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MPPT - Solar Charge Controller on 400ah of battery

I have a mppt 100/20 controller and I want to add a dc/dc charger 12/12/30. I will have 400ah of battery with 200 watts of solar. Is this mppt enough or should I bump it up? Any guidance on this is appreciated.

yelper asked
Sarah answered ·

1 Answer

Minimum load power to start

Hello everyone,

I would like to know what is the minimum Watts the load needs to be in order to allow the inverter to work.
I'm asking this because a client of mine needs a 24V-1600 Phoenix Smart to power a 9W LED light 24/7 + other loads only a few times a day.
Actually the question arose due to another site where a 7W LED light doesn't turn on if no other load is connected as well.


fgs-energie asked
fgs-energie commented ·

1 Answer

BMV 501 voltage error ?

I am on a sailboat and we have four 100 Amph AGM batteries that are powered by six solar panels and alternators on the Diesel engines. That butteries are less than 5 years old. I did not install the system and am beginning to learn how it works. A Phoenix Multiplus controls the charging input. Right now the BMV 501 meter says the batteries are at 97% but voltage says 11.0V. A multimeter reading at the battery bank shows a reading of 13.0V under no charge/discharge condition. Can anyone help me start to investigate what’s going on? Thanks Rob.

robrob91 asked
robrob91 answered ·

2 Answers

48v Multiplus Invertor with 12v batteries


I'm fitting out my boat and have bought a 48v Victron Multiplus 8kw Charger Invertor. I went big as I'm looking to reduce my reliance on gas and got fed up with a 3kw invertor and the limitations of it when I want to run a lot of items. I also bought 4 x 205ah 12 volt batteries to satisfy the 48v, which I believe have to be wired in series.

I am told that if I wire in series then I effectively lose the 820ah potential of 4 batteries and would only in effect have the ah of just the one battery, or 205 ah.

Can anyone advise if this is correct and how I would go about accessing the 800+ amp hours I thought I'd got access to? Do I need 16 batteries to achieve 820 ah or can I in fact wire in parallel whilst keeping the invertor happy?

Thanks for any guidance here, I'm out of my depth :)

ironmancole asked
kevgermany answered ·

3 Answers

Only discharge battery when grid power is above certain threshold

Starting this year, our peak usage will be monitored and taxed. In the summer, PV can recharge the batteries fully and there is no issue. However, in the winter, the batteries do not get fully charged and I would like to configure them so they are only used when peak usage is detected.

What I would like to do is to have the battery only discharge when power usage is above a certain threshold, let's say 2000 Watts.

By manipulating the AcPowerSetPoint (grid setpoint) via MQTT I can create something close to what I want.

I set the grid setpoint at 2000 watts and the battery will only discharge if usage is over 2000 watts. However, this also means that if the usage is less than 2000 watts, it will charge the battery. This is not what I want.

I can continuously monitor the usage and adapt the grid setpoint, but if that process fails, it could mean the battery fully charges, which is not supposed to happen and could be costly.

Is this my best option or are there other ways of implementing this?

peterb asked
peterb commented ·

1 Answer

Minimum specification for Phoenix 24/5000 inverter.

Is the minimum 400Ah 24v pack recommended in the manual for the Phoenix 24/5000 inverter based on lead acid battery chemistry?

Would I be correct in assuming that as LiFePo4 chemistry has more than double the usable energy of lead, that a 200Ah 24v LiFePo4 would suffice (with a BMS of 1C continuous / 3C for 1s burst) ?

dion-patelis asked
dion-patelis commented ·

2 Answers

Which battery temperature sensor do I use

I’m moving through my Victron instal with AGM batteries. I’ve a temperature sensor with the Cerbo and one with the multiplus. Do I fit them both or is there some setup that I need to do?

rupez1 asked
Stefanie commented ·

1 Answer

ET112 meters

Hi all,

I have 2 ET112 meters on my PV & B install - one of them is measuring the generated energy from my PV and the second is import / export grid meter. As it stands both signals are then RS485'd into my CCGX controller.

Due to a spare unit becoming available - i am now going to add a second battery system (not victron) to my home and so need the same signals into my new battery. ( i will then configure the 2 systems so that they work together rather than compete with each other - but thats a later issue).

Can i effectively take 2 x outputs from each ET112 to save me fitting any other meters / CTs for the second battery system?

Your thoughts / solutions welcomed please - thanks in advance :)

gavgolf asked
jeffrorrt answered ·

4 Answers

question to experts :what are the differences between ip65 and ip67 ?

if one can detail the differences between ip65 and ip67 that would help me i feel confused reading the pdf..

yeswhynot asked
kevgermany commented ·

8 Answers

Integration between Color Control GX and Sodium Battery 48TL200

Hello, i want to integrate the Color Control GX with my sodium batteries (Fiamm 48TL200), but, unfortunately the Collor Control GX does not support this batteries BMS, i want to develop the support. There's some tutorial or some kind of documents i can use to do this integration?

lucashubner asked
smueff1970 commented ·

5 Answers

What's Your Battery Round Trip Efficiency?

I've always wondered how we fared compared to others, either Pb or Li etc with our second hand Hoppekke 2v Flooded lead acid cells, this will not be very scientific and quite a few factors will skew the results, but it would still be interesting to compare for fun.

We have:

Hoppekke 930Ah (C5) x 24 = 1,860Ah (C5) @ 24v / Quattro 8k (batteries probably 4-5years old)

VRM / Connect Battery History:


For the lazy maths calculation:


So for my 5 year old-ish FLA's roughly 85%

That's mine, what's yours!? Imaginary prizes for the most efficient and the least efficient :)

Al asked
multivictor commented ·

7 Answers

ESS large battery draw on Scheduled Charge

System details :

  • MultiPlus-II 48/3000
  • Pylontech US2000B Plus 4.8kWh Li-Ion Battery
  • Venus GX
  • ESS

I'm running an ESS system and noticed that the startup of large AC loads are being powered from the battery / inverter when on scheduled charge. The scenario is as follows:

  • Scheduled charge period
  • Target charge has been reached
  • Grid is available
  • Zero PV

Under these conditions, my understanding is that the system should be relying on the grid to power the loads (with minor background losses). What I'm seeing is that the batteries are used to support the startup of large loads while the grid contribution is slowly ramped up over a few seconds. In the screenshot below, we were using a clothes iron that switched on and off frequently. This resulted in large loads being pulled from the battery each time the element switched on and corresponding charges pushed to the battery when the load switched off. Any way to change the behaviour and get the system to rely on the grid in this scenrio?




Here is less extreme example where a kettle is switched on and pulls 14A from the battery during a scheduled charge period:


kempza asked
Hendrik Coetzee edited ·

1 Answer

Discharging instead of charging on dash: is my setup actually working? Or are these issues serious?


I'm a newbie with a new installation in East Africa (Victron Multiplus 5KVa, Smart Solar 250/100, Venus Cerbo GX, 10 solar panels of 345W and one Weco 4k4 battery). It's fully off-grid.

There seems to be a few issues with the setup and I was hoping some here would know how to fix it, or let me know if there's nothing wrong. Any help would be really welcome, thanks!!

I had a professional install this but there seems to be mistakes in their setup (e.g. initially there was no power usage showing on the dashboard) and so I want to check that everything is in order.

1 - The charging lights on the 4k4 Weco battery always indicate that it's discharged, even fully charged:


2 - The Cerbo dashboard is showing the battery discharging when it's actually charging and vice-versa, like here:


3 - At night, the system (fridge mostly) takes 0.05KWh of power on average for around 11-12h. It starts discharging from 6pm (until then it's 99% full) and charging from 6am. But it looses 1kWh during the night and the battery is at 70% charge in then morning (6am) when the sun comes back. I'm guessing my math is wrong but can't make sense of this.


4 - Should the DVCC be activated (it is now)? I couldn't find out which settings should be used.


5 - Bonus question: how bad is it to discharge the battery to 30-40% on some nights? Should I get a second one? What happens if it goes to 0%?

Thanks a lot!!


solarmanu asked
seb71 commented ·

11 Answers

Weco batteries not compatible with Victron?

I have a Victron setup with a Weco 4k4 battery. Weco claims that they're compatible with Victron but it doesn't work well.

Has anyone else got a similar setup? Similar issues? And solutions?

There's lots of problems with the system: the monitor on the battery (LED on the side) never shows that it's charged (it's always only one bar). On the Cerbo GX, the battery's monitor is always showing "charging" whereas it's discharging and vice versa. When the MPPT is used as the battery monitor, the battery never charges more than 95%.

The technician tried many things: a different data cable, resetting the Cerbo GX and even swapping for a new Weco battery. The problem didn't go away. It also seems other installations Victron/Weco are facing the same problem. Now the shop is saying that I need to get a different battery, so spend more money.

My setup is : Victron Multiplus 5KVa, Smart Solar 250/100, Venus Cerbo GX, 10 solar panels of 345W and one Weco 4k4 battery. It's fully off-grid.

solarmanu asked
weco-uae-1 commented ·

2 Answers

Which fanless chargeror powersupply can be set to specific parameter ?

hi i m new in this universe , i search for a silent charger so probably fanless that i can set for for a wheelchaire (2x 12v 75ah) charge voltage and

. Keep going until the current falls to a very low level around 1000 of capacity, or falls by less that 0.1A over an hour. Then its full.

or set the float voltage to a certain voltage.

!any suggestions?

2 can the charger be used for agm and gel batteries provided i change its setting?

3 how hard is it for a custumer to set those numbers?

psim in canada so 120 wallplug.

pps if possible charging at around 25 amp but if not possible 12 or 13 amp could be ok

yeswhynot asked
Matthias Lange - DE commented ·

3 Answers

Battery cable Quattro 10 kVA 3 phase system

Hello Everyone,
What should be the proper size of my battery cables in a 3 phase system with 3 quattro 10 kVA-120V-48VDC?

Gedeon Paris asked
Paul B answered ·

1 Answer

Cabel legnth?

I know that red and blue cables to each battery should be equal length.

But should the cables to both batteries be equal length.

So all 4 cables i the same length.

Or can battery 1 have one length and battery 2 a another length?


Carl asked
Matthias Lange - DE answered ·

1 Answer

Smart Shunt - Wiring Extra Bow Battery


How should I connect my extra bow battery to see the correct load in the Smart shunt. Today it´s connected as the attached picture. The problem is for example when I use my aft anchor winch, then the extra bow battery charges my main bank and the battery capacity is not correct. I assume I will have the same problem when i use my bow thruster and all my other consumers.

Does anyone know how I should wire my bow battery to have everything work correctly?


karlsvan asked
karlsvan answered ·

2 Answers

Batería 67 voltios

Hola a todos. Tengo una duda y necesito saber si alguien tiene la solución.

Tengo una instalación ac couplin Victron fronius. Mis baterías pueden llegar a 67 voltios durante la carga. Ahora mismo no consigo subirlas de 64V debido a que él múltiples II no me permite más. Estoy pensando en poner un cargador mppt smart solar, el cual me deja llegar a esa tensión sin problemas. Mi duda es si él múltiplus me desconectará la instalación por batería alta o trabajará sin problemas. En el fondo es si alguien sabe si se puede o necesito cambiar el equipo.

Raul Ibañez asked

0 Answers

Enabling nighttime export from DC-coupled battery inverter to grid (in addition to daytime export from AC-coupled PV inverter)

I have had a simple grid-tied 5kW PV system for some years.

I have recently added 3 x RedFlow ZBM2 batteries, which means a total of 30kWh, but an available usable 20kWh at any instant (allowing for maintenance strip cycle of these batteries).

I want to reserve 4kWh for my own grid-failure backup use, and export the additional 16kWh to the grid each night. I have rooftop capacity for charging the batteries.

Once the system is configured to export this additional 16kWh to the grid each night, I will know how many more batteries to install, with the ultimate goal of exporting 5kW (1Ø household limit) to the grid constantly, day and night.

As far as I can tell, I have had all the necessary hardware installed, including:

  • MultiPlus-II GX 48|5000|70 battery inverter;
  • SmartSolar MPPT 250|100 MC4 VE.Can charge controller (for the DC-coupled PV array I added); and
  • The associated accessory hardware.

So far, the system is working correctly, charging the batteries, and providing backup power for the house, but the additional grid export is not happening yet, and I'll make the system available to the utility for FCAS once I've sorted the export out. I have not yet seen any additional grid export at all - my usual daily averages of 35kWh production / 21kWh consumption have continued unchanged.

Any suggestions for getting the additional export from the batteries happening?

el-gallo-azul asked
David Gould commented ·

1 Answer

Why does charging voltage need to be higher in lower temperatures for lead-acid batteries?

I came across this blog entry which basically says that, for lead acid batteries, lower temperatures require higher charging voltage. Can anyone please explain why this is true, or point to an authoritative source?

I did ask this question on Chemistry SE a while ago, and those guys seem to be of the opposite opinion: higher temps need higher voltage.

Intuitively I disagree with them and agree with the blog post: lower temps need more power to move molecules around, remove sulphate crystals etc. But I seek a definitive authoritative explanation.

greendrake asked
francesco answered ·

2 Answers

Cerbo GX & Pylontech LV-Hub Issue

Howdy Guys, I’ve got 2 Pylontech US2000B+ strings wired via CAN bus into a Pylontech LV-Hub. Then using the Victron cable from LV-Hub CAN output into the Cerbo GX BMS-CAN connection.

While running the LV-Hub on v1.1 this was working ok, though felt it was lacking data. As the Pylontech batteries have a lot more data than the Cerbo was displaying.

So I decided to update all the firmwares to current.

After this, I found the Cerbo was no longer seeing any Pylontech batteries via the LV-Hub. I can see on the Cerbo that there are CAN packets moving around both TX and RX.

Is this likely just a matter of the Cerbo not accepting v1.7 firmware of the LV-Hub?

Any help, greatly appreciated!

Cerbo running latest firmware v2.73

Victron system is a Quattro 15000, 2 x MPPT 450/100, Cerbo GX with Colour Touch.

tenacioustech asked
Rob Duthie answered ·

1 Answer

Managing a dual alternator system

We have a two alternator 12V system, 1 for traction (capacity unsure) and one for leisure/house batteries (500Ah). For clarity this is a narrowboat fitted with a Nanni 43hp diesel. Both alternators are run off the crankshaft, via different pulleys.

Historically we have had battery charging issues and are considering a DC-DC connection (Orion) to allow the traction alternator output to be made available to the leisure batteries.

Does anybody have any dual alternator schematics? All the standard Victron offerings are for single alternator systems.

For completeness we are also considering solar panels with MPPT charge control.


thebounder asked
Sam Salwei answered ·

1 Answer

Mixing New Battery with One Year Old Lead-Carbon Battery

I have a four battery Narada serial battery string giving 24V, which is 11 months old.
I want to add four more batteries to the string to make it a 48V setup.
Someone told me you should not mix old batteries with new ones.
(But, how do you define an "old" battery ? Does one or two cycles make it "old" ?)
I don't want to sell the existing batteries and buy 8 new ones, I only want to buy 4 more.
Does anyone have any advice for me ?

However, my existing batteries are still fairly new, and have only undergone, I guess about this history of discharge:
200 days at 15% DoD
50 days at 30% DoD
50 days at 50% DoD
30 days at 75% DoD
My feeling is that my existing batteries are quite close in condition to new batteries, and so adding another 4 new ones will not disturb them all too much.

ALSO, if I equalise the "old" batteries before I add the new ones, will that help ?

geoffrey-rathbun asked
JohnC answered ·

3 Answers

Quattro Compatibility with REVOV Lithium Iron Phosphate Battery

I currently have x15 Quattro48/10000 set up in a 3-phase configuration (5 units each phase). I am looking to retire the existing FLA battery bank and replace it with Lithium Iron Phosphate Batteries.

The supplier I have been in contact with is REVOV who claims that their batteries will work with Victron Quattros as they have other installations running a similar setup.

Does anyone have any insight or experience with REVOV batteries and if they work with the Quattro devices? I have attached the information on the REVOV batteries for reference.

Thank you.

1life REVOV_LiFeC8_Product_Specs_Oct2020_v9 (1).pdf

carver asked
shaneyake answered ·

4 Answers

Upgraded battery. How to see the capacity changed?

We recently upgraded doubled our battery pack from 10.5KW to 21KW.
But at this point we are not 100% sure if we installed it correctly. Feels like we didn't gain much.

Is there a way to see the battery capacity in VRM or Victron Connect?
Just to double check. Or are there other ways to validate?

We have now 6x polytech us3000c modules connected with Cerbo GX.
Below a picture of our System
Here you can see our Public Dashboard:

Thanks for the help


dave-hakkens asked
dave-hakkens edited ·

5 Answers

Battery voltage remains on Smart MPPT after battery removal

Hello all,

Does anyone know why on a 100/20 MPPT, having removed a battery pack, but with the PV still connected, the app still shows 13.5V in float mode for Battery? Testing the voltage across the terminals confirms this. Is the controller trying to do something it shouldn't? Having a problem sensing presence or lack of a battery?


ahib asked
seb71 commented ·

1 Answer

Gel Battery Storage - use MPPT or Multiplus

I have twelve new 110AH Victron Gel batteries for a 660AH 24V battery bank, I'm keen to look after them carefully! The bank is charged either by solar via a MPPT 100/50 or a Victron Multiplus 24V 3000W 70A.

I am about to store my boat onshore in Greece for the winter (6-7 months). What is the best way to leave my Gel batteries powered with the MPPT or Multiplus? I ask because I note the Multiplus has a storage mode whereas the MPPT does not.

dcrisp asked
Alexandra answered ·

1 Answer

Scuba compressor in campervan, which invertor ? battery ?

Hi everyone, please help ...

We are a van conversion company. One of our next customers is a scuba diver and will be off grid with I suppose 370W solar panel. His Sprinter 2019 doesn't have a smart alternator. He wants to have a compressor in his van to fill the Oxygen tank. He wants Victron material with about 300W solar panel and a relay charger. He will have a hook up possibility but won't have regular access. Traveling in Africa and Scotland ... extreme temperature.

the compressor that would run for about 30min every 2-3 days.

I emailed the company to have more info regarding the starting power, here tare the different answers I received.

“The start up current for the MCH6, 2.2kW 50hZ compressor is approximately 66 Amps

The compressor must be free of residue pressure, the gauge must read 0 bar before start up otherwise AMPS could be more”

“The answer is 83 Amps.

At the start, the electric motors need a variable amount of Ampere from 3 to over 5 times those written on the plate.

It depends on the type of engine and where you get the electrical power from.

I'll give you an example:

3kw 16Ampere in the house and the compressor is able to start and work.

However, if you have to use a power generator, it must be at least 8KVA otherwise it won't start.”

In top of this compressor,

electric induction hob, 12V fridge 100L, lights, laptop 4h/day, phone charging, standard 12v lights.

I don’t know which type of investor /MPPT and batteries he should use ? Plus other useful bits ...

Thanks for advising me. XX



vanpuravida asked
Mike Dorsett edited ·

1 Answer

Multiplus Compact not charging on new bank while showing it does

I just connected for charge my new battery bank to the multi but nothing is happening.

My bank is 12X 2v 605Ah SOPzS that require 30v abs, 28.8 float. The 2 multis I have are Multiplus Compact 24/2000 50ah. (old ones, in their original packaging since 2012).

Prior to connection I checked all the cells individually, each had exactly 2.05v. When patched all together, I measured exactly 24.6. I set the dip switch 30v and switched on the charger.

The charger led is lit permanently, but the charger is not drawing current from AC, I only see 15w drawn from my smart plug..measuring the poles on the bank I see 28.9v when connected. 7h later still the meter did not show any more current drawn. switched off charger and measured, still 24.6v...

While the multi does make a "charging" sound when in charge, the batteries are not warming up either, at 20oC as initial.

When disconnecting AC the multi stays on powering from DC, but I have not tried to put any load since I want to charge them before doing so.

Any ideas on what to check? After first attempt I disconnected the temperature sensor. All battery connection srews are well tight.

Update: Today I set again to charger mode. On the poles I measured 30v today, maybe the dip switch settings wanted reboot? After 6h 40min I saw the multi charge led blinking, which means floating? I measured the poles 27.6v. Does this mean the max absorption time (6h? for the 30v setting) elpased and switched to floating?

How is it that the batteries are not charging?

I am waiting the mk3 usb cable next week to check that the dip switch setting are properly applied

Minas Papageorgiou asked
kevgermany answered ·

1 Answer


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