Trickle Charging

[Zed Baron]

Recently a new member was asking about battery life and leaving the car unattended for a period of time. Lots of suggestions of trickle chargers, now I have mine on a Ctek trickle charger connected to the red terminal etc under the bonnet, another member suggested forget that and link the charger direct to battery in the boot. So just to clarify what is the correct way (if any) and why?

 

[mr.tourette]

iirc bmw recommend under the bonnet.. I have run a permanent long flylead to down by the kidney grills for easy connection without having to open the bonnet each time

 

[Pondrew]

Well the handbook says to charge from the auxiliary terminals under the bonnet, make of that what you will.
Surely the whole point of BM putting the positive terminal and the ground stump on the suspension mount under the bonnet is for convenience and ease of use, so why make it more difficult?
My charger also fits nicely in the recess above the o/s headlight, so I can shut the bonnet and just leave it. Easy peasy.

 

[enuff_zed]

I may be well off course with this, but all my reading on here seemed to point to the fact that on the E85/6 you could connect straight to the battery, but on the E89 it was recommended to use the under bonnet connections as then it ran through the IBS. I suppose going straight to the battery would negate all that clever stuff about modifying the charging profile to suit the age of the battery?
Being a cautious soul (for which read: scared of the unknown :roll: ) I always connect under the bonnet.

 

[Marcoose]

Unless there’s an electric component between the leads under the bonnet and the battery, something that would improve the quality of the charge, then there’s no difference. And I don’t know whether there’s or not.

 

[Zed Baron]

I had a look around on the interweb and found this, "If you hookup directly to battery you bypass the IBS (intelligent battery sensor) monitoring, raising the battery's state of charge (SOC) and run the risk of the alternator over charging the battery until the next sleep cycle determines the battery's SOC".... So or :thumbsdown:

 

[enuff_zed]

I had a look around on the interweb and found this, "If you hookup directly to battery you bypass the IBS (intelligent battery sensor) monitoring, raising the battery's state of charge (SOC) and run the risk of the alternator over charging the battery until the next sleep cycle determines the battery's SOC".... So or :thumbsdown:

Which is basically what I was saying.
Use the engine bay ones. If it's a stretch across to the negative terminal on the OSF strut tower, you can clip on to the multi earth point mounting stud, about 6" down below the NSF top mount instead.
I then run the lead out through the gap on the inner edge of the NS headlight so the bonnet will close properly.

 

[Zed Baron]

Which is basically what I was saying.

Yeah but I had to find out what the IBS was.... glad its mechanical and not medical!

 

[Marcoose]

Intelligent Battery Sensors. Blimey.

Sometimes the Bavarians are too smart for their own good.

 

[Pondrew]

So if the car has the facility to intelligently monitor charging, does that mean that theoretically "intelligent" (read expensive) chargers are a waste of money, as the car already has the facility built-in? :?

Or not?

 

[Zed Baron]

So if the car has the facility to intelligently monitor charging, does that mean that theoretically "intelligent" (read expensive) chargers are a waste of money, as the car already has the facility built-in? :?

Or not?

I've been looking on Realoem at the BMW charger (which looks very much like a Ctek charger) and 61432289103
the battery comfort indicator which seems to plug into the charger (saves attaching to terminals, Ctek have a similar product), it has eyelets but I cant find where you attach it. Does it fit under the bonnet or in the boot with the battery, if it is the latter then it contradicts everything.

 

[mr.tourette]

So if the car has the facility to intelligently monitor charging, does that mean that theoretically "intelligent" (read expensive) chargers are a waste of money, as the car already has the facility built-in? :?

Or not?

I charge mine on a 30 quid motorcycle charger, its still classed as a smart charger though as it monitors charge and requirement but a lot cheaper than the cteks everyone raves about

 

[Smartbear]

So if the car has the facility to intelligently monitor charging, does that mean that theoretically "intelligent" (read expensive) chargers are a waste of money, as the car already has the facility built-in? :?

Or not?

If you’re not using the car for some time you’re still going to need a charger (preferably an intelligent one)
The ibs system won’t regulate a non smartcharger, it doesn’t work like that
Rob

 

[Pondrew]

If you’re not using the car for some time you’re still going to need a charger (preferably an intelligent one)
The ibs system won’t regulate a non smartcharger, it doesn’t work like that

How does this Irritable Bowel Syndrome work then? What I was really getting at was;
If I had a low amperage charger, say 2 amp, without the ability to sense a full-charge point; ie not intelligent, then would the IBS not shut the current off to the battery anyway, regardless of what the charger does?

 

[Scubaregs]

Porsche charger is a Porsche branded CTEK. I used the CTEK cig lighter connection on the 718.

 

[Pondrew]

Porsche charger is a Porsche branded CTEK. I used the CTEK cig lighter connection on the 718.

I have a trickle/ maintenance charger. This is purely theoretical, as I am interested in the magic that is this mythical IBS.

 

[Scubaregs]

Porsche charger is a Porsche branded CTEK. I used the CTEK cig lighter connection on the 718.

I have a trickle/ maintenance charger. This is purely theoretical, as I am interested in the magic that is this mythical IBS.

Porsche has a similar system, the recommendation is to use the cig lighter connection, or the positive battery terminal and the earthing connection on the chassis (not the negative battery terminal) so you do not bypass the smart battery tech.

 

[Smartbear]

If you’re not using the car for some time you’re still going to need a charger (preferably an intelligent one)
The ibs system won’t regulate a non smartcharger, it doesn’t work like that

How does this Irritable Bowel Syndrome work then? What I was really getting at was;
If I had a low amperage charger, say 2 amp, without the ability to sense a full-charge point; ie not intelligent, then would the IBS not shut the current off to the battery anyway, regardless of what the charger does?

It wouldn’t do that, it reports back to the ecu which controls the output of the alternator according to an algorithm.
It’s interesting to plug in a voltmeter to the ciggy port, the charge rate increases when your coasting with no throttle & also when you’re braking, it then reduces when you accelerate again.
Rob

 

[Pondrew]

It’s interesting to plug in a voltmeter to the ciggy port, the charge rate increases when your coasting with no throttle & also when you’re braking, it then reduces when you accelerate again.

But the voltage doesn't give a charge rate, surely. Only an ammeter could do that?
If that's the case, then that's been coined by the PR boys as a "mild hybrid" IIRC

 

[Smartbear]

It’s interesting to plug in a voltmeter to the ciggy port, the charge rate increases when your coasting with no throttle & also when you’re braking, it then reduces when you accelerate again.

But the voltage doesn't give a charge rate, surely. Only an ammeter could do that?
If that's the case, then that's been coined by the PR boys as a "mild hybrid" IIRC

When the voltage increases it’s a pretty good sign the charge rate has increased even though you’re just seeing volts, it’s called regenerative braking by bmw although the brakes themselves don’t contribute to the battery charging, it’s just the application of them that steps up the alternator output.
Rob