car battery problem, any advice please?

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If you need to maintain charge over a long period and it's not practical to remove the battery, then get something like an Optimate. All my bikes are permanently on these when in storage over the winter. If you need to run an extension lead then you will find an ordinary black builders bucket fits nicely over it to keep the rain off. But agree that if it keeps going flat then there is something wrong. If you have an ordinary multimeter just set it to dc volts and measure the battery voltage, should be a little over 12 if it's good. Now start the engine and check that rises to a maximum of usually about 14 volts. If it doesn't get that high chances are your alternator is faulty. If you hold the revs at about 2000 and the voltage keeps on climbing to much more than 14 v then your regulator may be faulty. You should be able to find the regulator cut off value for your particular vehicle on the net, but it's commonly about 14.2.
 
Where did you buy your battery from?

I had a bad experience buying batteries from eBay, won't make that mistake again, very difficult to prove a fault and shipping is expensive so it's uneconomical to send back, of course the sellers know this which is why they sell that way.

Now I buy from Eurocarparts, they have a depot not that far away so I can go pick it up or they will usually deliver for free. I buy their cheapest battery which is still of decent quality (I get 3 years easy and it comes with a 3 year warranty anyway) and of course if I have a problem I can take it back to the depot in person and complain.

Before I adopted this method family and I used a local battery shop, they provided excellent batteries for a fair price, and would come to your house to install it for an extra tenner which was very convenient if the car wouldn't start. However they were very funny about letting you keep the old battery.
 
What are you doing to run down your battery.
For normal driving a good battery should not need charging.
When a battery lets me down twice, and the rest of the system is good, I buy a new battery.
It's not that expensive to avoid a lot of hassle

This depends very much on the car. I run a Lotus and, if left standing for a couple of weeks the battery dies (the alarm continually uses power which is a bit rubbish). I have installed a switch in line with the battery so I remove a bit of plastic when she's parked up. Problem solved.

I used to have a P38 range rover and the reset sequence after a battery change was a complete pain (recalibrating electric windows, sunroof etc) so on some cars this would not be a good solution)
 
Many modern cars have electrical circuits running even when the car is not being used .. mainly the alarm systems. Our Volvo has a warning 'Battery Low Voltage' that comes on if the battery voltage falls below a certain level ... maybe 12.7v. This can generally come on if the car has only been used for short journeys, say 3m or less or has been left unused for maybe 2 weeks or so .. very common in these lockdown days. When the warning comes on there is no problem starting the car but I do then put a trickle charger on. I run a cable from the garage to the car and connect charger to the battery +ve and car earth point, as advised. Charger sits under the mostly closed bonnet. When we had more freedom of movement and regularly did much longer journeys there was no problem.
Cheers, Phil
 
How are you going to use the second battery? Regularly swapping batteries would be a bit of a chore. Easier to just connect the charged second battery to the car with jump leads to give the car battery a bit of a boost occasionally. I do that with an unused car and the battery from my ride-one mower, which I keep and charge inside during the winter.
Just as a back up with jump leads til we can get back to doing some mileage again, might even strap in boot, our car door was frozen last week. I was quoted 90 minutes for back up last week when parked at doctors for the wife, and she did moan.
 
Either you have a failing battery, faulty circuit in car or you only use your car every three weeks or so for a couple of miles
Shouldnt really need to charge a battery these days.
 
Accumate trickle charger with optional extension lead so that the charger and all electrics are in garage and it’s just the charging cable which is outside. Put a permanent connector plug on the battery terminals then it’s literally a few secs to connect up. Bonnet can normally be closed properly while it’s connected too.
However, a decent battery shouldn’t need to be kept on trickle unless car really not being used at all
 
we're going to trade our 3 series in March and I will never ever own a BMW again!
Interesting. How old is your 3 series? What is the worst problem you have experienced?

My wife has had a 325 ci since 2003 or 2004. I don't like the car but she likes it and it has been reliable. The original battery lasted 13 years - not bad in our climate with the car always parked outside and no plug-in heaters or anything. The replacement battery is still fine. We have had basically no issues with the car.

Of course individual anecdotes are meaningless so this BMW may be an outlier. Certainly I have heard of plenty of other people having less satisfactory experiences.
 
My car developed a habit of running down if not used for a couple of weeks or so. Assuming the battery was past it, I got a new one. Same problem, so, thinking the new one was faulty, I returned it for a replacement. When that one gave the same problem, I called in a vehicle electrician who found that the built in battery in the alarm had short circuited which meant that it was continuously drawing power from the car battery, trying to recharge it. The alarm battery was a sealed in part of the alarm and I was given the option of £300 plus fitting for a new alarm or he removed the fuse . Guess which one I chose!!
 
The alarm battery was a sealed in part of the alarm and I was given the option of £300 plus fitting for a new alarm or he removed the fuse . Guess which one I chose!!
Did you actually see the battery in situ? Was it not possible to replace ot?

I had a similar issue with a circuit board in our heat pump. I pulled the board out and it was easy enough to remove the battery and solder in a replacement for a £2 fix instead of a few hundred.
 
Did you actually see the battery in situ? Was it not possible to replace ot?

I had a similar issue with a circuit board in our heat pump. I pulled the board out and it was easy enough to remove the battery and solder in a replacement for a £2 fix instead of a few hundred.
The battery was inside the alarm which is a sealed unit, situated in the offside wing under the inner wing cover (Skoda Octavia), so not readily accessible.
I'd had the car from 2 years old and didn't even know it had an alarm as it had never gone off in the 2 years I had it so couldn't see the point of replacing it.
 
My car developed a habit of running down if not used for a couple of weeks or so. Assuming the battery was past it, I got a new one. Same problem, so, thinking the new one was faulty, I returned it for a replacement. When that one gave the same problem, I called in a vehicle electrician who found that the built in battery in the alarm had short circuited which meant that it was continuously drawing power from the car battery, trying to recharge it. The alarm battery was a sealed in part of the alarm and I was given the option of £300 plus fitting for a new alarm or he removed the fuse . Guess which one I chose!!
Same with my Merc. hasn't done any long journeys for months and just the occasional 5 mile trip. I have had the odd message sent to my 'phone that the battery needs a charge but easily and quickly solved. It's simple to stick a charger on them when necessary. I can't remember the last time I needed to buy a car battery.

Any battery will slowly lose capacity if left unused, doesn't matter how new or what quality it's the nature of the beast, well documented, easy to prove with a voltmeter and when fitted to a high spec. modern car will run down as there are numerous components in the vehicle drawing small amounts of power, alarms, trackers, monitoring systems, I certainly wouldn't disconnect the battery on mine or my wife's Mini as setting them up again is a pita, even our motorhome is similar and we have a little Citigo for which you have to jump through hoops with Skoda to get the radio reprogrammed if battery power is lost.
 
FIAT...= Fix It Again Tony....

My last and only BMW car was a 5 series around 30 years ago..a total dream, if heavy on petrol....even my KT1100 was rubbish....
new ones Phah......
only own vehicles pre 2000....as they dont rot here.....no electronics, sweet.....
 
I had a x3 for a few years and feel the same.
I think it's the same with all makes Artie, I had 3 BMWs over 8 years and not an issue with any of them apart from a very slight occasional shudder on the clutch of a 320d which they diagnosed during a service and got a clutch replacement under warranty. You're either lucky or not.

I had an issue with my current GLC when Mercedes issued a revised front wishbone solution to known crabbing issues at low speed but the problem was with the cr*p dealers not fitting the parts properly and was then compounded them covering it up and lying so I needed to get pretty heavy to make them do it properly.
The idiots didn't even disconnect the dashcam properly so I could review what they said they'd done but didn't. :LOL:
 
Same with my Merc. hasn't done any long journeys for months and just the occasional 5 mile trip. I have had the odd message sent to my 'phone that the battery needs a charge but easily and quickly solved. It's simple to stick a charger on them when necessary. I can't remember the last time I needed to buy a car battery.

Any battery will slowly lose capacity if left unused, doesn't matter how new or what quality it's the nature of the beast, well documented, easy to prove with a voltmeter and when fitted to a high spec. modern car will run down as there are numerous components in the vehicle drawing small amounts of power, alarms, trackers, monitoring systems, I certainly wouldn't disconnect the battery on mine or my wife's Mini as setting them up again is a pita, even our motorhome is similar and we have a little Citigo for which you have to jump through hoops with Skoda to get the radio reprogrammed if battery power is lost.
Until recently we always went to our second home in France for 7 months every year and I would lock the wife's little Peugeot in the garage until we came back. Never failed to start 1st time every time on return.
 
As I foiund out to my cost, even a new battery will die faily quickly unless either a car is used regualrly, or the battery is kept charged. I was forced to lay up a 5-series BMW for several months when my wife fell ill. I was running a company car. The original battery died after a couple of months and I replaced it with a new one from Halfords. I neglected to keep it charged (other priorities at the time) and the car sat unused and unloved for three months. When I did finally get round to selling the car the battery wouldn't hold a charge. So the lesson I learned was, lead-acid batteries need to be kept charged or they die.
 
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