MOT=Ministry of Transport test
CV Boot = Constant Velocity joint rubber cover or "gaiter"
stood = the past tense and past participle of stand

Translation =The CV joint cover was bad because the car was sitting for (3) months.
(Or more likely, because it was an old dry CV boot.)
(Or maybe because it was made by VW)

Of course, it did start, which would be unlikely for a X3 tha "stood" for 3 months.

I left my X3 another 2 weeks w/o starting it in the garage and when I came back to it, the only issue I had was the battery message which went away after I started it up for a few minutes.

Lotus7 wrote

Depending on the state of charge (which can vary dramatically), options on the vehicle, and ambient temperature a X3 battery can be depleted in as little as 18 days.

Comparisons with other vehicle brands & models are totally irrelevant. The X3 BER system changes everything. This has been discussed and explained in this thread:

X3 LOW BATTERY

Posts No. 20 & 22 address this issue in detail.

Many thanks for those links L7.

If the Stop/Start system is switched off, does that mean the battery will go to full charge?

I am particularly concerned that the alarm system might be switched off - a car that is uninsured (due to no operational alarm) if I leave it at an airport for a lengthy period is a major concern!

Even a photo-voltaic cell system is likely to be ineffective in the darkness of a multi-story car park. Has anyone had any experience with these units or similar?

Bill S wrote

Many thanks for those links L7.

If the Stop/Start system is switched off, does that mean the battery will go to full charge?...

It's not the "Start-Stop" system that allows the X3 to sometimes have a low battery charge. It's the [totally different] Brake Energy Regeneration (BER) system. That system will "shut off" the alternator unless the vehicle is coasting or braking. The OEM battery specified for F25 X3s is designed to resist damage from being allowed to "sit" for long times at a partial charge, but that still won't stop it from discharging because of the vehicle's always on electronics in a short time if it's not fully charged.

If you know you're going to have to leave a X3(f25) for a long time, it's wise to be sure that the battery is at full charge. The only way to really do that is to connect a charger a few days before. With a B&D 10 Amp fully automatic charger it will take 6 or 7 hours to bring a X3 battery from 40% charge to 100%. A CTEK 3300 will do it in 18 hours, and with a "Battery Tender" it will take as much as 48 hours.

All three of the above chargers work well with the X3s Saturated Mat battery.

Lotus7 wrote

It's not the "Start-Stop" system that allows the X3 to sometimes have a low battery charge. It's the [totally different] Brake Energy Regeneration (BER) system. That system will "shut off" the alternator unless the vehicle is coasting or braking. The OEM battery specified for F25 X3s is designed to resist damage from being allowed to "sit" for long times at a partial charge, but that still won't stop it from discharging because of the vehicle's always on electronics in a short time if it's not fully charged.

If you know you're going to have to leave a X3(f25) for a long time, it's wise to be sure that the battery is at full charge. The only way to really do that is to connect a charger a few days before. With a B&D 10 Amp fully automatic charger it will take 6 or 7 hours to bring a X3 battery from 40% charge to 100%. A CTEK 3300 will do it in 18 hours, and with a "Battery Tender" it will take as much as 48 hours.

All three of the above chargers work well with the X3s Saturated Mat battery.

Thanks for the prompt reply L7.
Unfortunately a mains charger is not a viable option as I've a 150ml journey to the airport. So I have to rely upon the alternator charge.

It seems that high ancillary current drain & the BER may be a massive disadvantage to the BMW (at least for my usage).

At least BM seem to be attempting to control the drain by shutting down systems but it would be useful to know exactly what systems are closed down, and when, and to have a way to switch off a select range (not including alarm) if car is planned to be left for a prolonged period.

Bill S wrote

Many thanks for those links L7.

If the Stop/Start system is switched off, does that mean the battery will go to full charge?

I am particularly concerned that the alarm system might be switched off - a car that is uninsured (due to no operational alarm) if I leave it at an airport for a lengthy period is a major concern!

Even a photo-voltaic cell system is likely to be ineffective in the darkness of a multi-story car park. Has anyone had any experience with these units or similar?

Interesting. Previous posts had said that the "Cigaretter Lighter" adapter ports would be disabled, and unsuited for trickle charging, This device uses the OBD2 port.

02420X3 wrote

Interesting. Previous posts had said that the "Cigaretter Lighter" adapter ports would be disabled, and unsuited for trickle charging, This device uses the OBD2 port.

Using the OBD-II port is an interesting idea. The "lighter" sockets on the X3 are definitely disconnected after a 5 to 15 minute accessories time-out period, so are useless for charging. Unfortunately, it's also possible that the same is true of the X3's OBD-II port. I have a OBD-II reader and will check the port power pin when I get a chance.

Lotus7 wrote

Using the OBD-II port is an interesting idea. The "lighter" sockets on the X3 are definitely disconnected after a 5 to 15 minute accessories time-out period, so are useless for charging. Unfortunately, it's also possible that the same is true of the X3's OBD-II port. I have a OBD-II reader and will check the port power pin when I get a chance.

Thanks L7, that would be useful to know.
I have ordered one up (£39.99 from amazon.co.uk but don't seem available on amazon.com). Unfortunately it does not have any indication when/whether it's working. I've also ordered a OBD breakout box so when that eventually arrives from China I should be able to connect a meter.

Bill S wrote

Thanks L7, that would be useful to know.
I have ordered one up (£39.99 from amazon.co.uk but don't seem available on amazon.com). Unfortunately it does not have any indication when/whether it's working. I've also ordered a OBD breakout box so when that eventually arrives from China I should be able to connect a meter.

Today, I was able to check for power on the OBD - II port.

The good news is that the power pin on the OBD-II connector is always "hot", so can be used as access to the battery for "light load" accessories or as a way to connect a low current "battery maintainer" type charger or a solar panel charger.

However, one caution that should be observed is that this connector pin is fused at only 5 Amperes. That means that it's probably safe to connect a small charger like the CTEK 3300 (3.3 Amps.) or a 45 Watt solar panel, but nothing using or providing any more power.

To test the connector power supply I attached a digital voltmeter to the appropriate connector pins and monitored the voltage from the point the car was locked using the key remote.

Door open, car unlocked, "lighter accessory outlets": ON, Interior lights: ON: 12.40 V. @ OBD-II connector

Time: "zero" car locked, "lighter accessory outlets": ON, Interior Lights: ON: 12.40 V.

Time: 0:00:30 car locked, "lighter accessory outlets": ON, Interior Lights: OFF: 12.53 V. (Voltage increased because of Interior light "time out".)

Time: 0:02:30 car locked, "lighter accessory outlets": ON, Interior Lights: OFF: 12.53 V.

Time: 0:05:00 car locked, "lighter accessory outlets": OFF, Interior Lights: OFF: 12.62 V. (The accessory outlet timer shut off the outlets and other acc. circuits.)

Time: 0:10:00 car locked, "lighter accessory outlets": OFF, Interior Lights: OFF: 12.62 V.

Time: 0:30:00 car locked, "lighter accessory outlets": OFF, Interior Lights: OFF: 12.62 V.

Time: 1:00:00 car locked, "lighter accessory outlets": OFF, Interior Lights: OFF: 12.62 V.

Time: 1:01:00 car unlocked, "lighter accessory outlets": ON, Interior Lights: ON: 12.30 V. (Key Remote "Unlock Button pressed - Lights and accessory outlets powered up: Voltage dropped due to load.)

The 12 V. "battery" pin on the OBD-II port is pin (16)
The power ground pin is pin (4)

The OBD-II port power is fused through Fuse No. 3 (5 Amperes)
That fuse is in the "front" fuse block (located behind the glove box), not the big one in the rear fender.

Hope this is of some use. Please keep in mind that this test was on a NA car. It's possible, but unlikely, that UK, Asian or continental vehicles are wired differently.

This photo shows the voltmeter connections to pins 4 and 16.:

Many thanks Lotus.
I will post pictures of the solar unit when I get it but it may be a while before the breakout cables arrive and I can test voltages as it is working.

Also I will soon be leaving the car for 2 months with valet parking while I'm in the US - it may or may not be a good test depending on whether it is parked in sunlight (hopefully I will find out from them) and whether I can get the drivers to plug in and unplug the solar unit when it is stored.

Bill S wrote

Many thanks Lotus.
I will post pictures of the solar unit when I get it but it may be a while before the breakout cables arrive and I can test voltages as it is working.

Also I will soon be leaving the car for 2 months with valet parking while I'm in the US - it may or may not be a good test depending on whether it is parked in sunlight (hopefully I will find out from them) and whether I can get the drivers to plug in and unplug the solar unit when it is stored.

One thing to be aware of about the X3's OBD-II connector is that it is somewhat recessed behind the door jamb cover panel. If you connect using a typical plug, which is 30 or 35 mm long, it is extremely difficult to remove the plug because there is not enough of the plug body remaining beyond the panel, the panel opening is quite small, and the connector is very tight.

For the plugs on my port reader and the Ultra Gauge I use to measure engine sensor readings and vehicle parameters, I had to add a steel rod "pull-handle" to be able to remove the plug without having to revert to using pliers on the connector.

The specifications for ICP/Sunsei Solar Charger mention that it has a charge regulator and that it's only rated at 240 mA. It should be safe to leave connected permanently, even in bright sunlight. The X3's deep-cycle saturated mat battery can take a continuous charge voltage of 14.6 V. without being overcharged.

Here are photos of the modification of an OBD-II plug I had to make to be able to use it in the X3. Note the epoxied-on, stainless steel handle.