That tells me there’s no weird power draw from the light/brake systems, which is good!
But, I would expect you to be in the 14’s voltage when running. I really don’t think your alternator is working properly.
‘94 RRC LWB battery light
- Thread starter Blueboy
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But, I would expect you to be in the 14’s voltage when running. I really don’t think your alternator is working properly.
The alternator has less than 2500 miles on it. Not sure if I ever saw 14 volts although that is what the manual says it should. Its a Bosch that I got from Will. I’m going to check the Disco and see what it is pumping out.
My battery fully charged shows 12.6 volts while the Saab shows 13.1. So if the alternator is pushing 13.1 volts to a battery with only 12.6 wouldn’t the battery light dimly light?
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I would think so but I don’t actually know the answer for certain. But it’s barely charging enough to keep up. You should be able to look up your exact alternator and see what the normal output should be.
One additional question…. Did you reuse the belt pulley from your old alternator? If not, maybe the new pulley is much bigger diameter so it’s not spinning as fast as it should be??
Just a thought.
I can vouch for that being a possibility as I had it happen on a used one I installed. My 95 Disco takes the smaller pulley than later models.
If you have the 4 rib belt, I believe the correct diameter should be 2.5 inches. So if your pulcer is larger than that, the alternator may not be spinning fast enough.
If your pulley is correct, check one more voltage reading. Turn everything possible on… lights, radio, air conditioner, fan on high etc. Just to see how it reads with a maximum load.
If your pulley is correct, check one more voltage reading. Turn everything possible on… lights, radio, air conditioner, fan on high etc. Just to see how it reads with a maximum load.
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Ok, yet, lets keep in mind this is a recent situation. When I installed the new alternator everything was fine. No battery charging light with high beams on plus 2 Hella driving lights illuminated. I would trust Will T sold me a correct alternator.
However something seems off. Rangie is hibernating now in any case as Winter / salt has settled in so the issue goes to Spring.
Thanks for all the input and suggestions. Will follow up on this if we get a few nice days.
I’m sure he got you the correct alt, but the pulley could be wrong.
And also, it’s an electrical part. So it might last forever or die after a month.
But seems like once you drive it enough to fully charge the battery, it’s doing enough to get by.
Keep us posted if you find something.
Thinking back I did use the pulley from the old alternator as had to bring out my battery powered impact tool to remove the nut. Remember calling Will and asking why it didn’t come with a pulley and he said there are various sizes so use the one from the old one.
Looks like some nice weather next week. Will check the voltage under heavy load like the frt and rear embedded defrost along with everything else.
To err on the safe side will purchase a new battery come Spring.
Thx again for the help.
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Just some additional info on the exact spec from Bosch since I thought 13.4v seemed much lower than it should be ….
“Greetings Todd, the normal charging output for AL9346X would be 14.5 volts.”
So maybe borrow a different battery to see if it shows a better charge reading. If it’s the same, I would have the alternator tested. Worst case, autozone/oReilly etc carry your alternator with lifetime free replacement. That’s definitely worth considering. FYI.
“Greetings Todd, the normal charging output for AL9346X would be 14.5 volts.”
So maybe borrow a different battery to see if it shows a better charge reading. If it’s the same, I would have the alternator tested. Worst case, autozone/oReilly etc carry your alternator with lifetime free replacement. That’s definitely worth considering. FYI.
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Thanks again for the help and research. Will get it tested. We have a local Autozone. At least I know how to install one if necessary.
No problem. I just wanted to verify the specs so I wasn’t telling you the wrong thing.Thanks again for the help and research. Will get it tested. We have a local Autozone. At least I know how to install one if necessary.
And why in the back of mind the alternator isn’t the problem. Of course it could be yet not sure what it is as the Rover is 27 years old and basically original wiring. Have lots of good information and come Spring will dive into it more. Thanks again for the help. Really appreciate it.
"Just because a part is new does not mean that it is good." Not sure where I first heard that, but it's something to remember when diagnosing.
Yep, especially with electrics. That’s why I thought it’ only charging around 13.4v is an issue because it should be closer to 14.5.
Ok, as it Christmas and no snow/salt on the road drove the Beast to family get together. 120 miles round trip. Voltage at start 13.1 as new battery. Voltage upon return 12.2. WTF! So checked the alternator. Voltage at battery cable as it comes out of the alternator ≈ 14.2 at idle. Voltage on same alternator cable at battery terminal 12.2! Where am I losing the circuit? Is this a ground problem?? And pouring rain both ways.