Multiplus tripping 50 amp shore breaker plus error code 24: Switch-over system protection initiated

[rockbust]

Hello, I just installed a new multiplus 12v 2x120 on my motorhome to replace my Magnum. I also have a cerbo with display screen. no solar hooked in yet. original agm batters still in. I connected the output to my circuit breaker panel and tested the unit and the invverter works fine. Ran my microwave and fridge. I then hooked up my shore power feed to the multiplus input and the trouble began. When I turn on the 50 amp breaker it trips instantly. I also get an error on my cerbo panel that says error code 24: Switch-over system protection initiated. yesterday for some odd reason one time it did not blow the breaker and ran perfectly all night. this morning I disconected shore power and tried to reconnect and it has tripped it a dozen times.

I have really programed the multiplus since the mk3 was backordered.
some general troubleshooting:
1. Verified my wiring from shore power is correct. i even connected my surge protector and lights indicated the 50 amp recepticle is correct also.
2. bypassed my onboard ATS that switches between gen and shore. no effect
note: with shore power off i was annoyed by the beeping error and flipped the inverter switch off and on. so when I reconnected my ATS to the INPUT of the multiplus I got zapped and noticed AC on L1 and L2 on the inverter input while inverting.
3 tried switching off multiplus, even remoing battery terminals. still blows breaker
4. removed L2 of the input and oddly the inverter worked passing ac to my breaker panel and charging. but I am losing half my amps from L2
5. removed only L1 on the input and works also.

I do not know where to go from here.

 

[Q-Dog]

Here is an explanation of the code and some troubleshooting. If that doesn't solve your problem you will need to contact your dealer for help.

VE.Bus Error Codes [Victron Energy]

www.victronenergy.com

 

[rockbust]

Here is an explanation of the code and some troubleshooting. If that doesn't solve your problem you will need to contact your dealer for help.

VE.Bus Error Codes [Victron Energy]

www.victronenergy.com

Thank you, I have read that. fyi this happens when there is no load on the multiplus. the main breaker in output is off.

 

[740GLE]

What do you have that takes 240v in the RV?

 

[rockbust]

What do you have that takes 240v in the RV?

I have nothing that takes 240. I do have 3 air conditioners 2 are on 1 leg and one on the other when shore is passed through.

 

[RCinFLA]

Sounds like you want parallel 120vac operation but since you are talking about L1 and L2, you are feeding two parallel connected inverters with opposite phases for AC input.

For L1/L2/neutral 240vac shore power you need to setup for series stacking of inverters.

 

[Q-Dog]

Voltage on the input connection while inverting suggests the backfeed relay didn't open. Possible failure.

 

[rockbust]

Voltage on the input connection while inverting suggests the backfeed relay didn't open. Possible failure.

That is what it sounds like to me.. Strange why it is not throwing an error when LI or L2 input is removed.

 

[Brucey]

Sounds like you want parallel 120vac operation but since you are talking about L1 and L2, you are feeding two parallel connected inverters with opposite phases for AC input.

For L1/L2/neutral 240vac shore power you need to setup for series stacking of inverters.

The Victron 2X120 units are designed for RVs, and can pass 120/240V when in pass thru. When inverting, it will deliver 120V to both legs (and 0V to any 240V loads).

MultiPlus-II 2x 120V - Victron Energy

The MultiPlus-II 2 x120V is the perfect one-box mobile solution for standard North American 50A 120/240VAC split-phase applications.

www.victronenergy.com

 

[RCinFLA]

Series stacked (split-phase) or paralleled inverters have one inverter be phase master when no AC input is present. Whether they are configured in user setup for series stacked or parallel operation determines if they follow the master inverter 180 degs out of phase, or in-phase, respectively. To produce 240vac/120vac, the two series stacked inverters must stay 180 degrees out of phase whether with or without AC input.

When AC input is detected, while pass-through relay is open, all inverters slew their phasing to follow their respective AC input phase before closing pass-through relay connecting AC input to AC output. They stop following the off-grid assigned master inverter phase and switch to following their respective AC input phasing,

The trouble arises when AC input or AC output is wired inconsistent to how the user configured parallel or series stacked (split-phase) operation of the inverters.

 

[rockbust]

Sounds like you want parallel 120vac operation but since you are talking about L1 and L2, you are feeding two parallel connected inverters with opposite phases for AC input.

For L1/L2/neutral 240vac shore power you need to setup for series stacking of inverters.

I have a 2x120 which I believe can pass through 240v

The Victron 2X120 units are designed for RVs, and can pass 120/240V when in pass thru. When inverting, it will deliver 120V to both legs (and 0V to any 240V loads).

MultiPlus-II 2x 120V - Victron Energy

The MultiPlus-II 2 x120V is the perfect one-box mobile solution for standard North American 50A 120/240VAC split-phase applications.

www.victronenergy.com

Correct. the breaker is tripping when i send in 220-240. oddly if i input 110-120 on 1 leg it works fine. Whe I say the breaker trips it acts as if there is a direct short.

 

[RCinFLA]

I have a 2x120 which I believe can pass through 240v

'which I believe' does not sound good.

You probably have inverters set for parallel operation or independent operation.

With no AC input check inverters' output voltage from L1 to L2 to see if it is solid at 240vac. If 240vac varies inverters are running independent (default setup). If solid at near zero volts between L1 and L2 it means you have inverters set for parallel operation.

I also assume you have the serial link cable between units that provides the master sync'g.

 

[HighTechLab]

'which I believe' does not sound good.

You probably have inverters set for parallel operation or independent operation.

With no AC input check inverters' output voltage from L1 to L2 to see if it is solid at 240vac. If 240vac varies inverters are running independent (default setup). If solid at near zero volts between L1 and L2 it means you have inverters set for parallel operation.

I also assume you have the serial link cable between units that provides the master sync'g.

I don't think he has two inverters, just one. I don't see where in this thread he says he has two inverters.

@rockbust you will want to contact your place of purchase for troubleshooting / warranty. If you purchased somewhere such as Amazon, you can find your place of purchase by entering the serial number in the search box here: https://www.victronenergy.com/support

 

[RCinFLA]

I don't think he has two inverters, just one. I don't see where in this thread he says he has two inverters.

@rockbust you will want to contact your place of purchase for troubleshooting / warranty. If you purchased somewhere such as Amazon, you can find your place of purchase by entering the serial number in the search box here: https://www.victronenergy.com/support

Why is he talking about L1 and L2 then? Is he trying to dump 240vac into a 120vac inverter?

 

[RCinFLA]

I have a 2x120 which I believe can pass through 240v

What does this mean, other than two series connected inverters.

 

[DougfromdaUP]

This is from a Victron document:

The MultiPlus switches to inverter operation when no AC source is available. The inverter output is also 120V single phase. In inverter mode, the MultiPlus-II 2x120V internally connects both lines L1 and L2 together to provide 120VAC to loads on either output. Therefore, in all connection circumstances, both sides of a distribution panel will be supplied with 120V. However, 240VAC is only available when the MultiPlus is supplied by a split phase 120/240VAC source.

 

[Brucey]

What does this mean, other than two series connected inverters.

Look at the link provided. It's a single Victron charger/inverter designed for RVs, will power both L1 and L2 with 120V when inverting, and pass thru L1 and L2 from shore/generator (could be 120V or split phase 120/240).

 

[Brucey]

Why is he talking about L1 and L2 then? Is he trying to dump 240vac into a 120vac inverter?

 

[HighTechLab]

Block diagram of the inverter.

You can see the actual inverter only feeds power to L1 - in inverting mode, or when fed with a 120v source, a relay bridges L1 to L2 so that L2 isn't off.

 

[sunshine_eggo]

The 2x120 is a 120V inverter that intelligently handles single and split phase shore power automatically.

No AC input: inverts single phase 120VAC supplied to both legs of the 50A RV AC panel. Can PowerAssist.
15/30A 120V single phase input: Passes through 120VAC supplied to both legs of the 50A RV AC panel. It will charge the battery with any surplus AC input. Can PowerAssist.
50A split phase shore power: Passes through 120V to L1 and can charge from that leg. Passes through shore L2 120V to L2 at the panel. Pure pass through. No charging from L2. Can PowerAssist on L1.