# Charging Engine Battery from Leisure Battery



## alshymer (Nov 4, 2007)

Hi
I have just read somewhere that the Adria range have a 'BatteryMaster' type system fitted as standard although I cannot find a statement in the brochure to that effect.
Can someone enlighten me?
Kind regards
Alshymer


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## Jmdarr (Oct 9, 2013)

See have an adria never heard that one before


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## rayc (Jun 3, 2008)

I have read the Adria handbook and cannot see a function that will pass current from the leisure to cab battery e.g. as the battery master does. 
The Adria will charge the cab battery automatically whilst on EHU but there is no connection between the leisure and cab battery when not connected to EHU. My solar panel also charges both.

The handbook says "The electronic energy centre is equipped with a 70A disconnect relay.This disconnects the cab battery from the leisure battery when the engine is switched off so that the function of the starter battery is maintained."


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## alshymer (Nov 4, 2007)

Hi
In the new Adria handbook, page 50 section 10.4.1 it says-- When the living area battery is fully loaded, the transformer/rectifier automatically charges the starter battery of the base vehicle.
Kind regards
Alshymer


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## powerplus (Oct 6, 2014)

hi alshymer

i think it meens when on hook up

the transformer/rectifier would indicate to me when on mains

i might be wrong

the same as my sargent unit

barry

barry


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## nicholsong (May 26, 2009)

*Charging Engine Battery from Leisure Battery

Is an impossibility. Charging a battery needs a charging source - Alternator/EHU/Solar/Generator. Without that there is no charging.

Any connection of two sets of batteries only shares the existing charge between them. If one set is already below its useful level both might soon be the same.

Think of connecting 9at low leve) a full water tank with an empty one - result both half full. 
*


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## listerdiesel (Aug 3, 2012)

You could use a DC-DC converter, Geoff, I played with the idea for the Mercedes, but as the Merc batteries are 24V it was difficult to get a step-up switcher to give a decent output.

Going back to the OP, it does seem to me that the motorhome needs to be on EHU and the leisure battery charged, before power is diverted to the vehicle battery.

Which also begs the question, what settings are used for charging the VB? same as the LB or different?

Peter


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## powerplus (Oct 6, 2014)

hi peter (listerdiesel)

while we are on the subject of charging batterys

my sargent controller allows up to 100w solar panel input and will control charge to both batterys engine and leasure

i am looking at 2 , 100w panels
and was wandering if i could connect 1 panel to the sargent controller and 1 panel through a regulator to the leasure battery

would this work or would both supplies fight each other when trying to charge the leasure battery

barry


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## listerdiesel (Aug 3, 2012)

Power supplies normally don't 'fight' over which one does the job, it is always the one with the highest output voltage that will dominate the charge.

BUT

There's always a 'but' isn't there? :grin2::grin2:

Imagine you have two power sources, can be charger or controller, charging the same battery. No1 is slightly higher on voltage on the bulk charge phase, but lower in the float phase. No2 is higher on the float phase but lower on the bulk charge phase.

What will happen then is that charging will switch from one to another at different points in the charge.

Personally I have a set of solar controllers that are 3-stage charging and mains chargers that are single stage. The mains chargers are set slightly higher than the float stage of the solar controllers so they will take over charging once the solar controllers have been through their cycle. I have nothing else, it is 25A solar charging or 50A mains charging/shore supply if we are on EHU.

Note that should the EHU be on and the batteries are really low, the mains chargers will help the solar to charge the batteries.

Having two 3-stage charging systems may cause some lights flickering as they swap the charge over.

Peter


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## powerplus (Oct 6, 2014)

thanks peter
there is allways something to think about with a motorhome

barry


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