generator on 2,5dse

sarstad · Nov 20, 2010

hey i have bin looking a bit around on a bmw site .
ant discovered that moastog the bmw 525td and 530td is running with a 140-150ah generator...

the range rover p38 2,5 dse is on a 95ah generator .

have anyone changede there generator to a bigger one ? mabye that is what shout be don to solve the electric problems vi have all the time with
over heatet gearbox an so on ..

any input´s

Datatek · Nov 20, 2010

The standard alternator should be fine if it's working properly, if the battery is good and you do not have a lot of power consuming non standard extras fitted.
Whatever size alternator you fit, it won't keep the battery up if all you do is very short runs.

sarstad · Nov 20, 2010

but then way do they deliver a bigger generator to the same car

Datatek · Nov 21, 2010

sarstad said:
but then way do they deliver a bigger generator to the same car

To power bigger lights, SAT Nav systems, stereo amps, dozens of bloody ECU's and so on, it's called progress. If it was just a matter of charging the battery a 25amp alternator like I have on my digger would do the job

sarstad · Nov 21, 2010

that i can understand but there is a lot more electronic on a rr than on a bmw 525d og 530d

wammers · Nov 21, 2010

sarstad said:
that i can understand but there is a lot more electronic on a rr than on a bmw 525d og 530d

Maybe BMW have been a little more thoughtful in their application. I think many systems on the P38 are driven directly from the alternator and not from the battery. As you would need a battery the size of a bungalow otherwise. The P38 battery is fairly small amperage for the amount of electrical systems used. That is why you get systems going down if the alternator starts to fail. If they were driven from the battery the alternator could not charge it fast enough to maintain voltage. BMW on the other hand have taken system power from maybe a slightly higher AMP battery and provided a larger generator to maintain the voltage. Is that a reasonable theory?

sarstad · Nov 21, 2010

wammers said:
Maybe BMW have been a little more thoughtful in their application. I think many systems on the P38 are driven directly from the alternator and not from the battery. As you would need a battery the size of a bungalow otherwise. The P38 battery is fairly small amperage for the amount of electrical systems used. That is why you get systems going down if the alternator starts to fail. If they were driven from the battery the alternator could not charge it fast enough to maintain voltage. BMW on the other hand have taken system power from maybe a slightly higher AMP battery and provided a larger generator to maintain the voltage. Is that a reasonable theory?

yes

if i ask landrover her in dk they want to fit a 100AH batt .
and if the generator is on 95ah and the car are running on the generator all the time than there i a quoit small amount left to charge the bat right ??
then the bat is only 95% up and after sometime 85% and so on .

if there is a lager charging capacity then the bat will be between 95 and 100% all the time ..

am i totally off in my theory ??

wammers · Nov 21, 2010

sarstad said:
yes
if i ask landrover her in dk they want to fit a 100AH batt .
and if the generator is on 95ah and the car are running on the generator all the time than there i a quoit small amount left to charge the bat right ??
then the bat is only 95% up and after sometime 85% and so on .

if there is a lager charging capacity then the bat will be between 95 and 100% all the time ..

am i totally off in my theory ??

I would say fit the largest battery you can get in there. It has to be said that the diesels with the larger amperage battery (needed for cranking) suffer a lot less from system problems than does the V8 with the much smaller capacity battery. So that maybe the way to go.

sarstad · Nov 21, 2010

wammers said:
I would say fit the largest battery you can get in there. It has to be said that the diesels with the larger amperage battery (needed for cranking) suffer a lot less from system problems than does the V8 with the much smaller capacity battery. So that maybe the way to go.

ma by that is the way .
i will say it have to be tested and see if it a better up-great and fit a lager generator and a large battery.
if i can keep the gearbox, and other fails away

on both the 2,5 and the v8

wammers · Nov 21, 2010

sarstad said:
ma by that is the way .
i will say it have to be tested and see if it a better up-great and fit a lager generator and a large battery.
if i can keep the gearbox, and other fails away on both the 2,5 and the v8

Don't think you need to fit a bigger alternator just a battery. But it's up to you.

sarstad · Nov 21, 2010

wammers said:
Don't think you need to fit a bigger alternator just a battery. But it's up to you.

I will then start with a larger battery and then when the alternator go bad then go for the 140ah one an see what happens

wammers · Nov 21, 2010

sarstad said:
I will then start with a larger battery and then when the alternator go bad then go for the 140ah one an see what happens

Think that's the way to go. I suppose up where you are it is dark for longer and sooner at certain times of the year than down here, so the extra battery capacity for running with lights on makes absolute sense to me.

sarstad · Nov 21, 2010

wammers said:
Think that's the way to go. I suppose up where you are it is dark for longer and sooner at certain times of the year than down here, so the extra battery capacity for running with lights on makes absolute sense to me.

her the sun sets around 0400 pm am back up at 0730-0800am

wammers · Nov 21, 2010

sarstad said:
her the sun sets around 0400 pm am back up at 0730-0800am

Bit confused now does that mean it is dark longer or light longer at this time of year? Are you saying dark at 4 in the afternoon and sunrise 7.30 to 8.00 in the morning.

gtland · Nov 21, 2010

Gotta agree with previous posts, that the biggest battery you can fit will do no harm, and may even last longer as it should be less stressed in use. If your original alternator breaks then by all means replace with a larger unit, (check it`s physical size first tho`), but probably not necessary.
Don`t the BMWs have the battery hidden under the rear seat? Lot`s of space, good place for a heavy lump (low & between the wheels), and bigger batteries require less maintenance (for similar use). Just a thought.

Datatek · Nov 21, 2010

Most alternators will never fully charge a battery. The internal regulator is fixed at 14.7 volts plus or minus 0.2 volts. The charging current reduces as the the battery voltage approaches 14.7 volts as there is no longer a potential difference. A good smart battery charger on the other hand maintains a constant current for a period of time, then reduces the rate charge and finally goes into a float charge mode.
When the engine is running all systems are effectively powered by the alternator. The low impedance of the battery serves to absorb sudden surge current demands such as from an electric window being operated and help maintain a constant voltage.

The bigger the battery the better as far as I'm concerned. An 85% charged 140 amp hour battery obviously has more starting power available than an 85% charged 90 amp hour battery.

On boats we used to chuck the internal alternator regulator away and fit an external microprocessor controlled regulator that had the same charge characteristics as a smart battery charger. With this it was possible to ensure the batteries were as fully charged as possible in the shortest time possible.

generator on 2,5dse

sarstad

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sarstad

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sarstad

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sarstad

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wammers

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sarstad

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