Catch 22 situation - Help please

[allington73]

Hi all,

My Boxster 3.2 has suddenly begun to lose all charge on the battery in a very short space of time. Thought problem was under-use so fully charged battery. Then went on 1.5 hour drive only for to lose all electrics and then power whilst driving (engine totally cut out). Garage checked over and said it was battery so recharged again only for battery to totally drain itself within a day or two (and set the alarm off at 2 am).

I now have the alternator fault light on and the nearest local and Porsche garage reckon it needs a new alternator.

Problem is they are also saying it might be an electrics fault.........heres the issue ! We have no local auto electrics experts and I do not trust the car to get me to where there is one. So I am almost stuck having to buy a new alternator and hope this fixes it.

Do any of you guys have any thoughts ?

Any help would be appriaciated before I shell out £400-£500 !

 

[edgiee]

The first thing to do is to put a voltmeter (multimeter on DC volts) across the battery terminals. If it reads anything under 12 volts you have a flat battery. Depending on the age of the battery, if it is flat then it will reach a condition where it will not re-charge, no matter how many miles you drive. So the first thing to do is buy an approved Bosch battery for about £80 and fit that. If you still have problems then call the auto-electricians. Hope this helps.

 

[juliany27]

If you do fit a new battery I believe that you will have to re-set the radio and PCM etc. if fitted. You might find the necessary codes in your Porsche documents or will have to go to an OPC with proof of ownership of your car so that they can look up the codes.

 

[jaunebox]

I had the same problem, it's almost certainly your alternator. I don't know how mechanically minded you are but it can be fairly easily removed, and either overhauled, or replaced, relatively inexpensively (compared to OPC prices)
Bring the seats forward and remove the engine panel behind them, access is then available, remove the bolts, the long one on the right has to be loosened a few turns and knocked back, before complete removal, to free the unit. Remove the wires, turn and wiggle the alternator out, it's not as difficult as it sounds.
Good luck

 

[mascanes]

Hi,

I used to be have my auto electrical business so maybe I can help.

First, of all it's very easy to chack the alternator. Firstly if the alternator is playing up normaly you will get an dash borad warning light. But as it's a Boxster nothing is "normal. So, go and get you self a cheap DVM (Digital Volt meter) from Maplin or where ever. find an old mobile phone charger, hack the off. and wire the DVM carefully using terminal block and tape it up so it doesnt short out on anything and plug that goes into the cigarette lighter. You can now drive around for a bit and see what the state of charge is. It should be in the 13-14 volt range. I had this little rig up when in the business and still have it The reason was is that alternators have habit of been interminent and you can see this from the cockpit.

Secondly, Go find a local garage that has high discharge device this will determin if the battery can hold a charge, you need to get some votls in it to start with though.

Conclusion is that you will get a fairly reliabble idea wether it's a battery or alternator.

Finally ....... if its the alternator, as one of threads above suggested you could change it your self. If it's the battery DONT!!! buy one from Porsche they are over priced and you can one of the high capacity Bosche Silver S5 batteries much cheaper, and a much higher capacity.

During this winter I had the same problem as you have, and after much hunting around, I purchased a Bosche Silver S5 S 5010 009250100 from Allparts in Hemel Hempstead mentiond the Porsche Club, showed them my club card and got a further discount. The bill came our at $106.06. I will put my money on your problem that it's the battery in your case, but you need to chack everything first, these cars are notorious for this.

Best of luck hope it helps, cheers

 

[mascanes]

Hi again ........... god male blindess !!!sorry [&:] ......... have just read your thread again, and you say have got the alternator light on ....ok ....... this sort of tells you that it's the alternator then, but it could be worth checking the output voltage just to be sure. You could also have a look at the plug wiring while your under there. Anyway your call.
cheers

 

[allington73]

Thanks very much for the help so far.

On reading back I have missed a few details which I think may help. It has been to the garage twice when it has been discharging the battery. The first time the mechanic said the alternator was charging low and the second charging high (up to 18 amps or maybe volts..........excuse my electrical ignorance)

Battery is more or less brand new and there are no discharge points.

Think I am fairly certain its the alternator but its worrying not being able to say 100%

 

[Mark_Bennett]

ORIGINAL: mascanes

DONT!!! buy one from Porsche they are over priced and you can one of the high capacity Bosche Silver S5 batteries much cheaper, and a much higher capacity.

If you can find one [&:]
I spent a weekend trying to find one anywhere near me (Farnborough, Hampshire).
Nowhere had one. No, not German and Swedish, nor Eurocarparts either...

I ended up buying a new Porsche battery and fitted it myself (saved £100 that way!). The old one lasted 8 years so I hope the new one will not be too bad []

 

[Oceanbox]

Just a quick note my next door neighbour has a 997 c4s and had very similar problems as did another one of our friends who also owns a 997. My neighbour bought a higher powered/rated battery from the net the other chap listened to his local Porsche dealership and had a new wiring loom put in!!!! (Same symptons different fix!).

 

[akwaugh]

Speaking as one who has recently replaced a battery with much the same symptoms, agree with some comments here but advise you should just buy a new battery, dead easy to do, easy to fit and if you follow the instruction book and don't take all day over it you won't lose your codes. PCM will reset after you have driven the car, again in the instructions. If you've got a new-ish battery installed don't be fooled - it could be a dud, just bad luck if it is.

Trouble with this type of problem is that you've got to work through it. Battery first, then alternator. Ask yourself, how many times have you heard of an alternator go phut?.
As for driving, as one of the replies states, if your battery is dud the alternator won't charge it as it can only recharge a fit battery, I think at +13 volts. Won't charge a flat battery.
If you manage to start your car, that's the end of the battery's job, the spinning alt. takes on all loads which is why theoretically you could drive a car these days without a battery.
Oh for the days and joys of a dynamo and voltage regulator - you knew where you stood with that lot!! (age related issue!!)

Oh and one more thing about jump starting, if you do, when you get your car started, you should load up the system by putting on heated seats, window etc., as this gives your own alternator a load to handle, balancing that provided by the other vehicle/battery. I think that's in the manual too. check it out, might be talking rubbish but don't think so.

good luck

 

[akwaugh]

PS - a battery is a battery, just a lump of plastic, lead and acid. Halfords, Porsche, whatever, all the same. Get a standard one for around £80 or if you've aircon maybe £90.
If you do a lot of winter cold starts, get the heavier duty on as for aircon anyway. Cheers

 

[allington73]

Cheers for everything so far guys.

Think I am more confused than when I started ! []

Do you not think the under/over charging is much of an issue then ? The local Porsche garage stated it was a alternator regulator fault causing this and thus would need a new alternator.

Its gonna be a costly job if it is the battery.......£400 for new alternator that may not fix it (which I have already ordered) and then another £80 for new battery if it is that. !!!!! []

 

[colinbythesea]

It's quite simple really but I can see how it all gets confusing despite the excellent advice given.

Think of it this way, the battery is full of electricity which you use to start the car. When the car is running the alternator, like a power station driven from the engine, runs the car and gives left over electricity to the battery so you can start it again. If the battery is not holding electricity the eventually it will stop starting the car. A bit like trying to keep water in a bucket with a hole in.

My own Boxster battery gave up and it was really bad but still started the car. It was only turning out 9 of its 12 volts. I bought a proper rating good manufacturers one for £40 from the local motor factors. As has been said before a battery is a battery really Halfords, and official garages know how to charge for them.

Your next problem is the most probable, the power station of the alternator doesn't turn out enough electricity to run the car and charge the battery due to a fault so the battery doesn't have the power to start the car. When this happens the alternator light will usually show and if you have a voltmeter it usually shows a reading below 14v at the battery with the engine running. The battery could also have been damaged at this point due to having to work too hard.

Before you go paying a fortune for a new alternator think about this, but it is probably more a diy thing. When my 944 alternator gave up I removed it and had a look. An alternator is not difficult to get off of an engine just awkward in a Boxster. Back to the 944 alternator, it was a Bosch one and on it was a regulator which came off (2 screws) and allowed access to a set of brushes which were worn out. These simple graphite blocks take the electricity from the moving part of the alternator so wear out. I went to the motor factors and they got their Bosch catalogue out and ordered a new set of brushes. It was a 10 minute job to clip the new ones in and they cost around a fiver. Some time later 944 alternator went again I took it off again the brushes were still good so I bought a regulator at the motor factors from their Bosch book as the old one had a Bosch part number on. If I remember it was about £20. Fixed and ran on OK.

I have not had the alternator out on my Boxster, and hope it stays put, but I would guess they are much the same still. They are simple devices and need brushes and regulators. I often wonder how many people have spent a fortune on new alternators and where all the economically fixable ones go.

 

[Glyn]

I would plum for the alternator - If the battery discharges when left unused it could have a high current drain - and this can be a result of a faulty alternator (drawing current like an electric motor - when the diode pack fails)

However, If the battery looses all power even during a journey then its almost certainly the alternator - With a flat battery but engine running the motor will run all day just by the alternator output, however a simple test at any battery supplier (heavy duty discharge test) will prove the battery is either good or bad - but beware - If a battery supplier gets the slightest whif of a sale they will reccommend a new battery irrespective - just ask for a test

 

[allington73]

Thanks for all the responses guys.......much appriaciated.

Had it confirmed off garage today that it is new alternator and suspected diode failure. Gonna be out of pocket a fair bit but at least my car is back !

 

[Black80XSA]

Probably too late now but the diode pack is shared with a mercedes part number, both being supplied by Bosch. Mercedes will sell the diode pack for about £30, the OPC will charge you £300 for a full alternator.