Range without alternator

[mpc007]

Hi and a beautiful saturday to everyone,

but unfortunately I won't be able to enjoy it with my recently acquired Zed because the alternator seemingly gave out Yesterday got the red battery light, thought I might go away so drove a bit further. Then all sorts of different lights on the cluster lit up (and went out) which was for me a sign that there wás indeed something seriously wrong and I drove home directly. Managed to make it, but along the way all sorts of functions started to fall out, from abs / dsc in the beginning unto power steering and the smg box in the end (indicated by the lights on the cluster not only flashing but also staying on). Of course I turned all accessories down to save power. When I reached home I just had enough juice to roll up the windows, but the top didn't want to close.

Luckily had a spare 74Ah battery charged in the garage, so picked it up, connected, and was able to close the top, start the car, and move it to a place where it could stand for a few days. Also measured it with the multimeter, voltage while running was below 12V indicating the alternator didn't do a darn thing. I could also hear it rattle when opening the hood.

So I'm bringing it to the place where I bought it to have the alternator looked after and most likely service it or swap it for a new one (belt was still on and running so i'ts not that) but the problem is that place is about a 30 minute drive (~25km) from my home. So I'd like to know if i''m able to reach that with two 74Ah batteries and a non-working alternator or that I'm still at risk being left stranded.. Of course I'll leave all accessories off (lites, satnav, radio, etc) but I still have my SMG computer working and of course the coilpacks / sparkplugs asking energy. So I'm curious what you guys are thinking

 

[Anonymous]

I would think one fully 75ah charged battery should do it easily providing all unnecessary loads are off..

On complex compression ignition aircraft we reckoned a 14 ah battery could keep us going for 30 minutes

So two should be fine..IMHO ..never having tried it

 

[Tyreman]

A similar thing happened recently to my friend with a Mk1 Audi TT, the AA recovered him and told him that the car would cover approximately 15 miles on a freshly charged battery, he set off to the specialist a few days later and broke down after about ten miles.

It was a right drama and the specialist had to recover him for a second time within a week.

 

[firebobby]

My battery light came on last year, I bought and fitted a regulator off eBay.
It's easy to do and fixed the problem. Total cost was less than £30.
You can do this with the alternator still on the car.

 

[mpc007]

Thanks for your replies! Just had Netherlands road side assistance (ANWB) look at it, they recharged the current 74Ah battery to the max and said that with the secondary 74Ah in the back as backup might I need it I would make the 30 minute trip to the repair shop for sure. They couldn't say what part of the alternator was faulty, just that indeed did NOT charge the battery at all. They remarked the belt drive was fine, but I'd already concluded the same. They did give two pointers for the main brake vacuum line (looked all twisted) and the disa valve (some rattle coming from it) so I'll have the repair shop check those while it's there.

My battery light came on last year, I bought and fitted a regulator off eBay.
It's easy to do and fixed the problem. Total cost was less than £30.
You can do this with the alternator still on the car.

Is there a way to find out if its the regulator needing replacement or the inner workings of the alternator (carbon brushes etc) itself?

 

[firebobby]

I checked the charging rate with the engine running and it was slowly dropping. I can't remember an exact way to test the parts, (search the forum) but I believe an alternator will cost hundreds of £££. The regulator is a cheap and easy fix if it's the issue. I believe it's the main problem with these alternators.
My car had do 90 k and the rest of the alternator was fine.

 

[mpc007]

Thought it nice to place an update for other owners struggling with the range question.

Two days ago took the drive to the repair shop, I had two full 74Ah Varta batteries with me. I switched all amenities I could think of off, even the ventilation blower (A/C itself was of course off too). Rolled the windows halfway down in order to not get smoked inside, since the top was staying closed (apparently that takes quite a bit of juice as I saw earlier). Satnav screen was off and put down, dsc off, smg in manual mode and tried to change gears as economical as possible, since with every gear change the computer has to work the clutch. steering also economical, to use power steering least as possible. With all these hassle, I was able to complete the 35 minute / 25km drive to the shop with no problems or flashing cluster, apart from the red battery icon of course on the single 74Ah battery.

Repair shop is now sending the alternator of for revision, they didn't trust the cheaper non-OEM alternatives I sent and said a full revision would make the OEM alternator new for the same price, so doing that. After they get it back, they'll swap the multibelt at the same time, so that's also good to go. Hope to get the car back by saturday!

 

[mmm-five]

I hope you don’t have the same issue I went through in a previous car (an e34 M5).

Had a similar charging problem, so got the alternator rebuilt at the local Bosch service centre…all the bench tests passed, so ready to head to Dover the following weekend for a Ring weekend.

Got to the office in London (from Liverpool) fine, and about 3am the morning of travel I left London for Dover…got 50 miles and started getting the same electrical power losses…the alternator failed again

Got the car to the ferry check-in, but couldn’t risk it getting stuck abroad, so arranged to leave it parked in Dover docks for the weekend and carried on as a passenger in a friend’s GT-R.

Came back, got recovered home and got the Bosch service centre to fix the alternator under warranty.

Travelled down to London the following week and started losing electrical power again…luckily I’d decided to carry a spare battery & charger and knew I only had to get to the hotel to be able to charge the battery…which would get me home.

Finally got back home and back to the Bosch service centre once again.

This time I asked what they’d replaced at each of the previous, failed rebuilds, and was told they’d put a new regulator on (as they would on every rebuild) and replaced the worn down bushes. I then asked them what could keep pushing out the bushes within 500 miles, considering it worked fine on a 20 minute bench test, so they checked the commutator ring and found out it was not quite round…and was gradually pushing the bushes out

Got that fixed, and they also spotted a couple of blow diodes they wouldn’t normally replace (alternator would still work fine with a few of these failed).

The further fixes cost me nothing in the end, but I did have to rent a ramp to remove & refit the blasted thing 3 times…and I missed my Ring trip :x

 

[mpc007]

I hope you don’t have the same issue I went through in a previous car (an e34 M5).

Had a similar charging problem, so got the alternator rebuilt at the local Bosch service centre…all the bench tests passed, so ready to head to Dover the following weekend for a Ring weekend.

Got to the office in London (from Liverpool) fine, and about 3am the morning of travel I left London for Dover…got 50 miles and started getting the same electrical power losses…the alternator failed again

Got the car to the ferry check-in, but couldn’t risk it getting stuck abroad, so arranged to leave it parked in Dover docks for the weekend and carried on as a passenger in a friend’s GT-R.

Came back, got recovered home and got the Bosch service centre to fix the alternator under warranty.

Travelled down to London the following week and started losing electrical power again…luckily I’d decided to carry a spare battery & charger and knew I only had to get to the hotel to be able to charge the battery…which would get me home.

Finally got back home and back to the Bosch service centre once again.

This time I asked what they’d replaced at each of the previous, failed rebuilds, and was told they’d put a new regulator on (as they would on every rebuild) and replaced the worn down bushes. I then asked them what could keep pushing out the bushes within 500 miles, considering it worked fine on a 20 minute bench test, so they checked the commutator ring and found out it was not quite round…and was gradually pushing the bushes out

Got that fixed, and they also spotted a couple of blow diodes they wouldn’t normally replace (alternator would still work fine with a few of these failed).

The further fixes cost me nothing in the end, but I did have to rent a ramp to remove & refit the blasted thing 3 times…and I missed my Ring trip :x

What a story, definitely hope I’m not having the same. It’s also bad publicity for Bosch, you’d expect more from an established brand, and also from the joke they dare call a revision. A revision should imply ALL parts of the unit that undergo wear are replaced, and a very thorough check of the parts that are not. Otherwise you could as well fetch anew regulator and use that with an old alternator from the scrapyard. Sine that will most likely get you just as far before failure. Mine got revised by an independent local firm, it certainly looks fresh and fully revised to me