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charge controller compatibility

Mismatched Solar Panels - Can this setup be salvaged

Wanted to try to fit solar panels around my Maxxair fan so opted to go with mismatched Solar panels. Did a good amount of research and thought i had concluded on a good plan to wire them all in Parallel. The panels are similar in Voltage but not in Amps. However realized i might have a problem when I was watching a video yesterday that stated there is a minimum voltage for MPPT Solar Charge controllers. I dug in a bit and it seems that Victron solar charge controllers need battery voltage (12v) + 5v to start charging. The lowest voltage for my panels is 17.95. However it seems that the panels likely won't reach that voltage until mid morning if at all, leading to a solid amount of effeciency loss

Panel stats

Panel Wattage 175 watt 100 watt 50 watt 50 watt
Optimum Operating Voltage (Vmp) 17.95V 20.3V 18V 18V
Optimum Operating Current (Imp) 9.75A 4.93A 3.01A 3.01A

Wired in parellell, 99% effeciency could be achieved. But I don't see any other configuration (series or series parelell) where I could even get about 70% efficiency.

I've purchased a Victron MPPT charge controller. Is there another option that might work or a panel configuration i'm missing

bobby-gallahue asked
bobby-gallahue commented ·

1 Answer

Wind Turbines and victron charge controllers

hi, i would like to know if victron mppt charge controllers support wind turbines? if yes could i run 2 controllers in parallel, one with solar and one with a wind turbine?



lief ryan asked
rodenberger answered ·

22 Answers

Solar Charge settings for 14.4V LI-ion Battery

The battery specs I have are: 14.4V, 16500mAh, 237.6Wh Rechargeable Li-ion Battery

The 110V charger that came with the battery has a 16.7V, 4.0A 66W output.

Could I charge this battery with a 100/10 charge controller?

Thanks in advance!

coachconclave asked
kevgermany commented ·

2 Answers

Can a Blue Smart Charger trigger an Orion DC-DC charger to charge a secondary bank?


I'm looking to rewire my charging circuit as a result of a burnt battery caused by a rather mysterious wiring scheme on a boat I recently acquired. Won't go in to details how it was wired, but need help on wiring it properly. I have a Volvo Penta D1-20, with a voltage sensing alternator (sensing in image as a yellow line). I'm wondering if connecting the shore power using a Victron Blue Smart charger and the alternator connected only to the start battery bank and then charging the house battery bank (AGM) via an Orion DC DC 12V charger would also charge the house battery when on shore power only. A.k.a would the smart charging voltages put out by the AC charger confuse the DC-DC charger or could one expect that when the AC charger is connected to shore, it would charge the start battery bank and via the DC-DC charger also the house battery in all normal cases (assuming start battery is not in low charge state). I'm looking to configure the DC-DC charger in a way that it will only charge the house battery when the alternator or shore power is connected, presumably using the engine on detection logic. It would never be used as a battery to battery charger. Basic idea pictured below, not including fuses etc, just a rough sketch. Any other solutions are mostly welcome as well. Thank you in advance!


Best regards,


portlysailor asked
kevgermany answered ·

1 Answer

Charge Controllers not syncing settings

I just setup a new system and have two different Solar Arrays and controllers connected to one battery system. In my previous setup the two charge-controllers would synchronize settings (absorption, float..etc), but in my new system they are not doing that. If I change the float value on one, it does not update on the other.

I have verified they are both on the same Bluetooth network.

They are running different firmware but they are both up-to-date according to VRM and the app.



hummingbear asked
hummingbear edited ·

1 Answer

Single 12v Panel capable of Charging 24v battery array MPPT 75


I have had a supplier incorrectly supply solar panels that are 12v and its impossible to return them as we remote.

Specs: 140w

Open circuit: 22.68V

Optimal operation: 18.90v

Short Circuit: 8.00A

Optimal Operation: 7.41A

Will a single panel charge 24v 24ah (2x 12v 24ah "gels" in series)

Using a Victron MPPT 75 | 15 (NO BT)


darren-1 asked
kevgermany commented ·

1 Answer

Will a Multiplus in charge-only mode play nice with 3 x parallel Phoenix Inv, Pylontech battery?

I am building a system that will have 4 x MPPT 250/85, 3 x Phoenix 48/5000 inverters in parallel and a Pylontech 48V battery bank. I will not be using a backup generator source but I do have a RV parked in my driveway with a 12V 6.6 kWh battery and an Easysolar 12/1600/70 installed. This is wasted capacity when we are not using the RV, so I may as well put it to good use.

Obviously, the 12V battery in the RV and the 48V Pylontech battery in the house need to have some method of interfacing. 12VDC to 48VDC conversion is not the answer, so I looked into using the 240V output of the Easysolar to run a 48V charger for the Pylontech batteries. Naturally, I want this to be controllable to ensure that my very expensive batteries don't overcharge. I can already ensure that the RV batteries don't over-discharge as that system is fully integrated into Home Assistant and customisable via automations.

I looked into Skylla 48V chargers but they are essentially dumb units and don't appear to be controllable by the Pylontech battey BMS and Cerbo GX. Next option is to use a Multiplus in charge-only mode. The Multiplus 48/1600/20 matches well with the output of the Easysolar in the RV and has a VE Bus connection but I cannot definitively find out whether its output would be controlled by the Pylontech BMS in the same manner that the MPPTs are.

Any help would be much appreciated.

away asked
away edited ·

1 Answer

Cyrix Li Ct

Hi Victron Community* On a customer's boat, I connected the alternator with a Cyrix Li ct to the lead-acid starter battery and to the Li batteries with integrated BMS (third-party product). I set up the "Charge disconect" of the CyLiCt using a simple on-off switch to manually interrupt the charging of the Li batteries. Now the regulator of the alternato has broken. The starter batteries were cooked with 16V. My questions now for confirmation: Can the CyLiCt be used in the installation type described without Victron BMS and? I assumed so far. And; "Does it absolutely need a DC/DC converter/charge controller to protect the alternator from overcurrents, despite the integrated BMS of the batteries and could the damage have been caused by the missing converter/charge controller? I'm looking forward for answers.

Robert M.O. Seidel asked

0 Answers

RS 48V 6000VA Smart Solar + MPPT Blue Solar 150/70 + VenusGX


I would like to add a second string of panels and also upgrade the inverter that I use, as I have growing peak ac power needs.

My current setup:

  • Venus GX
  • 13.4 Kw/h of 48V Pylontech lithium batteries
  • Multiplus II 48V 3000VA (I now require something bigger >=5000VA)
  • MPPT Blue Solar 150/70
  • 4.5 Kw of panels (I have plenty space with no shadows for a second string)

I would like to:

  • Buy RS 48V 6000VA Smart Solar
  • Add 8x450W panels in a single string (400V) connected the RS 48V 6000VA
  • Have the Multiplus II just working as a charger from the generator (in charger mode)

My specific questions:

  1. Can the charging work with the RS and the Blue Solar properly coordinating via the Venus GX?
  2. Can the Multiplus II work alongside the RS (in charger mode)?

As an alternative, I've also evaluated to add a second Multiplus II in parallel and add PV's via AC coupling, having the parallel Multiplus II doing the charge but as the RS 48V 6000V is such a good value, I would rather keep it with DC coupling as I have zero experience with AC coupling and I've read some mixed experiences.


lluisball asked
lluisball answered ·

2 Answers

Blue Solar Charge Controller Duo 12V 24V 20A LCD USB not charging batteries

We have a Blue Solar Duo charge controller charging two Battery Banks, one starter battery and 5 house batteries as 50/50 charge all AGM. The charger was installed in February and was working fine, it has now stopped charging anything. Temperature at that point showing on the charger was 31 degrees.

We have two solar panels in parallel connected to the charger.

The solar panels are each

64 cell (it states this on the back of the panel) in 4 banks of 16
rated power 120W
Max Peak 18V
Voc 21.6V
Max Current 6.67A

When we check the Voc from the panels it was showing 15V but as soon as we connected to the charger the reading across the screw connections was only 3V and the charger not showing anything charging.

We realise that the recommended no of cells for each panel should be a 36 cell solar panel but given that that was a recommendation and not a specific requirement and all other parameters were within the chargers limits thought that would be OK.

We disconnected all inputs in the required order and left for 30 minutes and reconnected and the charger worked so we do not think it is fried but after a short time it stopped charging again.

Should the charger still work with this setup?

shiba asked
klim8skeptic answered ·

1 Answer

Understanding: Series Vs Parallel for 2 x150W panels with SmartSolar 75/15

Wow... I've read a LOT of great info on this site. But there are a lot of numbers and my pea-sized brain still has a couple of questions. Here's what I know: (Please correct anything I've misunderstood!)

* Panels in SERIES Voltages add, and current remains the same, while for panels in PARALLEL their Amps add together and voltages remain the same.

* Battery charging begins once the panel Voltage is more than 5V above the voltage of the battery.

* SmartSolar controllers can handle more amps from the panel(s) than indicated by their model numbers - they just don't push more than that charge into the battery above the limit (eg my SmartSolar 75/15 will limit Amps into the battery to 15A

* Voltage indicated by the model number (eg 75V for my SmartSolar75/15) is a hard limit that will damage the controller if exceeded by the total open circuit voltage stated on the panel(s).

I already have a SmartSolar 75/15 and one 12V 150W panel with these specs:

VOC 22.3V and Vmp 17.9V with max current 8.73A

I currently have a 21V 150Ah AGM battery but plan on replacing it with a 200Ah LiFePO4

I have a second panel the same that is not connected, and the possibility of a separate 310W panel also. Here are the questions:

Assuming I don't want to buy another Charge Controller - 1. If I connect the second 150W panel in Series will I start charging earlier in the day or if its cloudy or partially shaded because the voltages are added and therefore higher earlier in the day than if they were in Parallel?

2. In series voltages add. So 2 panels at Voc 22.3 x 2 = 44.6V This is under the 75Vlimit... any problem with this aspect?

3. In Series the current is the same - since the panels put out 8.73A my 15 A controller wont be close to the max it can push to the battery. Is this a waste of the potential of the panels?

3b. Would It be smarter to put the same 2 panels in parallel, accept that they wont start charging as early in the day or as often in partial shade or cloud but get more amps (which might on rare occasions when everything is perfect exceed 15A since 2 x 8.73A = 17.46A, and therefor be limited to 15 A by the controller)?

4. If i were to replace the 150W panel with a singe 310W 12V ( Voc 40.5V, Imp 9.4A) panel would I get similar results to the total 300W of a 2-panel in parallel setup?

I know there is fair bit here. I hope your answers can not only educate me but also help clarify for future readers who, like me, spent a long time trying to understand this stuff by amalgamating knowledge from previous posts...

Stephen asked
Stephen commented ·

1 Answer

Getting the Right Victron MPTT and Cable Sizing (SmartSolar 150/60?)

Hi Alll,

I am wanting to set up a small-ish solar system on my property to eventually be off-grid one day. This is my initial foray into solar and will likely want to do something a lot larger in the next 3-5 years. The charge controller is the brain the system (imo) so I wanted what I read to be the best brand. That is why I came to this forum for help.

I have "settled on" the following based upon my perceived (and future unperceived) needs as to power consumption/storage. I will keep the following "generic" as to brand seeing that this is a Victron-sponsored forum.

1) 4 x 200W (12V) panels that will be wired in series

2) 2 x 200 A-hr (12V) LiFePO4 batteries

3) 3000W-4000W (12V) inverter

4) Right-sized Victron Charge Controller

Here are my observations/questions:

A) I now need to know if I am picking the correct MPTT charge controller. I used the "calculator" that Victron provides and it lead me to the SmartSolar 150/60 (MC4). I do believe that this is correct. Am I? ;-) I will have ~800W of power and the 150/60 handles up to 880. The 60A output confuses me because I believe that my panels will generate a max of 11.7A being in series in optimal conditions.

B) I am also concerned about using the correct MC4 cables to connect the solar array to the Victron. I believe that they standardly come in 12/10/8 AWG. Looking at the spec sheet for the 150/60, it looks like the MC4 connections (footnoted) are limited to 30A that I believe would put me in a 10AWG cable? Am I correct?

C) My next question would be what gauge of wire would I want to connect the charge controller to the battery with? Once again - I believe the spec sheet states AWG2 wire. Looking at the charge controller pictures (alone without any other reference to size), and the real estate available for the wiring, it does not look like a beefy AWG2 wire would fit, that is why I am asking. Is AWG2 the correct wire size?

I have been all over the web looking to learn solar energy system design and integration ;-) I have a fair understanding of electrical (Ohm's Law and the basics), however, I do not do this for a living or am I specialized in it. I do not want to buy a "kit" or have to work with a dedicated dealer. I am just trying to build this on my own, getting it right the first time, without the markup of buying from one source.

Any help would be greatly appreciated! Thanks in advance!


jawrobo13 asked
Sarah answered ·

2 Answers

Lifepo battery compatibility question

Hi! I think I have an easy one that I just want to confirm. Current setup is 2x Renogy 100 watt panels to a SmartSolar MPPT 75/15 to 2x 100ah AGM batteries in parallel. The AGMs are getting up there in age (came with the camper) and I’ll be replacing them in the next couple months. Can I plug and play 2x lifepo batteries with that setup? 12v system. Using a Smart BMV712 to monitor.



vinman asked
kevgermany commented ·

1 Answer

can i use any solar controller with victron lynx distributor

can i use any solar controller with victron lynx distributor
or more accuratlly can i use a "Renogy 40A Rover Li MPPT Solar Charge Controller" or multiple ?

and is the lynx distributor compatible with "kings 12v slimline AGM deep cycle battery's " or kings lithium 12v battery's

jay112 asked
jay112 edited ·

0 Answers

Dakota battery brand support

Does Victron support Dakota Lithium battery products?

laurits asked
nickdb answered ·

1 Answer


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