If the battery is in the trunk, it barely gets charged if you drive it only for 30mins at 1C outdoor temperature. Cold battery is very difficult and slow to charge, even if it's AGM. Charge it overnight inside warm garage, then see the battery capacity. For my new fully charged 105Ah AGM battery at 15C, the capacity reads 65Ah and voltage 12.2V at -32A battery current (ignition on, AC, radio and heat seating etc. on) and 79Ah & 12.5V at -13A (just after turning ignition off). So take note that the high vs low current affects the capacity reading (because if you go over 0.1C discharge rate, which means 9.5A for a 95Ah battery, you will not be able to use the full rated capacity of the battery). The total energy throughput (lifetime of a battery) is typically 240 Cycles (360 cycles for AGM), so for 95Ah battery it's at least 20 000Ah. Internal resistance is also a useful measurement. My original 8 years old 105Ah AGM battery with total energy throughput of 24500 Ah reads 3.4mOhm, and the brand new battery has 2.2 mOhm. For 105Ah AGM battery, 6.2 mOhm is the high limit where you should replace the battery at the latest.
Thanks for the info how to check battery condition. Just checked mine as the stop start stopped working and alarm kept going off late at night. My battery goneski! Lol
The mmi meter is worthless. For example: A 70% charged battery shows up as 100% charged on mmi. So it's not showing real values, it dumbs them down, so probably people don't think they have a bad battery when it's a bit discharged.
My OEM 8 year old vart 68 ah 680 A had 32 available capacity but fired up golf 7 1.6 tdi. Durin last winter SOC dropped suddenly to 70% has morning longer crank but fired up. Nevertheless decided to replace it. New one had 54 ah availabe capacity (new battery) from its origiinal 70ah why? Do I need to recharge it a few times?
After coding my battery has only 43 amps from 70. I don't see any battery that reaches the top of manufacturer value. The old one when i changed , the remaining amps were 17 and voltage after 80 kms was only 12.0 volts. So, i decided to change it.
Your battery might not be fully charged and the car does not yet see the "full" capacity. But, overall, yes, no battery will show the max stated by the manufacturer.
In block 18, battery current is negative, It shows -5.8v, is this bad? I changed battery 2 months ago and startstop is not working since yesterday, that's why I am checking battery levels. Battery level shows 88%
Hi, i fit a new battery in my car same as one in your video, the battery capacity (actual/available) shows 64Ah, but battery like yours is a 95Ah battery in your other video (bosch, 95Ah, 800cca). does this mean the battery is not new and I should contact seller to sort out?
Hi. Did you recode the new battery as I did in my other video? Only after recoding it will show full capacity. Also, when you buy it, it might not be 100% charged.
@@UltimateDIY hi, thank you for replying. I charged the battery before fitting and yes i recoded with vcds, the numbers it showed me was after everything was done. My old battery showed 15Ah with vcds, but i used a battery tester device today but now im confused as that says that battery is good.
I never trusted battery testers. But then again, we can't know 100% sure how accurate the estimated info from the ECU is. Did you have issues with the old battery before replacing it?
@@UltimateDIY hi, yes i aslo dont trust the tester or reading via vcds but its all i have to go by. Battery was changed as due to short journeys the battery became weak and sometimes struggled, also power management was active, but then i drove for 3 hours and cleared error and was fine since. However since taking battery out and charging up and testing its voltage reads 12.7v with multimeter and looks to be fine. It is almost 4 years old. Thank you for reaponding. I will but yhe old battery back in and recode again and see how i get on. Any issues will put the new one back in, if all fine then will return new battery. Have a good day
It's not a specific software/dongle version. Just get something fairly recent, above version 17 for example. Search in your local area websites for VCDS and see what pops up.
It's fairly accurate. It shows the calculated capacity left in the battery at that point. After a long trip it will show more, as some capacity is regained. You can watch your battery degrade more and more over time by checking this value.
Ultimate DIY so would you say my battery is failing if it dropped that low? Mine at the moment is 29 ah, last week it was 16 ah. Battery is rated 68 ah
@@Mickytdi not necessarily. It would fail soon if it would not go above 20ah for example. If yours goes to 29 it's still half decent. But try to keep it charged as much as possible and don't trust it too much.
Ultimate DIY For the last few days my battery was reading 80% soc and 29ah. Today it dropped to 68% and 19ah, weird! How old was your battery? Was it AGM?
