Does battery need replacing?

[d3matt]

A bit of background.....I've just brought a 2003 3-litre Z4 and the following day (after driving at least 5 hours trouble free) I had an amber handbrake + amber DSC lights on permanently and the alarm has been going off occasionally.
First step was to buy a k-line cable from bcables.com. This arrived yesterday and I've loaded all the software on my laptop. So tonight I've gone to have a play with it connected to the car.
I've never used any of this software before and its all a bit confusing. But I connected the cable and loaded the DIS software.
Then I was given this message.

And can anyone explain what these two graphs mean?

I assume the top is showing the car battery.
So on this basis, do you think I should be buying a new battery?

PS. After playing with the software, not knowing what I was doing really, but looking through some diagnostics, I disconnected and now the amber handbrake and DSC lights have gone out. Well that was worth the £26 anyway.

 

[Scooba_Steve]

I believe the software is fooled into thinking the car is on charge. Leave it overnight and test with a voltmeter in the morning, should give at least 12.35V and anything less I'd consider changing - not urgently if you use it as a daily but add it to the list.

 

[d3matt]

The Z4 wont be a daily run around car. Its just a weekend/sunny day play car. So it will be sitting in the garage for at least a week between uses, sometimes much longer. So I need a good battery.
I'll test it tomorrow.

 

[Scooba_Steve]

Worth getting a battery maintainer if you will leave it laid up for a week or more, prevention is better than cure.

 

[cj10jeeper]

Worth getting a battery maintainer if you will leave it laid up for a week or more, prevention is better than cure.

I'd echo this and get a decent battery maintainer. Mine often lays up unused for a week, but beyond that I know it will struggle so have it on charge to avoid the risk of damaging my battery.

Most on here use CTEK's. Just pick one suitable for you battery type and size.

 

[d3matt]

Worth getting a battery maintainer if you will leave it laid up for a week or more, prevention is better than cure.

I was thinking I should invest in one. I have a normal mains battery charger, but I guess I can't leave that switched on.
Anyone got any recommendations for a battery maintainer?

 

[85genius]

I got one from aldi, does trickle charge and fast charge and was cheap as chips

 

[d3matt]

After reading about them for the last 45 mins or so, I've just ordered an Optimate 2 maintainer for £35. Seems to be more geared to long term maintaining rather than outright charging, which is what I need.
http://optimate.co.uk/optimate%202%20leaflet.pdf

 

[d3matt]

Plugged my Optimate 2 on tonight and its showing that it needs charging, even after about 2-3 hours of driving today.
I'll see what its showing in the morning.

One question - are you better to connect a battery maintainer direct to the battery in the boot, or to the studs under the bonnet? I intend to leave this connected up pretty much all the time when the car is parked up.

 

[cj10jeeper]

I don't think it makes any difference for charging. I connect mine to the under bonnet points for ease as I can close the bonnet.

Jump stating should be done on the under bonnet points

 

[Scooba_Steve]

Use whatever location is most practical for you. If the battery has gone flat at any point you should replace it anyway as it will never hold full charge again. Not so much of an issue for a daily driver but still worthwhile. I got a very good Varta E44 online for about £60, better capacity and cranking.

 

[d3matt]

Now I have my battery maintainer, it was showing that the battery needed charging after every drive. So I've invested in a new battery - a Varta E44.
Cheapest place I could find this is here...
https://www.tayna.co.uk/E44-Varta-Silver-Car-Battery-577400078-P7726.html
Seems very good pricing on all brands of batteries.

 

[Scooba_Steve]

Once they've gone flat they will never be the same again! I've been very happy with the Varta and I'm sure you'll be fine keeping it topped up now.

 

[SonnyA85]

is the k line cable the best value for money option?

would that also work on a R56 mini?

 

[d3matt]

Can't fault Tayna batteries. Cheapest online and the battery arrived next day, with texts to tell me the time slot within 1 hour. And it was very well packaged.

 

[cj10jeeper]

Once they've gone flat they will never be the same again!

This depends on the battery type.
Lead acid - 100% true They just don't tolerate it.

Gel batteries and AGM (often mistaken but not the same) much less of an issue.

I rip the heart out of my red top and yellow top gel batteries on Jeeps with winching to near zero charge time after time with no ill effect

Wrong chargers and not correctly charging causes way more issues

 

[Scooba_Steve]

Agree, I was only referring to 'normal' lead acid types. I considered getting an AGM battery but couldn't really justify the difference in cost.

 

[Mike6]

Just a point about attaching battery maintainer. If you connect directly to battery and leave the boot undone your boot light will probably remain on and dischartge battery quicker than the maintainer will charge. I have removed the boot light to prevent this happening.

 

[d3matt]

Just a point about attaching battery maintainer. If you connect directly to battery and leave the boot undone your boot light will probably remain on and dischartge battery quicker than the maintainer will charge. I have removed the boot light to prevent this happening.

Yes thought of this. The boot shuts properly though with the wire squashed into the rubber seal.
Its certainly easier connecting up in the boot, rather than the bonnet.
I've used this cable that came with the Optimate 2, and it hooks over the edge of the carpet floor.

 

[d3matt]

Strange thing with my new battery......

Went out to do some diagnostics on the Z4 tonight (as I have a DSC error). The car has been parked up since I last drove it 5 or 6 days ago. But all that time it has been connected up to my new Optimate 2 battery maintainer.
First thing the diagnostic software says is battery is low again!!

Didn't believe it. I have a brand new high spec battery that is only 1 week old and its been connected to the battery maintainer.
Then after I finished playing with the diagnostic software, I looked at the back of the car and found that the Optimate 2 was indeed showing that the battery is low!


Why would this be low? It was fully charged when I last drove the car 5 days ago and when I disconnected the Optimate 2 before driving it, the lights were all green, meaning the battery was fully charged and ok. Now 5 days later, after being on charge all this time, it is showing that its low!



Can anyone shed any light/ideas as to what's going on? I did have the door open and ignition on while I was using the diagnostic software, but that was only for about 1-2 minutes before the software displayed the low battery warning and for only about 6 mins in total. This 1-2 mins shouldn't be enough to deteriorate the battery to that extent.