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AC Cable sizing for Multiplus II 48/5000/230

Speccing out a home battery storage system using a multiplus II 48/5000 230v. Looking at the maximum AC in - this is rated at 50amps (11500va), so could be run in 10mm2 cabling, however if I've understood correctly the AC out side with powerassist could potentially deliver the grid feed in of 11500va plus a further 5000va from the inverter. So at 16500va (or 16.5kW) you would need 16mm2 cabling to feed back to the load side (consumer unit) - using online cable size calculator. Looking at the spec sheet the inverter only has 13mm2 terminals? So here in the UK, it's either 10mm or 16mm. 10mm is under-specced and 16mm won't fit in the inverters terminals. What am I missing?

flamegrilledmatt asked
flamegrilledmatt commented ·

6 Answers

Multiplus 24/1200/25 switching between charger and inverter

I have a Victron Multiplus 24/1200/25 hooked up to a set of series parallel Blue Nova BN13V-108-1.4k lithium iron phosphate batteries. I also make use of a Victron Battery Monitor BMV-702. I use the Multiplus as a backup/UPS to provide power during power outages at my house. I observe the following behaviour of the Multiplus:

• When AC power is lost, the Multiplus switches to the inverter and provides power, as expected.

• When the AC power is restored, the Multiplus starts charging the batteries, as expected.

• After a few minutes, the inverter will kick in again, and the fan will spin up.

• After a few seconds, the fan turns off, and the charger starts charging the batteries again.

• After a few minutes, the inverter and the fan turn on again.

• After a few seconds, the charger turns on again, but this time the fan remains on. The charger and fan remain on until the batteries are fully charged.

• Once the batteries are charged, the fan stops, and the charger goes into absorption mode.

This pattern consistently repeats itself each time the AC power is restored. This happens even if I unplug the Multiplus, and plug it in again after some use (ie, without an actual AC interruption from the utility). Is this pattern of switching between charging and inverting expected each time the AC power is restored? I would expect it to switch to charging only once, once AC power is restored. If this pattern is not expected, what could cause this?

frodob asked
frodob answered ·

3 Answers

Is AC Consumption a measured value?

My AC loads are supplied by the grid before Quattro. The critical loads on AC L1 are on the AC out of the Quattro, in addition to PV Inverter. Are my AC consumption values measured (how?) or are they calculated values?


shubham asked
shubham commented ·

1 Answer

How do I get the Multi RS solar to accept my AC IN from the generator.

Hi there, I have wired my setup virtually identical to the one shown in the manual for the Multi RS solar, with the exception of the BMS i/o but this is not relevant here.

I'm trying to get the multi rs solar to start charging my batteries, (and / or pass electricity through the multi) from the AC supplied by a generator.

However when It's all connected I get just a few watts being registered if any, - AC IN relay states that it is open, and I get a flashing plug icon on the multi RS.

I have tested the ac and all seems as it should, save for a small amount of voltage detected between neutral and earth. - So I gave the system a dedicated clean earth to eliminate this and still have the same issue.

I have also looked at the knowledge base for similar issues and scoured the web - and any answers that seem like they could solve my problem dont seem to apply for me.

For example, on other units there seems to be a tick box option to accept lower quality AC from generators. which is not available on the menus for the multi rs solar from the victron connect app.

I don't have solar connected at the moment as my panels haven't arrived. and am not sure if that's in any way relevant.

What is it that the multi is looking for in order to accept the AC that i can provide?

Many thanks in advance for any advice here


Neil M asked
wkirby commented ·

2 Answers

Neutre et phase en court-circuit sur AC Out 1


Je suis en train de réaliser une installation solaire hors réseau en Guyane (Multiplus 2 48/5000, RS Solar 450/100, batteries Pylontech US 5000). Pour l'instant aucun équipement n'a été mis sous tension car nous n'avons pas reçu les batteries, En vérifiant mes branchements, j'ai trouvé un court-circuit phase/neutre (l'ohm-mètre affiche 0), j'ai tout d'abord pensé avoir commis une erreur de câblage, après recherches ce n'est pas le cas, le court-circuit provient de la sortie AC Out 1 du Multiplus 2, la phase et le neutre sont reliées. S'agit-il d'un problème de l'appareil ou de l'effet d'une protection contre les éventuelles erreurs de branchement (le réseau sur la sortie onduleur par exemple)?
Merci pour vos retours,
Très cordialement.


jacques-v asked
jacques-v answered ·

2 Answers

by pass AC input to AC out 1,2 when inverter fails

Hello all I am wondering if there is a setting using the programmable relay or other relays in the inverter that can be helpful to do so :

bypassing the AC input 1 to the loads those are connected to AC out 1 & 2 in case the inverter fails or shutdowns due to some errors.

eyub asked
Alexandra answered ·

1 Answer

Can setting low temp cutoff in BMV-712 stop AC converter charging?

I am running the BMV-712, Battery Smart Temp Sensor and the MPPT 100/15 with a 2x LiFePo4 200amp hour battery bank. The battery bank has BMS onboard but a low temp cutoff is not included unfortunately. I have things set with the MPPT to cutoff charging at 3deg C but that is only when charging from solar. It looked like if I set the BMV-712 relay low temp cutoff setting to 3deg C, it would cut charging regardless of whether it was from solar or the AC charge converter but my tests are showing the relay closed when it's supposed to be, however the AC charge converter is still charging the battery bank. Any thoughts or ideas? Thank you in advance.

jdhaasdmb asked
avk13 answered ·

2 Answers

Ac loads incorrect readings

I replaced all my flourescent tubes yesterday and noticed that when I turned the lights on they were still using about 50watts each acording to my ac loads in vrm, so today I put one on a meter I have and it was reading 23 Watts, a bit more checking and it appears my AC loads reading in vrm and also direct ve bus reading from the multi is miles out, way over on some things switched on and way under on others.
Anyone any ideas why this is happening ?
Setup is 48v 930ah traction battery
Victron 48/8000/110
Fronius 8.2-1
250/100MPPT ve can
Smartshunt 500
Cerbo GX
Thanks for any help

scraggs asked
scraggs answered ·

3 Answers

Multiplus charger only mode maximum watt transiting through ?

Hi everyone,

I have a small multiplus 500, i was wondering if it is possible to power up a 1000watt tools while charging in charger only mode with the citypower.

I can easily understand why i can’t connect the object without city power but will the multiplus be able to handle the use of the 1000 watt tools if it is just transiting through ac in / ac out ?

Thanks !!

lele asked
nickdb answered ·

1 Answer

Multiplus-II GX and 230v AC with no neutral (still distributed in some part of Italy)

It Italy there still areas where distributor provide 230v AC without neutral (based on distribution of 3-phase 230v with no neutral)

In this situation, to connect the AC to a Multiplus-II GX in with no neutral it is enough to disable ground relay? (and connecting the ground to device chassis)

There is a specific procedure to do so?

Kind Regards,


blackstar asked
tokke commented ·

1 Answer

Powercontrol prioritization

I'm about to get AC current sensors for grid (Victron external sensor) and for AC PV (Victron ac sensor) next week.

If I've understood correctly, this makes my Easysolar 2 GX aware of AC PV grid feed and I can utilize it to charge my batteries or power my "critical loads" or AC loads that are in my ACout (I've just now come to assume that without a "real" grid meter I cant really see them separately?).

However, I'm not sure if this will lead to also battery power being expended for my non-critical ac loads where I wanted to only use excess solar for them? Is there another measurement for ACout or how will this work out after all? Is it in any way possible to use both the external AC sensor (as "grid meter") and the internal one in ACin (critical loads)?

Kari Saaranen asked
Kari Saaranen answered ·

4 Answers

Protection AC OUT Multiplus-II 5000VA


Concernant la protection de l'AC OUT d'un Multiplus-II 48/5000 GX, le manuel en ligne ( précise :

"Grâce à la fonction PowerAssist, le Multi peut ajouter à la sortie une puissance de jusqu'à 3 kVA (ce qui fait : 3000 / 230 = 13 A) lorsque des périodes de puissance de pointe sont requises. Avec un courant d’entrée maximum de 32 A, cela signifie que la sortie peut fournir jusqu’à 32 + 13 = 45 A.

Un interrupteur différentiel et un fusible, ou un disjoncteur, configurés pour supporter une charge déterminée doivent être fournis en série avec la sortie, et la section de câble doit être adaptée en conséquence."

  1. Est-ce que la règle de dimensionnement du disjoncteur (+13A) est valable pour tous les modèles de Multiplus, ou bien il faut adapter pour 5000VA (50A+22A=72A ou bien 50A+13A=63A) ?
  2. Est-ce qu'un disjoncteur est requis sur AC OUT, ou bien je peux directement raccorder mon TGBT secouru (dont la somme des calibres des disjoncteurs dépasse 72A) ?

Merci d'avance,
Bien cordialement

pcpv-fr asked
pcpv-fr answered ·

3 Answers

using MPPT solar inverter DC input with an AC generator


I have a question regarding the possibility of using an AC generator with an MPPT solar inverter.

So basically I have a wind power turbine, the generator is a 3 phases permanent magnet synchrone generator.

In order to have a DC voltage, I will use a diode bridge with a DC/DC converter to meet the requirement of DC input of the inverter.

Lets say I will use the Victron EasySolar-II GX (who handle a DC input between 38V - 66V) without battery, and I'm able with the diode bridge and the DC/DC converter to convert the voltage of the AC generator to a DC voltage that oscillate between 38V - 66V. Will the inverter be able to generate power and behave normally ?

I want to know too how the MPPT will work under those circumstances. Feel free to correct me if I'm mistaken, from what I understood, the MPPT algorithme changes the value of the voltage on the DC input in order to find and drag maximum power. In the system that I explained above, the source imposes the voltage I believe, how the MPPT algorithm will be able to find the maximum power point?

Feel free to ask more questions if I misexplain something.

Thanks in advance


cydrox asked
cydrox commented ·

1 Answer

Multiplus 24v on subpanel

I'm not using my solar setp as a backup, but to run lower watt/amp circuits off grid. The multiplus is set to ignore AC until battery < 50% and then the inverter is run by the AC line from the main panel. My question is:
1. can I move circuits from the main panel to the sub panel so that they are powered by the inverter with batteries until < 50% and then electrical (which at that point would be the same as if it were in the main panel)
2. Can I move only the hot (black) line from the main panel to the sub, leaving the nuetral (white) and ground in the main box? or do all 3 need moved to the sub panel?

I do have concerns with #2, but the box is old and the entire line will be difficult to move, however if I leave Nuetral and Ground in the main box, and there is excess AC supplied by the inverter it would be returned to the main box? Would that cause issues?

kiab115 asked
Kevin Windrem answered ·

1 Answer

Relay to activate contactor on ac input

Hello All,

I want to add a contactor on ACinput, ie, when supply fails, the contactor must open so it cannot feedback to grid. When grid returns, the contactor must close again. This is a legal requirement here in SA, and I want to use Quattro and not Multi II

Can I do this on either the relay in the quattro, or the relay in GX device?

How would I program this?


leonb asked
ian-c commented ·

3 Answers

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