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Output of solar panels

Hi. I bought 2 panels rated as 300w@30v. On a full sunny day, midday, my victron controller measured 254 w @ 19v, 13.1 amps? I then measured one panel only, I got, 154w@19v, 7.4 amps! Full sunny day! I believe these panels are falsely advertised? Can anyone assist me to ascertain whether these panels are faulty,? Or have I been scammed??

Thanks already.

fallingbear asked
MichelG commented ·

3 Answers

Number of Cells in Series or Array Voltage. Which is more important?

I have reviewed manuals for several SmartSolar MPPT charge controllers. Section 3.3 "PV Configuration" lays out the guidelines for the solar array. It gives minimum, recommended and maximum number of individual solar cells in series, i.e. " Minimum number of cells in series: 72 (2x 12V panel in series or one 24V panel)".

Is the number of cells important or is this a generalization to get the user in the correct operating voltage range? That voltage range being Vbat+5 to 10-15% below the voltage limit.

For example, charging a 12v battery bank with a controller that has a recommended series cell count of 72. Using a single 24v panel, would it matter if the panel had 72 cells or 60 cells as long as the voltage is within the parameters?

I am using the Victron Energy MPPT Calculator Excel spreadsheet to determine voltage range vs temperature for individual panels.


COghst asked
childcarepro answered ·

2 Answers

Low solar wattage in full sun

Hi guys,

Have been trying to figure this one out by myself and by reading other posts but I’m not getting anywhere. Hopefully somebody here can help.

I live in a van and have the following setup:

160w Blackline solar panel

2x 12V DC 75Ah Batteries in parallel

Victron MPPT 75/15 (no Bluetooth for app)

Victron Multiplus Compact 12/800/35-16

Victron Battery Display

We spent the last two months in very warm weather. Most of the days in full sun.

Yet I haven’t seen the wattage go above 90 watts. I’m sure it’s not in float since it even stays fairly low around 70%.

Yesterday I left the van in the morning around 09.00 and came back at 17.00 with all appliances turned off. It was in full sun all day and yet it only charged from 63% to 78%.

The previous owner tells me that, on a sunny day, it should do around 150 watts and that he got to 125 watts in February. I’m now in Italy in summer and I am not seeing those numbers. Recently it’s even been not much more than 50.

The whole thing has quite an impact on the way we live because we end up driving a lot more simply to charge our batteries.

Hope somebody has an idea.


Tomka asked
spirou commented ·

1 Answer

What do you think of this system?

Hi everyone, im setting up a new PV system off-grid and I would appreciate to receive some feedback of this configuration, for a consumption of about 5kWh/day. Thanks!!

-16x400Wp monocrystalline

-4x2,4kW pylontech US2000

-MPPT Victron 250V100A + display

-Inverter Victron MultiPlus-II 48V 5000VA 70+50A

-Victron Control Color GX

-Genset 5000W as backup

tpwchr asked
tpwchr answered ·

1 Answer

Leisure Battery not charging

I am running a 200W panel through a 75/15 MPPT controller charging a 75Ah leisure battery. This system is used in a motor home and has been fine for over a year, however recently the battery is no longer charging. I have checked all fuses and connections and proven continuity in the wires from the panel to the controller.

My leisure battery reads 12.4V on a multimeter, however as can be seen in the attached image the controller states this to be 13.77. (Have I interpreted the screen correctly?).

I am also getting only 1W and 0A on a warm summer day in direct sunlight. The voltage stated in the image attached is 20.24V however when I put a voltmeter across the terminals on the controller I get nothing.

Also does the wattage display what power the solar panel can harness regardless of what charge the battery has. So even if I were to have a fully charged battery this would still display for example 130W in good weather?


Siddy.97 asked
WKirby answered ·

1 Answer

Restring PV array to not exceed MPPT limit

I have a 150/60 MPPT with a string of 12 panels (Voc = 37.4 each). It's been in place for about 3 years, but about 4 or 5 times a year I get a VRM warning that the voltage is greater than 150V, which then clears after 30 seconds or so. I've never worried about this, assuming it was just a transient issue. However I've just read @Guy comments on other posts that even if it a couple of volts over 150 then I must immediately switch off the device, and reconfigure the strings. I don't know how they are currently configured, but am I right that if the voltage is maxxing out at just over 150V , then they will be in 3 parallel sets of 4 series panels. So must I change this to 4 parallel sets of 3 panels, which will bring the max voltage to 114V which is well below the 150 limit? What is the downside to doing this?

Ant asked
Paul B answered ·

3 Answers

Solar panel work in parallel but not in series string

Hi all

I'm trying to help out a friend with a solar panel issue, it's 4x 100W 18V panels.

One of the panels doesn't seam to work in a series string, however it works just fine when connected to the controller on its own, going over 17V around 4A, my conditions wasn't perfect.

The other 3 panels work just fine, I can string them in series, but as soon as I add the 4th one the string doesn't work, I even tried to swop it around to give it another position in the string. I also tried it just with a string of 2 panels but still nothing.

All these tests were done on my Smartsolar 100/20 and I know the controller is good, since I have similar size panels which works as expected.

What can be wrong with this panel, can it be something simple like a fuse or something and is it easy to fix? I never opened a solar panel before.


bigboy529 asked
MichelG answered ·

4 Answers

Can I combine a Blue Smart Charger and a MPPT BlueSolar charge controller

I have a 12V Optima Yellowtop AGM battery in my 4x4 as a secondary battery which is connected to a 75W solar panel via a MPPT 75/15 BlueSolar charge controller. When my car is parked inside I want to connect the battery to my IP65 Blue Smart Charger. Do I have to disconnect the solar panels or can I leave them connected?

hans van rafelghem asked
edbaak answered ·

2 Answers

Do I parallel or series connect 12V panels to charge a 48V battery?

4 x victron 175W 12V open circuit V 23.7 ,9.03Amps will these work in Paralell on their own string going into a MTTP ? 48V

(do we work of open circuit voltage to trigger the MTTP ?

Timbo44 asked
The Doon answered ·

2 Answers

MPPT Solar Choice: 1, 2 or 4 MPPT controllers

I know this is asked all the time, but I need a bit of clarification.

I am adding 4x Panasonic 340 W panels to my van. I have run the calculator and I think I know my options. Any option will communicate to a cerbo and will provide power to 4x tesla model s modules in parallel at ~24v.

I am slightly concerned with shading. System performance is more important than cost.

Would I be better served with option:

1) Qty 1 SmartSolar 150/70. Panels in a 2x2 configuration.

2) Qty 2 SmartSolar 150/35. 2 series panels on each MPPT.

3) Qty 4 SmartSolar 75/15. 1 Panel on each MPPT.

I am leaning towards option 3 for the following reasons.

A) If each panel had it's own MPPT, then partial shading will be less of an issue. Is this true?

B) This is also the lowest cost option? Might be equal once I have to get cables for each MPPT.

C) I can use a powered USB hub on the cerbo to communicate with all of these MPPT controllers and create a "singular" solar module in software.

D) I get 4 more software accessible relays? Can I get at these from the cerbo and touch gx?

The only downsides I see are wiring complexity and extra MPPTs to package.

Thanks in advance!


Mike Deau asked
Mike Deau commented ·

1 Answer

BMV 712 smart, loses data...

Our BMV 712 loses data after our lithium battery dischages. Then when we initiate recharging, the BMV shows no data on the SOC, no Consumed ah, and Time remaining shows "nanm", etc.

We depend on solar charge only and we rarely reach the 100% SOC in order to sync the BMV.

To put it simple: - How can we know how many amps are in the battery after a charging session that have charge the battery only partly?

zuzullo asked
zuzullo answered ·

4 Answers

converting a 12v system into 24v

hey there, i am planning to change the panel configuration from 12v (parallel connection) into a 24v one so that i can charge my 12v battery efficiently. should i set my victron mppt controller into 24v or this is auto-detected?when "system voltage" is mentioned, are we talking about the panels voltage or the battery?

sorry for the silly question but i am a novice in solar stuff, cheers

greekgeek asked
WKirby answered ·

1 Answer

4 panels, 2x2 in series, then parallel them, Best configuration?

Have a 100/30 controller, 4 -200w panels, 2-100 amp Lipo battery’s in parallel. What’s the best configuration of the 4 panels? 2 sets of 2 panels in series, then parallel them?

JoeLox asked
warwick edited ·

2 Answers

North orientation vs east/west split

I have a choice of either mounting my array on a north facing roof with a single mppt or as a east/west split with 2 mppts, my question is which scenario would give me the most charge throughout the day? I have been told that north only gives me about 4 hours in the middle of the day at peak angle where as east/west gives more overall hours throughout the day as the east gets the morning sun then after midday the west takes over.

Dan.H asked
Dan.H commented ·

4 Answers

Solarpanel kaputt? Mppt 75/15 Laderegler


Ich habe den Laderegler Mppt 75/15 mit Bluetooth neu eingebaut (mit Konkurrenzprodukten habe ich aber das gleiche Problem).
Ich habe die Leerlaufspannung gemessen ca. 21-22 Volt die Kurzschlussstromstärke beträgt ca. 3,5-5 Amp bei einem 120 Wp Panel.

wenn ich das Panel an den Regler anschließe sackt die Spannung auf die Batteriespannung runter obwohl genug Sonne auf das Panel scheint.

Der Regler gibt dann keine Ladung weiter da er sagt die Panelspannung ist zu niedrig.

Heute morgen um 7:00 dann kurz die App angemacht und siehe da die Leerlaufspannung pendelte zwischen 15 und 20V und er hat in 10 Wh geladen (trotz so gut wie keiner Sonne; bewölkt).

Jetzt wo die Sonne wieder draufscheint sackt die angezeigte Panelspannung in der App wieder auf 12,3V runter und es wird nicht mehr geladen.

Versteht das hier vielleicht jemand?

Grüße Tom

ps. Vor der Winterpause hat das Panel noch funktioniert.

TinaB asked
tilo answered ·

1 Answer

Spannung fällt beim Anschluss an den Solarregler

Hallo, kann mir hier vielleicht jemand helfen. Es geht um Solar. Unser neuer alter Wohnwagen hat Solar auf dem Dach. Jedoch wird die Batterie nicht geladen. Ich habe schon den Laderegler gewechselt gegen einen Victron 100/20 mit den selben Symptomen. Vom Solar aus gemessen kommen ca 18-20V an.Es befinden sich zwei Panel auf dem Dach. Ich habe noch nicht geschaut ob Parallel oder in Reihe, aber vielleicht kann man das anhand der Spannung evt erahnen? Sobald das Solar am Laderegler angeschlossen wird, fällt die Spannung auf ca. 12,5 v runter. Selbst wenn ich so ein Voltmeter die man einbauen kann anschließe fällt sofort die Spannung. Jemand vielleicht eine Idee woran das liegen kann? In Sachen Solar kenne ich mich noch nicht so gut aus. Dachte erst das der alte Regler defekt sei, aber leider besteht das Problem weiterhin.





defjam asked
tilo answered ·

4 Answers

4 x 320 Watt Panels (2 pairs in parallel and the pairs in series) 100/50 Controller

I currently have 2 - 320 watt panels in parallel with the Smart Solar 100/50. Looking for some peer review to see if I am correct. I want to add another 2 identical panels to my array. The only issue I see is exceeding the max wattage but the controller says it will reduce any wattage over 700 (and how likely are the panels to see max watts laying flat on a trailer). The panels would be approx. 20.28 isc and 80.2 voc. Both under the specs of this controller? My panels are the 320 watt on this document.

Trent asked
billknny answered ·

2 Answers

80V Leerlaufspannung an MPPT 75/15

Kann ich zwei 24V-Panele in Reihe an einen MPPT 75/15 anschließen? Die theoretische Leerlaufspannung sind dann 80V. Ich sage theoretisch, weil die Module flach montiert werden sollen.

Ist dann überhaupt mit einer so hohen Leerlaufspannung zu rechnen und falls die 80V erreicht werden sollten (sicher nur kurzzeitig), kann der 75/15 das noch vertragen?

Grüße Dirk

Megatroniker asked
Megatroniker answered ·

2 Answers

Argofet and MPPT compatibility question

HI guys,

Can someone with expertise with the Argofet help me, I want to add an Argofet to split charge my VRSLA start battery and my LFP house bank. Easy so far. I want to connect an MPPT controller to the input of the FET and utilize the alternator energize circuit to tell the MPPT that there is voltage. The solar controller needs to see voltage at the battery terminals or it wont start charging.

This is what I had in mind, will it work?


The following is from Victron ArgoFet documentation...

Alternator energize input
Some alternators need DC voltage on the B+ output to start charging.
Obviously, DC will be present when the alternator is directly connected to
a battery. Inserting a Diode or FET splitter will however prevent any
return voltage/current from the batteries to the B+, and the alternator will
not start.
The new Argofet isolators have a special current limited energize input
that will power the B+ when the engine run/stop switch is closed.

Jafa Russell asked
kogir edited ·

2 Answers

Why isn't Solar charging showing on BMV-712?

I've had the BMV-712 monitoring 2-100AmpHour AGM batteries in my motorhome for about 2 years. When connected to shore power, it charges the batteries and shows INFINITE for time remaining. When disconnected from Shore Power, it shows 12 +/- days remaining and slowly drains showing depleting battery charge and reduced days remaining. That's all great.

Recently, I added 4-100 Watt solar panels and a ZAMP-30 Controller wired to the Batteries.

The BMV-712 does not show any charge input or accumulation from the solar panels and shows declining battery state and days remaining, even though the ZAMP Controller shows that my Batteries are full.

I assume the Solar contribution is not being seen by the BMV, but am not sure how to rewire the setup.

Any help would be greatly appreciated.

jdalaska asked
jdalaska published ·

1 Answer

Solar panels not reaching 400W

Hi guys!

i have 4x100W solar panels connected in parallel. Today at around 1pm ET I turned on the inverter to run my water heater (Bosch 4gl electric water heater) which pull around 12A at 120V.

My batteries were sitting at 100%. After 20 minutes of the heater running my batteries reached 85%. So I checked the VictronConnect app for my MPPT and the solar was pulling 274W.

Any idea why they are not pulling the 400W or at least close to this number? There is no shading on them at all. See screenshot from today.


Mariorda91 asked
Leslieanne answered ·

5 Answers

Series-Parallel vs Parallel Efficency

Currently I have (3) 100W panels wired in parallel that typically operate in the 17-19v range. During full sun they generate power in the 15-20A range. These are wired into an MPPT 100/50 unit that I purposely over-sized as I expect to grow the array incrementally over time. I have currently chosen the parallel configuration as it seems to have more immunity to partial shading, but I probably incur a penalty during full-sun conversion in terms of efficiency.

Aside from the extra power generated by adding a 4th 100 watt panel, would my full-sun power generation efficiency increase significantly by creating two pairs of series panels (for 34-38v) and then running these two series pairs in parallel? I'm sure the voltage increase would help with any cable losses I might have built into the system. Presently my smallest cable is the 10ga at the panels, but I do have nearly 40ft of 8ga and 6ga flexible copper cabling. The (3) 100W panels are set up as a portable/re-positionable ground array for replentishing (2) series-wired T105 6v deep-cycle golf-cart batteries on my RV. Basically I want to be able to recharge the 30% or so battery capacity that I consumed the previous overnight as fast as the batteries can handle (10% of 225Ah). Maybe someday I'll be able to afford to switch over to Lithium cells, but that will have to wait for now.

Honestly, setting up two separate two-panel arrays might seem like more work, but I think the lighter weight of two hinged panels vs the current three might make things easier to move around. It would also, of course, mean building more cabling and another panel frame mount.

Any relevant wisdom would be greatly appreciated.


BTW, what is it with the spell-checker on this site? I don't think I made up any new words today. It seems to red underline several legitimate words as well as much of the jargon I would expect used on this site....

packrat1969 asked
Wildebus answered ·

3 Answers

Charge controller advice


What charge controller do you recommend for 2 solar panels 300W / 24V.

Thank you!

Sorin T. asked
Sorin T. commented ·

2 Answers

Victron BlueSolar PWM Controller with 95AH Deep Cycle LA Battery and 20 Amp trolling motor not working as planned. Please help!

Hi, I am a newbie. My goal is to use my trolling motor to power my canoe primarily using solar energy. The Trolling motor draws anywhere from 6-22 amps depending on speed I choose. I own a single 100 Watt solar panel that outputs has these specs:

  • Open circuit voltage (Voc): 21.6V
  • Max power voltage (Vpm): 18V
  • Short circuit current (Isc): 6.11A
  • Working current (Iop): 5.55A
  • Output Tolerance: ±3%

I have verified the current output to be 5.5 amps in direct sun.

I bought a Victron BlueSolar PWM Controller 20amp, and connected it to my fully charged (resting voltage = 13.1V) brand new 12 V deep cycle battery from Costco that I keep fully charged using my 12amp smart charger for 12V lead acid batteries. Then I connected the solar panel as per manual and lastly I connected my battery to the trolling motor directly. When I turn on the trolling motor to max speed and panel is in direct sun, I was expecting the controller to push all 5.5 amps to the battery since motor is drawing 22 amps. Instead I only get between 0.8-1.7 amps being sent and 4.7-3.8 amps being wasted. After having my motor on max speed for 3 hours and theoretically using up 66 of its 95 AH the controller finally starts pushing out more amps but still only 4-4.8 amps! This higher amperage only occurred near the last 15 mins of the test, I didn't want to keep going because I know that discharging even a deep cycle battery past 30% remaining (70% used capacity) will not be good for its long term health. So instead of getting 16.5 amps charged back into my battery over 3 hours (5.5 *3) I only got roughly 6 to 8 amps!?? I am confused by this and think maybe I don't have the correct setup. Can anyone help me understand, my guess is that solar controller only send less amps because it is in the wrong stage of charging (not Bulk stage but maybe boost or something?). My understanding is in bulk charge stage all current is sent to battery. Please help!

1) What I did wrong or what wrong equipment I'm using?

2) Can I achieve my goal of either having all amps produced by panel get put back into the battery , OR send those amps directly to the motor so it draws less from the battery? (I just don't want to waste them)

3) Should I buy an MPPT controller and be able to program it to push all amps coming from panel at all times until battery is 100% full? It this how mppt can work?

4) interesting note, when I try connecting motor to controller load terminals and turn on motor to 1st speed (low) this draws 6 amps, the motor will spin for about 5 seconds and then then controller turns offs the power to the load terminals and screen flashes with error symbol, even though the controller is rated for 20 amps! I think this is because voltage of battery drops when motor is on and maybe it drops lower than min setting on controller. This is why I end up connecting motor directly to battery. I verified there is no spike in current drawn when motor is first turned on using an amp meter, and amps never go past 6.5 on low speed.

Note, If I can figure this out, I will buy a second 100 Watt panel and hopefully get 10-11 amps, with the plan of going on long back country trips where I use motor at max speed for a few hours a day, and then the sun charges the battery back up and next day I can do it all over again!

mikeoes1 asked

0 Answers

Solar overvoltage protection - necessary?


I’m installing solar to charge an existing 12v lead acid battery system, I’ve got 2 panels, a 100/50 smart solar mppt controller and I’m also going to install a smart shunt or BMV 712 smart to monitor the battery state of charge etc... ( the current system doesn’t have any battery monitoring in place)

My question is do I need to be concerned about protecting the batteries from an overvoltage event from the solar charging, or will the charge controller provide protection? I was considering using the ve direct non inverting on/off cable between the shunt/BMV and the charge controller?

Thanks in advance!

WillCful asked
KevP answered ·

1 Answer

I am just beginning and want to use solar in my tiny house.

I have no idea what I am doing. Can I use a different type of battery brand with a different type of solar panel system brand? I need all the help anyone is willing to offer.

Jessica Hounshell asked
Guy Stewart (Victron Community Manager) answered ·

3 Answers

VictronConnect App zeigt seit Installation 0W


ich habe letzte Woche meine Solaranlage angeschlossen. Ich habe einen MPPT 75/15 Laderegler und eine 12V Lithium-Batterie. In der App wird mir dauerhaft Spannung (V) angezeigt, jedoch kein Watt oder Ah. Woran kann das liegen, dass das Paneel nichts einspeist und somit anfängt die Batterie zu laden?
kann das an der Reihenfolge der Montage liegen? Ich hatte auch bereits gelesen, dass die PV Spannung 5V höher sein muss, damit der Laderegler anfängt zu laden.

Janek Buss asked
Janek Buss commented ·

2 Answers


I will be adding my solar panels this weekend to the boat and want to check where I should have fuses.

At the moment the wiring from the 4x 150W panels will be 2x parallel then the 2x parallel in to series before going to the Victron MPPT 150/60 via MC4 connections. Should I have a fuse on the +ve input to the MPPT? There is then a 32A DC DIN Mount Breaker 125V MCB C curve on the +ve going to the batteries.

Secondly i’ll be putting an ET-112 from my onboard generator to give me power info to my Venus GX (no multiplus or Quattro onboard) I see there is a fuse to go on the neutral side of the ET-112 but it doesn’t say how much it should be, the generator is a Paguro 4SY, that puts out 3.5KW @230V.

Bora asked
njordan answered ·

2 Answers

Easysolar 12/1600 install in a van, panel wiring and LiFeYPO4 settings


Bought into Victrons sales speech for Easysolar 12/1600 product for a van project, but it seems some things still remain unanswered. I've read the manual and done the search. This setup will be used year round in different locations, some shaded some not and temperatures will vary mostly between -5 to +25 celsius. I will be living off-grid full time in the vehicle, so i opted for what i believe is a quality product from a European manufacturer, and i really want to like it.

Being that solar power is somewhat of a new option in the energy market (for the average consumer i mean) and it's popularity will grow together with the advance of battery technology. I find that that the manual and available information for a product labeled as Easysolar is lacking. I really think Victron is on to something here, but the documentation needs to be improved.

Ranting aside, to avoid frying my expensive gear and to get this right the first time, i have come here at the fountain of knowledge to be assisted and educated. So please take time to read this post thoroughly.

My setup will be:

Easysolar 12/1600

3x GWL SunnyPoly 165w panels

12v 260ah LiFeYPO4 winston battery with BMS123Smart for monitoring (link is to 200ah battery, otherwise specs should be similar)

Now for the list of actual questions:

1. Series or parallel panel wiring:

-I am under the assumption that parallel wiring would be better for shaded areas, but series better for more challenging conditions. So far I'm going for parallel wiring, will this work? Do i have enough voltage coming out of the paralleled panels to charge my system when in less optimal conditions? Is there a reason i should consider series?

2. If wired parallel, where to connect:

-there are inputs for 3 strings of panels on the Easysolar, is there a difference whether i connect the panels parallel in the roof and come down with one set of connectors and wires or is it better to wire and connect all 3 panels separately? I am inclined to wire them separately just because it would seem more serviceable and more robust to have less connectors and all 3 panels having their own set of cabling all the way from panel to the CC, this make any sense?

3. Inverter/charger settings

-i do not have any kind of color control monitor or such, i only have one VEdirect to usb -cable which i gather is not compatible with the inverter/charger portion of Easysolar but would need a VEbus to usb cable(?). However, when i check the manual page 16 for the table for dip-switch operable voltage settings - there is no setting for lithium batteries to be found at all? What settings do i NEED and HOW to set them now (with either dip-switches or by acquiring the VEbus-cable)?

4. Charge controller settings:

-now this one seems to have a rotary selector for LiFePO4, so that's something that is finally Easy as the name suggests. Apart from flicking the switch to seven is there any additional settings i NEED to change in order to keep my battery healthy? I quess this would be done with the VEdirect to usb cable and a computer then?

5. Is there anything else i need to reconsider before going with this setup?

-i've already acquired the gear mentioned above and will install these in the coming weeks. This will be the single most important aspect of my van, so i would like it to work since it will be a pain in the ass to redo once the project is finished.

Thank you for reading this far, please reply if you have an answer to one of my questions.


MHakulinen asked
Alexandra commented ·

2 Answers

Solar current during bulk much lower than open circuit current measured on solar panels

I have an MPPT 75/15 and I am getting much less current from my solar than rated.

Right now, in full sun, I read 5.25 amps from my panel open circuit. However, when I plug my solar panel into the MPPT 75/15, I am only getting 2.9 to 3.0 amps.

This happens 100% of the time, even with my other solar panels on trips out to the desert (full sun).

I understand that current will taper as the battery reaches full capacity, but this is even at the start of a bulk cycle in the morning.

I checked the maximum charge current in the settings and it is right there at 15 amps factory default.

Any help is appreciated.



cnrsd asked
waninae39 answered ·

5 Answers


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