 13, 2019 Oh boy, hopefully works out one way or other in end . 1 Quote Link to comment Share on other sites More sharing options...
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