Long term hook up

[pluc99]

I’m in the same position, and occasionally don’t drive for 6 weeks. I know that is not ideal, but I do check the battery charge occasionally and doesn’t deplete quickly at all. Last check was >60hrs after not driving for 3 weeks.
It’s crossed my mind to drive it for the sake of the batteries, but that doesn’t sit well with me, and I’ve thought about an eco flow or similar but can’t bring myself to pay £1000 when there isn’t (yet) an issue. But will brace for £500 to replace the batteries in due course, perhaps quicker than if I’d plugged in monthly.

I get the impression that you're thinking mainly about the leisure batteries, which are unlikely to drain significantly in just 6 weeks. It's the starter battery that is more at risk when stationary for longer periods.

 

[dspuk]

I could be mistaken but I think I read that on the T6.1 the built in charger also trickle charged the engine battery. You could check with a Multimeter and measure the engine battery voltage before and after plugging into EHU, but wait until Leisure Batteries are fully charged before the 2nd measurement.

It does. Have checked a few times and also trickle the starter, for what it is worth, via my solar setup.

 

[Greg&Mel Australian Cali]

Any suggestions for keeping the leisure battery charged on a Beach without EHU?

 

[WelshGas]

Any suggestions for keeping the leisure battery charged on a Beach without EHU?

1 . Fit an EHU socket under the bonnet connected to a RCD switch and then an internal, to vehicle, mains socket and / or a 12v smart charger connected to Leisure Battery.

2. Hard wire a 12v high amp socket permenantly to your Leisure Battery. Then household extension lead through door/window with a 12 v smart charger to charge battery. Ctek battery charger 10amp is one common in the U.K.

Advantages of 1 is that you can use campsite EHU as well as home with appropriate connector.

 

[Viktorgeorge]

You could try reading the manual for yourself!

There are a lot of comments re the charging regime from people that have never owned a T6.1, let alone read the manual.

The alternator charging regime is the same as any other car/ van with stop start, how often do you put your car on charge just to get it up to 100% full?

If I was leaving mine parked for a long spell I would be using the max charge button on the last drive before parking up, other than that as long as it has a decent drive every couple of weeks there's no need to do anything.

The important thing is not to put it away with the batteries depleted.

I think you missed my point @andyinluton .

Replacing not one but three batteries is not going to be cheap. So I and I am sure others would like to preserve our batteries. Some posters here talk about 10-15 years on batteries, whilst others rather less.

So my question (which I don’t believe the manual addresses but please prove me wrong) is how to MAXIMISE battery life span.

I have no expertise on this but others posters appear to, in particular @yossarian . He has suggested that lead batteries last longest if kept fully charged. Your point - by deduction - is that as long as they are no depleted (say below 12v for example?) then when left there is no difference to battery longevity.

I don’t know who is more correct, and invite expert thoughts.

 

[Wildcamper]

In my experience batteries like being fully charged or near full. They also like to be used. If this is done and they are kept dry then in my experience one can expect a long life.

 

[yossarian]

There's some good information here: https://batteryuniversity.com/article/bu-804-how-to-prolong-lead-acid-batteries

In general, in the California, the factor you can control the most is partial state of charge leading to sulphation. Battery temperature and cycles less so, depth of discharge to some extent.

Modern AGMs are very robust compared to the lead calcium flooded varieties (and gel types) I cut my teeth on 30 years ago. But they are still similar technology with similar care requirements.

 

[66tim99]

In my experience batteries like being fully charged or near full. They also like to be used. If this is done and they are kept dry then in my experience one can expect a long life.

In that case @andyinluton advice (if leaving parked up for long periods) seems sound. Use max charge before parking and it will slowly deplete (are ‘used’?). Might be better than keeping it plugged in and charged? Though I know that will only top it up to 80%.
I’m not sure about using max charge as only once, when I left a wardrobe light on, has it deplete to even near 25% (in fact it depleted to zero - ouch!). And I understand these batteries should only be charged to 100% irregularly, ie when you won’t be plugged in on a campsite for several days…?

 

[andyinluton]

I think you missed my point @andyinluton .

Replacing not one but three batteries is not going to be cheap. So I and I am sure others would like to preserve our batteries. Some posters here talk about 10-15 years on batteries, whilst others rather less.

So my question (which I don’t believe the manual addresses but please prove me wrong) is how to MAXIMISE battery life span.

I have no expertise on this but others posters appear to, in particular @yossarian . He has suggested that lead batteries last longest if kept fully charged. Your point - by deduction - is that as long as they are no depleted (say below 12v for example?) then when left there is no difference to battery longevity.

I don’t know who is more correct, and invite expert thoughts.

No one has ever managed 15 years on a cali with the smart alternator - they've only been fitted since 2013

The batteries in my 2014 van were fine when I sold it at 7 years old - they still lasted 3 days off hookup with the heater & fridge running. The only time that van was ever plugged in was on campsites & Christmas if we needed the fridge!

Charging for 24 hours a month for that sort of timespan will cost more in electricity bills than you save in replacement batteries.

The biggest difference I suppose is how you use your van, if you have 100% charge when you next drive it the alternator won't charge until the starter battery drops below 80%, every time the split charge relay connects it will draw a massive charge from the leisure batteries to equalise the voltage between those & the starter one until all are back to 80%.
As my van is used most days the minute its up to 100% chances are the van will be driven & they will be straight back down to 80%

My van has not been driven since Monday & not had a journey of more than 10 miles in three weeks, I havn't used max charge & my batteries are at 12.7 volts. I'm not sure how sticking it on a charger is going to improve that. The best maintenance in my view is to use it.

 

[Viktorgeorge]

There's some good information here: https://batteryuniversity.com/article/bu-804-how-to-prolong-lead-acid-batteries

In general, in the California, the factor you can control the most is partial state of charge leading to sulphation. Battery temperature and cycles less so, depth of discharge to some extent.

Modern AGMs are very robust compared to the lead calcium flooded varieties (and gel types) I cut my teeth on 30 years ago. But they are still similar technology with similar care requirements.

Thank you @yossarian I have studied that link, which is helpful. In particular your focus on avoiding sulphation. Thank you also @andyinluton for your thoughts.

I am left with a few questions.

- Can I assume that the factory fitted charging in the T6.1 is 'intelligent' i.e. it can be left on longer term because it reverts to trickle charging? In other words, is permanent EHU potentially damaging, or just unecessary?

- Does the factory fitted charging charge to 80% (as the alternator does, normally) or to 100% (as in MAX charge)?

- Whilst I understand (from other postings) that EHU charges the two leisure batteries first, then, once they have been charged, it goes on to trickle charge the starter battery: what precentage charge (80% or near to 100%) would the three batteries eventually achieve, if left on EHU long term (without the California being in use).

 

[WelshGas]

Thank you @yossarian I have studied that link, which is helpful. In particular your focus on avoiding sulphation. Thank you also @andyinluton for your thoughts.

I am left with a few questions.

- Can I assume that the factory fitted charging in the T6.1 is 'intelligent' i.e. it can be left on longer term because it reverts trickle charging? In other words, is permanent EHU potentially damaging, or just unecessary?

- Does the factory fitted charging charge to 80% (as the alternator does, normally) or to 100% (as in MAX charge)?

- Whilst I understand (from other postings) that EHU charges the two leisure batteries first, then, once they have been charged, it goes on to trickle charge the starter battery: what precentage charge (80% or near to 100%) would the three batteries eventually achieve, if left on EHU long term (without the California being in use).

Q1. Yes
Q2. 100%
Q3. 100%

 

[Viktorgeorge]

Q1. Yes
Q2. 100%
Q3. 100%

Thanks, @WelshGas !

I take it that on Q1, permanent EHU is not damaging.

 

[yossarian]

Whilst I understand (from other postings) that EHU charges the two leisure batteries first, then, once they have been charged, it goes on to trickle charge the starter battery

This appears to be inaccurate for the 6.1.

The observed behaviour is that hookup results in a closed split charge relay and 3 batteries charged at constant current followed by constant voltage.

There may be more to this logic and it may differ between model years and VW might change it in future via a software update.

 

[WelshGas]

Thanks, @WelshGas !

I take it that on Q1, permanent EHU is not damaging.

Correct. Only to your wallet.

 

[Viktorgeorge]

Correct. Only to your wallet.

Sure!

 

[Viktorgeorge]

This appears to be inaccurate for the 6.1.

The observed behaviour is that hookup results in a closed split charge relay and 3 batteries charged at constant current followed by constant voltage.

There may be more to this logic and it may differ between model years and VW might change it in future via a software update.

Thanks @yossarian, I think I understand that!

So, in layman’s, if I put one 12v to USB adaptor with voltage reading in the rear ‘leisure battery zone’ (under the sliding seat) and another one in the front cab ‘starter battery zone’ (in the over dash socket, I have two of these adaptors anyway): I could monitor the voltage which will likely be 14+ volts initially and drop to 13+ (trickle) after a while in both ‘zones’?

 

[chockswahay]

Well here’s a weird one….. I have found that if I fully charge the leisure batteries on EHU (say, over a week for example) then when I next drive the van the overhead panel shows a load on the leisure batteries until they drop to 80 % It appears to be the leisure batteries discharging to the vehicle battery. I can only stop this by pressing the max charge ……….

 

[andyinluton]

Well here’s a weird one….. I have found that if I fully charge the leisure batteries on EHU (say, over a week for example) then when I next drive the van the overhead panel shows a load on the leisure batteries until they drop to 80 % It appears to be the leisure batteries discharging to the vehicle battery. I can only stop this by pressing the max charge ……….

It's what I said in post 59 above - charge them to 100% and when you drive they will drop to 80% so absolutely no point charging to 100% if you intend driving soon.

It does improve your fuel consumption though as the alternator won't be working until you drop to 80%

 

[Viktorgeorge]

Correct. Only to your wallet.

Following your above post @WelshGas, I have been musing on what might be the cost of trickle charging the batteries - and have now bought a plug socket meter so I can determine this.

I had imagined that trickle changing would be a nominal expense, certainly in the context of optimising the life of three batteries. Perhaps I will be quite wrong.

 

[Viktorgeorge]

It's what I said in post 59 above - charge them to 100% and when you drive they will drop to 80% so absolutely no point charging to 100% if you intend driving soon.

It does improve your fuel consumption though as the alternator won't be working until you drop to 80%

This gets more complicated but interesting on each posting.

What interests me is if the batteries all revert to 80% charge in use (unless MAX is selected) is it better for battery life longevity to not have them being ‘exercised’ between 80% and 100% by EHU when parked up or is there sulphating advantage to have 100% charged whenever practicable.

 

[yossarian]

New batteries are good for about 420 camping trips at 50% dod or 1600+ discharges from 100 to 80%. If you're doing that once a week that's 32 years.

Other factors are probably going to influence your battery life more significantly.

 

[dspuk]

Thanks @yossarian, I think I understand that!

So, in layman’s, if I put one 12v to USB adaptor with voltage reading in the rear ‘leisure battery zone’ (under the sliding seat) and another one in the front cab ‘starter battery zone’ (in the over dash socket, I have two of these adaptors anyway): I could monitor the voltage which will likely be 14+ volts initially and drop to 13+ (trickle) after a while in both ‘zones’?

Note on my 6.1 ALL the 12v sockets are fed by the leisures, breaking the "in front of the seats is the starter zone" rule.

 

[Viktorgeorge]

Note on my 6.1 ALL the 12v sockets are fed by the leisures, breaking the "in front of the seats is the starter zone" rule.

Thanks @dspuk , that certainly explains why my testing, so far, gives identical readings between front and back 12v volt sockets. I was using the top of dashboard 12v but if both dashboard 12v sockets, on recent T6.1, are all on leisure (which I can understand for starter battery protection) then I would need to have a local bluetooth device attached to the starter battery to observe overall charging behaviour.

This is probably all pretty academic: as @yossarian has explained, there is only so much that can be done with the vehicle to optimise battery life, the balance being beyond an owner's control without changing usage habits and needs - which would be silly.

I do remain interested in the cost of trickle charging through EHU, and at what point that reaches the starter battery on recent T6.1 California, if different to previous.

 

[yossarian]

cost of trickle charging through EHU,

I have a golf cart with 4 x 200Ah 150Ah flooded batteries which I monitor long term charged with a modern charger. It uses about 1kWh per 3 days on float. At the local price that's around $10 per year.

at what point that reaches the starter battery

Reread Post 63

 

[Viktorgeorge]

I have a golf cart with 4 x 200Ah 150Ah flooded batteries which I monitor long term charged with a modern charger. It uses about 1kWh per 3 days on float. At the local price that's around $10 per year. View attachment 115768

Reread Post 63

As I hoped, trickle or “float” charging costs are nominal. Thanks @yossarian .

I re-read Post 63 as you suggested, some of the wording is a bit technical for me (embarrassingly) but as I understand it you are saying the T6.1 charging runs in concord, you believe, but you qualify this saying there may be variations both between and within models plus a potential for future changes via ‘updates’. I guess it is those last caveats that lead me to want to check what my specific vehicle has. After all earlier California, unless I have misunderstood other postings, had a range of charging regimes/setups.