Battery charge issues

[Dave1300GLS]

Hello folks a bought an X5 3.0d 2003  2weeks ago. My problem is when I travel home at night, a distance of 10 miles on a fast dual carriage way, if I stop at the shop near my house and get in my car to start it the starter struggles to turn over!  The following morning all is fine it starts OK.  I have tested the alternator and it is putting out 14.2v and the voltage of the battery after a rest overnight is 12.3v. I was using scanner 1.4.0 in my lunch to tweak some settings like doors to lock at 8mph etc, it took about 30 min with the ignition on and when I went to start the car it was flat! I put it on the charger for the rest of the day and it started fine at home time, but when I travelled the 10 miles home I restarted it outside my house and the starter was slow after a good charge and drive home. My question is if the alternator is charging what am I missing here, surely the alternator is burly enough to power xenon lights on the drive home?? Any help please folks

[Horizon]

Some of the E53's of that era were fitted with the Magneti  maranelli( probably spelt that wrong, X5 Sport will be able to clarify

[X5Sport]

Could be a starter issue.  You will need to use a current clamp to check that the cranking current is no higher than 180A.  If it is much over this then your starter needs replacing.  Mine drew 560A and 900A+

As said above, years 2003-2005 seem to suffer starter issues with the Magnetti Marelli name appearing most often.  Both of my 30d cars from that year block needed new starters.

A failure within the windings means that they can often draw more than the battery can deliver, or take a significant charge level out of the battery.  The alternator never gets a chance to recharge the battery.  The E46 needed recharging after every 60 mile commute with just two starts!

Replacements can be for for around £200 inc surcharge from places such as Eurocarparts.  I fitted a Bosch 2.2kW (180A) unit to our E46 with the same engine.  Fiddly but can be diy.  You’ll need a set of Torx type wrenches and sockets.  The bolts are seriously tight, and if you remove the reinforcement plate under the front of the E53 then you should replace those bolts as they are single-use ‘stretch bolts’.  Someone on here did a change a couple of weeks back I think.

[Dave1300GLS]

Many thanks for the great advice folk, really helpful and will look into the starter ampage load. Also heard these X5's can get dodgy earth's on the engine and that's worse with heat. Either way will get back in the near future with the conclusion. Thanks again Dave

[Dave1300GLS]

Just as an update the mechanic said the battery is getting tired, so am gonna change that. But when I asked what load was the starter pulling he said "oh not much"..... did he check it?? Anyways will report any updates.