BMW and CTEK charger

im4gine3 · 30 Jan 2021 at 20:49

Hey guys,

Since lockdown started, decided to invest in a battery charger for my 16' F36 435i. Many short stints to the supermarket ain't doing no good to the battery.

I understand the battery is located in the boot, but also understand there are positive and negative terminals located under the bonnet.

Where would i connect the MXS5.0 (front or back) or does it not matter?

mikehhhhhhh · 30 Jan 2021 at 21:16

Supposedly, you can upset the battery controller by charging the battery directly.

I've done it on previous M cars with no ill-effects, but if you have an easy choice, apparently BMW say the front is the place to do it from.

robj20 · 30 Jan 2021 at 21:23

Where ever you manual says to jump start is a safe bet for a charger as well.
If you're 12v socket is live while the car is off your can do it via that as well with an adapter.

Amos91 · 30 Jan 2021 at 21:51

Always connect to the terminals under the bonnet.

jackboy · 30 Jan 2021 at 21:59

I have the same charger and for the same reason, using on my F10 330d, I did lots of research and conclusion was only use charge points under bonnet, as said above!
Reason appears to be that if you charge via the terminals in the boot the brains of the car does not register the charge going into the battery so eventually it gets messed up.....well that is what I was told.
Excellent charger by the way.........way faster than my old one.

chaparral · 30 Jan 2021 at 22:41

im4gine3 said:
Many short stints to the supermarket ain't doing no good to the battery.

This really shouldn't be a problem

My normally work journey is only about 2 1/2 miles (about 7 minutes) each way and i have never had to put my car battery on charge

How short are these short stints your doing ?

im4gine3 · 31 Jan 2021 at 00:23

jackboy said:
I have the same charger and for the same reason, using on my F10 330d, I did lots of research and conclusion was only use charge points under bonnet, as said above!
Reason appears to be that if you charge via the terminals in the boot the brains of the car does not register the charge going into the battery so eventually it gets messed up.....well that is what I was told.
Excellent charger by the way.........way faster than my old one.

Cool thanks.. the charger arrives tomorrow so will give it a go.

chaparral said:
How short are these short stints your doing ?

haha less than a mile give or take, but not only that, infrequent use of the car say once or twice every 2 weeks. I did take it in to a bmw dealer for an mot few weeks back and was told the battery running low is most likely due to this

HoneyBadger · 31 Jan 2021 at 00:26

im4gine3 said:
haha less than a mile give or take. I did take it in to a bmw dealer for an mot few weeks back and was told the battery running low is most likely due to this

Not surprised if it’s 1 mile or less! Not good for the battery or the car as a whole. Sounds like you need an EV or just walk more!

im4gine3 · 31 Jan 2021 at 00:29

HoneyBadger said:
Not surprised if it’s 1 mile or less! Not good for the battery or the car as a whole. Sounds like you need an EV or just walk more!

Ha I would but typically shop for a family of 5 rather than a family of 2.. simply put, I’m lazy to walk

HoneyBadger · 31 Jan 2021 at 00:30

im4gine3 said:
Ha I would but typically shop for a family of 5 rather than a family of 2.. simply put, I’m lazy to walk

Fair enough, at least you’re honest.

just take it for a little run every now and again, get it up to temp and blow out the cob webs.

DarrenM343 · 31 Jan 2021 at 08:46

chaparral said:
This really shouldn't be a problem

My normally work journey is only about 2 1/2 miles (about 7 minutes) each way and i have never had to put my car battery on charge

How short are these short stints your doing ?

Does your car have stop/start technology?
I did the same thing in a BMW X1, lots of short journeys for a few years, and it didn't take too long until the stop/start stopped working. Later took a trip to London and arriving home the stop start still wouldn't kick in. Took it to BMW and it turned out the battery wouldn't charge over something like 40%. Was a cheap battery however - the new one they fitted was made in Germany , the original factory fitted one wasn't. Fitting a new battery also made the rear window demister start working again too

. I reckon the battery was like that for at least 2 years so thankfully never led to a non-start situation.

I always use a Ctek on my cars now, at least once a month. Just because the car starts may not mean the battery is in great health, if left at low charge states for long periods.

Obviously stop/start works differently in different cars but in the case of my X1 it was an indication that the battery wasn't in a great condition after doing lots of short journeys.

jpaul · 31 Jan 2021 at 08:56

I need a trickle charger, but it would be nice if they would now tell you, like the smart nimh ones, how much charge they are putting back into the battery, so that you could monitor discharge from stuff in the car, battery degradation, and just the toll of now irregular short trips.

Nasher · 31 Jan 2021 at 09:45

Get the hardwire kit for the Cteks and just leave it connected to the battery: https://www.amazon.co.uk/CTEK-Indic...words=ctek+hardwire+kit&qid=1612086330&sr=8-8

chaparral · 31 Jan 2021 at 11:44

DarrenM343 said:
Does your car have stop/start technology?
I did the same thing in a BMW X1, lots of short journeys for a few years, and it didn't take too long until the stop/start stopped working. Later took a trip to London and arriving home the stop start still wouldn't kick in. Took it to BMW and it turned out the battery wouldn't charge over something like 40%. Was a cheap battery however - the new one they fitted was made in Germany , the original factory fitted one wasn't. Fitting a new battery also made the rear window demister start working again too . I reckon the battery was like that for at least 2 years so thankfully never led to a non-start situation.

I always use a Ctek on my cars now, at least once a month. Just because the car starts may not mean the battery is in great health, if left at low charge states for long periods.

Obviously stop/start works differently in different cars but in the case of my X1 it was an indication that the battery wasn't in a great condition after doing lots of short journeys.

Start/Stop seemed to been working fine till i added a F770 dashcam which was also draining the battery in parking mode multi times a day every day

Scythe · 31 Jan 2021 at 11:57

Connection points under the bonnet on an F30. Connect the positive to the positive point under the red flap at the top left of the bonnet (when facing the car), under the positive point there is a negative (earth) peg off the chassis to save you scratching any painted regions.

Did the same with my F30 320d & CTEK MXS5.0 when I had to have 6 months off driving for medical reasons. Using these points, you can get the CTEK connected and left in the engine bay so it doesn't get wet. You can then fully close the bonnet and lock the car this way for security, you may choose to route through the grill for ease.

On an MXS5.0, don't forget to select CAR & AGM using the mode button.

im4gine3 · 31 Jan 2021 at 15:03

chaparral said:
Start/Stop seemed to been working fine till i added a F770 dashcam which was also draining the battery in parking mode multi times a day every day

I emailed CTEK direct regarding start/stop cars as i heard MXS5.0 will not work with certain manufacturers/models. Thankfully they told me it would be fine, just to make sure the charger was set to the AGM function since it's an AGM battery

Scythe said:
Connection points under the bonnet on an F30. Connect the positive to the positive point under the red flap at the top left of the bonnet (when facing the car), under the positive point there is a negative (earth) peg off the chassis to save you scratching any painted regions.

Did the same with my F30 320d & CTEK MXS5.0 when I had to have 6 months off driving for medical reasons. Using these points, you can get the CTEK connected and left in the engine bay so it doesn't get wet. You can then fully close the bonnet and lock the car this way for security, you may choose to route through the grill for ease.

On an MXS5.0, don't forget to select CAR & AGM using the mode button.

I purchased the extension cable with the charger so plan to connect them as you mentioned, but wire the extension lead from the gap near the windshield through my letterbox and plugged inside

Scythe · 31 Jan 2021 at 15:52

im4gine3 said:
I emailed CTEK direct regarding start/stop cars as i heard MXS5.0 will not work with certain manufacturers/models. Thankfully they told me it would be fine, just to make sure the charger was set to the AGM function since it's an AGM battery

I purchased the extension cable with the charger so plan to connect them as you mentioned, but wire the extension lead from the gap near the windshield through my letterbox and plugged inside

I am surprised that people would say that, given that many manufacturer's branded chargers are actually rebranded CTEK units. I suppose some manufacturer's may have specific charging systems, or people are incorrectly charging and blaming the charger.

chaparral · 31 Jan 2021 at 15:57

Scythe said:
I am surprised that people would say that, given that many manufacturer's branded chargers are actually rebranded CTEK units. I suppose some manufacturer's may have specific charging systems, or people are incorrectly charging and blaming the charger.

I also heard charging the battery or changing the battery in cars with smart charging systems can upset & confuse the charging system and sometimes you need to get them reset or you can get all kinds of problems..

These new smart charging systems in cars seem to be a really huge step backwards compared to what we had before

gone are the days where you could just buy a new 12v battery and throw it in

[TW]Fox · 31 Jan 2021 at 16:13

Nasher said:
Get the hardwire kit for the Cteks and just leave it connected to the battery: https://www.amazon.co.uk/CTEK-Indic...words=ctek+hardwire+kit&qid=1612086330&sr=8-8

Do not do this with an F Series BMW - it is poor advice. Instead, read the owners manual where it says, and I quote:

BMW Owners Manual said:
Recharge the battery only with the engine stopped, via the jump-starting connections in the engine compartment

I also have a CTEK MXS 5.0 and currently have it connected up to my F10 via the jump start connections - I've not used the car for about a month and it's parked up in the garage.

im4gine3 · 31 Jan 2021 at 16:15

[TW]Fox said:
Do not do this with an F Series BMW - it is poor advice. Instead, read the owners manual where it says, and I quote:

I also have a CTEK MXS 5.0 and currently have it connected up to my F10 via the jump start connections - I've not used the car for about a month and it's parked up in the garage.

Good to know. Thanks for the heads up