battery drain

[peanut]

CAN ANYBODY HELP

I HAVE BEEN SUFFERING FROM MY BATTERY DRAINING, SOMTIMES FLAT AS A PANCAKE.I ONLY USE CAR WEEKENDS.

I HAVE FULLY CHARGED BATTERY LOCKED IT UP AND IN ABOUT 5 TO 8 DAYS BATTERY IS SO FLAT I HAVE TO USE BOOSTER TO START IT.BATTERY IS NEW AND HOLDS CHARGE WHEN NOT FITTED IN CAR. CAN ANYBODY HELP AND GIVE ME SOME CLUES OF WHERE TO START LOOKING.

[sean f]

There is a lot of info / discussion on this.

Normally the problem is the alarm / remote locking system. The early units are sensitive to all sorts of signals in the right general frequency such as remote control garage doors, door bells, cameras, weather stations and possible broadband routers although I have seen this disputed. As soon as it detects a signal the system wakes up listens for it activation code for a few minutes then shuts down again, this happening constantly flattens the battery, the factor fix was a more frequency sensitivy detector so it needed the correct code before it woke up, These can be retro fitted. Origionally when the cars were new there were less remote control devices about so it was less of a problem although cases of batteries going flat when cars were left next to transmitters such as at hospitals or airports were quite common.

Another fix is to remove the aerial from the detector in the car, the remote can still be used but you need to be a lot closer so it is less sensitive to false signals.

Do a search on google and you will find a variety of sites giving advice and instructions on removing the aerial (it easy to put it back on if it still doesn't fix it).

Also try parking somewhere else, I found parking in the road the battery lasted longer than parked in my drive feet away from a broadband router.

The electrics of the P38 a notoriously complex so it is possible something else has partially failed causing a short.

I tried a few things with limited success but now if I am going to leave the car for more than a few days I disconnect the battery and leave it like that.

[q-rover]

A quick check to see if it is the alarm/ BECM is to watch the light by the gearlever

once you have locked the car.

It should stay on for about 3mins then go out, this signifies the BECM has gone to

sleep. If it comes back on again then something is waking up the BECM.

What happens is when the BECM is asleep the drain on the battery will be insignificant

(0.1A or something) but when the BECM is awake it is draining over 1A I believe.

[peanut]

There is a lot of info / discussion on this.

Normally the problem is the alarm / remote locking system. The early units are sensitive to all sorts of signals in the right general frequency such as remote control garage doors, door bells, cameras, weather stations and possible broadband routers although I have seen this disputed. As soon as it detects a signal the system wakes up listens for it activation code for a few minutes then shuts down again, this happening constantly flattens the battery, the factor fix was a more frequency sensitivy detector so it needed the correct code before it woke up, These can be retro fitted. Origionally when the cars were new there were less remote control devices about so it was less of a problem although cases of batteries going flat when cars were left next to transmitters such as at hospitals or airports were quite common.

Another fix is to remove the aerial from the detector in the car, the remote can still be used but you need to be a lot closer so it is less sensitive to false signals.

Do a search on google and you will find a variety of sites giving advice and instructions on removing the aerial (it easy to put it back on if it still doesn't fix it).

Also try parking somewhere else, I found parking in the road the battery lasted longer than parked in my drive feet away from a broadband router.

The electrics of the P38 a notoriously complex so it is possible something else has partially failed causing a short.

I tried a few things with limited success but now if I am going to leave the car for more than a few days I disconnect the battery and leave it like that.

thanks for taking the time to answer my question, i will try parking in the road and see how it gets on

[peanut]

A quick check to see if it is the alarm/ BECM is to watch the light by the gearlever

once you have locked the car.

It should stay on for about 3mins then go out, this signifies the BECM has gone to

sleep. If it comes back on again then something is waking up the BECM.

What happens is when the BECM is asleep the drain on the battery will be insignificant

(0.1A or something) but when the BECM is awake it is draining over 1A I believe.

thanks for taking the time to answer my question

[uksniper1]

hi,i had low an flat battery probs for a while,then my battery light stuck on,it was a shorting alternator in the end,changed it ,and havent had a flat battery or the warning light being stuck on since..

[v8bobber]

hi,

I had a similar problem with my P38, it's a good idea to search the web and do the various tests with the test meter to find out if the BECM is going to "sleep" or not.

I found that even though the battery tested ok at the local battery place I bought a good quality new one with a decent Ah rating which solved the problem. My RR gets left for a week at a time and fires up straight away even when it's cold. I found that the problem was getting worse over time, and by that I mean that the amount of time for the battery to discharge was getting less and less each time, and reckoned that it must therefore be the battery.

It's not a difficult problem to solve either way (hopefully)

Dave