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dtcassist avatar image
dtcassist asked

Quattros in parallel system not accepting shore power?

Hi,

We have a system set up in a motorhome, consisting of 2 Quattro 24/5000/120 units in parallel. We have a single 120v circuit running loads inside. The system works great in ON mode, running off the batteries.

When switching to Charger only with shore power on, I'm getting a flashing 'Mains' light on the master for about 10 seconds, then a loud relay noise and the lights go dead. The slave is flashing 'Float', and keeps flashing after the master goes dark. Stays like this until restarting both units. Will work fine in ON mode, just using inverter only.

I have a Color Control GX hooked up, and it is not showing any details about shore power. From what I'm reading it looks like it doesn't like my shore power, but can't figure out why. Tests 119.6v at each inverter on AC-In 2. Tried adjusting current with Digital multi control, no change.

Thanks for any ideas - system is as follows:

12.8 LifePO4 batteries

Digital Multi Control

Ve.Bus BMS

Ve.Bus Mains Detector

2x Quattro 24/5000/120 units - setup as master/slave parallel, both have Vebus BMS Assistant

Color Control GX

MultiPlus Quattro Inverter Charger
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2 Answers
Paul B avatar image
Paul B answered ·

Check the shore power wiring as you may have the A and N connected the wrong way around or even the E incorrectly wired. on the incoming power.

Also check the incoming voltage as you maybe connected to a 220V mains input instead of a 110 input.


Also check the AC in wiring betweeen the two inverters to make sure the A goes to A and the N to N and the E to E between the the two units.


Has it worked in the past at another location

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dtcassist avatar image dtcassist commented ·

Thanks for your response. I will spend some time going through the incoming wiring. I know it is hooked up through an adapter on a 3 phase power system so I suspect we have something wrong there.


I mostly wanted to verify that the way the Quattros were reacting was because of an incoming power issue? The warning lights and shut off weren't covered in any user manual i can find. Hopefully the system shutting off is a protection and hasn't harmed anything.

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Kevin Windrem avatar image
Kevin Windrem answered ·

The relay noise you are hearing is the AC input relay opening. This only happens in OFF mode or if the Quatro doesn't like something about incoming power.

When in ON mode, the inverter/charger core is allowed to either charge the battery or function as in inverter assisting AC input to supply the AC loads or supply the AC loads from the battery when incoming AC is not present.

In CHARGER ONLY mode, the inverter function is disabled but the core will still function as a charger. The AC input relay should remain closed. The fact that the AC input relay is opening when in charger only mode is suspicious since the same AC input tests would apply in both modes.

You didn't indicate what loads are losing power. AC loads? DC loads? Both?

Loosing DC loads is also suspicious since these would be connected to the battery bank and there is no way the Quatros would interrupt that power unless a main DC breaker or fuse is opening.

How much load is on the Quatros when this condition exists? Are you exceeding the incoming AC's maximum current? I'm not certain but that could explain why the AC input relay is opening.

If you are losing AC power only, check to see the loads are connected to the AC 1 output. The AC 2 output is only active when shore power is active. I don't think charger only affects this but documentation isn't clear.

I would disconnect the slave Quatro and see of the master works properly. If not, connect only the slave and reprogram it as master and try that one alone. Once you have both units working properly as masters, reconnect them both and make sure one is the master and one is the slave.

I wonder why in a 50 amp 120/240 volt RV you are running all your loads from 120 volts. Trying to make this work when utilizing both legs of the 240 volt incoming power is a challenge at best.

Care to share a wiring diagram? That might help us diagnose your problem.

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dtcassist avatar image dtcassist commented ·

Thank you for all of these details. I think i've come up with the problem but haven't been to the shop in person to verify. I believe the two inverters are wired to different phases of 120v. They are not wired together directly at the inverters, but some unclear details on how the entry is wired - I can't test beyond seeing that there is in fact 120v. Would this cause the AC input relay trip if the two inverters don't have the same phase coming in?


This is all a freshly modified system that has not run with this hardware before. It seems to ignore the AC-in during ON mode, (working fine inverting from batteries) and nothing at all in Charger only. (the only loads are AC connected to AC-out 1) trying with minimal loads.


You hit the nail on the head with your question about running off of an 50v RV 240v drop. There is two separate 120v junction boxes in the cab, no 240v service. The owner had been told that he needed a parallel configuration on the quattros to make it work. So the initial solution had been to combine the incoming and outgoing 120v circuits in the vehicle to make the parallel setup work. Do you have any better suggestions? Running in Split phase had been brought up but we don't need the 240v, and want the option of a single 120v shore line.


Thanks a lot!

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Kevin Windrem avatar image Kevin Windrem dtcassist commented ·

Feeding separate phases, 120 degrees apart into each Quatro then connecting the outputs together will definitely cause issues.

I think your best option would be a split-phase configuration with one Quatro on each leg. Split-phase systems normally have 180 degrees between legs but your connection to two legs of 3-phase power means 120 between phases. And running both legs from a single 120 volt source means there is 0 degrees between legs.

There's a configuration option for a 2-phase system that allows the L2 phase to "float". I can't find a description but it MAY accommodate your plans for single 120 volt, split phase and 2 legs of 3-phase shore power. I'd get confirmation from someone that knows about Victron inverter/chargers and RV power sources.

Note: If both Quatros run in a 0 degree phase relationship, the neutral current can double. Choose a neutral wiring topology and/or wire size accordingly. E.g., separate neutral wires from each Quatro to the distribution panel's neutral bus.

Very few RV loads are 240 volt yet the 50 amp power systems are still wired split-phase as that's what is available in the parks and you get a total of 100 amps (12KW) to spread around the RV. I don't know how many RV campgrounds actually provide 2 legs of 3-phase power to the 50-amp receptacle but I suspect a few do.

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