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Can one parallel a 100/20 and a 75/15 if each has own PV panels but share 24V batteries?

I read an earlier post of someone here having three 75/15 MPPT chargers in parallel on the same battery bank, not synchronising well with charging duties. I have a compact 1200/24 Inverter with three 150W PV panels (450W) in series running through my existing 75/15 to a battery bank of 24V 200A and I wish to generate a bit more energy to utilize the 1200W inverter better. Thought of just adding another 75/15 or going a bit biggere with say 2 x 300W panels through a 100/20 - but have some concerns of compatibility? Any advice guys? thanks

lyndiesel asked
lyndiesel commented ·

1 Answer

Grid assist application

Hello everyone.

my question is about grid parallel.

can i add to the Grid source the power of the Inverter when the load is high and prioritize the Pv power first

Can the load go over the max and be bigger then the nom power or the courant of the MultiPlus so the inverter can be underrated compared to the maximum courant required by the load

I have a 3 phases system with high load (2 pumps. AC, heat system plus the house consumption ) and i want to install 3 MP3000/48 in parallel so i use PV and when the load is high it powered from the grid.

i heard about grid assist but i have no idea how to make it run..... how to do that in practice

Thank you

redsam asked
michaelvausr answered ·

1 Answer

2 x MP-II 5k not working in Inverter mode, why?


I have 2 Multiplus-II 5k-70 parallel, connected to 6 x US3000, Cebro GX (2.62) and a Fronius Primo on AC-Out1. What I don't understand is why the MP-II stops working when they are connected to the grid and in 'Inverter' mode. They work when connected to the grid and in 'Charge only' mode. They also work when they are in 'Inverter' mode and NOT connected to the grid. Who can help me to find the problem why they don't work when connected to the grid and in Inverter mode? Dealer is saying they configured the Multiplus correct and can't find a wrong setting.

To test and to find the problem I exclude the cabling and the in-house circuit (also the Fronius) therefore I connected the Multiplus's directly from the Main grid circuit breaker to the Multiplus 'AC-In's (cables are same length, no fuses or busbar in between). On the AC-Out1 I directly connected a load (no busbar or breakers). When I switch the MP-II on it takes them multiple tries before connecting to the grid. When and if it succeeds the loading to the battery is very unregular and fluctuating. One of the multiplus is making a unregular fluctuating humming sound. After 2-6 minutes the MP-II shutdown (no error in the VRM portal). Sometimes they restore and sometimes they stay off.

All settings that I know of (from the manuals) are set. 'Limit Inverter Power' is switched off.

I am lost... why does it work in other modes and not when in Inverter mode?


robertg66 asked
robertg66 commented ·

5 Answers

Strange DC at MPPT input at night

My 150/70 is having a strange DC at its input during some nights, not all. Here's an example:


Almost 18V at input. Suddenly around 23.56 it has gone to zero but it came again as you can see.

This MPPT is a part of a bluetooth parallel network, with 2 more 250/60 in which none of them shows this behavior.

What could be this about? It is connected to 3 strings, it's chassis is grounded, as well as the panels frames.

Running fw version 1.54.

elimac asked
marc-de-montreal commented ·

7 Answers

Multi parallel generator issue

Hi all,

A client's install has two 48V, 5kVA Multi ii paralleled: up to date matching firmware, identical AC and DC cabling, CCGX, gel battery & suitable solar input. The client has an isolated, completely independent back-up system (via AC transfer switch) incl. its own solar and battery.

With the occasional need for diesel gen back-up (we're in a sunny part of Spain), the client switches the transfer switch to power the loads from the back-up system (cleaner signal to the loads & maximum input into the batt). Then when the batt is full, they switch back to run the house from the Multi system.

The system has worked fine for a few months, and then (following a generator service) last week, when charging through the Multis, the generator stalls almost every time, almost immediately before it's got up to steam.

The gen is fully tested, and works fine powering loads or when charging the separate back-up system.

I've tried swapping master and slave allocation, and this seems to have helped, but as I can't say that this has 100% fixed the issue, the client is understandably twitchy.

If the gen is also powering the loads through the Multis, the gen stalls less often, but still does. This makes me wonder if there's some backfeed issue, explaining why it's much more common when only charging the batt rather than also having a load to supply.

Any thoughts/ experiences appreciated!

simons asked
simons commented ·

2 Answers

3 x Parallel Connected Batteries can take 10 amps each, can I charge them at 30 amps

I have a battery bank with 3 X Yuasa EFB 100Amh batteries which are rated to take up to 10 amps each. Can I charge the bank at 30 amps with a MPPT 100/30 Charge Controller?

stevecounsell asked
alan answered ·

4 Answers

Existing multiplus parallel setup needs to accomodate 3phase load

Hi! o/

I presently have 2 x 48V 3000 VA Multiplus VICTRON PMP483021010 in parallel connected to a LiPo Freedom Won 20/14 LifeP04 KWh battery working great in an offgrid config (+ victron solar gear charging + genset).

Soon I will need to add two three phase devices as load 400 V AC (+-15%) / 3 ~ max actual 32,6A. In addition I need to accommodate the current maximums allowed by my current setup (<=6000W peak, ~4400W sustained on single phase max ambient temp 40C in summer). The three phase loads will never be used at the same time as the max output of a single phase. This is for a small workshop, it's either or, never both. The three phase loads are large compressor + plasma CNC.

Below are the options I think I have. They are in order of preference by cost:

  • Option 1: add additional Multiplus in parallel allowing sustained ~6600w on a single phase + appropriately sized Variable Frequency Device (VFD) devicre to connect the 3 phase load.
  • Option 2: All Multiplus identical: phase 1: 2 x multiplus, phase 2: 1 x multiplus, phase 3: 1 x multiplus - will this work?
  • Option 3: 3 phase: each phase as single Multiplus 48/3000/50 + additional separate single phase circuit with Multiplus 48/5000/70.

Are any of these options non viable? Are there better options? Ideally option 2 would be 3 phase solution with a single phase using the Multiplus 48/5000/70 + the other 2 phases using my existing Multiplus 48/3000/50s - but I am told should never happen and Bad Things(tm) will happen - and so is excluded for that reason.



nanzikambe asked
Guy Stewart (Victron Community Manager) answered ·

1 Answer

Can an EasySolar be parallel with EasySolar / MultiPlus / Phoenix / Quatro

Two EasySolars (5kV / 48V) can be configured in parallel.

But is it possible to configure an EasySolar (5kV / 48V) parallel with an MultiPlus, Phoenix or Quatro (of 5kV / 48V)?

I don't know what kind of firmware / chipset these other models have. But it seems a bit redundant to combine 2 EasySolars (to have 2 times the build in MTTP capacity / 2 times a Color Control).

I need more output then one EasySolar can provide.

freddy asked
andy156 commented ·

1 Answer

Skylla IP65 parallel

As we all know, two Skylla IP65 can be used in parallel with a Can.Bus cable.

What about the 3A starter battery connector? Can this connector can be used in parallel also, to get a 6A output for the starter battery?

Thanks, Peter

bricki asked

0 Answers

Help with switching simple 12v marine system from PWM to MPPT. Which compnents needed?

Hi Everyone,

I am new to the community.

I have a simple to moderate 12v solar system on my 26ft. sailboat. Because of weight, I want to switch from PWM and lead acid to MPPT and lithium. While money isn’t really and issue, I would still rather not have overkill with components that I might not need, so was looking for some advice as to the exact components that I need.

Current specs:

· 720ah wet batt. bank (lead acid)

· 40A 12v PWM controller (Steca Solarix 4040)

· 350W solar (all in parallel - different sizes because of the shape of the boat):

o 2x 16.7 V Max. (each) / 5.99 A Max. (each) (100Wp) ETFE Mono-Flex

o 3x 17.2 V Max. (each) / 2.92 A Max. (each) (50Wp) ETFE Mono-Flex

· All loads (except motor) connected with terminal bar and then to PWM load terminal (including 2 small 300w inverters for port and starboard), everything with on/off switches and fuses (max combined current @ 35 amps)

· External max 60A 12v trolling motor connected directly to battery, also with fuse and switch.

First of all, am I correct in assuming that I cannot connect different wattage (amperage) panels in series for an mppt system (as the lowest amperage would be taken), and would therefore have to keep everything in parallel?

After the research, this is what I envisioned (using all Victron parts, except for batteries):

· 4x 120ah lithium batts…total 480ah

· Victron smart controller mppt 100/30 (

· The above 350w solar panels in parallel. I know mppt would work better with higher voltages, but I am assuming if I put them in series, it would take the lowest amperage and therefore lose 50% efficiency?

· Cerbo GX ( I know this seems like overkill, but I need to be able to remoter monitor charge and temp, plus connect a few devices….

· All loads, including motor directly connected to batt through 100A battery protector ( whereas the protector would be connected to the Cerbo (is that possible?)

· Mppt control display connected to cerbo?? (

· Temp sensor connected to cerbo? (

The reason I want to switch to a Victron mppt system, is because the batteries are so expensive, that I want to ensure maximum life. So am I missing anything above, component wise? Should I be using a BMV instead of the mppt control display or a BMS in stead of/or in conjunction with the battery protector? Do I need a smart shunt, relay switch or any other components to make this system work efficiently and hassle free?

My goal is to get advice on the exact components to buy. Any and all advice or information is greatly appreciated!



mpmattman asked

0 Answers

What size array for Victron 100/50?

I have 4 x 250watt panels 38v open cct and 8.8 amp short cct current as labelled on back of panels.

If I hook up the panels in parallel (volts should remain at 38v) and current should be 4 X 8.8 = 35.2 amps.

Is this correct, can I use this setup with a 100/50 Victron smart controller?


mealingr asked
mealingr commented ·

2 Answers

0 Answers

Problem with Cyrix ct contact 86
good morning.
I have a problem with the victronenergy Cyrix Ct 120.
I did a somewhat different installation from the manual.
I put a switch on contact 85 start assist to start the engine with the service batteries.
In addition I also put a switch on the negative contact 86 of the coil.
In this way I disconnect the cyrix to prevent the panels from charging an already charged engine battery every day.

but if one day I decide to reconnect the cyrix with the switch on the negative contact, once the cyrix closes with voltage greater than 13.2v, it is always closed ... and does not open with voltage less than 12.8v.
To get it to work properly again, I have to operate the "start assist" contact switch and then turn off the "start assist".
In this way, the cyrix resumes its automatic functioning.
But every time I turn it off from the negative and then reconnect it, it then gets stuck in the closed position.
Anyone know why this happens?

francesco asked
francesco commented ·

0 Answers

AC load data display conflicting with 2 x 10kva quattro in parallel

i have 2 x 10 kva quattro in parrallel

2 x fronius 8.2 and a mppt 150 / 85

bmv 702 and ccgx

Ac load data is incorrect in the home screen and in the menu

even the volts x amps does not = watts

screen shots attached

Ant thoughts





hananmcgrory asked
hananmcgrory published ·

1 Answer

Multiplus II PMP482305010 rev 08 and rev 09 parallel compatibility

Hello!, are the 08 and 09 hardware revision of the PMP482305010 fully compatible for a parallel setup?

Best regards.

alfredo asked
warwick commented ·

1 Answer

Parallel connection of Multiplus II, ESS, several houses to a common grid connection


I need help judge, whether this connection will work. The requirement is, no overflow of energy into the grid. The premise is that solar energy will only be transferred between houses.

Thank you in advance for the consultation


jkalous asked
jkalous answered ·

2 Answers

MPPT 75/10 and blue smart charger in parallel?

Hey, i'm currently working on a small mobile solar station with a Victron Li-Ion-Battery for education purposes. When the station is outside it should yield its energy via an solar panel and the Victron MPPT charge controller. When not in use, it will probably stay inside for a longer time. For this case it would be great if the battery coulld be charged via the Victron Blue Smart charger off the grid. Is it possible to connect both devices, the Blue Smart Charger and the MPPT solar charger, in parallel to the Li-Ion battery? (VE.Bus BMS will be installed)

To my understanding, since both devices work in the same output voltage range, this shouldn't be a problem.

Many thanks in advance


andi asked
Alexandra answered ·

1 Answer

Quattro 48/500/ 2x100 and Multiplus 48/5000 - Single Phase parallel

Greetings Guys,

I have 2 Victron inverters, one Quattro 48/5000 and one Multiplus 48/5000.

I want to set them up as Split Phase parallel working units, I know that the main criteria for the system to work is to have 2 or more identically units running in parallel, but I'm not sure if the units needs also to be from the same ''family'' like Quattro with Quattro and Multi's with Multi's.

Thanks in advance for the advice.

Best Regards,

Ungureanu Gheorghe Aurelian

Aurelian Ungureanu asked
Daniël Boekel (Victron Energy Staff) answered ·

1 Answer

600V from micro hydro generator, to battery bank?

I plan to add a battery bank to an existing micro hydro system. I would like to parallel 3 of the Victron Quattro 10kVA 120V to take power from the 24kW capacity hydro generator (or a diesel backup generator) to charge the battery bank and feed through / invert to 120V AC for household power. The problem is that the hydro generator produces power at 600V AC whereas the Victron Quattro inverter-chargers will accept only between 90V and 140V AC input. I could put a 600V to 120V step-down transformer between the hydro generator and the Quattros but this would reduce efficiencies.

Is there a way to set up a Victron product to handle the 600V AC output of my hydro generator? Or else is there an inverter-charger on the market that can handle that input voltage directly?

wahlet asked
mt-geek commented ·

0 Answers

Using two battery balancers for 4 parallel strings

I need some help with proper configuration of my victron battery balancers for 4 parallel strings of 24 volts. My set up has a Quattro 5000/24v and eight(8) Trojan SAGM 205 batteries configured in 4 strings of 24 volts (820AH)

I am using two battery balancers, as I read one unit can only balance up to 3 parallel strings. So I have separately connected the midpoints of the first two parallel strings and the next two parallel strings. schematic is below.



chisom-onuegbu asked
Herve RV Nizard answered ·

3 Answers

Parallel operation of new Centaur charger with 10 year old Centaur charger?

I have a 10 year old Centaur 12/30 charger installed on my narrowboat. I want to install a new 12/50 to run in parallel with it (to decrease charge time). Want to know a) If parallel operation is ok? b) would the charge characteristics be the same between old and new models - with different ratings?

paintertype asked

0 Answers

Victron Deep Cycle 12V/200Ah max number in parallel


I often use the Victron Deep Cycle AGM 12V 200Ah battery (telecom style batterie BAT412181164) in a 24V battery bank, consisting of 14 batteries. So 2 Batteries in Series, 7 in parallel. I have no problems with it, works since years perfect.

Now I was told that the maximum number of batteries in parallel is 5. Is this is that true and is there a reason for it? There is nothing written on the Victron product page. There is only the brochure to download, but no manual for this battery.

I am a little concerned because I have planned systems with 10 batteries in parallel for the future.

Best regards and thanks for the help.

offshore asked
warwick commented ·

2 Answers

How to connect Orion-Tr Smart 12/12 30a in parallel

Hi. I have one victron orion-tr 12/12 30a in my van and I'd like to install another to give me 60amps,total charging. Can anyone advice my how I'd need to wire the 2 units many thanks

moonhead911 asked
cpurchas commented ·

3 Answers

Upgrading with a second PV system - What are the possible and valid variants? (Parallel, cascading...)

Hello there!

I would like to propose a game for Victron experts and enthusiasts who are reading this post. Let's imagine we have a typical PV system with panels, batteries, an inverter charger, loads and the presence of the utility grid. If, at some stage, we want to keep the present system (which is not too old, and its size is not small, not too large) and add a second system of similar size or even larger than the first one, what variants or possibilities would be the most optimal/advisable or more advantageous? Which ones would be valid, but not advisable? Which ones are not technically possible? I know it is a bit of an open question, but it would be interesting to read all opinions. Please take it as a game.

As a general guideline the aim is to increase the size of the system, while keeping the original one. Loads should still be supplied in the case of grid failure. Excess energy can be fed or not to the grid (up to you).

If you like you can give opinions based on the following diagrams (I believe they are all self explanatory, but if not please ask). Number 1 is the original system. For the others, in red the system I believe is not possible technically. In purple a system I believe has little benefit, but still possible. In green all other viable possibilities. For these, subindexes 1 and 2 do not mean 'original' and 'new' inverter - please feel free to place every inverter/charger in the position you like.

I know its obvious, but here you have the meaning of each letter (panels, charge regulators and grid-tie inverters are not depicted in the diagrams, in order not to add complexity, but both AC and DC coupling can be considered for any or both of the inverter/chargers).

U stands for Utility grid.

I stands for Inverter/charger (Multi, Quattro)

L stands for Loads

B stands for Battery

And of course please let me know if I am wrong in any of my assumptions!! :)



mm-azimut360 asked
machined answered ·

2 Answers

Should i see 2 batteries in VRM?

I just installed a second BMZ battery to my Victron system. Should I be able to see that the system has 2 batteries somewhere in VRM? Thank you...

pbilka asked
pbilka commented ·

1 Answer

Quattro and MPPT entering absorption and float at different times

The set up is:

2 X Quattro 48V 10000 in parallel

MPPT 170/70 Smart

BMV 712

Any way of syncing them up so that they enter the different charge settings together?

Just seems odd when the Quattros are in absorption and the MPPT is still in Bulk

obo asked

0 Answers

EasySolar-II GX and MultiPlus-II in parallel. Is it correct?

I have paralleled a Multiplus-II to my EasySolar-II GX. I have it working but I’m not sure if it’s 100% correct as I couldn’t get the assistants to work. It’s an off-grid setup with battery charging done by solar and if I need a boost charge I temporarily connect a portable generator. I followed the paralleling tutorial and combined the 2 units via the system configuration tool and all went well. Then it came to the configuration of the 2 units, it all started going wrong when I selected ESS assistant as I have grid code “none”. Then I changed grid code to one of the Australian codes and next I had bus errors, low voltage alarm etc. Pushed ahead and loaded the file into the Multi as well. Couldn’t get the units to output power and bulk/float lights flashing on Multi. Went back in and put grid code back to none and deleted assistant, uploaded both units with this file. EasySolar fired back up but Multi still had mains and inverting lights alternating. Started to pack away so I could work on it again tomorrow and when I got close I could hear the Multi humming. Turns out the system is up and running even though the mains and inverting green lights are alternating on the Multi. I test ran my lathe and it started no problem multiple times. Before the paralleling I couldn’t get the lathe to start at all.

Can anyone confirm if this sounds to be correct or should the lights not be alternating on the Multi?

the-doon asked
the-doon edited ·

0 Answers

bluesmart mppt 75/15 parallel

Für eine temporäre Installation einer Solarladeanlage würde mich interessieren, ob es für den bluesmart MPPT 75/15 ein Problem ist, wenn die Batterieen während des ladens von eienr anderen Quelle zusätzlich geladen werden (Lichtmaschine oder Landanschluss)...

kdietmar asked
Matthias Lange - DE answered ·

1 Answer

Paralleling Li Batteries


I seen a number of references to the number of Li batteries that can be paralleled, either 5 or 10.

Which is correct? Also what is the reason for this number of packs?


kathys asked
Alexandra commented ·

2 Answers

Can I parallel a Quattro and a multiplus of the same size and rating?

Hi there,

I have a Quattro 48/5000/70 and i want to try paralleling it with a multiplus of the same spec,
as I understand it as long as they have the same firmware this should work?

ryan-bernic asked
wkirby answered ·

1 Answer


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