[Radar314]

Is there an easy place to connect a trickle charger to the X3 vehicle?
My other vehicle just experienced a battery charge problem because I have not used the vehicle much since last March. The battery just kept getting more and more depleted due to lack of use. Maybe 2 to 3 times a week for short trips. I solved it by connecting a trickle charger. Rather than seeing the battery voltage at 14.7 Vdc all the time, it went down to 12.8 Vdc on my last drive after a day of external charging. The other vehicle has a special port in the back rear of the vehicle that is provided to plug in a charger.
I am curious if the X3 has something too.

[gugin]

There is no convenient plug or socket in the car. I am connecting my trickle charger to the positive and negative posts in the engine bay. Though I am now thinking about installing a Ctek comfort harness to speed up the process of connecting and disconnecting the charger. The BMW charger is compatible with the Ctek comfort connector (it seems that Ctek manufactures the charger for BMW). See here: https://f80.bimmerpost.com/forums/sh....php?t=1555310

I was also considering the installation of a permanent Ctek socket in the trunk (https://www.amazon.com/CTEK-56-380-C...dp/B002OHXX60/), but read online that our car's battery can be damaged if the charging cables are connected directly to the battery. If the cables are connected to the posts in the engine bay, apparently one of the car's ECUs is "live" and monitors the charge. I don't know if it's true or it's one of those things you read on the web that has no basis in reality. But I figured that one way or another, I will either have to leave the engine hood open or the trunk door open, so having a socket in the trunk rather than a connector in the engine bay is not a order of magnitude better solution.

[Radar314]

Thank you for the nice explanation. My other car came with a factory option that includes an installed 12 Vdc outlet in the trunk area and a Ctek charger. I was too lazy to use it. The week after week of low use catches up to you after a while. I will make an effort to connect a charger once in a while under the hood to top off the battery.

[gugin]

Even if our car had a 12 volt socket in the trunk, you could not use it to charge the battery. The manual specifically warns against doing this. It says "Battery chargers for the vehicle battery can work with high voltages and currents, which means that the 12 volt on-board network can be overloaded or damaged. There is a risk of damage to property. Only connect battery chargers for the vehicle battery to the starting aid terminals in the engine compartment."

[Yellowmattei]

I travel a good bit for my job, and leave the car sometimes for 8-10 weeks without driving it. I use a Battery Tender trickle charger, and it's worked great on both my BMW's.

Incidentally, the instructions on this trickle charger say that the red should be connected to the red, but the black clip just has to be connected to metal. I clip it to a bolt top near the battery, and it has kept the battery in perfect working condition for both cars.

[TheusBimmer]

Def trickle charge with Ctek/noco product that are capable to charge AGM batteries (not all Ctek trickle chargers are able to do that - our X3 have agm battery and cost around 200 bucks if dyi and 500 at dealership). Clamp the cables per bmw's user manual app (at the terminal of the hood) - see attached:

Let it charge for a day. Ideally u want and can keep it charged even for longer period (especially ur case to recondition the battery).

I would also purchase the app Bimmelink and the obdii ethernet cable and adapter to ur phone (lightning cable adapter for iphone for example), to check the percentage status of your battery from time to time to keep it tip top shape. Our x3 consume more battery power than I thought and mine had to be replaced (under warranty) after only one year from new. Granted I had kept it garaged for long period of time without the trickle charger aa you did. Learned my lesson and invested in good auto-charge trickle charger and the above mentioned Bimmerlink app. Now I'm obsessed in keeping the battery charged weekly m. As you, I hardly drive it these days.

[Bristle Hound]

My X3 hooked up to the Ctek battery conditioner as Uk back in lockdown

[JDsX3]

As others have noted, the best and safest means is to use a maintainer like the CTEK (4.3, 5.0 etc.) and connect it to the positive post in the engine bay
and negative post.

[Radar314]

I put the trickle charger on for 10 hours. I opened the driver door to remove the static charge from the battery. Then I measured the voltage at the under the hood point where I had connected the charger. It measured 12.3 Vdc. That seems low to me. Has anyone measured the voltage at the terminals located under the hood?

[TheusBimmer]

I will have to check it out. Perhaps it is purposely at 12.8 but for that need to defer bmw technician freshdough.

Have you tried BimmerLink to check status of battery? Also is ur ctek or trickle charger AGM capable? The basic ones aren't. Other point of charge would be directly to battery but HIGHLY discouraged by bmw.

[HighlandPete]

Originally Posted by Radar314

I put the trickle charger on for 10 hours. I opened the driver door to remove the static charge from the battery. Then I measured the voltage at the under the hood point where I had connected the charger. It measured 12.3 Vdc. That seems low to me. Has anyone measured the voltage at the terminals located under the hood?

If the car is unlocked, door just opened and background systems in operation, most likely 0.3 - 0.4V down on actual battery voltage.

I find that mine is ~0.4V down, compared to sleeping voltage.