Mercedes Suffolk battery charging

Had the AA out today as battery was flat in Mercedes Sprinter Suffolk. (2011)
This happened last year too and this year I have been taking her out for a run once  a month.  (Our last Pug could stand all winter and then start first time!!)
I also have a look at the battery condition on the control panel about once a week.  It was fine a week ago , but now was so dead it had to be replaced.

The AA man said if I put on hook up it will charge the vehicle battery as well as the leisure battery.  (Previous AA man just suggested a trickle charger).
There is a toggle switch on the control panel to change between leisure and vehicle battery, but the hand book is a bit ambiguous.  It says the battery that is toggled on is the one that will be used, but it is not clear if it is the one being charged by the hook up.  I previously thought the hook up only charged the leisure battery.  (Our old van had solar panel which charged both.)

Can anyone clarify this?

(Also just for info, the AA man said battery would only be replaced under warranty if the vehicle did at least 5000 miles per year!!)

Many thanks

The battery chosen on the panel is the one supplying 12v to hab area and the one that is charged by the PSU charger.

Thanks . Sorry to be so stupid but is PSU charger the electric hook up to the mains?  So does that mean when electric is hooked up to mains and the control panel toggle is on vehicle battery, the vehicle battery is being charged? 
Thanks

Yes, which ever battery you choose with the toggle gets charged.

Why do AS make this so difficult.  My last van was an 08 and my current one is 16 and on both the batteries are charged together - no switching necessary.  When the starter battery is at 70% it switches to the leisure then both are float charged, is this too challenging for AS?
Rich..

PLOUGHLIN wrote:Yes, which ever battery you choose with the toggle gets charged.

Thanks for your help. 
 We are going to be away from home for 4 weeks (not in the van).
  Is it ok to leave it plugged into the mains, charging the vehicle battery for 4 weeks? 
 Can it be overcharged, damaging the battery?  
I don't want to come home to another completely dead battery.
thanks

It's okay to leave it on.     Mine is on all the time.

As I understand the leisure battery is charged  first  ,then the charge is sent to the engine battery .

I think your understanding is wrong, unless the standard system is modified.

I have a 2014 Winchcombe & also do not have a clear understanding regarding the Battery charging...when the 'shutdown' button is out (Hab management system off) & a power supply is hooked up,the green charger light is on & the charger still works,ie green float charge light is on,or the red boost light is on...which battery is being charged?

In around 2013/14, the Power system was replaced with the Sargent EC500 that operates differently to earlier system.

With earlier systems the on board charger charged either the leisure battery or vehicle battery, a switch used for selection. Solar charging could be to either batteries or both simultaneously depending on how it was installed.


The EC500 when switched off uses solar energy to charge just the leisure battery. When the EC500 is switched on, and with either charger or solar power, a smart charging system is activated. That will start to charge the leisure battery but when it finds the voltage of the vehicle battery has dropped to 12.5v, it will switch the charge to the vehicle battery for 4 hours and then revert. This is a continuing process.


In theory an appropriate charger can be left permanently connected to a battery but if either the battery or charger does not operate perfectly, then the battery can be damaged and also possibly generate excessive explosive gas. I personally therefore advocate charging for eight hours once a week.

Based on my personal experience, our 2014 van has been on permanent EHU (Solar Panel is shaded at home) all of the while it is not been used for the last 5 years and all batteries are currently functioning fine and indicating a healthy condition - just been away for the first time this year and no problems!
The EC500 does a good job of managing battery charging providing you follow the instruction as per your owners manual.
Modern vehicles and motorhome habitation equipment need a power supply in order for Alarms, Trackers, and Managements System to continue to operate. This ensures that your batteries (Vehicle & Habitation) are continually been topped up as required by the EC500 system charger.

Thank's Peter & Liam,
I understand that when the EC500 is switched on the smart charging kick's in....My confusion is when the EC500 is switched off & 240vac supply is still on,that the Charger still indicates via the red (boost) & green (float) output light's?...or is this caused because the charger see's an open circuit when the EC500 is switched off?

andrewlowe wrote:Thank's Peter & Liam,
I understand that when the EC500 is switched on the smart charging kick's in....My confusion is when the EC500 is switched off & 240vac supply is still on,that the Charger still indicates via the red (boost) & green (float) output light's?...or is this caused because the charger see's an open circuit when the EC500 is switched off?

I am slightly confused (it happens a lot as you get older!) but providing you have the van connected to EHU then the green charger light should be the only light showing, providing it is in the "on" position. 
The only red lights (on the EC500) are;- Reverse Polarity Indicator - which is indicating that you have a problem with your supply, both the Space Heater & Water Heater switches indicate Red when they are switched on. There is no boost or float indicators or switches that I am aware of on the EC500.
The Shutdown Switch must be pressed in (ie. "on") in order for the EC500 smart charging to work.
EC500 layout below for ease of reference.



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I would guess that AndrewLowe is referring to the operation of the separate PX-300 power supply which is fitted to some conversions. Unfortunately AS don't seem to document exactly how the power to the PX-300 is controlled - my guess is that it is completely separate (i.e. even with the EC500 in shutdown mode, the PX-300 will be operating while on mains).

Roopert wrote:I would guess that AndrewLowe is referring to the operation of the separate PX-300 power supply which is fitted to some conversions. Unfortunately AS don't seem to document exactly how the power to the PX-300 is controlled - my guess is that it is completely separate (i.e. even with the EC500 in shutdown mode, the PX-300 will be operating while on mains).

As far as I am aware the 2014 Winchcombe has exactly the same electrical layout as the 2014 Malvern where the PX-300 battery charger is integrated within the built of the overall EC500 unit and does not permit any control over the PX-300 function other than through the EC500 as described in my earlier post.

The output from the PX 300 connects to the EC 500 from where its output is managed. With the EC500 switched off, the charger is connected to the leisure battery only.

Thank's Gent's,
Peter's theory sounds good that the charger connect's to the Leisure Battery only..Anybody know why the Leisure Battery & not the Vehicle Battery?

andrewlowe wrote:Thank's Gent's,
Peter's theory sounds good that the charger connect's to the Leisure Battery only..Anybody know why the Leisure Battery & not the Vehicle Battery?

Peter's theory is indeed fact (Leisure battery only served) and is the scenario when the EC500 "Shutdown" switch is in the "off" position.
Both Vehicle and Leisure batteries are served if you engage the EC500 "Shutdown" switch in the "on" position - i.e. smart charging mode - when you may be getting power supply from either Solar or EHU or indeed, both.