Good/bad batteries or parasitic drain?
Discussion
Panamax said:
My personal opinion is these batteries need to undergo a proper high current drop test before anything else is done. I'd be interested to hear how old they are. If the batteries are fine then earth connections are next.
He said they are 7 years old and seemed to be fitted when he had an alternator fault resulting in a new one.I’d say the batteries are shot but testing could save £80 if one of them turned out to be ok.
Richard-D said:
E-bmw said:
Brilliant advice IF it were cranking.
If it isn't cranking it can tell you even more. If there's no voltage drop you don't need to be looking at the battery. If there is voltage drop you need to find out at which connection it's happening. The engine doesn't have to turn at all. It's always good to try to help and I'm sure people appreciate it. But when you're trying to give people advice on a subject you don't understand you will end up causing the guy more problems.
My own personal experience tells me that, while you are not necessarily wrong about a cranking test, while it isn't cranking, lets get the basics out of the way first, then we know what we are left with.
I have lost count of the number of "battery/starter/alternator" problems I have sorted over the years when sorting either a battery/engine/chassis earth not quite right or a poor main 12v connection.
It has ever since the first one ALWAYS been my first check and has bourn out dozens of times.
I have fixed many cars that have been to garages & come back with £100's of estimated work required, when all it needed was a few minutes of eyes open, & use hands to check first.
trickywoo said:
He said they are 7 years old and seemed to be fitted when he had an alternator fault resulting in a new one. I'd say the batteries are shot but testing could save £80 if one of them turned out to be ok.
Sorry, I'd missed the 7 years. Anyway, I'm pretty darned sure this is a case of knackered batteries. Proper testing should put things beyond doubt, one way or another.PelicanHead said:
Ok, so a bit more confusion for me.
I've just taken the batteries off.
I thought I'd test them before starting the charge.
One is reading 13.02 the other 13.03, the van hasn't moved for a week or so.
Why would they both read higher than the 'required' 12.6 but fail to turn the engine over?
Because you need amps to turn an engine over, Volts push the amps along the wire.I've just taken the batteries off.
I thought I'd test them before starting the charge.
One is reading 13.02 the other 13.03, the van hasn't moved for a week or so.
Why would they both read higher than the 'required' 12.6 but fail to turn the engine over?
If the battery is show 13 volts and it doe not turn the engine over it is fecked.
If you can fit it to the car and get it to turn the engine over do a load test with your MM.
https://www.youtube.com/watch?v=gq0iey9VC94
kestral said:
PelicanHead said:
Ok, so a bit more confusion for me.
I've just taken the batteries off.
I thought I'd test them before starting the charge.
One is reading 13.02 the other 13.03, the van hasn't moved for a week or so.
Why would they both read higher than the 'required' 12.6 but fail to turn the engine over?
Because you need amps to turn an engine over, Volts push the amps along the wire.I've just taken the batteries off.
I thought I'd test them before starting the charge.
One is reading 13.02 the other 13.03, the van hasn't moved for a week or so.
Why would they both read higher than the 'required' 12.6 but fail to turn the engine over?
If the battery is show 13 volts and it doe not turn the engine over it is fecked.
If you can fit it to the car and get it to turn the engine over do a load test with your MM.
https://www.youtube.com/watch?v=gq0iey9VC94
https://www.amazon.co.uk/%E3%80%90NEW%E3%80%91Car-...
Will tell you what you need to know about your batteries.
If you pulled them off the van at over 13v then you must have driven the van within half an hour or so (did you?)
As said, they should settle to 12.6v at rest after a charge - takes around 30 mins for them to settle. Resting voltage doesn't prove a battery is ok, but its a good start. Generally, when batteries whoe good voltage but then have no real power, the settled voltage is often odd, like over 12.6v, so this could be what you have.
I had a Bongo with 2 batteries japanese vervion - doubles the AH for winter starting in cold climates. Whereas my Transit has 2 batteries, one for starting, one for accessories.
Will tell you what you need to know about your batteries.
If you pulled them off the van at over 13v then you must have driven the van within half an hour or so (did you?)
As said, they should settle to 12.6v at rest after a charge - takes around 30 mins for them to settle. Resting voltage doesn't prove a battery is ok, but its a good start. Generally, when batteries whoe good voltage but then have no real power, the settled voltage is often odd, like over 12.6v, so this could be what you have.
I had a Bongo with 2 batteries japanese vervion - doubles the AH for winter starting in cold climates. Whereas my Transit has 2 batteries, one for starting, one for accessories.
Thanks for all the contributions.
Update.
I went to the battery bloke yesterday, he told me the true age of the batteries from a date on one and a code on the other.
One is 2017, the other.............2013!!!!!!!
He 'tested' my batteries and the printout stated they were both good.
Thing is, as I was driving back home I thought, hang on, they are wired parallel.
He didn't isolate them, so any reading is across both batteries, so that was a waste of time.
So, this morning I spent a while testing. Thanks for the link kestral, that is what I was after in my first post.
With batteries wired parallel, both batteries were at 13.25, no surprise as they are still connected.
Isolated, the 2017 read 13.25, the 2013, 13.20, likely because the older battery is parasitic and taking charge from the 'better' battery maybe?
So I tried to start the van using just the 2013, there was a pathetic shrug, but didn't turn over once.
I tried the 2017 battery on its own, it started the van, but with a struggle, as would be expected anyway as it really needs the two.
I tried load testing just the 2017 battery.
Read between 15.06-15.17 running.
Starting produced a 09.25 ish reading, and it would start 3 times in quick succession with the reading lower each time.
I don't think it would have started a fourth time.
With both connected, running the reading was 15.30.
First start was 10.53, then around 09.75 - 09.24. I did four starts in quick succession, so a positive result.
Conclusion, the 2013 battery has had it, although it is adding that bit of extra oomph needed, until it gets tired.
The 2017 battery is, I think, at around 85% good, so I need one battery.
All contributions have been much appreciated as I've learned a fair bit.
Oh yeah, the battery guy, despite his faux pas with the testing, had some interesting stuff to tell me.
They supply BMW with batteries, and he told me BMW have complained to them because their batteries are lasting too long, which is affecting their after sales. Wow!
He also told me about two batteries that are sold, one I forget the make of the car it was for, but it costs in the region of £350, the other is for a Porsche, and that costs around £550, yet both batteries are identical. Disgraceful behaviour all round.
Anyway, all that stated, I now have a red light with a key symbol flashing on the dash. Aaaarrrgghh!
Update.
I went to the battery bloke yesterday, he told me the true age of the batteries from a date on one and a code on the other.
One is 2017, the other.............2013!!!!!!!
He 'tested' my batteries and the printout stated they were both good.
Thing is, as I was driving back home I thought, hang on, they are wired parallel.
He didn't isolate them, so any reading is across both batteries, so that was a waste of time.
So, this morning I spent a while testing. Thanks for the link kestral, that is what I was after in my first post.
With batteries wired parallel, both batteries were at 13.25, no surprise as they are still connected.
Isolated, the 2017 read 13.25, the 2013, 13.20, likely because the older battery is parasitic and taking charge from the 'better' battery maybe?
So I tried to start the van using just the 2013, there was a pathetic shrug, but didn't turn over once.
I tried the 2017 battery on its own, it started the van, but with a struggle, as would be expected anyway as it really needs the two.
I tried load testing just the 2017 battery.
Read between 15.06-15.17 running.
Starting produced a 09.25 ish reading, and it would start 3 times in quick succession with the reading lower each time.
I don't think it would have started a fourth time.
With both connected, running the reading was 15.30.
First start was 10.53, then around 09.75 - 09.24. I did four starts in quick succession, so a positive result.
Conclusion, the 2013 battery has had it, although it is adding that bit of extra oomph needed, until it gets tired.
The 2017 battery is, I think, at around 85% good, so I need one battery.
All contributions have been much appreciated as I've learned a fair bit.
Oh yeah, the battery guy, despite his faux pas with the testing, had some interesting stuff to tell me.
They supply BMW with batteries, and he told me BMW have complained to them because their batteries are lasting too long, which is affecting their after sales. Wow!
He also told me about two batteries that are sold, one I forget the make of the car it was for, but it costs in the region of £350, the other is for a Porsche, and that costs around £550, yet both batteries are identical. Disgraceful behaviour all round.
Anyway, all that stated, I now have a red light with a key symbol flashing on the dash. Aaaarrrgghh!
PelicanHead said:
So I tried to start the van using just the 2013, there was a pathetic shrug, but didn't turn over once.
I tried the 2017 battery on its own, it started the van, but with a struggle, as would be expected anyway as it really needs the two.
What was the voltage of the batteries after testing?I tried the 2017 battery on its own, it started the van, but with a struggle, as would be expected anyway as it really needs the two.
You've got odd readings there without explaining when and how you took them.
"Isolated, the 2017 read 13.25, the 2013, 13.20, likely because the older battery is parasitic and taking charge from the 'better' battery maybe?" - How long did you wait before taking the readings? because they are meaningless if taken immediately after being charged. You need to wait a good 30 mins, - 1 hour to be sure. )Neither battery will be "charging " the other once pulled off charge - they'll eqialise a bit but they are both settling back to 12.6v
2013 - bin it, just based on age alone.
"it started the van, but with a struggle, as would be expected anyway as it really needs the two." - I very much doubt it - you have 2 probably for cold weather (Japanese van). I don't know the specs of your batteries but even a 70Ah battery should start most engines fine. More likely your 2018 battery is on the way.
.
"Read between 15.06-15.17 running." - that's very damaging overcharging - your alternator regulator is shot.
I'd bin both batteries tbh. Even your 2017 is 8+ years old.
"Isolated, the 2017 read 13.25, the 2013, 13.20, likely because the older battery is parasitic and taking charge from the 'better' battery maybe?" - How long did you wait before taking the readings? because they are meaningless if taken immediately after being charged. You need to wait a good 30 mins, - 1 hour to be sure. )Neither battery will be "charging " the other once pulled off charge - they'll eqialise a bit but they are both settling back to 12.6v
2013 - bin it, just based on age alone.
"it started the van, but with a struggle, as would be expected anyway as it really needs the two." - I very much doubt it - you have 2 probably for cold weather (Japanese van). I don't know the specs of your batteries but even a 70Ah battery should start most engines fine. More likely your 2018 battery is on the way.
.
"Read between 15.06-15.17 running." - that's very damaging overcharging - your alternator regulator is shot.
I'd bin both batteries tbh. Even your 2017 is 8+ years old.
Edited by Griffith4ever on Friday 7th November 16:15
Griffith4ever said:
You've got odd readings there without explaining when and how you took them.
"Isolated, the 2017 read 13.25, the 2013, 13.20, likely because the older battery is parasitic and taking charge from the 'better' battery maybe?" - How long did you wait before taking the readings? because they are meaningless if taken immediately after being charged. You need to wait a good 30 mins, - 1 hour to be sure. )Neither battery will be "charging " the other once pulled off charge - they'll eqialise a bit but they are both settling back to 12.6v
2013 - bin it, just based on age alone.
"it started the van, but with a struggle, as would be expected anyway as it really needs the two." - I very much doubt it - you have 2 probably for cold weather (Japanese van). I don't know the specs of your batteries but even a 70Ah battery should start most engines fine. More likely your 2018 battery is on the way.
.
"Read between 15.06-15.17 running." - that's very damaging overcharging - your alternator regulator is shot.
I'd bin both batteries tbh. Even your 2017 is 8+ years old.
As stated previously, they have been off the van on other days for up to 48 hours and read similar."Isolated, the 2017 read 13.25, the 2013, 13.20, likely because the older battery is parasitic and taking charge from the 'better' battery maybe?" - How long did you wait before taking the readings? because they are meaningless if taken immediately after being charged. You need to wait a good 30 mins, - 1 hour to be sure. )Neither battery will be "charging " the other once pulled off charge - they'll eqialise a bit but they are both settling back to 12.6v
2013 - bin it, just based on age alone.
"it started the van, but with a struggle, as would be expected anyway as it really needs the two." - I very much doubt it - you have 2 probably for cold weather (Japanese van). I don't know the specs of your batteries but even a 70Ah battery should start most engines fine. More likely your 2018 battery is on the way.
.
"Read between 15.06-15.17 running." - that's very damaging overcharging - your alternator regulator is shot.
I'd bin both batteries tbh. Even your 2017 is 8+ years old.
Edited by Griffith4ever on Friday 7th November 16:15
They took a fair while to reach 12.7 but neither ever fell below, which puzzled me further.
The 2013, I agree.
In regards to the 2017 battery, if you read on, it started the van 3 times in quick succession, which isn't bad for a battery that may be at 85%.
I likely thought it sounded a struggle as I'm used to the two battery scenario.
On the overcharging likelihood, you can get such a reading from bad batteries, from what I've read, so not necessarily a dodgy alternator.
As I've stated, I'm likely selling it in the new year (but I've said that before, so I'll probably still have it this time next year) so if one is showing good - 85%, I'm reluctant to bin it and buy two. Plus, don't forget, we need to save the planet!
That's my excuse anyway.That said, the guy said I could have two for £140 instead of £80 each, so...
PelicanHead said:
E-bmw said:
What was the voltage of the batteries after testing?
Around 13.4While a battery can show 13.4v it would be immediately off a charger with absolutely zero usage even for a few seconds.
Went out in it 2 days ago so it's been sitting for around 48hrs.
Just took a reading now and it was 13.12.
Starts like I've got new batteries, at the moment.
Not had time to get new ones/one yet as dealing with the car insurance (see 5th November post), which is more of a pain than my battery issue.
Just took a reading now and it was 13.12.
Starts like I've got new batteries, at the moment.
Not had time to get new ones/one yet as dealing with the car insurance (see 5th November post), which is more of a pain than my battery issue.
PelicanHead said:
Went out in it 2 days ago so it's been sitting for around 48hrs.
Just took a reading now and it was 13.12.
I would suggest that 13.12 is a very unlikely real number. Do you know anyone else who has a multimeter you could borrow to cross-check this? As an example, after about two days of standing, my MX-5 is at about 12.5-12.55 and that battery is only 6 weeks old.Just took a reading now and it was 13.12.
As above that voltage is too high, your meter is not reading correctly, especially after a period of time.
It 100% should be under 12.6 volts.
Without an accurate reading your testing thus far is pointless.
ETA.
There are thousands out there like this, cheap as chips & generally extremely accurate & useful.
https://www.amazon.co.uk/AstroAI-Multimeters-Capac...
It 100% should be under 12.6 volts.
Without an accurate reading your testing thus far is pointless.
ETA.
There are thousands out there like this, cheap as chips & generally extremely accurate & useful.
https://www.amazon.co.uk/AstroAI-Multimeters-Capac...
Edited by E-bmw on Thursday 13th November 08:06
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