Leisure Battery not reaching full charge on Alternator

paulhelenwilko

Full Member

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382
We have recently acquired a 2013 Ducato and have noticed that the Leisure battery does not seem to get fully charged even after a long run (50 plus miles).

Any suggestions ?

(Get a generator is not a correct answer)

Paul
 

nickvanbitz

Full Member

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129
Any Dc-Dc charger or B2B charger (Sterling, Voltronic, Victron). Will also future proof you if you decided to go down the route of LiFePO4 (Lithium Batteries) one day 👍🏻.
The problem is mass production vans use basic split-charge relays/systems which are fundamentally 4-pin relays either soldered into a circuit board or hard wired using very poor quality cable. Idealy for best results, uprated cables with something more substantial such as a Dc-Dc charger will improve the engine to leisure charging no end and as the Dc-Dc charger is fundamentally a pro-charger powered when the engine is running, you are getting a much improved rate of charge With improved results.
 
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Millie Master

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545
I wouldn't mind betting that your LB @paulhelenwilko could do with a deep cycle recharging session.

Both of my LB's were not only not holding their charge but even after charging them for a week or more with a standard chargerneither of them reached more than 12.8 volts which they then both started to loose (without any loading) at approx. .5 volt per week.

I then subjected them both to very long deep cycle recharging sessions and they now top out at 14.2 volts which they also hold when not connected to the system.
 

paulhelenwilko

Full Member

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382
I have read a lot recently about smart alternators - could a 2013 Ducato have one ?

Does the motorhome mains charger have a deep cycle ?
 

paulhelenwilko

Full Member

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382
I should also ask how you are determining if the battery is full or not, I am guessing the readout on the control panel?
If so have you put a calibrated meter on the batteries?
Can I put a multimeter across the battery and get a true reading without disconnecting the battery ?

Paul
 

Molly 3

Full Member

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819
I had a 2013 citrone van with a smart alternator I bought a cheap CIG lighter fit volt meter .that confirmed how poor the output was .the cure is a battery to battery charger for smart alternator . if it is not a smart alternator you are probably expecting to much from your alternator your fridge on 12 v uses a lot of available amps .
 
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Millie Master

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545
Almost no standard alternator will come close to fully charging a house battery
Best you might do is 85% and then only after several hours of driving
I don't know how you have come to that conclusion Tony as for instance in my self built installation where I have a van battery which is connected via a split charge relay to 2 leisure batteries and at the end of a 2 to 3 hour journey all 3 batteries are showing over 14v when tested.
 

Okta

Full Member

Messages
499
Some motorhome manufacturers use very feeble wiring and the voltage drop between engine and leisure battery is sufficient to stop meaningful leisure battery charging. In my opinion leisure battery charging is best done by a B2B and not left to incidental flows from the alternator if you need a full battery when you pitch up. Vital if you have a smart alternator.
 

Molly 3

Full Member

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819
I don't know how you have come to that conclusion Tony as for instance in my self built installation where I have a van battery which is connected via a split charge relay to 2 leisure batteries and at the end of a 2 to 3 hour journey all 3 batteries are showing over 14v when tested.
Because the engine battery is only charged to 85 %
 

xsilvergs

Full Member

Messages
98
Here is charging from a 2017 Fiat Ducato alternator. This was a drive down a motorway, a bit stop - start and slow progress due to an accident. I will be fitting a B2B charger

Crox_to_S-Birm.png
 
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Molly 3

Full Member

Messages
819
I don't know how you have come to that conclusion Tony as for instance in my self built installation where I have a van battery which is connected via a split charge relay to 2 leisure batteries and at the end of a 2 to 3 hour journey all 3 batteries are showing over 14v when tested.
A 12 v battery con not be charged to 14 volts .check after a cooling of period about 6 hours 12.7 is fully charged .
 

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