Wayne-J Posted October 21, 2014 Share Posted October 21, 2014 Hi guys. Registered for the site in the hope that somebody can prevent me from parking my Mondeo in the canal! Had a 1.8 diesel 2007 (mk4) Mondeo for 2 years now. I'm on my third battery. The most recent has gone dead twice in 4 months. Most recently about 2 weeks after I had my alternator replaced. Obviously I'm reluctant to take car in for the diagnosis of the fault because I can't really afford a massive garage bill. And after my local garage diagnosed the fault as being alternator, I'm worried I might get another incorrect diagnosis and still have the problem. I know there are many suffering from flat battery issues through browsing the net looking for a fix. Anybody have a miracle cure? Appreciate your help. Quote Link to comment Share on other sites More sharing options...
BOF Posted October 21, 2014 Share Posted October 21, 2014 The batteries that you have had, have they really been suitable (manufacturer, capacity and spec)? Have you measured any voltage at any time? What else has been checked? Quote Link to comment Share on other sites More sharing options...
Wayne-J Posted October 21, 2014 Author Share Posted October 21, 2014 Original battery was a ford branded one, replaced with a Bosch from Halfords, had a 5 year guarantee so I claimed after 20 months. They don't do Bosch anymore, so i was given a Yuasa of the same value. Had alternator replaced due to it putting out low voltage. Got a voltage reader for cigarette lighter socket (I know won't be 100% accurate, just allows me to keep an eye). Car regularly sits on 11.7 volts before started, then voltage typically jumps anywhere up to about 13.9 but then almost immediately back to 12.2. However some days I will only get 11.0 (these are the days when I expect car to not start once parked up). I've measured voltage at the alternator with a multimeter and can see typically 14.0 volts. However battery doesn't go above 11.7 volts. battery has been charged whilst removed from car, but always goes back to a steady 11.7volts. Took parents to Scotland in August and had the battery light on dash light up, turned off car and almost didn't get it restarted. My dad heard a relay click, and then it started? Thanks for reply Quote Link to comment Share on other sites More sharing options...
Wayne-J Posted October 21, 2014 Author Share Posted October 21, 2014 I've also looked as best I can for any damaged wiring in case of shorting, but can't see anything. Although I had a mate look under the bonnet whilst I started car when I was having low voltage. He said he saw a spark about 12 inches long shoot out around the left of battery box across towards engine. This was before alternator was replaced. Quote Link to comment Share on other sites More sharing options...
BOF Posted October 21, 2014 Share Posted October 21, 2014 He said he saw a spark about 12 inches long shoot out around the left of battery box across towards engine. I don't know what that means, but it seems significant. I mean it isn't totally normal for 12 inch long sparks to be emerging from anywhere, in the same way that it is probably a bad day if I have to dodge Godzilla to get to work. Given that it is the battery box and that the battery is in there and it is the battery that is at question, maybe there is a connection between the flame coming from the battery box and the limited life of the battery. Original battery was a ford branded one, replaced with a Bosch from halfords, had a 5 year guarantee so I claimed after 20 months. They don't do Bosch anymore, so i was given a Yuasa of the same value. OK, so assuming that your Ford battery was original fit ( ~5 years life would be neither dramatically good nor dramatically bad), then, at least, things seem to have been ok for most of its life. The question then is whether the replacement batteries were of the correct spec. What spec were they? Car regularly sits on 11.7 volts before started, then voltage typically jumps anywhere up to about 13.9 but then almost immediately back to 12.2. However some days I will only get 11.0 (these are the days when I expect car to not start once parked up). So, the car doesn't start, sometimes. You are seeing 11.0 volts, sometimes (is this when it is still running or after you have switched off?). When you have seen this, it is predictable that it doesn't start? Quote Link to comment Share on other sites More sharing options...
mgaking Posted October 21, 2014 Share Posted October 21, 2014 I've measured voltage at the alternator with a multimeter and can see typically 14.0 volts. However battery doesn't go above 11.7 volts. If both these measurements are with the engine running then it suggests a wiring fault. Quote Link to comment Share on other sites More sharing options...
Wayne-J Posted October 21, 2014 Author Share Posted October 21, 2014 I see the voltage drop whilst the car is in use. If i see a low voltage whilst driving, I will put both heated screens and the blower on max and I usually see a voltage increase (always higher than before even though I have a higher demand on the car), which shows that the alternator is clearly working correctly. Sometimes, however I will see the voltage go as low as 10volts with everything on, and no increase almost like the alternator isn't kicking in. I read somewhere about a Mondeo ST having a mega fuse of 175A between alternator and battery. Does a standard mondeo have this? Could the fuse have blown?? Unfortunately I have no knowledge of car electrical systems so I am immediately coming to the conclusion that there must be a break in a cable. Or maybe a bad earth connection somewhere?? Obviously concerned that a garage other than Ford will suck air through their teeth and give me a good shafting without fixing the problem. But on the flip side, Ford could find the problem and charge 1000 times as much! Quote Link to comment Share on other sites More sharing options...
Wayne-J Posted October 21, 2014 Author Share Posted October 21, 2014 Also, as the battery I am currently using was in use with my old bad alternator, if it has been undercharged to say 11.7volts regularly, could the battery learn that this is its new maximum charge? As a consequence new alternator appears to not be doing its job? I really appreciate everybody's input/advice, I've been pulling my hair out over this for quite a while now, but hate the garage mentality of charging over the odds. Took a work vehicle in for some repairs, they called to say that a bulb was out, so I obviously said go ahead and replace it. Total cost for bulb and "labour" came to just short of £17!!! And that was a Ford garage by the way, hence my reluctance to just bite the bullet. Quote Link to comment Share on other sites More sharing options...
mgaking Posted October 22, 2014 Share Posted October 22, 2014 Could be wrong on this but in my head there are no active components between the battery and alternator. The battery is connected to the chassis; the alternator is bolted the the engine which is connected to the chassis. Then there is a cable connecting alternator output to the battery positive. A difference of over 2 volts to me is loose connections or dodgy cables. As you say the alt is putting out 14V then it seems to be doing what it should do - its just not getting to the battery. Quote Link to comment Share on other sites More sharing options...
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