Breaker for aux-battery ??
Thread Starter
Super Member
Joined: Apr 2012
Posts: 616
Likes: 5
From: Planet Earth
S500
Breaker for aux-battery ??
Yesterday I came back from 2weeks work abroad, then I wanted to take the Benz for a spin .
No power to anything so doors don't open.
Luckily I could use the key (that tiny thing in the fob) to open the door,all the interiour lighting was still off, but upon pushing the 'start' button it fired right up.Obviously the starter baterry was fine.
After this drive,with no issues ,only joyjoyjoy. I parked it back up in the unheated garage and this morning everything was fine again, all systems are go.
Questions:
1.it it normal that the aux-battery in the rear compartiment discharges within 2 weeks time?
2.if yes, is it possible to mount a circuit breaker or such for the aux-batt.. and where? To avoid this in the future.Especcially when cold, my battery would freeze to dead without charge.
3 or is there another solution...
No power to anything so doors don't open.
Luckily I could use the key (that tiny thing in the fob) to open the door,all the interiour lighting was still off, but upon pushing the 'start' button it fired right up.Obviously the starter baterry was fine.
After this drive,with no issues ,only joyjoyjoy. I parked it back up in the unheated garage and this morning everything was fine again, all systems are go.
Questions:
1.it it normal that the aux-battery in the rear compartiment discharges within 2 weeks time?
2.if yes, is it possible to mount a circuit breaker or such for the aux-batt.. and where? To avoid this in the future.Especcially when cold, my battery would freeze to dead without charge.
3 or is there another solution...
Member
Joined: Dec 2009
Posts: 164
Likes: 3
2007 S 65
Yesterday I came back from 2weeks work abroad, then I wanted to take the Benz for a spin .
No power to anything so doors don't open.
Luckily I could use the key (that tiny thing in the fob) to open the door,all the interiour lighting was still off, but upon pushing the 'start' button it fired right up.Obviously the starter baterry was fine.
After this drive,with no issues ,only joyjoyjoy. I parked it back up in the unheated garage and this morning everything was fine again, all systems are go.
Questions:
1.it it normal that the aux-battery in the rear compartiment discharges within 2 weeks time? No! A good battery should hold up longer than two weeks. But remember there is a constant discharge going on.
2.if yes, is it possible to mount a circuit breaker or such for the aux-batt.. and where? To avoid this in the future.Especcially when cold, my battery would freeze to dead without charge. You could use a circuit breaker but it is better to put on a trickle charger. They are cheap, easy to hook up and can be used to keep both batteries in good shape, especially for a vehicle on in constant use.
3 or is there another solution...
No power to anything so doors don't open.
Luckily I could use the key (that tiny thing in the fob) to open the door,all the interiour lighting was still off, but upon pushing the 'start' button it fired right up.Obviously the starter baterry was fine.
After this drive,with no issues ,only joyjoyjoy. I parked it back up in the unheated garage and this morning everything was fine again, all systems are go.
Questions:
1.it it normal that the aux-battery in the rear compartiment discharges within 2 weeks time? No! A good battery should hold up longer than two weeks. But remember there is a constant discharge going on.
2.if yes, is it possible to mount a circuit breaker or such for the aux-batt.. and where? To avoid this in the future.Especcially when cold, my battery would freeze to dead without charge. You could use a circuit breaker but it is better to put on a trickle charger. They are cheap, easy to hook up and can be used to keep both batteries in good shape, especially for a vehicle on in constant use.
3 or is there another solution...
Thread Starter
Super Member
Joined: Apr 2012
Posts: 616
Likes: 5
From: Planet Earth
S500
Thanks! How many amps would you suggest and where to connect it please?
I know there is some 'plastic' cover next to/in front of the starter-battery. If you remove that rectangular cover: that should be the leads going into the aux-batt. (the + connector very close to the chassis)
Would that be it to connect to?
Then I would want to make something permanent: mount the charger under the hood or somewhere, so I only have to plug in the mains when I arrive, to stop for longer time...thus not to having to open the bonnet everytime.. any thoughts or suggestions always welcome.
I know there is some 'plastic' cover next to/in front of the starter-battery. If you remove that rectangular cover: that should be the leads going into the aux-batt. (the + connector very close to the chassis)
Would that be it to connect to?
Then I would want to make something permanent: mount the charger under the hood or somewhere, so I only have to plug in the mains when I arrive, to stop for longer time...thus not to having to open the bonnet everytime.. any thoughts or suggestions always welcome.
Member
Joined: Dec 2009
Posts: 164
Likes: 3
2007 S 65
This is what I use.
http://www.batterymart.com/p-del-021-0128.html,
I connect it to the starter battery or the aux battery but it mostly stays on the aux battery during winter. The connecting point is right under that plastic cover. Just leave the neg terminal connected to the battery and move the pos terminal to the tall pin under the cover.
I did not permanently mount mine to the car. I have it sitting on a shelf next to the car. I just lift the hood connect the two terminals and plug it in. About once a month I'll connect it to the starter battery until it goes green then I'll reconnect it to the aux battery.
http://www.batterymart.com/p-del-021-0128.html,
I connect it to the starter battery or the aux battery but it mostly stays on the aux battery during winter. The connecting point is right under that plastic cover. Just leave the neg terminal connected to the battery and move the pos terminal to the tall pin under the cover.
I did not permanently mount mine to the car. I have it sitting on a shelf next to the car. I just lift the hood connect the two terminals and plug it in. About once a month I'll connect it to the starter battery until it goes green then I'll reconnect it to the aux battery.
Last edited by tonykharper; Apr 24, 2012 at 08:43 AM.
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Thread Starter
Super Member
Joined: Apr 2012
Posts: 616
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From: Planet Earth
S500
Great info! I can live with 2 months of 'standby' time, but indeed 2 weeks seemed a very short time..
Have emailed the dealer and they offered to do a power-leak check, if it happens again (its still under Star-warranty).
Just out of curiousity: I have added two pix of the setup in the back.
Does this look OK to you: a 60 AH aux-battery(MB says its OK)
and that 7.5A fuse looks very un-original to me:
Have emailed the dealer and they offered to do a power-leak check, if it happens again (its still under Star-warranty).
Just out of curiousity: I have added two pix of the setup in the back.
Does this look OK to you: a 60 AH aux-battery(MB says its OK)
and that 7.5A fuse looks very un-original to me:
Member
Joined: Dec 2009
Posts: 164
Likes: 3
2007 S 65
Great info! I can live with 2 months of 'standby' time, but indeed 2 weeks seemed a very short time..
Have emailed the dealer and they offered to do a power-leak check, if it happens again (its still under Star-warranty).
Just out of curiousity: I have added two pix of the setup in the back.
Does this look OK to you: a 60 AH aux-battery(MB says its OK)
Attachment 234621
and that 7.5A fuse looks very un-original to me:
Attachment 234622
Have emailed the dealer and they offered to do a power-leak check, if it happens again (its still under Star-warranty).
Just out of curiousity: I have added two pix of the setup in the back.
Does this look OK to you: a 60 AH aux-battery(MB says its OK)
Attachment 234621
and that 7.5A fuse looks very un-original to me:
Attachment 234622
You can charge your trunk battery by hooking it up under the hood.
On the passenger side just left of the starter battery there is a black plastic box. Remove the cover and you will see the power points for the rear trunk mounted battery. The tall terminal, the one near the front, is the positive terminal. Connect your positive lead there and hook the negative lead to the negative terminal on the starter battery. If you want to charge the starter battery just move your positive lead six inches to the positive battery terminal. Hope this make sense.
Tony
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Thread Starter
Super Member
Joined: Apr 2012
Posts: 616
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From: Planet Earth
S500
Not at the moment. I thought it wouldn't be from the factory, with those blue connectors etc.. thanks for confirming that!
I can only guess ..sat-tracker ??There are no crazy accessoiries afaik besides the standard option list.
Good that I bought the car from an MB-dealer with 6 months warranty,they do have the full history, since they sold the car new as well ,so if this issue plays up again, when I am back,
I get down there and start asking more questions ..and they will measure leak-current as they promised.
@Tonykharper: thank you for those instructions !
I can only guess ..sat-tracker ??There are no crazy accessoiries afaik besides the standard option list.
Good that I bought the car from an MB-dealer with 6 months warranty,they do have the full history, since they sold the car new as well ,so if this issue plays up again, when I am back,
I get down there and start asking more questions ..and they will measure leak-current as they promised.
@Tonykharper: thank you for those instructions !
Last edited by marthyh; May 2, 2012 at 04:24 PM.
