9 hours ago, J.R. said:

 J.R.  I  would appreciate it if someone else can cast an eye over my figures and tell me if I have made a mistake 👍

 

Can't tell you if you have made a mistake, can tell you I for one thought your post a good read and easy enough to understand.👍

 

Still not sure if I should swap to a new 096 or stick to a new 027 battery, do know throuh others, the swap is easy enough.

 

"Mine are a bit contrary to the battery charging obsessive fetishist evangelists"

 

Not sure I'm one of them but flogging my existing car battery back into some use does have an appeal.😀

Edited 5 February, 20233 yr by cado

8 hours ago, Carlodiesel said:

Just for info

 

096 ENDUROLINE AGM STOP START CAR BATTERY 12V 70AH  £123.65 + Postage £7.99 from Tayna batteries.co.uk

027 ENDUROLINE CAR BATTERY 60AH  £60.97 + postage £7.99 or, a Bosch 63ah £75.97 + postage

Or 

096 EFB 72ah heavy duty, more power than AGM. £84.99 free postage from ebay 312816513693.  278L x 175W x 190H (mm)

Of course do your homework & check warranty data.

Not sure if prices quoted for Tayna are start/stop batteries.  If I have a slight knee jerk, it would be purchasing a car battery off ebay

 

There are of course lots of honest sellers on ebay, lots of fakes on ebay to.

096 100 START STOP EFB 72AH 70AH Heavy Duty 12V Car Battery More power than AGM

Is from Tayna Batteries. Ebay No.  312816513693   £84.99

096 EFB Powerline Start Stop Car Battery 70Ah

Edited 5 February, 20233 yr by Carlodiesel

1 hour ago, Carlodiesel said:

096 100 START STOP EFB 72AH 70AH Heavy Duty 12V Car Battery More power than AGM

Is from Tayna Batteries. Ebay No.  312816513693   £84.99

096 EFB Powerline Start Stop Car Battery 70Ah

Hi,

Yes I was aware of this.

 It was the 027 prices you quote I could not find a match for on Tayna's site.

 

Was wondering if those prices were for standard non-start stop batteries.

 

My coment on buying batteries of ebay was just that, caution!.

Edited 6 February, 20233 yr by cado

13 hours ago, cado said:

Not sure if prices quoted for Tayna are start/stop batteries.

If you select what car it's for this is the first question you're asked.

I did an expermint today, it was inspired by @J.R. doing some rough calculations on putting back the charge into the battery.

Car had been left for a few days, measured Voltage on meter was 12.3V at the terminals (60% State of Charge.)

 

So got in the car and fired up VCDS logging, and set about an experiment.

Alternator = 180Amp, temperature was 8°C, no additional load was added (lights/heated seat/rear or front window) just the climate control and infotainment was running (no volume)

 

In the logs, with ignition on, it dropped down to 12.0V to be expected as the climate control will be on, and a fair few control modules/fuel pump etc are being prepared.

Cranked engine, and it drops to 10.0V momentarily, before settling higher.

 

You can see smart charging doing it's thing here in the steps, and this is all done at idle rpm.  It took less than 3 minutes to replace the power it used initially, and raise the SOC.

Had I been driving the car, this time would probably been shorter, but not that long at all.

Were you monitoring something else to know when the SOC was raised above what it was before the engine start?

 

Terminal 30 voltage?

 

Or do you know from experience that when it drops to 400 watts that it is a maintenance charge?

 

Editted, you said you were monitoring the voltage, 400 watts = 33 amps, more than a maintenance charge, you can tell that I dont work with these units often!

 

Interesting to see that it was charging at 75 amps on a battery at 60% SOC, there is a lot of headroom with a 180 amp alternator.

Edited 6 February, 20233 yr by J.R.

32 minutes ago, J.R. said:

Were you monitoring something else to know when the SOC was raised above what it was before the engine start?

 

Terminal 30 voltage?

 

Or do you know from experience that when it drops to 400 watts that it is a maintenance charge?

 

Editted, you said you were monitoring the voltage, 400 watts = 33 amps, more than a maintenance charge, you can tell that I dont work with these units often!

 

Interesting to see that it was charging at 75 amps on a battery at 60% SOC, there is a lot of headroom with a 180 amp alternator.

I use a multimeter to show the SOC before I touch car/ignition, it seems to agree with the car reported voltages roughly (need to verify)  I have left the car a week, it never seems to go below 60% SOC.

 

The Terminal 30 Voltage at least in VCDS = Battery Voltage reported, so I just log Battery Voltage for the graph.

 

I go for an hour roughly each week with son for driving lesson, and checked the other week how many Watts were reported, so know that 400-500W is the baseline.  It is amazing how many control modules munch power, there are some rough values here and there in some SSP's, it's an eye opener.  After a long drive it was around 500W, so when it read 400W, I knew it was probably happy with the battery SOC.

 

If you take the say 900W, take off 400W if we assume that is baseline, then that leaves 500W being used to charge, at 14.7V, so a rough 35Amp charge, again math's could be wrong.  How much of the 400W "baseline" is being used to trickle charge the battery, or indeed maybe no charging was taking place... hard to say I think (at least for me!)

 

 

Anyhow, I find it fascinating, and happy to go experiment and grab data.

IIRC at almost idle, the Alternator can output some serious power, I put on heated screens both front and rear to reach 2000W from it, and I can make it run at 2800W with heated seats on also.  Idle barely increases, maybe another 50rpm?

 

Edit: Forgot to add a quick picture of the raw values, sorry that VCDS has 3x time columns, was 12.3V on multimeter, and drops to 12.0V when you turn ignition to position II

Edited 6 February, 20233 yr by varooom

Tayna were excellent, next day delivery, in the end I got a Bosch EFB 027 battery.