Page 3 of 4 FirstFirst 1234 LastLast
Results 21 to 30 of 39

Thread: Battery

  1. #21
    Verified VCDS User
    Join Date
    Feb 2020
    Location
    Longford, Ireland
    Posts
    18
    Post Thanks / Like
    How did the SOC and capacity compare on your 5 year old battery?

  2. #22
    Verified VCDS User
    Join Date
    Apr 2019
    Location
    Worcester, UK
    Posts
    25
    Post Thanks / Like
    For comparison, the label on the battery in my Tiguan said VARTA 7P0915105 12V 68Ah 380A DIN 680A EN/SAE/GS

    I've dug out all the information I have and it looks like I might have given you some duff info - sorry about that.

    In March 2019 when the car was behaving it was giving me

    Battery Aging (Charge) 84%, Battery Aging (Power) 77%, Voltage 12.224V, SOC 84%, Available Current 40Ah

    In Sept 2019 when it wouldn't start it was giving me

    Battery Aging (Charge) 71%, Battery Aging (Power) 66%, Voltage 10.6V SOC 12% Available Current 0Ah

    After an overnight charge it was giving me

    Battery Aging (Charge) 71%, Battery Aging (Power) 66%, Voltage 12.54V SOC 70% Available Current 29Ah

    The thing is, a week or so later it was still fine and the dealer gave it a clean bill of health, which I think speaks volumes considering it wasn't covered by the warranty.
    Last edited by technodevotee; 05-23-2020 at 02:02 AM.

  3. Likes PetrolDave liked this post
  4. #23
    Verified VCDS User
    Join Date
    Feb 2020
    Location
    Longford, Ireland
    Posts
    18
    Post Thanks / Like
    Thanks for posting the info. Not sure if it shows on the logs i posted but i remember one stage It logged a very low SOC and capacity and went into phase 1 ( something to that effect) power management. Never failed to start though.

  5. #24
    Verified VCDS User
    Join Date
    Apr 2019
    Location
    Worcester, UK
    Posts
    25
    Post Thanks / Like
    Should show up in the battery history as long as it wasn't too long ago.

  6. #25
    Verified VCDS User
    Join Date
    Feb 2020
    Location
    Longford, Ireland
    Posts
    18
    Post Thanks / Like
    I just ordered one of those CTEK battery sense monitors. Should be interesting to log the SOC over the 7 days to see what % it maintains.

  7. #26
    Verified VCDS User
    Join Date
    Feb 2020
    Location
    Longford, Ireland
    Posts
    18
    Post Thanks / Like
    I bought one of those bluetooth battery monitors that works with a phone app and its quite interesting how the charging system works on these cars. The car seems to depend more on the battery than the alternator. It only seems to charge the battery when it needs it. The alternator mostly puts full output out when de accelerating/braking. That means the battery is working harder than on older cars where the alternator keeps batteries fully charging at all times. So its not surprising a battery after 3 years showing signs of wear.

    The bluetooth monitor also logs cranking voltage. It recorded a low voltage warning crank of 8.9volts this morning on first crank of the day. Outside temp was a mild 16 degrees C. Im guessing not a good sign for the AGM battery

  8. Likes Uwe liked this post
  9. #27
    Benevolent Dictator Uwe's Avatar
    Join Date
    Jan 2014
    Location
    Earth
    Posts
    28,992
    Post Thanks / Like
    Blog Entries
    1
    Quote Originally Posted by Micky 32 View Post
    The car seems to depend more on the battery than the alternator. It only seems to charge the battery when it needs it. The alternator mostly puts full output out when de accelerating/braking.
    Right, when you are decelerating or braking, there is free energy available and they try to use this to keep the battery charged rather than using a tiny bit more fuel to do so the rest of the time.

    Quote Originally Posted by Micky 32 View Post
    That means the battery is working harder than on older cars where the alternator keeps batteries fully charging at all times. So it’s not surprising a battery after 3 years showing signs of wear.
    Correct. They save a tiny bit of fuel with this nonsense, but at the cost of having to replace the battery more often. I wonder if anyone has analyzed how much energy is consumed in recycling the battery into a new one and how this compares with the energy/fuel savings? Car batteries generally are recycled, but melting and purifying the lead certainly isn't an energy- or pollution-free process.

    It's a similar situation with more aggressive hybrids. There was recently a thread from a guy with a 8V A3 e-tron hybrid. He's got fault codes indicating an internal isolation failure in his battery at 127,000 miles. Now he needs a new hybrid battery that costs 8600 Euros. I wonder if he as saved 8600 in fuel by driving that car rather than a more conventional one?

    One thing that might help battery life in a car like yours would be to put a trickle charger on the battery at night?

    -Uwe-
    Lock-down of sick people: Quarantine
    Lock-down of healthy people: Tyranny

  10. Likes PetrolDave liked this post
  11. #28
    Verified VCDS User
    Join Date
    Feb 2020
    Location
    Longford, Ireland
    Posts
    18
    Post Thanks / Like
    Just a bit more info to add, when driving along the voltage at the battery today was a constant 12.9 v ( i believe its closer to 14v on old non start stop cars) and then when you release accelerator it jumps to 14.3v. Interestingly when the car was locked up for a few hours the resting voltage reads a healthy 12.7v.

  12. #29
    Verified VCDS User PetrolDave's Avatar
    Join Date
    Dec 2014
    Location
    South Molton, UK
    Posts
    3,514
    Post Thanks / Like
    Quote Originally Posted by Micky 32 View Post
    Just a bit more info to add, when driving along the voltage at the battery today was a constant 12.9 v ( i believe it’s closer to 14v on old non start stop cars) and then when you release accelerator it jumps to 14.3v. Interestingly when the car was locked up for a few hours the resting voltage reads a healthy 12.7v.
    I've been using a battery voltage monitor plugged into the accessory socket during lockdown. That shows pretty similar results to yours, except when the battery was really discharged when it showed 14.3V for most of a 10 mile drive but on the way back (when the battery was in better charge state) the voltage was 12.7V when on the throttle and 14.3V when off the throttle.

    BMS in operation...

  13. Likes Uwe liked this post
  14. #30
    Benevolent Dictator Uwe's Avatar
    Join Date
    Jan 2014
    Location
    Earth
    Posts
    28,992
    Post Thanks / Like
    Blog Entries
    1
    Quote Originally Posted by Micky 32 View Post
    Just a bit more info to add, when driving along the voltage at the battery today was a constant 12.9 v ( i believe it’s closer to 14v on old non start stop cars) and then when you release accelerator it jumps to 14.3v. Interestingly when the car was locked up for a few hours the resting voltage reads a healthy 12.7v.
    12.9V is not horrible. It's enough to keep the battery from discharging, but it sure isn't going to put a full charge into it either.

    -Uwe-
    Lock-down of sick people: Quarantine
    Lock-down of healthy people: Tyranny

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •