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deangi avatar image
deangi asked

Orion in RV discharging leisure battery when driving!

I have a 12v Multiplus/Cerbo/SmartSolar/Orion setup in my RV. Everything works fine except when driving.

I have a Thetford 3 way fridge which is supposed to use the alternator when driving (connected to the D+ signal).

What is happening is that the leisure battery (lithium) discharges when driving to power the fridge!

Looking in VRM I can see a draw of 20A when the fridge is on 12v. If I turn the fridge off, this stops.

The Orion has D+ connected to H, so only kicks in when the engine is running, and has Engine shutdown detection turned off. (I tried it turned on and it makes no difference).

The input voltage lockouts are set to 12.2 and 12.5. What happens (if I watch the Orion in VictronConnect), is that the input on the vehicle battery starts at around 12.8v. When I start the engine, it starts outputting at around 14v into the leisure battery. BUT this causes a drop in voltage on the vehicle battery to around 11.8v, so the Orion stops. Because it stops, the vehicle battery then goes back up to over 12.5v so starts again. It is stuck in this cycle.

If I turn the fridge off, I still get this constant cycling.

I am presuming there is a link to the fridge problem and the Orion, but who knows!

Any help very much appreciated.

Thanks

Dean







orion-tr smart
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4 Answers
liam-hogan avatar image
liam-hogan answered ·

Hi Dean,

There are a few curious things about what you have mentioned that point to this being an issue with the physical set up. 20A is way too high a draw for a 12V fridge, even a very large one. Additionally, if your starter battery / vehicle 12V bus is dropping to 11.8V whilst the engine running, there is a big problem. Either your alternator is too small to handle the load current, or your cabling is inadequate and causing a big voltage drop under load, or there is another issue with a wiring error.

To help you further I would need some more information including: Vehicle model or alternator rating, leisure battery specs, which Orion model you have, how you have things connected (ideally a diagram would be great)

Cheers

Liam

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deangi avatar image deangi commented ·

Thanks Liam,


The RV is only a year old, so would hope the Smart Alternator is sufficient, but of course, you never know!

It is a UK Adria Matrix based on a Fiat Ducato. Leisure battery is a 100ah Poweroad Lithium.

Cabling is very straightforward in that one positive cable is marked vehicle battery and one leisure battery. The negatives are commoned into the Orion. It is a 12/12/30 Smart TR non-isolated. I replaced the factory fitted B2B with this one, so being perfectly honest, I cannot vouch for the cable destinations, so may have to start again and run new cables from scratch.

Thanks

Dean

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deangi avatar image
deangi answered ·

Fridge issue is a mis-nomer. It is happening with the fridge on gas, so I have a cabling problem on the Orion.

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deangi avatar image
deangi answered ·

Looks like it is a cabling issue. Will redo the cabling.


Thanks

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deangi avatar image
deangi answered ·

Just an update on this for anyone interested. The problem seems to have been the input voltage lockouts. By disabling these and letting the smart alternator "do its thing", then all is good. Power flows from the alternator to the leisure battery. The cab battery, after 300 miles yesterday, is full and so is the leisure battery. The down side is that the Orion was very hot at the end of the day..... I dont know if there is a way around that.

I have now realised the 12v side of the fridge is wired through the Nordelettronica NE350 (which controls the factory fitted electronics in the motorhome). The fridge takes its power from the NE350 (signalled by the D+), which, if the Orion is not outputting only has the leisure battery for power. A bit peculiar, but I think it makes sense.....

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