Author Topic: Battery flat - Immobiliser  (Read 1459 times)

JB89

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Battery flat - Immobiliser
« on: March 31, 2020, 14:10:34 »
Hey Everyone,

With the pandemic happening my wife and I ran away from London to my in laws house in Germany, which happens to be where I keep my SL280Auto.
Thinking it might relieve some of the anxiety to go for a little drive as the weather here is nice and sunny, I then realised when it was dropped off it wasn't put on its trickle charge.
We had an immobiliser installed which has helped keep it safe in London, but now Im not sure how to charge the battery or jump start it with the immobiliser on?
Or wether I need to change the battery completely (What I did last time this happened)
Hoping there is a way to get it running.

Any thoughts greatly appreciated

Thanks,

J


Cees Klumper

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Re: Battery flat - Immobiliser
« Reply #1 on: March 31, 2020, 15:53:47 »
There is a possibility that your battery has 'expired' since, unless it is a deep-cycle one, it is not made to be fully discharged and sitting for an extended period without any charge can ruin it.
That said, you may be able to bring it back to life with the right charger. I would start with whatever charger you have, after disconnecting the immobilizer (however check the manual for that, if you have it someplace) so the battery is isolated from the car + immobilizer. If that does not produce result (in my experience, a battery may not respond to a charger if totally flat) then a special charger may be needed. I have had good results with my 80 Watt solar panel charger, that for some reason was able to resuccitate flat batteries that other chargers could not. Maybe you can take it to a garage to have them give it a try (although I might not take the additional risk that brings of getting infected).
Cees Klumper
1969 Mercedes 280 SL automatic
1968 Ford Mustang 302 V8
1961 Alfa Romeo Giulietta Sprint Coupe 1600
1962 FIAT 1500S OSCA convertible
1972 Lancia Fulvia Coupe 1.3
1983 Porsche 944 2.5
1990 Ford Bronco II

MikeSimon

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Re: Battery flat - Immobiliser
« Reply #2 on: March 31, 2020, 17:10:35 »
There are small, inexpensive chargers available (here in the U.S., at least) that have a "desulfating" setting. It will revive deep discharged batteries in most cases.
1970/71 280SL Automatic
Sandy Beige
Parchment Leather
Power Steering
Automatic
Hardtop
Heated Tinted Rear Window
German specs
3rd owner