S/S inactive, and Moll Electrolyte indicator

[AlexBlue]

Hi All

Nearly 3yo Octavia (1.5tsi), not driven too much in the last year (around 5k), mostly 20mi e/w commute and some local trips.

Since before Chrsitmas I've noticed that stop/start hasn't been working, so I suspect a battery charge issue. Never had problems starting the car though, but nothing changed after a 200mi drive (seeen that maybe battery charging isn't so great if the engine/alternatior isn't well loaded?).

 

Had a gander at the battery today and see the indicator denoting the low electrolyte is yellow. I can't find anything online to suggest if this is a positive for low electrolyte or not.

If it is, can it be topped up with distilled water, can I get Skoda to do it? I'm guessing it's not warranty?

 

And perhaps I should get a battery charger.

And somehting to measure the battery voltage at a 12V socket...

Battery is 12V 69Ah EFB.

 

Thanks
Alex

[Warrior193]

Hi Alex, I suspect your battery has died - possibly from low use during the winter, there has been mention of a dodgy batch of Molls, but I think this faulty batch was from more than three years ago. Unfortunately there is no practical way to top-up the electrolyte in these batteries. I rather suspect your Dealer will say "consumer item, not covered under warranty" but ask anyway.

I'd try charging it and giving it a test to see what happens - also check the alternator output voltage at the battery terminals.

[xman]

Found this ref motorcraft batteries but probably same as for Moll

 

 

Quote

The Magic Eye® that is used in Motorcraft batteries provides 4 stages of indication, they are:
1. Green: battery is charged and the acid level is good.
2. Yellow: Battery is partially dis-charged and the acid level is good. Re-charge the battery or drive the vehicle.
3. Red: Battery is dis-charged and the acid level is good. Charge the battery.
4. Clear and bright: Acid level is low!!! Add distilled water if possible. If not, change out the battery. Do not charge or jump start the battery!!!

While the Magic Eye® is only located in one cell, it is still quite accurate for indicating the state of charge of all cells as they are within 95% of the same condition. If there is a catastrophic failure such as an internal short circuit, the battery would be bad, but the eye would still show green as the density of the acid is still technically correct. This is very rare.

 

So low charge....

 

What has probably happened is the battery self discharge over winter has led the battery management system state of charge calcs (SOC) to get out of whack, as it can't track self discharge current. So you need to recharge the battery fully, preferably using an external means.

 

If you have a decent charger try recharging it first, a good 2–3 days will be required to fully recharge a lead acid battery, particularly if it has been partially discharged for an extended period. Take care to follow the instructions on the manual regarding charger connection. The negative lead MUST go on the earth tab at the bodywork end of the batteries negative lead.

 

Alternatively, when driving, always turn on your headlights, overide any auto setting (last position) and maybe other consumers such as fan, heated rear window. This will force the battery management to charge the battery instead of allowing it drift along in micro hybrid mode. It will still take a long time for the battery to return to full SOC.

 

 

Good luck

Edited 2 April, 2021 by xman

[AlexBlue]

Thank you for your advice and tips - and successful hunt for info on the indicator. Yes I would suspect this monitoring tech is similar amongst manufacturers - why it's not obvious on Moll website or datasheets I have no idea.

So hopefully not all is lost, as you suggest a slow charge to bring it up to Green seems like a good plan. I've seen a Ring 6A charger (~1/10 battery max discharge rate from what I read is rule of thumb) for £25 that works in a low current charge mode with very few complaints, so will likely be good enough here - though an 8A version is only a couple of pounds more. Will be slightly better than having to drive around in this weather with the heated seats and all the other heaters on (winter pack ftw!) and lights.

 

Thanks again

 

Edited 2 April, 2021 by AlexBlue

[PetrolDave]

Probably worth having a look at CTEK chargers as they can safely be left connected to EFB or AGM batteries.

[peter3197]

According to top of my Moll battery there are only 2 indicator colours, black and yellow. Black is good, yellow is knackered.

 

[Warrior193]

3 hours ago, AlexBlue said:

Thank you for your advice and tips - and successful hunt for info on the indicator. Yes I would suspect this monitoring tech is similar amongst manufacturers - why it's not obvious on Moll website or datasheets I have no idea.

So hopefully not all is lost, as you suggest a slow charge to bring it up to Green seems like a good plan. I've seen a Ring 6A charger (~1/10 battery max discharge rate from what I read is rule of thumb) for £25 that works in a low current charge mode with very few complaints, so will likely be good enough here - though an 8A version is only a couple of pounds more. Will be slightly better than having to drive around in this weather with the heated seats and all the other heaters on (winter pack ftw!) and lights.

 

Thanks again

 

If your budget can run to it, I can recommend one of the Ring RSC range of chargers - I have the RSC608 (8 Amp) Failing that, make sure the charger you do buy has a AGM/EFB setting.

[xman]

58 minutes ago, peter3197 said:

According to top of my Moll battery there are only 2 indicator colours, black and yellow. Black is good, yellow is knackered.

 

 

I think @peter3197  is right.  But may still be worth trying recharging before throwing the battery away.

 

https://www.moll-batterien.de/dateien/pdfs/Datenblaetter_Batterien/MOLL_startstop_engl.pdf

 

Key to looking after stop/start batteries is to recharge them with an external charger from time to time, especially if the car is not used a lot. So I recommend you invest in a good charger 

 

Edited 2 April, 2021 by xman

[AlexBlue]

1 hour ago, peter3197 said:

According to top of my Moll battery there are only 2 indicator colours, black and yellow. Black is good, yellow is knackered.

 

 

57 minutes ago, xman said:

 

I think @peter3197  is right.  But may still be worth trying recharging before throwing the battery away.

 

https://www.moll-batterien.de/dateien/pdfs/Datenblaetter_Batterien/MOLL_startstop_engl.pdf

 

Key to looking after stop/start batteries is to recharge them with an external charger from time to time, especially if the car is not used a lot. So I recommend you invest in a good charger 

 

 

 

aahh, so perhaps what I was looking at wasn't the indicator but the visual description of what the indicator means... with a window-looking area next to it (which a quick glance down couldn't see much, it was very dark down there)... feeling a bit dim now :(

 

But nevertheless, getting a charger seems to be a good plan in any case - because even if it's not knackered it's unlikely to be close to optimal. Various options around those mentioned above. ~£40-80 depending on how much detail or diagnostics are needed by the looks of it.

Appreciate the input and pointers

 

[Warrior193]

Hi Alex, let us know how you got on once you have given it a good charge, there are a lot of others who are not familiar with the performance characteristics of EFB and AGM batteries. It's useful to know if members manage to recover batteries with fading performance.  - NB. you don't need to remove the battery from the car to charge - just make sure you connect the Negative (black) charger clamp to the flat tag on the firewall (not to the battery terminal itself). 

[AlexBlue]

Success!

 

Took around 20 hours to 'Full', took Octy out today and S/S kicked in after a small number of miles.

 

I went for a Ring RSC806 - it doesn't have the diagnostic capability of the RSC6xx but it does have the same 7-stage charging profile which sounds fancy even if it's just snake oil!  Probably just means it takes a bit longer as it's taking its sweet time.

So now I'll look at topping up the battery every couple of months (or more in winter) as my longer journeys are fewer with more shorter ones in between.