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Founding Member 2006
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Do you have a SmartTop?
Did you buy your car used?
Any 3rd party device you know or might be unaware of like radar or car alarm or lights?
 

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Founding Member 2006
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108,881 Posts
Some early versions of the Smarttops had power drain issues but that was resolved. do you know when your SmartTop was made or what version?
I charge my car with a ctek 4.3 trickle charger/maintainer every week

how old is your battery? did u have same issue with any other battery?
 

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So how long does it take for your battery to go dead? When we bought our car last summer the dealer instructed us to put a trickle charger on the car whenever it sat for more than 14 days. This is due to the fact that a couple of the computers are never off. ( according to dealer anyway)
I have heard that bmw has a large problem with discharging batteries. Have a friend with a new x5 and he puts a trickle charger on if it sits for more than 7 days. And it has gone dead when he didn't. Of course it could be the smart top as well. I haven't put that on our car yet.
 

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Founding Member 2006
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Premium Member
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Discussion Starter · #8 ·
Some early versions of the Smarttops had power drain issues but that was resolved. do you know when your SmartTop was made or what version?
I charge my car with a ctek 4.3 trickle charger/maintainer every week

how old is your battery? did u have same issue with any other battery?

I have this one:

http://www.reinhold-engineering.de/pdf/CMR171_e.pdf


The battery is a BOSCH S4. It have 2 months old !!!
The previous battery was also a BOSCH S4 and it died in with less than 2 years old.
 

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Founding Member 2006
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108,881 Posts
your new battery might have been defective or had bad cells if it was not tested prior to installation. or you maybe have an alternator not working up to par

get a ctek charger and charge weekly :D
or that other brand smarttop is draining your battery
 

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Discussion Starter · #10 ·
So how long does it take for your battery to go dead? When we bought our car last summer the dealer instructed us to put a trickle charger on the car whenever it sat for more than 14 days. This is due to the fact that a couple of the computers are never off. ( according to dealer anyway)
I have heard that bmw has a large problem with discharging batteries. Have a friend with a new x5 and he puts a trickle charger on if it sits for more than 7 days. And it has gone dead when he didn't. Of course it could be the smart top as well. I haven't put that on our car yet.
The Battery goes dead in 3 to 4 days!
 

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Discussion Starter · #11 ·
your new battery might have been defective or had bad cells if it was not tested prior to installation. or you maybe have an alternator not working up to par

get a ctek charger and charge weekly :D
or that other brand smarttop is draining your battery
I had charged it already, and it goes for another 4 days.
I'll disconect the smarttop for a week and see what will happen !!!

Thanks for all the help ! :wink:
 

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Founding Member 2006
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108,881 Posts
i hear you but charging a 'bad' battery accomplishes nada :D
 

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Discussion Starter · #13 ·
i hear you but charging a 'bad' battery accomplishes nada :D
Yes, I understand that, but...

This is the second one. It happened with the old one, and know it's happening with this new one that only have 2 months.
When I Charged it, it stays OK for 3 or 4 days.
It only happens when I don´t ride the car for 3 or 4 days...

And I already mesure the corrent with "all OFF".
For what I know 240 mA It's not normal. It should be 30 to 50 mA.

Do you agree?
 

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Founding Member 2006
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Sean n others more qualified to answer that
But 4 days of no driving is common amount of time for battery to drain on our cars
 

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2008 SLK55 AMG
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Are you able to turn off or disconnect the aftermarket Reinhold module and see if the current draw is still 240mA?
 
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Sean n others more qualified to answer that
But 4 days of no driving is common amount of time for battery to drain on our cars
not common, not normal ..... on my original 8 years old battery (just replaced couple months ago) I left the car parked for 2, 3 weeks at the time (sometime longer), without trickle charged, and it started right up everytime. It eventually died of old age. I also have smarttop.... the only thing is since I parked in the garage, so never locked the door. I heard something likes locked car use more battery (due to sending out signal all the time)
 

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not common, not normal ..... on my original 8 years old battery (just replaced couple months ago) I left the car parked for 2, 3 weeks at the time (sometime longer), without trickle charged, and it started right up everytime. It eventually died of old age. I also have smarttop.... the only thing is since I parked in the garage, so never locked the door. I heard something likes locked car use more battery (due to sending out signal all the time)
did you ever charge that 8 year old battery?
my previous battery got replaced every 2 years like clockwork (4 times) until i started charging it
 

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* Founding Member #2
2008 SLK55 AMG
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IIRC, battery university states heat and humidity is not a car battery's friend.
 
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If you are drawing 240mA with all electrical items switched off then this is your parasitic drain regardless of battery condition.

The length of time your battery can handle this is an indication of it's condition.

You indicated that you removed all your fuses but the power drain was still present.
Can you confirm this as I would have expected at least one fuse to have an effect on the milliamp drain.

Are you using an amp meter in series?

I have a RC model battery charger that allows me to set a trickle charge rating from 50mA upwards in 50mA increments.

On my SLK 55 (with Smartop) the battery, when fully charged, will discharge slightly on a trickle charge of 50mA, it will almost hold power at 100mA and will charge up very slowly at 150mA. I set it at 200mA as I think my battery can handle this long term if required.
From the results that I have it looks like my battery drain when off is about 125mA so 240mA seems high.

Tell us what happens when you disconnect your roof controller.
 
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