5 replies to this topic

[Lenhamracer]

Hi,

 

I still have a problem with my 1998 MPI. It draws around 170ma from the battery and after a few days (1-2 weeks) the battery is empty. I checked all the fuses and the c4 fuse draws 80ma. It is for the radio, horn relay and?? I disconnected the radio and still 80ma. So the radio is fine. I took all the yellow relays out of the engine bay - still the same. Where is the horn relay?? Is it in the car behind the dash?

70ma are drawn by fuse number b6 which is responsible for the alarm and so on. This might be normal??

 

Thank you very much 

 

Thomas

 

[Steam]

Are you sure you disconne ted the radio completely, depending on model there can be more than 1 supply to it.

[68+86auto]

How are you measuring the current?

If the horn works then It won't be the horn relay.

[Lenhamracer]

Yes I disconnected the radio completely.

 

I measured the current by connecting an ammeter in the battery cable. 

[nichmoss]

According to Haynes, C4 runs Radio, Clock, brake system warning light, direction indicator/hazard warning unit, alarm indicator light, interior light.

B6 runs the alarm and horn.

According to the Owner's handbook, everything is the same but C4 is indicated as "alarm" and not just "alarm warning light". That's in addition to B6. Could just be the warning light. It's an LED so is probably taking 15-30mA. 80mA seems a bit high but not out of the question.

150mA is one Ah after about seven hours so, 3-4Ah per day. If you're running a 55Ah battery then ten days will see it essentially dead. I use a 70Ah battery in mine.

Many people say it's the immobiliser that kills the battery on these and from your figures, that seems about right. I run a continuous trickle charger from NOCO on mine.

Good luck, Chris

[Deeppockets]

I have experienced issues with battery discharging. I have resorted to fitting a "Discarnect" battery isolator when left standing.

 

The alarm, of course, is not active with the battery disconnected which is a risk - though when the battery is flat it is also off.