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Saftlad

Leaving car standing for long periods

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With the current situation, my car hasn't moved for 5 weeks.

 

Should I be looking to run the engine for a bit to charge the battery?  I don't need to go to the shops or anything like that.  We have a smart charger for the caravan battery too, but I'm wary of disconnecting the car battery.

Any advice?

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I think you can trickle charge the car through the cigarette lighter.  For Ctek chargers you have to buy a special adaptor . Never done it though so don't know the ins and outs :).  But disconnecting the battery to charge it seems to open a lot of problems as well

 

 https://www.amazon.co.uk/CTEK-CTE-56263-Cigarette-Lighter-Connector/dp/B0016LA5O8

 

Other than that make sure the tyres are at their upper pressure limits to prevent flat spots.  Maybe 35-40 psi

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2 hours ago, Saftlad said:

Should I be looking to run the engine for a bit to charge the battery?  I don't need to go to the shops or anything like that.  We have a smart charger for the caravan battery too, but I'm wary of disconnecting the car battery.

Any advice?

 

Personal opinion is that running the engine at idle in the hope of charging the battery is worse than leaving the car untouched. The process of starting the car uses much more energy than will possibly be replenished by leaving the car idling. 

 

If you do choose to charge the battery, make sure the charger has a setting specifically for the AGM battery fitted to you G31 and ONLY charge with the battery in situ and via the jump start poles found under the bonnet. This way the IBS (Intelligent Battery Sensor) is in the charging circuit. DON'T charge via the 12v sockets in the car. The electrical systems are very complex now and you don't want to fry something else connected to those circuits. 

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42 minutes ago, Matthew Ashton said:

 

 

Personal opinion is that running the engine at idle in the hope of charging the battery is worse than leaving the car untouched. The process of starting the car uses much more energy than will possibly be replenished by leaving the car idling. 

 


I’m not so sure about that.

 

My car takes under 2 seconds to start (actually almost immediately unless it needs the gloplugs) and the starter motor will take somewhere between 200 and 500 amps during that, say 1000 amp-seconds to be extreme. I think the alternator could easily charge at 50 amps but if you assume only 5 amps that would only equate to say 200 seconds. Of course a (pretty extreme) 500 amps would give the battery a disproportionately nasty jolt but you’ll get my meaning - a few minutes idling at even 5 amps charging would easily outweigh it.

Edited by Boba

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I think the issue that Matthew may have been pertaining to is the the fact that the alternator is not permanently engaged and charging. I believe that BMW remote services monitors battery levels but apart from that a short drive including plenty of coasting/overrun may be enough. 

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If the alternator is disengaged then it would be becasue the battery doesnt need charging.  If its been sitting for 5 weeks then some level of charging would be required

 

I would take the car for a short spin to bring it up to temperature, then let it idle for 10-15 minutes.   Warming the car up from idle is generally inefficient and bad for the injectors. Of course its a lot warmer now :)

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talking of warmer, can’t recall if this was the case but do G30’s have a “cold” indicator under temp gauge?

 

new iD7 has this and I find that my X5 is never showing cold with the warmer weather now. Wonder if there is enough residual heat from sun blazing down on car that engine is in fact warm at say 30/35 degrees.

 

anyways. Shopping trip should be enough to warm up engine and then leave idling to recharge battery for a couple of minutes. unless you have your shopping delivered that is
 

 

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Decided to take the 540i touring to the supermarket for a change, first time it's been used for almost 5 weeks. Started immediately and drove(as usual) like a brand new car, well, apart from the layer of dirt.

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On 16/04/2020 at 22:31, Matthew Ashton said:

If you do choose to charge the battery, make sure the charger has a setting specifically for the AGM battery fitted 

Would my CTEK  MXS 5.0 charger be ok for my G30 battery? 
Haven’t used it yet on the G30, I bought it for my E39 a few years back. 

Edited by ally

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38 minutes ago, ally said:

Would my CTEK  MXS 5.0 charger be ok for my G30 battery? 
Haven’t used it yet on the G30, I bought it for my E39 a few years back. 

 

Yes, perfect, my G32 is on charge using the CTEK MXS5.0 at the moment. It has an AGM mode that needs switching to.

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47 minutes ago, Matthew Ashton said:

 

Yes, perfect, my G32 is on charge using the CTEK MXS5.0 at the moment. It has an AGM mode that needs switching to.

Many thanks Matthew, I’ll have a look at that. 

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