TheSamba.com :: View topic - Charging voltage of new Bosch AL82N alternator?

Sat Feb 04, 2017 3:04 pm

1971 Bay Camper Bus
Can someone tell me what the charging voltage should be? I know that 13.9 is standard for alternators generally but I seem to remember a lower figure for the AL82N.
Here is the story: My charging voltage is 13.47. This is not a new one but one which seems to need a voltage regulator. It charges at the 13.47 rate when cold but does not charge when warmed up.
I contacted Bosch since it is supposedly a lifetime guarantee. But they are no honoring that. They are demanding a sales receipt. I bought the alternator in around 2005 but do not remember the vendor. It could be online or a place in Oregon. I do not think I should need a receipt since I filled out a warrantee card. But now they say that was not a warrantee card but a roadside service card. In addition, there is a number on the box which states it is proof of purchase number. But they are not accepting that either. (Of course I realize someone could get the alternator and box second hand but that is not the case with me.)
In any case, the issue now is whether I should replace the VR myself and forget about replacing the alternator. But if it has a shot diode in addition to the defective VR then that is not the way to go.
The bus does not get much use and I could see where the voltage might be a little low due to disuse.
I have searched the internet without finding the correct figure for a new alternator. Ratwell, for instance, l tells you everything else but that.
Finally, since I am offended with Bosch' attitude in handling the "lifetime warrantee" I would not be adverse to trying an alternative brand. I see very inexpensive choices but are they any good? Can anyone give me a review of how the cheaper alternators compare with the Bosch? As you can see I need something that will hold up long term! I am not looking for something that will last a year.

Sat Feb 04, 2017 3:28 pm

Welcome,
With the bus shut off and a volt meter connected across the battery what's the voltage?, does it rise when you start the bus and rev it a little?

You could just have a severly discharged battery and it'll take a while before it gets to 14, 13.9 doesn't sound bad if it maintains that even if you turn on the headlights.

Sat Feb 04, 2017 3:44 pm

check your belt tension,check and clean all the charging/battery connections and check your volt meter,if the brushes are worn out that would be considered a maint item.if the slip ring is worn they could say that was from dust.
forget about getting warranty,they would probably want you to ship the alt to them,they would test it,then tell you it did not fail due to manf defect,but due to other causes then charge you for testing it plus return shipping.

Sat Feb 04, 2017 4:55 pm

the difference between 13.47 and 13.9 is meaningless if you haven't calibrated the meter with a professional calibration source. I calibrated 3 expensive DC meters this year only to find that not one was accurate. I used a lab standard device to calibrate them. If you are showing 13.47 I would except it and move on. 13.5 to 14.5V DC is considered quite able anyway unless you are running a calcium based battery. The main job it does is start the car.

Sat Feb 04, 2017 5:34 pm

So far no intelligent answers. You know, you could just say you don't know and leave it unanswered.

Sat Feb 04, 2017 5:39 pm

richard123vmt wrote: So far no intelligent answers. You know, you could just say you don't know and leave it unanswered.

a few of the most helpful & knowledgeable people in this forum have taking time to answer your question.

13.4 is not abnormal and should be enough to charge your battery. I've tested a bunch of new voltage regulators and have seen everything from 13 to 14.5. Try another regulator if you're not satisfied.

Sat Feb 04, 2017 5:46 pm

If I don't get an answer to a simple question, at least it will be informative to VW owners that you cannot depend on the lifetime warranty. All those years I knew I had sent in a card and therefore felt a false sense of security that I could get a replacement as a last resort. Now I find out it is only for someone crazy enough to have a lifetime record of every purchase. Maybe we should ask for a receipt on archival paper?
But I would actually prefer to replace just the VR. I did not know when I called Bosch that you can buy a VR. The reason I would prefer it is I can replace it easier than the entire alternator which would require either removing the engine or a lot of work anyway to do it with the engine in place.
But that option is only valid if the VR is the only thing wrong. The fact that the VRs are so readily available on the retail market probably shows that there was a problem. Anyone would think they would accept responsibility.
I paid about $100 for the original. If I am going to go out now and pay $244 for a replacement, you have no idea how much badmouthing that would entail. I am not a happy camper.

Sat Feb 04, 2017 6:31 pm

richard123vmt wrote: You know, you could just say you don't know and leave it unanswered.

Confusious say, 'saying you have no answer, is still an answer, grasshopper'

Sat Feb 04, 2017 6:45 pm

I recommend you ask a moderator to move this topic to the late beetle forum, buses were never equipped with the AL82N in North America so unless someone has an orange Bentley for a late bug handy you aren't going to get an exact specified test voltage range, mine's out in the shop and it's dark and snowing, I might have made the effort to go look, but your attitude has changed my mind.

Good luck with your endeavour. :wink:

Sat Feb 04, 2017 7:37 pm

The Bosch AL82N warranty clearly requires a dated receipt or equivalent proof of purchase, and you are required to
go through the place of purchase to get warranty service. The "card" you sent in was only for the 24-month road assistnace
coverage. Folks who try to get warranty benefits without a receipt
are usually scammers. Tuff shit that you lost yours, maybe you should be more careful with your stuff.

Sat Feb 04, 2017 9:37 pm

Basically, a normal flooded lead acid battery doesn't really charge below 13.8 volts (although it maintains a charge at that voltage), and is typically fully charged at 14.4 volts. All voltages measured at the battery. But, all of these voltages vary with the temperature of the battery: more voltage if colder, less if warmer. Voltages are also slightly different for AGM batteries and spiral-wound batteries. Here's a link for the straight scoop.

Bosch has become famous for voltage regulators set on the low side. I finally got tired of that crap and changed my AL82N over to external regulation, then modified the external regulator to make it adjustable. See this.

Sun Feb 05, 2017 12:21 pm

richard123vmt wrote: So far no intelligent answers. You know, you could just say you don't know and leave it unanswered. I don't know.

Mon Feb 06, 2017 9:42 am

richard123vmt wrote: Can someone tell me what the charging voltage should be? I know that 13.9 is standard for alternators generally but I seem to remember a lower figure for the AL82N.
13.8v (min) @2000rpm when starting with a fully charged battery (one reading 12.6v at rest).

Your 13.47v reading is meaningless unless you also provide the voltage at your battery while it is at rest (confirming it was fully charged). This is why busdaddy asked what the voltage was at your battery... but you "blew off" his reply. :(
Also, you didn't mention if your voltage reading was at idle or at some higher rpm. Most alternators are not able to provide max current at idle rpms. 13.47v at idle is not a reflection of a good/bad charging system.

Also, VW alternators are dependent on the Gen light providing a "tickle charge" to get the field circuit going. If your Gen light is burnt out your alternator will never charge. Not a sign of your charging system needing to be replaced, just the driver not paying attention to their start up procedures.

For example, if your battery was discharged and only reading 12.0v at rest, there would probably be enough charge there to still crank your engine and get it started. But the voltage reading at the battery would be less than 13.8v @2000rpm leading you to think your charging system was not working well. This would be a mistake as the voltage reading at the battery is negatively impacted by the weak battery even though your charging system is working well.

Both the vr and diodes in your alternator can be replaced so a rebuild is an option. Whether you can do the rebuild yourself is another question.
If your alternator is actually bad, find a good/reputable shop that will rebuild your alternator and test it. Have them use the best quality parts they can find so you get the longest life from your rebuild (this doesn't mean the most expensive -- the price differences between cheapest and most expensive are crazy).

I believe the reason the replacement parts are more readily available is more related to these alternators being actively sold to/used by Beetle enthusiasts for the last 43-years. There is still a demand for them even though no Beetle has left a factory with one in the last 15-years!
BTW, Porsche 914s also came with Bosch alternators and the AL82 is a common replacement there as well.

There has recently also been a huge revival of classic car parts outside the VW Beetle community. Bosch has a whole division now geared just to the classic car enthusiast. They are not the only company to do this.
http://www.bosch-classic.com/en/internet/bosch_classic/startseite/startpage.html
Maybe this revival has something to do with parts being more available?

Mon Feb 06, 2017 11:26 am

The VR went in my Bosch AL82N ,you have to remove the alternator from the car and then remove the end plate . Because my beetle is my main car I bought a cheap chinese alternator to keep me mobile while I tracked down a VR and fitted it. I ended up leaving the cheapie on for about a year before refitting the bosch . In just over a year the Chinese alternator had play in the bearings so I would NOT recommend you buy a Chinese clone unless you drive a very low mileage

Mon Feb 06, 2017 1:23 pm

13.8~ 14.2 sould be good. if it dont charge hot somethen is rong....or the battery is fully charged and nothing is drawing any current...or jelly.

Mon Feb 06, 2017 8:34 pm

richard123vmt wrote: The fact that the VRs are so readily available on the retail market probably shows that there was a problem.

The real problem on the retail market is when the stock for genuine Bosch VRs is Zero. A high demand for Bosch VRs means more tequila, chiles and chipotle picoso for lunch! :P

95 Bosch VRs for AL82N alternator shipped by FedEx to Germany.

Fri Jul 28, 2017 7:31 pm

After all this time, I finally replaced the alternator with what is represented to be a rebuilt Bosch. But it is from Oreillys with a lifetime guarantee so I assume it is rebuilt with cheap parts. I took a toke from someone here who said he got one of these non-Bosch cheapies and the bearings went in a year. So I set up the belt a little looser than average.
Anyway, the in dash volt meter is now showing charging. If anything a bit high. I haven't measured it yet. at the alternator. The old one would charge at the 13.4 rate only until it warmed up. Then it was hardly charging at all. I couldn't drive it at night and had frequent recourse to the battery charger. So now I am sitting pretty.
As for collecting on the Bosch guarantee, I gave up. Then I got a return call only to tell me no. You always appreciate them taking the time to tell you no. But the matter had already been settled. By that time I had moved on so it was reopening an unpleasant issue. I have heard of keeping a receipt, yes. But I have also heard of them keeping track as your parts chains do. Anyway, the bottom line is that it WAS a defective Bosch alternator!!!!! And the car was on the road only 7 years. I think the trouble started while it was mostly idle. I tried cleaning the rings with spray but no good. Anyway, I still think Bosch makes good stuff.