Connect a ctek battery conditioner to battery or engine posts?

M

mikedelta

Member
I've just bought an E89 Z4 which will be for occasional, fun use. As it will not be used frequently over the winter I will connect a ctek battery conditioner but do I connect directly to the battery terminals or to the jump start connections under the bonnet? I don't want to fry an ecu or electronics etc.

Spot the dinosaur! I'm not up on modern car electronic systems.
 
mikedelta said:
I've just bought an E89 Z4 which will be for occasional, fun use. As it will not be used frequently over the winter I will connect a ctek battery conditioner but do I connect directly to the battery terminals or to the jump start connections under the bonnet? I don't want to fry an ecu or electronics etc.

Spot the dinosaur! I'm not up on modern car electronic systems.
Click to expand...

It doesn’t really make any difference, some say any sparks near the battery will cause a nuclear explosion but cases seem very rare :thumbsup:
Rob
 
The E89 has an IBS module which monitors the state of charge of the battery so if you bypass this by going straight on the battery it will contain incorrect information. Now personally I don’t think that is a major issue as the real time information that the IBS gathers will eventually sort it out (which is also why I believe battery coding is just a big money spinner). If you are an advocate of battery coding then you should apply the charger to the under bonnet charge points which doesn’t bypass the IBS.

On the E85 / E86 it doesn’t make a blind bit of difference which one you use.
 
I have the same charger and used the near engine connections. If you feed the mains cable between the engine and scuttle you can shut the bonnet, whereas I'm not sure how you could close the boot without crushing the mains cable. As Rob has said, I think the engine connections are there to prevent the risk of a spark in the vicinity of a battery 'gassing'.
 
I connect mine positive stud first, simply because that is the more awkward stud in the ///M engine bay. :) We also have no real option to connect directly on the ///M, as the battery is hiding in the boot. :)
 
You should connect it to the terminal in the engine bay.

I have hard wired a CTEK connector into my engine bay, they cost £4.99.
https://www.amazon.co.uk/gp/product/B002X67JYE/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1

When the car is in the garage (car is always garaged when I am home), lift the bonnet, plug in (CTEK is mounted on the wall right next to the nearside front wheel), bonnet down, switch on, job's a good 'un.
 
buzyg said:
I connect mine positive stud first, simply because that is the more awkward stud in the ///M engine bay. :) We also have no real option to connect directly on the ///M, as the battery is hiding in the boot. :)
Click to expand...

Mines connected directly to the battery in the boot and left with the boot closed.

Plenty of room for the low volt side cable to pass through the seal.
 
Further / clearer for your question info for an E89 is ...

The battery may only be recharged by means of chargers that have been approved by BMW and that have a constant charging voltage of 14.8 V.
If possible, the battery temperature should be between 15 °C and 25 °C during charging. Under these preconditions, the battery is adequately charged when the charge current drops below 2.5 amps.
If the battery is recharged at lower temperatures, the process should not be ended until the charge current drops below 1.5 amps.
On vehicles with IBS, recharging the battery directly at the battery terminals could lead to a misinterpretation of the battery condition and even unwanted Check Control messages or fault entries.
If the battery is recharged while it is installed, it must be recharged using the jump start terminal points, whenever jump start terminal points are provided in the engine compartment. Only then can you be sure that recharging is correctly recognised by the vehicle electronics on vehicles with intelligent battery sensor (IBS).

Source TIS
 
Smartbear said:
mikedelta said:
I've just bought an E89 Z4 which will be for occasional, fun use. As it will not be used frequently over the winter I will connect a ctek battery conditioner but do I connect directly to the battery terminals or to the jump start connections under the bonnet? I don't want to fry an ecu or electronics etc.

Spot the dinosaur! I'm not up on modern car electronic systems.
Click to expand...

It doesn’t really make any difference, some say any sparks near the battery will cause a nuclear explosion but cases seem very rare :thumbsup:
Rob
Click to expand...

AGM batteries as fitted to all E89s are sealed and do not gas, they recombine charging gases back to water internally ..they only gas if incorrectly charged..
 
My handbook is quite specific - only use the posts in the engine bay - BMW must have their reasons and Im not qualified to argue.
Previous posts over the years on this forum show many ignore this instruction and connect directly to the battery posts and have done so for years, but I'm not taking the risk of frying anything
 
Right, I shall connect the charger to the posts under the bonnet. Note to self: the positive terminal may be close to the bonnet when closed so watch for that. I'm assuming a ctek charger would do the job/not be a problem/meet with BMW approval. No point in asking the dealer if a ctek meets with approval, they can't even tell me the correct tyre pressures for our 330 coupe. :roll:
 
The BMW branded chargers that the main dealers sell at massively inflated prices are just Ctek units anyway!
 
Under the hood.
I used a solar trickle charger last summer that I connected to the battery terminals in the boot fot 2 months. No issues.
 
step_change said:
You should connect it to the terminal in the engine bay.

I have hard wired a CTEK connector into my engine bay, they cost £4.99.
https://www.amazon.co.uk/gp/product/B002X67JYE/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1

When the car is in the garage (car is always garaged when I am home), lift the bonnet, plug in (CTEK is mounted on the wall right next to the nearside front wheel), bonnet down, switch on, job's a good 'un.
Click to expand...

Hi, how do you connect the attached connector under the bonnet ? My positive does not have a screw on the under bonnet positive and the negative screw the manual mentions is too far away.

Thanks.
 
I
obelix54 said:
step_change said:
You should connect it to the terminal in the engine bay.

I have hard wired a CTEK connector into my engine bay, they cost £4.99.
https://www.amazon.co.uk/gp/product/B002X67JYE/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1

When the car is in the garage (car is always garaged when I am home), lift the bonnet, plug in (CTEK is mounted on the wall right next to the nearside front wheel), bonnet down, switch on, job's a good 'un.
Click to expand...

Hi, how do you connect the attached connector under the bonnet ? My positive does not have a screw on the under bonnet positive and the negative screw the manual mentions is too far away.

Thanks.
Click to expand...

I connected the black wire of the charging connecter (that I linked to above and is permanently wired in the car) to any chassis point I could find and the red goes up to the red charge point up in the engine bay near the windscreen wipers. I will take a photo later. Been like that since I bought the car - the first thing I did to it - since the battery is important and should be looked after properly. All manner of intermittent issues can be traced to dodgy batteries.

Be careful working near the positive terminal in the engine bay since you do not want a screwdriver or spanner connecting the +ve terminal to the chassis!

I don't connect it up as such *every* time it's in the garage but I will if it is garaged for a couple of days or more.
 
I have the C tec connector hard wired to my battery and have used it over winter for 3 consecutive years without problems. However I do take on board the comments re connecting to the under bonnet posts so this winter will change as its no hardship either way and seems sensible to do so based on the various comments and posts.
 
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