WANTED - ALTERNATOR

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thanuttiscotsman
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WANTED - ALTERNATOR

Post by thanuttiscotsman »

hi there,
does anyone have a good 80 amp diesel alternator? i need a replacement for my 50 amper as im always suffering flat batterys because of big ice etc.

cheers rossco
1989 BX 16v ph1 Chipped, k+N, full scorpion, weber throttle body, NOS 1990 BX 16v ph2
1996 transit 2.5di 80 swb
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jeremy
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Post by jeremy »

Will a bigger one go in - they won't on Turbo Diesels without considerable modification.

Sounds more like a battery or other electrical problem unless the thing is only used for very short runs. The alternator supplied should be able to cope - never had any trouble at all with my TD when it was driven 5 miles twice a day always in the dark, or any other car for that matter.

Or perhaps its another problem - is the thing generally reluctant to start?
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docchevron
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Post by docchevron »

Cant help you with an alternator, sorry Nutti!

I see your point though, ICE systems can draw a mahoosive current, several of the Chav Nova's that congregate round here have a battery in the boot just to run the ICE!

An 80 amp should fit the valver no problem, might be a bit of cow to get in the gap though...

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thanuttiscotsman
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Post by thanuttiscotsman »

hi there,
yeah i have a system that can draw up to 1200w so it can actually drain the battery even when it on tickover! but yeah the 1.9d alternator fits in no prob and gives an extra 30amp. but yeah my car doesnt get used its stored in muy garage and only gets run when i pull it out and let it tick over for a couple hours switching it off when its too hot and running it again for a while when its cooled. also just gets toddled round the car park to help keep the bearings and stuff in check. and sometimes gets a trip to the local disused glider strip for the 8krpm bouncing malarky. but i never keeps its battery power up for long when its not being used much. but i do love to pump my tunes when im working away on her but cant really just now cos it flattens the battery al the time. plus my battery is new its now a great expensive one but does the job. its one of those banner starting bull thingys.

but anyhow i still need an 80 amper if anyone has one sitting on the garage floor that would be great.

cheers rossco :wink:
1989 BX 16v ph1 Chipped, k+N, full scorpion, weber throttle body, NOS 1990 BX 16v ph2
1996 transit 2.5di 80 swb
2006 Suzuki GSR 600cc Fast as F**K!
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Mike E (uk)
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Post by Mike E (uk) »

Hi,

Have you checked you have not already got an 80A alternator?
I have checked 3 BX16Vs and they all had them.

Also, have you checked the current from the battery with the car switched off? Perhaps the stereo is draining the battery- often happens if there is no switched accessories 12V fed to the stereo-as on the BX- unless you add it yourself from the clock.

If it battery has run completely flat, this can permanently reduce its capacity.

Check you have at least 13.5V on the battery with the motor running.

Sorry if you have done these things,... sucking eggs etc....
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thanuttiscotsman
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Post by thanuttiscotsman »

hi there,
it seems cool as it usually reads about 14.2 volts when running. maybe i do have an 80 amp, how do i check this?

rossco
1989 BX 16v ph1 Chipped, k+N, full scorpion, weber throttle body, NOS 1990 BX 16v ph2
1996 transit 2.5di 80 swb
2006 Suzuki GSR 600cc Fast as F**K!
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Post by jeremy »

There is always a problem charging batteries fully. You've correctly measured a normal charging voltage - but at that voltage the alternator is producing very little output.

If you drain the battery - its voltage drops - and so the voltage difference between the alternator output and the battery increases, and more current flows. As the battery charges, its voltage rises and so the alternator output is reduced.

There are some electronics in the alternator to control its output - and basically they keep its voltage down. If it rises (which can happen by modification or damage) the electrics on the car can be damaged and the battery will boil and spit acid out (had it happen - lights worked much better, wiper went beserk and the indicators flashed rapidly)

So if you have a 50 amp-hr battery - which is empty - charging it at 50 amps for 1 hour is unlikely to charge it fully - and will mean running the alternator at about 3 or 4000 revs (it will revolve faster than the engine - probably about 1 1/2 times for a petrol.) Contrary to popular belief alternators do not produce much at idle - they are a bit better than the old dynamos - but this is simply because they are run faster

(dynamos were safe for about 6000 RPM - Alernators are safe for about 12,000 RPM - so for a good petrol engine of the 60's you could run a dynamo at engine revs - and an alternator 1 1/2 times engine revs)

So - are you giving it a chance - and would you be better with a powerful mains battery charger.

Incidentally - while your 1200 watt ICE would seem capable of pulling 100 amps at 12 volts - I doubt if it really is running more than 10 or 15 when averaged. I did meter output many years ago on a Hi Fi system and was quite surprised how little current (as a proportion of max) was drawn most of the time - peaks yes - rest of the time - no.

The turn-off point mentioned above is very valid. Unless every component has a click type switch it will draw a sizeable current when off - as I found out when a CD player ran my BX down over about 1 week. The easy way of curing this problem is to install a main switch - which can be incorporated in a battery terminal.
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thanuttiscotsman
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Post by thanuttiscotsman »

hi there,
thanks for the info. i have never had probs with this stereo draining batterys when its switched off. the only thing that does is the amp but i have a switch installed in the line so i can kill that drain which i do. but even with the car running at 3000rpm with the stereo turned up the lights in the car still dim down with every bassline :twisted: maybe i do have an 80 amp in but after a disscussion on the other forum im led to believe that the 16v has a 50 amp alternator. if so then i need to get an 80 amper in as i dont use the car barely so im always struggling for power. i do also have an 150 amp charger/booster which is pretty incredible how fast it charges. when the battery is completely dead ie no dash lights at all it will charge the battery enough to start after just 15 mins. but i cant be arsed with charging it all the time would just prefer that the car did that part itself.

cheers rossco
1989 BX 16v ph1 Chipped, k+N, full scorpion, weber throttle body, NOS 1990 BX 16v ph2
1996 transit 2.5di 80 swb
2006 Suzuki GSR 600cc Fast as F**K!
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Post by MULLEY »

Cant u rig up a double battery system? i thought that power hungry ice systems tended to have 2 rather than 1?
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Mike E (uk)
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Post by Mike E (uk) »

I am 95% sure you will have an 80A alternator already.
It will say on the back of it if you can see round there.

Mike
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Post by jeremy »

All circuits flicker to some extent - my house sometimes do if something taking a heavy current is switched on - and I noticed my BX clock flashing in time with the indicators the other day.
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Post by DavidRutherford »

The problem you have is that you don't drive the car.

From what you've said in the past, it either sits idling for hours on end, or is driven rather hard for a very short period. Alternators won't work particularly well in either of these situations

At idle, you could haven an eleventybillion amp alternator, and it won't produce any more output than a 30amp one.

Conversley, at 8000 rpm (12000 alternator rpm) you would only be able to produce 80amps if the battery is completely flat (and even then only for a moment), or you have 80 amps worth of other load on it. (which is some 1.1kw constant load.... I doubt it). If you do manage to spike the battery with 80A, the only thing you're likely to do is overheat the plates and ruin it.

To keep the battery in good condition, it needs to have charge on a regular basis, and at a sensible level. If the car was used on a regular basis, for a period of time, at sensible rpm, then you would not have a problem.

Remeber, it can take up to 300 miles of normal driving to charge a battery completely, as once the engine is running, the battery will probably only be taking 5A.

The best thing you can do is to use a trickle-charger on the battery on a regular basis. 5A overnight is much better than 150A for 10 minutes.... and thinking about it, if you've let the battery go completely flat, and then 150A charged it back to life more than about twice, the battery is probably knackered anyway.

A friend of mine had a Land-Rover with lots and lots of spotlamps, large(ish) ICE and just a 30A alternator. Not a problem.
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thanuttiscotsman
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Post by thanuttiscotsman »

hi folks,
david you are right the prob is that i dont use the car enough. but when i do it does get driven quite sensibly most of the time but quite often it does get wound up to near max power. but i think what i might do is take my other battery and install it in the boot and link it up to the other under the bonnet so i have twice the power.

Mike i think you may be right as my battery does charge up incredibly quickly when i have the car running. to be honest the battery isnt always totally flat when i go to the garage i really depends how long the interevals are between when iam there. sometimes i leave it for up to 3 weeks. but it depends, sometimes when i put loads of fuel in and let it tick over for about 30 mins or till the fans come on then let it cool then run it again for a while on and off for a total of maybe up to 3 hrs running time in total in one day then it stays powered up and starts no prob for weeks but mostly now iam there maybe 1 time per week.

but anyhow i will install the other battery and see how i get on with that.

cheers for the help, rossco
1989 BX 16v ph1 Chipped, k+N, full scorpion, weber throttle body, NOS 1990 BX 16v ph2
1996 transit 2.5di 80 swb
2006 Suzuki GSR 600cc Fast as F**K!
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