Starter battery voltage

[t0mb0]

Hi,

Our air suspension controller is complaining about low voltage from the starter battery as the electrics are turned on before ignition. It's fine once the engine is started and the alternator is running.

I measured the voltage (at a 12v socket so there may be some voltage drop from the wiring) at 12.4-12.5 volts before the electrics are on which seems a little on the low side as it would imply a battery charge of around 50%. The van has done some long'ish runs recently so I'd expect the charge to be near 80%. Is this normal, or do other T6 owners get more than this?

Once the electrics are on then the voltage seems to drop to 12.1v which seems extremely low. Obviously I'd expect some voltage sag if it's really under load but it's only really powering a few dashboard lights at this point.

I'm wondering whether we have an iffy starter battery.

 

[Pauly]

It's a tricky one measuring voltages with the engine running due to the variable output of the smart alternators, I'm not 100% sure what the correct voltage is/should be before or after keying on
@travelvolts may be able to give some more info on standby voltage ?

 

[t0mb0]

Yes, but this is all without the engine running. Once the engine is running, it's perfectly fine.

 

[travelvolts]

12.4 to 12.5 is normal, remember these vans keep the battery at around 80% to leave room for regen under braking.

 

[EdH]

Hi all, old thread. Just measured my Van's standby voltage and its indicating 12.1. Its brand new t6.1. Surely this is not right @travelvolts

 

[travelvolts]

Doesn't sound good. Are you sure of the meters accuracy?

 

[EdH]

Doesn't sound good. Are you sure of the meters accuracy?

Thank you very much for such prompt response. Standard voltmeter, its jumped to 12.2v now. Brand new conversion with a separate leisure battery. Compared with my 2008 Golf which indicates 12.6v. Also borrowed neighbours Lidl charger with display and it is shown exactly the same as per voltmeter now at 12.2v. When I started the campervan it went to 14.6v.

 

[travelvolts]

How long has it been standing to reach 12.1?

 

[EdH]

Van was not used since last Sunday, I went away on Friday for a 70mile trip. When I started the van on Friday to go, it was strange crank up to be honest. Got to my destination on Friday night and stayed over night. Saturday afternoon on my way back home it was again strange crank up but started it didn't struggle. Drove for 20 minutes to get fuel, filled up and engine started as normal. 70 miles back home, vehicle parked over night and I measured it this afternoon when I acquired the meter from a neighbour And I got the above figures some 18hrs after arriving back home. To be honest I don't use it every day at all, given the current situation we tend to just go for a day out over the weekend (80miles return journey even if that). From your professional experience do you think that there could be a battery issue (drain somewhere, we have used a very reputable converters RollingHomes), or lack of use (once a week)? Once again thank you for your assistance really appreciated.

 

[Ads_Essex]

Van was not used since last Sunday, I went away on Friday for a 70mile trip. When I started the van on Friday to go, it was strange crank up to be honest. Got to my destination on Friday night and stayed over night. Saturday afternoon on my way back home it was again strange crank up but started it didn't struggle. Drove for 20 minutes to get fuel, filled up and engine started as normal. 70 miles back home, vehicle parked over night and I measured it this afternoon when I acquired the meter from a neighbour And I got the above figures some 18hrs after arriving back home. To be honest I don't use it every day at all, given the current situation we tend to just go for a day out over the weekend (80miles return journey even if that). From your professional experience do you think that there could be a battery issue (drain somewhere, we have used a very reputable converters RollingHomes), or lack of use (once a week)? Once again thank you for your assistance really appreciated.

My BM2 told me that my van was at 12v last night / 11.98v this morning, it having been stood for a week. It started fine. Haven’t got a clue how accurate the BM2 is, mind.

 

[EdH]

So I noticed this just this Friday, bit of a sluggish start, not its usual sharp first crank start. So Friday would be its first trip this week since last Sunday.

 

[EdH]

It has been a cold week, we had few frosts this week and the van was just sitting unused for the whole week. Today when I noticed the above perimeters the van started totally fine comparing with Friday evening and Saturday on my way back home, and totally normal after fuel stop after 20min journey on my way back. I just don't want a hassle with this new pride and joy after 2 months of ownership. I would be surprised if it's a battery problem (faulty battery on a brand new T6.1 2L Tdi). Its charging at the moment and it's showing 13.2v.

 

[Pete C]

If we leave our van for 4 weeks, the battery voltage when the glow plugs are heating up is about 11.8 volts.
Starts perfectly every time.

Pete

 

[Jason Stancliffe]

Hi
My vans starter battery is always at 12v, or just under , starts ok no probs
Someone correct me if I’m wrong, but I thought the battery is kept at just 12v to leave spare capacity to be topped up from the regenerative braking system on the T6

 

[ThreeBridgeT6]

Interested to read this as I'm wondering exactly the same - see other thread here: Battery drain From the comments above I suspect that there's nothing wrong with mine after all as everyone's level seems to hover around the 12v mark, and they still start ok down at around 11.5v.

 

[EdH]

Interested to read this as I'm wondering exactly the same - see other thread here: Battery drain From the comments above I suspect that there's nothing wrong with mine after all as everyone's level seems to hover around the 12v mark, and they still start ok down at around 11.5v.

Hmmmm, it could then be normal thing with the level 12-12.2v or there abouts. It got me panicked a bit. First ever van/campervan and then this. I could just see the scenario converters saying it's VW issue, VW saying it's due to conversion..... It sounds like T6s are slightly running low then, while my 2009 Golf is on 12.6v. I left the charger plugged in at the moment, would that do any harm now?

 

[Pete C]

What type of charger is it ?

Pete

 

[EdH]

Lidl one 3.8v. I got Ctek 3.8v but I am using the Lidl one at the moment as it has LDC voltage display.

 

[ThreeBridgeT6]

Hmmmm, it could then be normal thing with the level 12-12.2v or there abouts. It got me panicked a bit. First ever van/campervan and then this. I could just see the scenario converters saying it's VW issue, VW saying it's due to conversion..... It sounds like T6s are slightly running low then, while my 2009 Golf is on 12.6v. I left the charger plugged in at the moment, would that do any harm now?

I'm no expert - there are plenty on here who are - but I suspect it depends upon the type of charger being used and the kit installed by your converter. I think (but I don't know) that most chargers these days are 'smart' in that they detect the level of charge required and therefore avoid damaging the battery by overcharging. Some three way chargers will monitor temperatures in order to avoid damaging lithium batteries by charging when the ambient temperature is too low. Mine has a three way which charges the starter and the leisure batteries when on hook-up, in conjunction with the solar panel and the alternator.

 

[CAB]

My camper goes to 12.7 - 12.8v after 24hr charging with a Ctek, but after a fortnight sat on the driveway is down to 12.4.

Have been told that it needs a couple of hours of driving to properly charge. The battery charger seems to give it 0.1 or 0.2 v more than driving it.