Alternator Lack Of Charging Causing Battery Failure.

[longtallmartin]

I have a 2017 T6 102hp 28cwt with approx 10,000 miles. Converted to camper with solar panel fit courtesy of Vamoose. I had to have a new battery at start of 2019 due to dead battery. After recharge by AA and diagnostic checks they scrapped original battery and replaced with new Varta battery. My van had a history of poor performance and endurance from the leisure battery.
Since the change I checked voltage of battery & became very aware of the battery voltage being low when engine idling. I have established that unless (A) I switch my heater blower to position 2 or above or (B) switch lights to main then my Alternator does not kick out a charge and my battery voltage at stationary will read 12.5v or lower depending upon vehicle charge. No indication of a no charge condition is indicated. Switch on A or B and I get 13.3v at the battery. I queried it with VW at service in march 2019 & they who say the van is perfectly serviceable. I am now trying to take VW to task as I believe this is another VW emissions fiasco. The no-charge alternator will give good emissions with nothing switched on. No cheating with emissions software but i have no charge to my van battery or leisure battery system when I drive the van on daytime conditions without blower on 2 or above.

Does anybody else have the same issues. I believe this wouldnt have helped the original battery and would likely have contributed to its failure. Local dealer suggested driving around with aircon switched on. Aircon switched on doesn't help unless at blower posn2.
I queried the vehicle again with AA who carried out battery change and technician confirmed my diagnosis as correct. Take back to VW he said as appears to have poor voltage sensing condition??
I now drive with A or B switched on and I then have excellent leisure battery condition. This may help you guys with start issues due to flat batteries. No indication when van charging system isn't charging ie a Mil light switched like in old dynamo days.

 

[Loz]

What you described is normal operation for bluemotion.
The alternator goes into idle once the starter battery is at 80% to save fuel and give headroom for the regenerative braking.
This means that power will flow from your leisure battery to the starter battery unless you replace the split charge relay for a dc-dc charger.
Was your previous battery a MOLL? As they are all faulty and being replaced.

Read this topic. How To Fit Travelvolts Dc-dc Charger Kit

 

[longtallmartin]

Hi i disagree. My van would only show battery at 12.2v weeks after battery changed. This voltage is not good for batteries. They shoud be 12.5v.
When van was serviced they advised i needs charging. This after a 109 mile journey day begore. I challenged adviced and queried faulty. Dealer would only give serviceability check after full charge. Next day at 12.8v battery declared ok and charging ok. I drove down Road and after 3 miles vehicle dropped to 12.5v, later checked at 12.2 after 100 mile journey. This showed that alternator was not charging with nothing switched on. As describe previously.

You are right it's considered ok by vw. However not a clever quality driven method of charging with no indication of no-charging. 12v batteries should be at 12.5v/12.6v
Why not have option to go into an eco-mode that performs in this manner. I cannot switch-on/switch off. Hence without knowledge this will kill battery in time. Vw happy to pay for 1st battery replacement. Would vw replace next so easily. Plus it kills my leisure battery.
Only way around it is to drive around with lights on or blower at posn2 or above. Piss-poor power management strategy unless trying to hide poor emissions.
PS running vehicle at idle for 30mins to charge a flat leisure battery after 1-2 days camping doesn't work. Now I know better I have to manage it. Other owners do not know. I was looking at replacing my charge controller/panel or doubling up to 2 leisure batteries and 2 solar panels. Cheers

 

[longtallmartin]

Vw when asked to give full details on normal and regen charging on my vehical said they would give it but conveniently couldn't find it???

Note they never charged me for 2 sets of re-charge and diagnostic checks. AA technician said charging looks iffy take back to VW!

If VW were being honest they would have shared service procedure info. Instead they gave me some bill shit about driving with aircon on. Technician when asked about regen braking there described an alternator with a clutch mechanism on it??? Not very convincing.

Example of my charging voltage.
Before start up battery 12.5v
Start up edle/rev 12.3v
Switch on screen heater 12.2v
Switch on lights or blower pos2 13.3v
Feel free to send me a link and decription as to how regen & normal charging works. Note I don't believe charging at 12.2 is sensible without some indication that eco no charge is in operation!

 

[andys]

No I’ve never had a problem, the alternator charging to 80% and regenerating on braking seems to work fine, would just be a waste of fuel forcing the alternator into charging all the time by loading it unnecessarily.
I agree that where a second battery is factory fitted it should be accompanied by a dc-dc charger though, doing it with a switching relay is cheaping out by VW, especially if you don’t realise that idling is not putting any charge into the leisure battery at all. Plenty of better aftermarket solutions on here though if you do a search.

 

[longtallmartin]

Hi if my battery was kept at a recommended 12.5v/12.6v without me having to switch devices on I would be happy. IE having intelligent charging but my vw transporter doesn't have intelligent charging. I drove 100 miles on a motorway and my voltage just keeps on dropping. Regen on a motorway doesn't work

 

[Lord Mfwic]

I have a Leisure battery fitted by @travelvolts and mine does recharge on idle. I have done this several times whilst camping. I assume mine is a dc-dc charger as mentioned above.

 

[Dellmassive]

What @Loz said... bluemotion and smart operation.

You need to fit a DC-DC charger for you leisure battery, an leave the smart alternator and starter battery to themselves..

Remember that it takes 15mins driving to replenish a cold morning van start, and even longer to charge the battery during winter with light and heaters on..... so be mindful of how long you are driving per day....

If it's not enough look at getting a maintenance battery charger...

I'd imagine your using the old style VSR or ignition relay to connect your leisure battery to the starter battery?....also rember your starter battery will discharge into your leisure battery when they are connected and vice versa as the batteries try to equalize themselves.... low voltage reading when things are switched on are an indication of volt drop due to current flow.

Have a quick look at these......


Stop/start...regen...smart Alternator... Dc-dc Charger For Leisure Battery Or Not?

.
Battery Chargers - How I Did It -
.



.Stop/start Doing Your Head In? Disabling It - How We Done It -

.
Dellmassive`s -- "how I Done It" -- Thread

.

 

[Loz]

Hi i disagree. My van would only show battery at 12.2v weeks after battery changed. This voltage is not good for batteries. They shoud be 12.5v.

You didn’t answer my question, was your original battery a MOLL and then replaced with a Varta?
I think you have had multiple issues and you need to separate them to understand what is going on.
I suspect your first battery was a faulty MOLL and yes you would have these issues.
I have a varta which is fine with the way it is charged. The vehicle has a battery monitor attached and regulates the charging.
However as we all agree if you want 100% charging of the leisure batteries you need a dc-dc charger as a simple split charge relay is nit suitable for smart alternators.

 

[Dellmassive]

MOLL battery issue.
Stop/start...regen...smart Alternator... Dc-dc Charger For Leisure Battery Or Not?

.

 

[Pete C]

I struggled in the words above to work out when you were talking about your van starter battery, and your leisure battery.

What device do you have to charge your leisure battery from your van starter battery ?

Peter

 

[t0mb0]

It’s not clear to me when you quote voltages whether you’re quoting them under load or at rest. The voltage on a battery will naturally sag under load.

Therefore, measuring 12.5v before it’s started could be fine and entirely consistent with the target 80% charge. Also, measuring 12.2v when under load could also be entirely consistent with 80% charge. The alternator should only come on to get it back to 80%, I’m not sure if it uses a voltage threshold at all.

If you want a properly charged leisure battery from the alternator, get a DC-DC charger. This will also have the side effect of sending your alternator high for much of the time so your starter will probably be often higher than the vw target 80%.

 

[Pete C]

And by the way, this style of intelligent alternator charging is used by all the major vehicle manufacturers.

Peter

 

[longtallmartin]

You didn’t answer my question, was your original battery a MOLL and then replaced with a Varta?
I think you have had multiple issues and you need to separate them to understand what is going on.
I suspect your first battery was a faulty MOLL and yes you would have these issues.
I have a varta which is fine with the way it is charged. The vehicle has a battery monitor attached and regulates the charging.
However as we all agree if you want 100% charging of the leisure batteries you need a dc-dc charger as a simple split charge relay is nit suitable for smart alternators.

Hi yes my battery was a moll replaced with a varta. My Alternator doesn't charge unless I switch on the lights or battery. Courtesy of vw charging logic. The charging of van and leisure work fine now i know we have switch on the lights or blower posn2 (A). Vw confimed no issues with discharge.
My complaint is non-professional method to charge battery. It isnt smart because, with low battety condition it doesnt charge battery unless (A). Vw dealers are hiding this issue.

 

[andys]

Hi yes my battery was a moll replaced with a varta. My Alternator doesn't charge unless I switch on the lights or battery. Courtesy of vw charging logic. The charging of van and leisure work fine now i know we have switch on the lights or blower posn2 (A). Vw confimed no issues with discharge.
My complaint is non-professional method to charge battery. It isnt smart because, with low battety condition it doesnt charge battery unless (A). Vw dealers are hiding this issue.

But none of the rest of us have to switch the lights or blower on to charge the starter battery, so either there is a fault or you're measuring it wrong.

 

[longtallmartin]

I'm posting because other people may have same issue. Vw say no fault. Therefore poor charging logic
I measure at battery across terminals.
1 please measure battery voltage before start up. (Mine 12.5v)
2 Measure after start up (Mine 12.3v)
3 Measure with lights on only (Mine 13.3v)
4 Measure with blower only at posn 1 & 2 and above (mine posn1 12.3v, posn2 13.3v)
5 measure with other items on and lights/blower off (Mine 12.3v or lower)
Thx Martin

 

[Dellmassive]

But none of the rest of us have to switch the lights or blower on to charge the starter battery, so either there is a fault or you're measuring it wrong.

looks like hes just switching loads on until the alternator goes full-field and gives him the charging voltage hes looking for, i dont think there is an issue here.

The thing is the "Energy management system" will only generate enough power to overcome the demanded electrical load and still keep the starter battery at 80%.

So i think what he is doing is a false economy and not realy fixing the issue,

my take on it is:

He needs to drive the van more to allow the system to charge itself via time/distance/regen braking.

or

Get a mains charger to top-up the battery every now and again.

and

get a DC-DC charger to charge his Aux battery (swap out the VSR/Relay already fitted)


Having said all that, all the information he needs has been posted above.

 

[Phil_G]

My van would only show battery at 12.2v weeks after battery changed.

In modern vehicles with active electronics its quite normal for the starter battery to be discharged after standing as little as 2 or 3 weeks.

If its a VSR (we still dont know) then occasionally bridging the relay whilst parked would top up the starter battery via solar.

Cheers
Phil

 

[Dellmassive]

its not poor charging logic - its by design . . . . . and now across all makes/models in modern Motoring.

Quote from VW : In detail, this function has been configured so that the alternator voltage is raised in the deceleration and braking phases. This leads to increased charging of the battery. This supports the deceleration of the vehicle. The alternator load is thus reduced in acceleration phases. This relieves the burden on the engine and thus reduces fuel consumption





@longtallmartin

have a look at these write ups for more info:

Ssp 426 - Start/stop System 2009


Aux Battery Charging With Smart Alternators | 12 Volt Planet

Spotlight on: smart alternators

Smart Alternator DC CTEK Split Charging System For VW T6 and Bluemotion T5 - J42667

Smart alternators and regenerative braking. - VW T4 Forum - VW T5 Forum

CTEK Crafter Smart Alternator Euro 6 Split Charger 12V D250SA


https://www.travelvolts.net/shop

 

[Pete C]

You say it is a fault, but do you have a problem starting the van ?
Unless there are issues arising as a result of what you consider to be a low voltage, then why worry ?
My T6 behaves in exactly the same way, and we don’t have any issues.

Peter