Alternator output

[scubamouse]

Silly question after the trouble I had with my battery,

Just asking what volts should the alternator put out as I check mine with a volt meter and on tickover I was only getting 13 volts across the battery could not check when reving the engine legs not long enough,  should this not be more like 14volts?

 

Mick

[KenONeill]

24 minutes ago, scubamouse said:

should this not be more like 14volts?

And the rest; try 14.4v on the 0-20v scale.

[Kenny R]

The alternator does not charge the battery as in ye olden days. To save fuel etc the alternator tends to switch off and only charge on the overrun. It also only charges the battery to around 80% to allow capacity for it to accept charge when you lift of the accelerator etc.

[scubamouse]

Thanks will have to look at getting a cigarette tester to see what’s happening to the battery.

 

they still say my dash cam permanent feed killed my old battery which I’m find hard to believe 

 

Mick

[don_kiddik]

1 hour ago, scubamouse said:

Thanks will have to look at getting a cigarette tester to see what’s happening to the battery.

 

they still say my dash cam permanent feed killed my old battery which I’m find hard to believe 

 

Mick

 

Hi @Scubamouse, I bought one of these:-

 

Dual USB Car Charger - JEBSENS Car Voltage Meter Car Charger with Two USB Ports, 4.8A / 24W, LED Display Built-in Safety Protection Fast Charging Compatible with All Smartphones and Tablets : Amazon.co.uk: Electronics & Photo

 

Hope this helps

[VRT24]

12 hours ago, scubamouse said:

They still say my dash cam permanent feed killed my old battery which I’m find hard to believe 

 

It will if you don't fit a purpose made hard wire kit. They monitor the battery voltage and disconnect feed to the dashcam when the voltage drops too low and thus preventing damage to the car battery. It's surprising how quickly a dashcam left powered up in a non-running car can drain down a battery, and if it keeps happening, then it will shorten the life of the battery.

[Warrior193]

13 hours ago, scubamouse said:

Thanks will have to look at getting a cigarette tester to see what’s happening to the battery.

 

they still say my dash cam permanent feed killed my old battery which I’m find hard to believe 

 

Mick

Hello Scuba, the problem seems to be that the fairly small constant drain from the dash-cam causes other systems to not fully shut down when vehicle is off and locked. Combined with the only partially charged state of the battery under usual conditions, this can cause issues with service life.     

Edited 10 July, 2021 by Warrior193
Typo

[KenONeill]

15 hours ago, Kenny R said:

To save fuel etc the alternator tends to switch off and only charge on the overrun.

If this is accurate, surely the meter reading should be a shade under 12v until the alternator software deigns to switch it on?

[PetrolDave]

14 minutes ago, KenONeill said:

If this is accurate, surely the meter reading should be a shade under 12v until the alternator software deigns to switch it on?

I was using a cigarette lighter socket voltage monitor last year during lockdown (1.4TSI original 5 year old battery):

-ignition off after 4 weeks stopped, 12.2V

- ignition on, 11,6V

- engine started, 14.5V

- while driving, initially 14.5V dropping to 12.6V then pulsing every few minutes up to 14.5V for a minute or so

 

No additional loads like dashcam, etc.

 

[smipx]

7 hours ago, PetrolDave said:

I was using a cigarette lighter socket voltage monitor last year during lockdown (1.4TSI original 5 year old battery):

-ignition off after 4 weeks stopped, 12.2V

- ignition on, 11,6V

- engine started, 14.5V

- while driving, initially 14.5V dropping to 12.6V then pulsing every few minutes up to 14.5V for a minute or so

 

No additional loads like dashcam, etc.

 

Thats how it was (pretty much) for me too.  I made sure in the depths of winter to check it then take a 15-20 minute drive with Auto Stop turned off just to make sure it kept topped up.  Had to do the same with the Wife's 2019 Fabia as well.  Hers was left for 2 weeks in February and the battery almost failed to turn over the engine.  After that I got a meter and monitored it and made sure to take both cars out weekly as a minimum during the cold snaps. It shouldn't really have to be that way but that's clever modern technology for you.   For me personally - Im about to order a CTEK MXS 5.0 while the prices are low.

[smipx]

Sorry to go slightly off-topic (but it is relevant I hope) I was Just about to order the Ctek MXS 5 but some kind fellow on my preferred ordering site suggested that the MXS 5 is not suitable for Stop/Start cars.  Is this really the case?  I think a lot of folk use this on here.  Pretty sure my battery is not an AGM (just like the majority of the Karoq owners I think it is an EFB battery from memory  Some other wise spark said it was but you must select AGM mode.  Not sure I trust either of those answers .

 

for the OP this is a great thread to read. It explains a lot to us novices to the world of Stop/Start and batteries: 

 

 

Edited 10 July, 2021 by smipx

[agedbriar]

The battery charging algorithm avoids charging at the expense of fuel consumption for as long as that policy is sustainable. But driving downhill I'm getting 15,0V, i.e. fast battery charging for free. The voltage drops as soon as the engine starts pulling again.

 

To charge the ESB battery with my Ctek MXS 5.0 charger, I select the conventional battery mode, which tops at 14.4V (while in the AGM mode it would top at 14.7V). In fact, the newer Ctek CT5 Start-Stop model, apparently designed to fit both ESB and AGM technologies, doesn't go higher than 14.55V.

 

Edited 10 July, 2021 by agedbriar

[smipx]

Thanks Agedbriar.  MXS 5.0 it is :-)

Also means the charger can be used for other "non Stop/Start" cars too.  I don't use Stop/Start anyway.  I find it too intrusive and always disable it with the button on every drive. I am so glad I have the 19 model that has that button !

[agedbriar]

I disable Start-Stop too.

 

But we still have to deal with the frugal battery charging algorithm, which often brings us home with an only partly charged battery, which in turn leads to premature battery sulfation (taking place when the battery is resting below 12.4V). Quite inappropriate for lockdown times.

 

Moreover, the battery voltage dropping speed at rest on my wife's 2006 Golf is much lower than on my 2019 Karoq. Due to all the electronics on standby, I presume.

 

Is the Start-Stop disable button banned already?

 

Edited 11 July, 2021 by agedbriar

[PetrolDave]

6 minutes ago, agedbriar said:

Is the Start-Stop disable button banned already?

Not banned, but the tweaks that permanently disable it no longer work (dieselgate issues).

 

If you want the battery to be fully charged to best (only?) way is to unplug the current sensor so the alternator output is then not controlled by state-of-charge only battery voltage.

[agedbriar]

6 minutes ago, PetrolDave said:

Not banned, but the tweaks that permanently disable it no longer work (dieselgate issues).

But that ban is due to happen, I read?

[PetrolDave]

2 minutes ago, agedbriar said:

But that ban is due to happen, I read?

Ban what? Banning stop/start or banning disabling stop/start?

 

Banning stop/start seems unlikely as it's sole alleged benefit is emissions reduction.

 

Banning disabling stop/start has effectively happened since 2019 when VAG stopped the tweaks from working.

[agedbriar]

Banning the Start-Stop disabling button, I mean.

[PetrolDave]

 

2 hours ago, agedbriar said:

Banning the Start-Stop disabling button, I mean.

I haven't heard any suggestion of that in the UK, have the EU suggested it officially? Google doesn't find anything?

Edited 11 July, 2021 by PetrolDave

[smipx]

Well I had a 2020 Octavia as a courtesy car the other day (manual) and it does not have a stop/start override button on the dashboard (not in any obvious place at any rate).  I think (and I am totally prepared to be corrected as I only had the car a short while) each time you start the engine have to navigate the infotainment system and disable it in their.  Turns a 1/4 second task that you can do while keeping both eyes on the road into a good few seconds (especially if the infotainment is turned off at the time) and having to glance away to complete all the necessary steps. Not exactly simple or safe. In my 2019 Karoq (so glad to have back) I can do it safely and quickly and without fuss. I can also do this in the Wife's 2019 Fabia - safely and quickly. In the Octavia I nearly crashed - and while on the subject of moving every useful feature into the infotainment system, don't get me started on the faff to disable the lane assist feature when driving on country roads.  That wonderful feature nearly nudged me into the path of a cyclist that I wanted to give a wide berth as I was overtaking. Yes, I fully accept that it may not have done so had in indicated but, there was no other traffic on the road and I did not indicate. To try to start to pull you back from the centre line into the path of a cyclist is just frikkin dangerous in my view. I will from now on always think of it as the "Let's run over a cyclist Assist".  That needs a big RED disable button all of its own.

 

If that is modern road safety and environmental technology at VAG's very best then, in the future, God help us all when the cars are allowed to drive themselves.  I hope that day is a loooooong time coming  :-)

 

Edited 11 July, 2021 by smipx

[agedbriar]

57 minutes ago, PetrolDave said:

 

I haven't heard any suggestion of that in the UK, have the EU suggested it officially? Google doesn't find anything?

 

I read about that somewhere... unofficial, but quite logical with all this emissions supervision.

It doesn't make sense for a car manufacturer to obtain a good WLTP score (thus avoiding heavy penalty) with the contribution of some technical device while letting the car owners drive in a more emissive mode by simply switching that nuisance off.

 

Edited 11 July, 2021 by agedbriar

[zappahey]

1 hour ago, smipx said:

Well I had a 2020 Octavia as a courtesy car the other day (manual) and it does not have a stop/start override button on the dashboard (not in any obvious place at any rate).  I think (and I am totally prepared to be corrected as I only had the car a short while) each time you start the engine have to navigate the infotainment system and disable it in their.  Turns a 1/4 second task that you can do while keeping both eyes on the road into a good few seconds (especially if the infotainment is turned off at the time) and having to glance away to complete all the necessary steps. Not exactly simple or safe. In my 2019 Karoq (so glad to have back) I can do it safely and quickly and without fuss. I can also do this in the Wife's 2019 Fabia - safely and quickly.

 

 

All you had to was stop somewhere and you could have disabled it perfectly safely.

[scubamouse]

On 10/07/2021 at 08:47, VRT24 said:

It will if you don't fit a purpose made hard wire kit. They monitor the battery voltage and disconnect feed to the dashcam when the voltage drops too low and thus preventing damage to the car battery. It's surprising how quickly a dashcam left powered up in a non-running car can drain down a battery, and if it keeps happening, then it will shorten the life of the battery.

 

thanks VRT24

i fitted a genuine Garmin hard wire kit with the jumper inside changed over to 12v  as some have said that 11.6v is to low. 

the car was only used for short journeys so that has not helped.

 

Mick