Leisure Battery Split Charger Question (again!)

[Rookie]

I have recently come to learn to my expense (new leisure battery required, prematurely imo) that my camper conversion has a traditional split charger relay , rather than a DCC charger that would be best suited to the T6 with smart alternator. I have tried to suggest to the convertor (award winning) that the they should amend their approach, but without success (after all vw still use the split relay on Cali's....etc.).

I am looking at fitting a DCC charger, but in the short term I am hoping that someone here with superior/expert knowledge can clarify something for me (please excuse any poor language; I am not fully electrical conversant!).

As I understand it the leisure battery is never going to achieve more than 80% from the alternator / current split relay. But I can fully charge the leisure battery from the EHU or solar when stationary.

But as the relay works in both directions my question is whether the leisure battery will in effect 'loose' the full charge as soon as the van is driven? When driving will the leisure battery in effect match the vehicle battery state of charge (ie. no more than 80% etc...)?

To put the question a different way, is there any point in fully charging the leisure battery whilst at home, or will its charge level have dropped anyway to 80% by the time I get to site?

(I appreciate that fully charging at home may improve the leisure battery condition and prolong its life expectancy).

 

[Deaky]

if the relay works both ways then you’ll be charging both batteries when at home or EHU

 

[Dellmassive]

yes . . . . unfortunately so.

because the batteries will effectively connected in parallel (when the van is running and the relay is on). . . the 100% aux battery will discharge into the 80% starter battery until they equalize. (you can use a clamp meter to see this, or if you had a calli there is a battery display)

The "energy management system" will see the power dissipate from the starter into the Aux battery via its sensor on the starter battery. (or the orther way . . . which ever battery has the higher voltage)

The Van will then command the alternator/stop/start/regen stages to keep the starter battery at 80% . . . . . . . . and in doing so will intimately keep your Aux battery around 80% too.



you could use a victron battery combiner . . . . . which is effectively a large diode, that would effectively stop the leisure battery draining back into the starter battery

 

[Nigel W]

I have recently come to learn to my expense (new leisure battery required, prematurely imo) that my camper conversion has a traditional split charger relay , rather than a DCC charger that would be best suited to the T6 with smart alternator. I have tried to suggest to the convertor (award winning) that the they should amend their approach, but without success (after all vw still use the split relay on Cali's....etc.).

I am looking at fitting a DCC charger, but in the short term I am hoping that someone here with superior/expert knowledge can clarify something for me (please excuse any poor language; I am not fully electrical conversant!).

As I understand it the leisure battery is never going to achieve more than 80% from the alternator / current split relay. But I can fully charge the leisure battery from the EHU or solar when stationary.

But as the relay works in both directions my question is whether the leisure battery will in effect 'loose' the full charge as soon as the van is driven? When driving will the leisure battery in effect match the vehicle battery state of charge (ie. no more than 80% etc...)?

To put the question a different way, is there any point in fully charging the leisure battery whilst at home, or will its charge level have dropped anyway to 80% by the time I get to site?

(I appreciate that fully charging at home may improve the leisure battery condition and prolong its life expectancy).

Are you sure the relay works in both directions? Any ‘decent’ converter would at least use a relay with an ‘engine run feed’ so that it was only active with the engine running.
My converter had originally fitted something similar (Sargent box) but once they were aware of the issue they retro fitted a Sterling charger under the drivers seat to fix the issue.

 

[Loz]

I think the use of the phrase "both ways", is referring to the current can flow both ways when it is energised...

 

[Rookie]

Are you sure the relay works in both directions? Any ‘decent’ converter would at least use a relay with an ‘engine run feed’ so that it was only active with the engine running.
My converter had originally fitted something similar (Sargent box) but once they were aware of the issue they retro fitted a Sterling charger under the drivers seat to fix the issue.

The relay in question......

 

[Dellmassive]

yep . . . so a standard SCR, probably connected to an ignition feed.

so once energized . . . . both batteries will be connected in parallel.

there is a good chance the 100% leisure battery will back flow into the 80% starter.



Though with that setup, next to the battery and with those cables and fuses . . . . . . fitting a DC-DC charger will be much easier.

 

[Martinf]

relay with an ‘engine run feed’

connected to an ignition feed

The diagram in my NDS Power Service Gold manual (link below) refers to a D+ feed (presumably 'engine run') with the text also mentioning, but less desirably, an Ignition+ feed (for ignition on). Is there a significant difference for the Euro 6 configuration?

My NDS Power Service Gold has been connected by the converter to the Ignition+. But I am having a couple of issues with the Vehicle battery and wondered if not connecting the D+ is a contributory factor. The noted issues are:

* the Vehicle battery can discharge alarmingly quickly in camping mode (battery load minimized but obviously frequent door opening and sometimes ignition on to adjust windows or other checks)
* the 'Start/Stop' can freeze in 'Stop' mode (ie freezing when the the engine not running but the ignition is on and the Leisure system therefore connected)

Could the connection to Ignition+ rather than D+ be contributing to these Vehicle issues? I have taken this up with my converter, but its always good to be better informed by this Forum!

NDS Power Service Gold manual would have my configuration on page 16 with an Ignition+ warning on page 19
https://www.roadpro.co.uk/userfiles...S/20180924 PWS Plus&Gold v3 [ENG] smaller.pdf

 

[mmi]

* the Vehicle battery can discharge alarmingly quickly in camping mode (battery load minimized but obviously frequent door opening and sometimes ignition on to adjust windows or other checks)

How do know/measure/detect this quick discharging? It is true that there is some current draw initiated by opening/closing doors but this shouldn't be a problem normally. There have been reported issues with MOLL batteries - you have one?

* the 'Start/Stop' can freeze in 'Stop' mode (ie freezing when the the engine not running but the ignition is on and the Leisure system therefore connected)

Apologies but I'm not sure if I understand this. Engine running, stopped by Start/Stop, then won't restart?

 

[Martinf]

@mmi, thanks, I’ll try to add more detail. Readings are taken from a CTEK Battery Sense. It is not a Moll battery.

Parked in my garage, locked but alarm off causes van battery charge loss of about 2% per day. However plot below shows fall from fully charged to about 42% charge over 2-3 days camping. First day (19/08) included about 3 hours travelling; no travelling on 20/08, then about 3 hours travelling on 21/08 followed by full external charge.

On the Start/Stop, when Stop is activated this is shown on the dash as a form of ‘A’. Often, but not always, after say 30 seconds a diagonal line (indicating a failure situation) appears across the dash ‘A’ display and the ignition has to be turned off and the van restarted.

 

[mmi]

Thanks for the details. I'm pretty sure in this kind of use the CTEK just doesn't report battery's state (of charge) correctly.
I posted an example how and when CTEK just loses track of actual state, have a look at ---> Battery Charging - Main Battery Earth Point -
So the bottom line is that the CTEK is very pessimistic when the battery has irregular loads on it - which is exactly what opening/closing doors, switching ign on is causing.

However, you could use CTEK to read actual voltage and use that figure to get a lot better and accurate estimate. To get accurate results using voltage reading the battery should have a rest for a moment - an hour would be fine.

The above applies partially also when your van is parked in garage as the battery is still drained by about 35 mA. But as the current is relatively small and constant the CTEK handles this a lot better - but still conservative way. If you would keep eye on CTEK's loss of charge rate (initially 2%/day) you would see that eventually the CTEK reading would "stabilize" indicating less and less daily discharge, which certainly isn't true.

On the Start/Stop - do you then get also message "Start manually". Just trying to understand the circumstances as diagonal line across A also indicates just Start/Stop disabled. So wondering if just depressing the clutch didn't restart the engine? Or taking foot off the brake with DSG.

 

[Martinf]

Yes I agree that the voltage reading itself is higher. So it appears that there is a complex algorithm that then ‘corrupts’ the battery state report?

On the Stop/Start, it is DSG and the system would be active and have stopped the engine on depressing the brake. It then ‘fails’ in the Stop state. Releasing the brake doesn’t restart the engine, rather it requires ignition off and a restart.

 

[mmi]

Yes I agree that the voltage reading itself is higher. So it appears that there is a complex algorithm that then ‘corrupts’ the battery state report?

Yes, definitely not reporting correctly.

Just browsed the NDS Power Service Gold manual. To me it seems that they have taken into account possibility of not having D+ but instead just IGN ON by delaying system activation so no loading before engine is running.

On the Stop/Start, it is DSG and the system would be active and have stopped the engine on depressing the brake. It then ‘fails’ in the Stop state. Releasing the brake doesn’t restart the engine, rather it requires ignition off and a restart.

That's weird. However, I can't see how your power management system being active (=draining main battery) could cause Start/Stop failure. I would expect that the drain would actually just start the engine.

As there are quite a few "valid" conditions that leave engine at state "Start manually", e.g. opening a door, releasing seat belt, etc., a failure in any of those sensors could be the actual culprit. However, I have to admit that there are a few definite misfunctions in current implementation of Start/Stop. A few more oddities --> I tell you what drives me mad about my T6

Anyways, there is an ECU update available to almost all EU6 T6 engines so my wishful thinking is that at least some of these oddities would disappear.

 

[Dellmassive]

I'd say there maybe a separate issue with your start/stop.....

Have you had it scanned for codes.?

 

[Martinf]

@Dellmassive the Carista scan is below.

A total of 7 faults recorded. I don’t really know the impact or relevance of them. The Immobiliser fault could be referencing the Ghost. However the most relevant is likely to be the Battery Regulator fault, which always returns after any fault record clearance. But what could it imply?

 

[t0mb0]

Thanks for the details. I'm pretty sure in this kind of use the CTEK just doesn't report battery's state (of charge) correctly.
I posted an example how and when CTEK just loses track of actual state, have a look at ---> Battery Charging - Main Battery Earth Point -
So the bottom line is that the CTEK is very pessimistic when the battery has irregular loads on it - which is exactly what opening/closing doors, switching ign on is causing.

However, you could use CTEK to read actual voltage and use that figure to get a lot better and accurate estimate. To get accurate results using voltage reading the battery should have a rest for a moment - an hour would be fine.

The above applies partially also when your van is parked in garage as the battery is still drained by about 35 mA. But as the current is relatively small and constant the CTEK handles this a lot better - but still conservative way. If you would keep eye on CTEK's loss of charge rate (initially 2%/day) you would see that eventually the CTEK reading would "stabilize" indicating less and less daily discharge, which certainly isn't true.

On the Start/Stop - do you then get also message "Start manually". Just trying to understand the circumstances as diagonal line across A also indicates just Start/Stop disabled. So wondering if just depressing the clutch didn't restart the engine? Or taking foot off the brake with DSG.

This is right in my experience. I have both the ctek and a victron bmv (which actually integrates current flow over time). The ctek is good for longer term, slow moving changes in state of charge but it can be wildly inaccurate with more dynamic loads. It definitely does tend to be pessimistic in general too.

The ctek also does history which the victron (very annoyingly for a £200 device!) doesn’t.

 

[mmi]

However the most relevant is likely to be the Battery Regulator fault, which always returns after any fault record clearance. But what could it imply?

Have a look at ---> Battery Regulator

 

[scunny nige]

getting back to the o/p I have been pondering this issue and not being electrical trained I was supprised that the van draws the leisure battery down to 80%
I plugged my van in last weekend (fri) , before we went away and gave it a 6hr boost , then a 2 hr drive , but the leisure went down on Saturday evening with only fridge and some lights on
I've also read the post on lithium batteries , would they not be drawn down the same ?, or am I expecting too much of my leisure ?
The battery combiner sounds good , would I be able to fit myself ?
sorry for the list of question , hope some one can help explain this for me
thanks nige

ps I have a sargent charge system

 

[travelvolts]

The diagram in my NDS Power Service Gold manual (link below) refers to a D+ feed (presumably 'engine run') with the text also mentioning, but less desirably, an Ignition+ feed (for ignition on). Is there a significant difference for the Euro 6 configuration?

My NDS Power Service Gold has been connected by the converter to the Ignition+. But I am having a couple of issues with the Vehicle battery and wondered if not connecting the D+ is a contributory factor. The noted issues are:

* the Vehicle battery can discharge alarmingly quickly in camping mode (battery load minimized but obviously frequent door opening and sometimes ignition on to adjust windows or other checks)
* the 'Start/Stop' can freeze in 'Stop' mode (ie freezing when the the engine not running but the ignition is on and the Leisure system therefore connected)

Could the connection to Ignition+ rather than D+ be contributing to these Vehicle issues? I have taken this up with my converter, but its always good to be better informed by this Forum!

NDS Power Service Gold manual would have my configuration on page 16 with an Ignition+ warning on page 19
https://www.roadpro.co.uk/userfiles/PDFs/product information/NDS/20180924 PWS Plus&Gold v3 [ENG] smaller.pdf

There is no D+ on an Intelligent alternator so I reckon that it is just connected to an ignition supply.

 

[travelvolts]

The relay in question......
View attachment 50697

I love this Amber Valley stuff. They certainly get the prize for optimism! I have bin full of their rubbish.