New alternator and power usage

rambrose

Full Member

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Fitted the new alternator last weekend and all is good. Thought I'd share some info.
I managed to drive from the centre of Scotland to Plymouth on the vehicle battery which was kept charged from the leisure batteries.

The van is a 2008 Citroën Relay with the 2.2 puma engine

Whilst the alternator was dead I took some current readings of how much stuff actually used

Just to keep the engine running uses 8 amps.
Side lights (just front and tail) - 3 amps.
Dipped headlights - 11 amps
Indicators - 4 amps
Wipers - 4 amps
Blowers on #1 - 3 amps
Blowers on #4 - 7 amps
Mirror heaters - 6 amps

Full beam headlights - 9 amps
Brake lights - 1 amp
Reversing (lights and sensors) - 3 amps
Cab interior lights - 2 amps
Electric windows - 5 amps each while moving, then 15 amps when they hit the stops.

This is my starter battery and I've numbered the cables. It may be useful for fault finding.
20251006_185001.jpg
#1 dc to dc cable
#2 - Electric windows
#3 - Wipers, side lights, dipped headlights, mirror heater, Indicators and courtesy lights.
#4 - Full beam, blowers, brake lights and reverse
#5 - alternator and starter motor

The new alternator is a WAI 150 amp one from GSFCARPARTS.COM.
With their discount code (they always have a code) it cost £161.
Has a 3 year garauntee.

It came with a test sheet that listed the output current at various revs
1600 rpm - 71 amps
2000 rpm - 105 amps
3500 rpm - 144 amps
5000 rpm - 155 amps

I did have a brief panic until I found out that the above is alternator rpm which is 2 or 3 times faster than engine rpm.

Disconnecting the alternator was easy enough. Getting it out of the engine bay not so easy.
Removing the mass airflow housing gave enough space to get it out via the driver's wheel arch
 
For measuring the current used by the windows, lights etc I used https://amzn.eu/d/8QRhiqS
A DC amp clamp. You don't have to put the meter "in" the circuit and it will handle more than 10amps.

The data on the output amps at a given rpm was provided by the manufacturer.
 
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