Big fuse diag with RS-AJP
Discussion
Hello !
The fuse has nothing to do with the difference. Either the new connection is better, either the old fuse had an airline crack I have not seen. As far as I've read, the low voltage at idle is normal for a Cerbera. Moreover idle is low at 850 instead of 950, which does not help. But I may be wrong!
Julien
The fuse has nothing to do with the difference. Either the new connection is better, either the old fuse had an airline crack I have not seen. As far as I've read, the low voltage at idle is normal for a Cerbera. Moreover idle is low at 850 instead of 950, which does not help. But I may be wrong!
Julien
aide said:
Okay, I see what you mean.
Many thanks for your insight, it is greatly appreciated
Aide
Many thanks for your insight, it is greatly appreciated
Aide
I run my car just over 1000rpm because of the charging issue with the ancillaries on. Measured with a ammeter as I still haven't got around to getting aides program
There is a very big difference between aide who chooses to run his car fast, and someone with a poorly set up engine who can't run their engine slow.
julian64 said:
aide said:
Okay, I see what you mean.
Many thanks for your insight, it is greatly appreciated
Aide
Many thanks for your insight, it is greatly appreciated
Aide
I run my car just over 1000rpm because of the charging issue with the ancillaries on. Measured with a ammeter as I still haven't got around to getting aides program
There is a very big difference between aide who chooses to run his car fast, and someone with a poorly set up engine who can't run their engine slow.
Fact is mine runs fine at the correct idle and always has done for 52000 miles in my care.
If someone wants to run theirs faster to make it run than that's fine, but you don't need to if your car is running correctly.
As you have just said, you run your car just over 1000rpm because of a charging issue.
My car gets used in all weathers through out the year and so far have never felt the need to mess with the idle.
Seems a very strange thing to want to do.
TheRainMaker said:
You can take the piss as much as you like
Fact is mine runs fine at the correct idle and always has done for 52000 miles in my care.
If someone wants to run theirs faster to make it run than that's fine, but you don't need to if your car is running correctly.
As you have just said, you run your car just over 1000rpm because of a charging issue.
My car gets used in all weathers through out the year and so far have never felt the need to mess with the idle.
Seems a very strange thing to want to do.
As the thread says. Sit your car in traffic while hot with the Air con on and possibly the lights (imagine its night time)Fact is mine runs fine at the correct idle and always has done for 52000 miles in my care.
If someone wants to run theirs faster to make it run than that's fine, but you don't need to if your car is running correctly.
As you have just said, you run your car just over 1000rpm because of a charging issue.
My car gets used in all weathers through out the year and so far have never felt the need to mess with the idle.
Seems a very strange thing to want to do.
And then measure the charge balance on the car at 850.
Then decide why we've both done it. Your car (unless you have a different alternator from stock) will not be balancing the charge going out of the car.
In a car, the battery should not take any stress like that while driving. it should only provide current during startup. The alternator should provide all the current for the car ancillaries while running, not the battery
julian64 said:
As the thread says. Sit your car in traffic while hot with the Air con on and possibly the lights (imagine its night time)
Mate, my car was used as my main car for over 5 years, all weathers all traffic conditions, commuting, tunnel runs, trackdays and a run down to the south of Spain.You can drop the sarcastic (imagine its night time) stuff.
I have never felt the need to mess with the idle or funnily enough had the car break down because it ran out of power.
From what I understand, there is a flaw in the design of the charging system of the cerbera : idle is set at 950rpm,but he alternator charges the battery from around 1050rpm (see my graphs). This puts stress on the battery, especially in town driven cars, and I think this is what led to the cerbera reputation of eating batteries. And this is what I think Aide and Julian64 want to overcome by setting the idle higher.
Julien
Julien
Jooles81 said:
From what I understand, there is a flaw in the design of the charging system of the cerbera : idle is set at 950rpm,but he alternator charges the battery from around 1050rpm (see my graphs). This puts stress on the battery, especially in town driven cars, and I think this is what led to the cerbera reputation of eating batteries. And this is what I think Aide and Julian64 want to overcome by setting the idle higher.
Julien
Woodrow Wilson, the voice of reason...Julien
tangerinedream said:
Jooles81 said:
From what I understand, there is a flaw in the design of the charging system of the cerbera : idle is set at 950rpm,but he alternator charges the battery from around 1050rpm (see my graphs). This puts stress on the battery, especially in town driven cars, and I think this is what led to the cerbera reputation of eating batteries. And this is what I think Aide and Julian64 want to overcome by setting the idle higher.
Julien
Woodrow Wilson, the voice of reason...Julien
Julien
TheRainMaker said:
Mate, my car was used as my main car for over 5 years, all weathers all traffic conditions, commuting, tunnel runs, trackdays and a run down to the south of Spain.
You can drop the sarcastic (imagine its night time) stuff.
I have never felt the need to mess with the idle or funnily enough had the car break down because it ran out of power.
Bit antagonistic, there was no sarcasm meant.You can drop the sarcastic (imagine its night time) stuff.
I have never felt the need to mess with the idle or funnily enough had the car break down because it ran out of power.
You assume you don't have a problem because you give the impression of having never checked for one. You'll only see it if you check the amp-age. In day to day traffic you will have no problem. A reasonable battery will keep your ancillaries working with the differential discharge probably for a couple of hours. Unless you sit in a traffic jam for over this time you will do just fine. The only thing you'll notice is going through batteries faster than normal.
Just for clarification my post wasn't meant to be sarcastic and I can't see that on re-reading. No ones asking you to change your idle speed, its just the explanation of why, with perfectly good engines we don't.
Very good data. There are actually two problems evident here:
1. The alternator is spinning to slowly - it is meant to provide a charge on idle. The proper fix for this would be an alternator pulley that is, say, up to 10% smaller. The concern here is to make sure the alternator stays below its rated max rpm at maximum engine rpm.
2. The charging voltage, above idle, is really too low. At 13.3 volts, the battery will never ever be fully charged unless you top it up very regularly with an external charger, and the battery will fairly quickly sulphate and loose most of its rated capacity. This is a common problem, btw, not only with Cerbs. Proper charging voltage is between 13.8 and 14.2 maybe 14.3 volts.
Would be interesting to study this closer.
1. The alternator is spinning to slowly - it is meant to provide a charge on idle. The proper fix for this would be an alternator pulley that is, say, up to 10% smaller. The concern here is to make sure the alternator stays below its rated max rpm at maximum engine rpm.
2. The charging voltage, above idle, is really too low. At 13.3 volts, the battery will never ever be fully charged unless you top it up very regularly with an external charger, and the battery will fairly quickly sulphate and loose most of its rated capacity. This is a common problem, btw, not only with Cerbs. Proper charging voltage is between 13.8 and 14.2 maybe 14.3 volts.
Would be interesting to study this closer.
Edited by egilkv on Monday 29th August 08:06
Jooles81 said:
From what I understand, there is a flaw in the design of the charging system of the cerbera : idle is set at 950rpm,but he alternator charges the battery from around 1050rpm (see my graphs). This puts stress on the battery, especially in town driven cars, and I think this is what led to the cerbera reputation of eating batteries. And this is what I think Aide and Julian64 want to overcome by setting the idle higher.
Julien
The alternator is off an old Range Rover that red lined at around 5500rpm, to stop the Cerb alternator over reving TVR put a bigger pulley on it he sees not charging at lower rpm.Julien
Actually, the alternator probably can not be spun faster as, as grufallo said, it comzs from a landy that redlines at 5500rpm.
Solution would be to find another alternator that fits and that can be spun faster.
On the other hand, what limits an alternator speed? Would it be possible to mod an alternator so it can spin faster?
Julien
Solution would be to find another alternator that fits and that can be spun faster.
On the other hand, what limits an alternator speed? Would it be possible to mod an alternator so it can spin faster?
Julien
Found those guys that can build heavy duty alternators for range rovers and the like. Maybe they could make one for the cerbera?
http://www.qualitypowerauto.com/category_106/Land-...
http://www.qualitypowerauto.com/category_106/Land-...
gruffalo said:
The alternator is off an old Range Rover that red lined at around 5500rpm, to stop the Cerb alternator over reving TVR put a bigger pulley on it he sees not charging at lower rpm.
The real data point is the max rpm rating of the alternator, versus the gearing provided by the crankshaft and alternator pulleys. Alternators are usually rated at 15000 rpm or higher. The Cerbera alternator is, afaik, based on the Lucas A127-100, but it is produced by Magneti Marelli. I have no authorative data on this, but I stumbled over data from New Holland that would indicate it could be 18000 rpm. http://92.50.156.82/manual/TM/Repair%20Manual%20TM... This needs to be verified.If someone could please measure the effective radius of the two pulleys, we can establish if a higher alternator gearing is feasible.
There are 2 other important points: minimal rotating speed to charge the battery, and why the regulated voltage is so low. From the graphs, the alternator regulates between 12.5 and 13.3V, instead of 13.6/ 14.4. Why? Could it be that the cables are so old and worn that the resistance is bringing voltage so low? Are Aide's and my regulators shagged to the point the regulate 1V too low?
Julien
Julien
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