overvoltage Image



Hallo zusammen,

ich habe ein System, bestehend aus folgenden Komponenten aufgebaut:

- Victron Multiplus II 48/3000

- 1x Pylontech Batteriemodul US3000C

- Venus GX

- Victron MPPT 100/20-48

- 6x 170 wp PV Module

und als Insellösung mit DVCC konfiguriert.

Funktioniert soweit auch alles wunderbar, bis auf die Tatsache, dass das System bis 54V lädt und dann das BMS mit overvoltage Alarm auslöst. So soll es natürlich nicht sein, das ist mir klar. Ich habe auch bereits gelesen, dass solche Alarme bei einer neuen Batterie auftreten können. In diesem Fall soll man die Cut-Off Voltage reduzieren. Habe ich auch gemacht. Das zieht allerdings nicht. Ich vermute, weil ich über den Regler lade und das Ladegerät im Multi abgeschaltet habe, die Einstellung wirkt wahrscheinlich nur bei Verwendung des Multi. Da es eine Insel sein soll, habe ich ja keinen Landstrom und deshalb das Ladegerät deaktiviert. Ist meine Vermutung richtig und wie kann ich das System so konfigurieren, dass bereits deutlich unter 54V nicht mehr geladen wird?

Danke für Eure Hilfe!

stromolot asked
Matthias Lange - DE commented ·

1 Answer

DVCC: "Max Charge Voltage" not considered when ESS in "keep batteries charged" mode?

Dear all,

I'm using ESS on a Multiplus 2. I've gone already to related posts in:

and I've configured the system according to: https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom

My Problem:

When I operate ESS in "keep batteries charged" mode, I get "High DC ripple" Alarms and "High Voltage" Alarms leading to shut down the Multiplus at high solar yields (as already described in other posts), even though I've set the "Max Charge Voltage" in DVCC to 51,7 or even less.
Observing the local terminal, I can see charging current although the battery voltage is above 51,7.

When I operate ESS in "Optimized with Battery life" mode, I don’t get Alarms nor shut downs. At the local terminal I can see even discharge currents in case the battery voltage exceeded the limit set in DVCC (after changing from "keep batteries charged" to "Optimized with Battery life" mode).

From what I've seen it appears to me DVCC limits are being not obeyed when operating ESS in "keep batteries charged" mode?

Anyone having similar problems respectively is there any solution to stable- and reliably run ESS in "keep batteries charged" mode ?

BR Andreas

My HW configuration is:

  • Multiplus-II 48/3000/35-32
  • Venus GX Firmware: v2.73
  • 4 x Pylontech US2000C Firmware: v2.7
  • SMA SunnyBoy on AC-Out 1

andreas-0676 asked
andreas-0676 edited ·

2 Answers

Smart Solar Chargers overcharging

I am hoping for advice on how to resolve over charging in my off grid eco home system. Although I have not posted before I have done lots of research on the forum and Victron website but not sure why I am having trouble stopping the charge controllers charging when they have reach absorption and then floating. My setup consists of currently 3kw of solar (to be increased to 10.5KW when I get the other panels mounted) >2x 250/100 smart solar ve can charge controllers (linked by can but only using one currently) Victron Venus GX, BMV 700, 10KVA Quattro (old firmware), 4x BMW I3 lithium 120amp 48V batteries in parallel and a 7.5KW backup generator. I have the charge controllers set to absorption for minimum time at 49.2V and originally had the float voltage at the same but recently changed to 49V to try and stop the charge controllers overshooting (has made no difference). I have my max battery voltage set below the max for the batteries so there is room for error but they are regularly charging to 49.5-49.6V and the charge controllers are still putting in more wattage than is being consumed even when floating. They do level out at this sort of voltage but its not whats set. I do have a SimpBMS battery management which is currently switched off as after a reset of the Venus GX to get the WIFI to reconnect it displayed the batteries were at 120V which is obviously incorrect. >The system has been running for nearly 2 years, last summer I had some issues of it over charging but not to the extent it is already doing this year. I am nervous about connecting the additional panels at the moment incase it increases the overcharge problem. I am also looking to set up load diversion to use excess PV for heating hot water through 2-3 elements in a 300+ litre thermal store. I would be keen to hear of other peoples experience in doing this in an off-grid setup, I am thinking of using a controller to output a 0-10v output to control a PWM controller outputting 0-230V connected to the heating elements in the thermal store. Appreciate any help and advice.

tarmacshredder asked
klim8skeptic commented ·

5 Answers

Battery voltage high


I have a fairly simple configuration with 1x 12V 130W Solar Panel, 1x SmartSolar MPPT 75/15 and recently added 1x Victron AGM Deep Charge 12V 8Ah Battery.

The battery type is set to Gel Victron deep discharge, and set to 12V.

Since I replaced the existing battery with a new Victron AGM, the voltage on the battery and load have gone up to 21V (visible on bluetooth app and with a multimeter) which is what the solar panel seems to be putting out.

This high voltage has now fried 2 fountain pumps and my patio lights.

It looks like the MPPT is not doing any voltage reduction like it should be.

I do not wish to connect any new load to the battery at this voltage (which I guess is probably damaged) as it will probably damage it as well.

Any suggestions on what might be going wrong?


svendickman asked
kevgermany commented ·

2 Answers

Lynx Smart BMS voltage discrepancy


Why would I have 13v on the distribution side of my BMS and 99v on the power-in side of my BMS, even when my batteries are disconnected from the power-in side via turning the battery switch off (confirmed off with multimeter)? No other sources of power touching the power-in side.

Distribution side is hooked up to the Quattro putting out 13v. BMS will not power on.

My configuration from left to right is:

Lynx power in-Lynx BMS-Lynx distributer-Lynx distributer.

Thank you for the help.


sv-freyja asked
jmbpac answered ·

1 Answer

Victron 3600W Isolation Transformer stepping up voltage???

Hi I wondered if some one could help we are using the victron 3600 to prove our equipment cabinets can work using IT mode. our input voltage into the transformer is 240V and the output is 256V?!?! I was under the impression it was 1:1 ratio so input=output. It is causing our ATS (automatic transfer switch) to persistently switch between A and B feed due o over voltage protection. Can anyone explain why we are having this issue



jameskitching asked
Rod edited ·

5 Answers

Orion Alternator over-voltage protection

On my catamaran with two alternators, I just had both Orion dc-dc chargers be “burned out” by one of the alternators running unregulated to a high voltage (like ~50vdc). This is per the distributor who installed them. What is the actual overvoltage protection for the Orion? Can they actually be “burned out” by overvoltage? This seems to be an unlikely explanation….

joshhockman asked
kevgermany answered ·

1 Answer

Can I dump to grid when my batteries reach a certain charge?

Say my batteries reach 90%, can I trigger a dump to grid?

Am using Home Assistant and modbus for control.

groundattack asked

0 Answers

Multiplus 12 800 35 Overcharging Lithium batteries and then tripping

I have the 12 800 35 MultiPlus connected to AC in, some load on AC out and 2x100Ah 12V Lithium batteries. From AC to inverter mode it switches seamlessly. After an Inverter cycle it will charge the battery but the Voltage goes up and peaks over 16V. The protection in the battery trips and that trips the whole unit for about 30seconds to a minute. In that time the 220V Load is also switched off. Then the unit starts up and it charges up again till it trips again. This happens a few times and then the inverter goes into a mode that I assume is float charging. I have set the dip settings 2=on and 3=off with no improvement.

I do not have the USB cable and app to adjust.

I have taken the unit back to the supplier. They say they have re-programmed it but the problem persists and they have stopped responding to my emails.

As the situation stands now the system is of very limited/no use to me as UPS for critical equipment.

fkirsten asked
trevor-bird answered ·

4 Answers

Battery Voltage set to 14.35 but Smart Solar 100/20 is charging with up to 14.9V!!!???

Hi Ladies & Gents,

today I realised that my SmartSolar is charging my battery with up to 14.9V even if I have set the limit to 14.35. It worked very accurate since I installed the SmartSolar 100/20. At the moment I'm testing the charger before I connect Li-Ion batteries to it to make sure I stay away from the Voltage limits of the batteries for safety reasons. But having more then 0.5V overvoltage during charging worries me quite a lot! What could be the reason for that and how can I get this under control?


senna1976 asked
Alexandra answered ·

1 Answer

Overvoltage on AC-Out on Dual Victron 3000s 50a RV Setup
  • 5th Wheel RV w/ 50amp
  • Dual Victron 3000s (Unit#1 on L1) (Unit#2 on L2)
  • 600ah Battleborn + 1300w solar
  • 2 (MPPTs) 100/75TR & 100/30
  • Cerbo GX w/ CTX-50 Display



I occasionally get this "OverVoltage on AC Out" error ONLY when the 2 inverters are programmed in single phase 110v Parallel mode (In RV world we call this 30a mode). I do not get this error anytime the 2 inverters are setup in Split Phase 180 deg offset (220v) mode (In RV world we call this 50a mode). Even in single phase parallel, I don't get the error all the time. The wiring is correct (I'm an EE by trade) and generally the system runs fine in either mode under light load conditions and heavy load conditions. I notice the error occurs more often in higher humidity conditions.

However, once it's starts throwing this error, it will continue to throw the error repeatedly causing the 2 Victrons to shutdown, remain off for a moment, and then power back up. This is not good for computer equipment in my RV that do not get a clean shutdown. Not too mention the havoc it wreaks on TVs and compressor type refrigerators that are constantly turning on/off every few minutes.

I think this might be due to unequal AC loading on L1/L2 where something either turns on or off causing a brief voltage spike on the line sensed by the unloaded Victron.

Is there a way to make this an "ALARM ONLY" so that it doesn't shut down the two Victrons? Or, can I adjust the voltage level that triggers the alarm? I think this could be a software fix as well. If either Victron detects a high voltage on AC Out, then check to see if the other "Tethered" or "Mated" Victron ALSO detects this overvoltage condition. If the other Victron does not detect a highvoltage on AC Out, then set the ALARM ONLY, do not shut the system down as it's likely just a glitch. Just some feedback.


hemiman asked

0 Answers

Why did Skylla drive voltage higher than the setting?

On a recent night I was woken up by an alarm on my CCGX saying the voltage was over my alarm setting of 14.8v.

My two Skylla IP44s are set for:

Charge algorithm: 7 (for my 1200Ah of Relion LiFePO batteries)

Absorption voltage: 14.2

Float voltage: 13.5

My system also has two MultiPlus 3000 inverters (master / slave) but they were not connected to shore power. I also have 1500 watts of solar panels. But this was at night. The Skyllas were plugged in to shore power. I cut off shore power and the alarm cleared.

Looking at the VRM history, I can see that one of the Skylla's (Sky2)was outputting significant current, spiking at the time and the output voltage going up to 15.03. The other Skylla did not appear to be outputting any current and had an output voltage of 14.83. Both Skyllas had been in Absorption mode and went to Off when shore power was cut.


This has not happened since, but I have not been using shore power much.

Any ideas why this happened?



patr asked
patr commented ·

1 Answer

SmartSolar MPPT output protection (OVP) against single component (statistical/random) failure

Dear forum,

how is the battery output of the solar charge controller protected against single component failures? My concern is that a single failure can result in a higher output voltage than the programmed charge characteristic. When converting a 100V solar voltage down to 12/24V. Since 12/24V BMS MOSFET blocking voltage is 40V-60V V_DS, a shoot through of the charger will result in a failure of BMS, battery and loads. Major internal components to look on might be:

  1. fail short of the switching transistor in step-down application. Or is an isolated topology used?
  2. micro controller crash/fault. Is an internal/external watchdog stopping the swichting?
  3. Drift or failures in AD-converters, references, or voltage deviders and general failure of the control loop. Is there an independet output OVP?
  4. Some kind of fusebraker/crowbar on the battery side?

Is some FMEA available to proove output OVP function under single fault conditions?

Where do I find MTTF values for victron products?



maxs asked
Johannes Boonstra (Victron Energy Staff) answered ·

1 Answer

ESS with VE.Bus BMS overvoltage with PV Inverter at ac out

ESS Multiplus with VE.Bus BMS overcharging Battery because ignoring voltage settings. AC in was off, PV-inverter at AC out was plugged in. In livedata you can see that mppt was stop charging, but Multiplus was still going on.

Is this happen because Multiplus can't stop the PV Inverter?

Why VE.Bus BMS doesn't shut down Mulitplus?

- Multiplus 12/1600 FW490 (max charging Voltage 14,14)

- VE.Bus BMS

- Victron 12V 200Ah (recommended stop charging Voltage 14,2)

- ET340 at ACout

- PV Inverter EVT300

- MPPT 75/15 (max charging Voltage 14,10)

- BMV712

- EM24 Ethernet (Grid)


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hardy-tuner asked
Jens Rephöhler answered ·

2 Answers

Wechselrichter Phoenix 12/500 Überlast

Ich hab an meinem Wechselrichter heute das Glätteisen meiner Frau angeschlossen. Die Daten passen eigentlich zusammen. Glätteisen 230V 150W, der Wechselrichter soll eine Spitzenlast von 900W und Dauerlast von 400W haben.

Wenn ich jetzt das Glätteisen einschalte geht es kurz an und dann geht der Wechselrichter gleich in überlast. Grüne LED leuchtet, und rote LED blinkt.

Angeschlossen ist der Wechselrichter laut den Herstellerangaben. PE geht mit 4qmm auf Erde/Masse, Masse geht mit 6qmm auf Minus der Lithiumbatterie (100Ah) und Plus geht auf Plus mit 6qmm. Länge der Leitungen sind knappe 1,5 Meter. Zuleitung zum Wechselrichter ist zusätzlich mit einer 80A Midi Sicherung abgesichert.

Hoffe mir kann irgendjemand Helfen und bedanke mich jetzt schon mal ganz herzlich.

Liebe Grüße


paulnadolny asked
paulnadolny commented ·

2 Answers

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