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battery system voltage

Pylontech abnormally high voltages after 2.60 update


After more than one year of perfectly stable operation with a ESS system comprised of a Multi-II 5KVA and a MPPT 150/100, 2x US2000B Venus OS 2.60, always in keep batteries charged mode, (for back-up for critical appliances) we've been experiencing random high and low voltage alarms from the system, which are unusually high (almost 54VCC sometimes). No LED alarm whatsoever on the batteries. DVCC is activated, SVS is off, MPPT in slave/BMS controlled.

We're trying to figure out this for two weeks now, we're in touch with Pylontech but so far they're not giving us conclusive answers. We've changed the battery monitor from "automatic" to "Pylontech Can.Bus" today to see if it changes anything. One explanation might be that they're not designed to run under a 100% SOC for extended period of times and thus might be internal cell imbalances that are not corrected as they're not discharged and cycled. Anyone can chime in ?

Thanks in advance,



perma-batteries asked
Guy Stewart (Victron Community Manager) commented ·

5 Answers

I measured 50V on a 24V system. How does that work?

Shema 50V problem.pdfI have a strange problem on a ship with a 24v system. When checking the electrical system, I found that if everything or Multiplus, MPPT, etc. is connected, apart from the negative consumer and the starter battery are also connected to the system, I can measure 50V on the negative cable of the consumer and the positive pole of the consumer batteries . If I remove the plus of the starter batteries, I measure normal about 24V. I don't think that's normal and it looks like a hidden series connection to me. If EVERYTHING is connected, the system has normal 24V and the 50V are no longer visible. Maybe I'm making a mistake and don't see the forest for the trees. Does anyone have any idea why that is?

Robert M.O. Seidel asked
redtute answered ·

3 Answers

Help me to understand Voltage drop ( decrease ) while under load vs at rest and state of charge

I was wondering what is the true reading of a AGM battery under a heavy load ( 150 watts)

The manufacture of my battery says the halfway mark is 12.4 volts ( 50% ) When I power on my television, I keep it on until it reaches 12.4 but then the voltage increases back up to 12.65 after it’s turned off

I guess my question would be this- would the 12.4 constitute a true halfway mark when running the television because of voltage decrease under a load ?
Or is it safe to run it lower than 12,4 if it bounces back to 12.65 ?
I have noticed that Victron records the lowest number under a load even after it bounces back up.

dallas asked
spirou commented ·

1 Answer

BVM-702 Voltage reading inaccurate

Hi all.

After reading all previous questions and answers associated with my issue I still cannot find a fix for my problem.

The BVM is mounted very close to the 24V battery (30cm) and connected with 35mm2 cable. The MPPT regulators are 100cm away and connected to the battery via 16mm2 cable.

The issue regards the inaccurate voltage reading on my BVM-702 as it does not agree with my two digital multi-meters nor my two Victron MPPT charge controllers. The BVM is consistently showing 0.8V lower than all these other devices.

I have tried replacing the in-line fuse on the BVM with a larger 1A fuse and even joined the wires together to bypass a fuse completely but the low reading is the same.

When measuring battery voltage using my meters, it makes no difference if I measure from the negative pole of the battery bank or either posts on the actual BVM shunt.

I tried replacing the communications cable from the shunt to the display just because I was running out of ideas........but it made no difference.

My final attempt at a fix was to swap out the shunt for a completely brand new one which I was able to borrow but unfortunately there was no change.

Any ideas very much appreciated

wishful-thinking asked

0 Answers

Victron 100/30 Voltage Settings for Winner Solar SMF


i have two Winner W280S (280Ah) as a Strip to get 24V for my inverter. Now i want to make a Profile for the correct Voltages for charging them both. Here are the voltages that Winner says they should be:

- Bulk 14,8V

- Absorption 15,4V

- Float 13,7V

so, i think i take them all as 2x. But whitch one is the right one in the profile? There i have:

- Absorption Voltage

- Float Voltage should be 27,4V

- Equalisation Voltage

Thanks a lot for your help!



solalasolar asked
solalasolar commented ·

2 Answers

Voltage Sense Wires using 2 Multiplus Inverters

I installed Voltage sense wires to my battery bank on the L2 or slave inverter and it does not seem to be seeing the difference in voltage that the batteries are at when under load. It still appear to be getting its info from the inverter cables. Do I need to enable this somewhere or does it need to be connected to the master inverter?

rjoustra asked
Matthias Lange - DE answered ·

1 Answer

Help Requested...Voltmeter doesn't match Victron products

I own a Victron MPPT and a Smartbattery Disconnect. I've tried Victron CS on several occasions to help me with my below problem; with the typical "no response" (Victron you should work on your customer service). My dilemma is this...

Both items listed above read in the 13.x volts when I charge my LiFePO4 12v batteries. The "read" is coming in on my BT Victron app. HOWEVER...when I put a voltmeter on each battery I get a reading for each battery as full (14V...ish). I know this is correct as I just charged them.

With that, I've tried to factory reset on both Victron items hoping that would resolve the issue. It didn't. What am I missing?

Thanks in advance for everyone's help.

captain-spear asked
Justin Cook - Bay Marine Supply USA answered ·

2 Answers

CCGX high battery voltage alarm


acdc-hansi asked
Matthias Lange - DE answered ·

1 Answer

MultiPlus. input voltage 66V DC

Hi. I have a 48/3000 multiplus. In the technical book it is written that the maximum input voltage = 66V DC. But when it reaches 64.7V it stops. How can I adjust it to work up to 66V. Thank you

ciprian-dobrescu asked
ciprian-dobrescu answered ·

2 Answers

New Batteries: Low voltage despite low usage


I just installed 2 new Duracell AGMs (100ah) in my camper. I reset the history on my BMV700. Watched a few hours of TV last night, ran the water pump a few times. Wake up in the morning to my batteries at 12.24V.

BMV shows SOC at 94% and only used 19AH. Why is my voltage so low? Did I get bad batteries?

leavenotrace asked
schlanbusch answered ·

1 Answer

MPPT 75/15 not stopping charge, high voltage alarm

I have rather simple system, I think, for my van. Trying to charge a house battery from solar and vehicle battery. For now I am just trying to get the Solar to work independently ( leave the DC/DC charge out of equation for now). I have looked at the Victron Van concept, which is much more over complicated in comparison to my setup. So I am having troubles understanding the schematic I need.

The MPPT keeps charging the battery well past 13.2V. (I recently changed this down from 13.9V, but it didnt help) It will continue on up towards and past 14V, then battery will read "Busy" , fully charged and stop taking charge. Then it sends a Over Voltage Alarm, referring to "Allow-to-charge contact"

What stops the MPPT or DC/DC from charging when the battery gets fully charged? Do I need an additional Battery Protect? I am not sure if I am missing equipment or have the wrong settings.

All Victron equipment:

12.8V 100Ah LiFePo4

Smart Solar MPPT 75/15

Orion Tr Smart 12/12-30

Smart Battery Protect 12/24-100 (1)

BMV 712 Smart


Lynx Distributor 1000 ( which I dont think I even need)

Solar Panels

2 - 100W Renogy







mbrun asked
spirou answered ·

1 Answer

Mobile studio rig, 120v to 230v

I own a Mercedes Sprinter with a Volta Power Systems 13.5kWh rig. It's being used for mobile sound recording. Wanna put a small 6000btu Mitsubishi MUZ-FH06NA in it, powered off the 120v supplied by the Volta batteries. Can I use the Victron autotransformer 120/240 32a? If not, what would be the best way to accomplish this?

dylanwest99 asked

0 Answers

Not reaching SOC limit

My system uses the ESS assistant and would normally discharge to the "minimum" or "active" SOC limit. Currently, this is at 30% for both. However, in the last month or so, the system is only reaching 38%, even if I switch off-grid. It seems to be switching at the sustain voltage (50v). The battery seems to be healthy and it's BMS is not giving any error. Also, the battery is charged to 100% every day. I even kept the batteries charged for 3 days but when trying it this morning it switches again at 38%.

Is this a setting issue (which has not been changed) or a battery issue? Or should I be checking something else?

adrianc asked
adrianc commented ·

1 Answer

Lead Crystal Battery Settings with BMV-712

Guys need help with a Lead Crystal Battery that I have (spec supplied) do I set the same as a AGM battery with my BMV -712 Smart?

Tony Alba asked

0 Answers

SmartSolar battery voltage spike

I have a SmartSolar 250/100 mc-4 with 3 280W panels connected to it. All goes to a 200 ah 12v lithium battery. Today I experienced voltage spikes from 13.9 to 26v and back multiple times. It burned my inverter and the house almost caught fire. What is the cause? Anyone?

roman asked
kosio86 answered ·

2 Answers

Battery 712 monitor showing slightly high voltage?


Have just installed a 712 battery monitor to 12v battery bank. Voltage seems to be showing a little high?

Peter Groves asked
Matthias Lange - DE commented ·

3 Answers

BMV 712 Smart Monitor dosnt work


Hey ,

I have Problems with my BMV 712 . Im Sure that i haf install everything correct, but the Monitor dosnt work.

Energy flows.

The battery Pol of the Shunt is connected with the minus Pol and the load Site of the Shunt is connected to the System ground.

+B1 -> Battery1 +, +B2 -> Battery2 +

I send the Monitor back, but the seller says it Works. He Send another Shunt, Same Problem ...

I Switch the phone cable, still nothing.

I tyried ist with other cables for the +B1/B2, also nothing.

now i Test the „Energy Flow“.

Shunt - to Shunt +B1/B2 has no Connection, i was mit able to get the 12.8V.

Anybody and idea ? What did i wrong?

Sorry for my english, thanks for help !



northernlightss asked
northernlightss commented ·

5 Answers

Help!!! Battery alarm.

Installed solar panel Saturday. With mppt 100/50 and bmv712 plus 1200w inverter. Everything was working fine yesterday. Now I can’t connect to controller Bluetooth, and the battery alarm has gone off saying charge?? There is nothing turned on ??? I’m worried I will damage something please help!

assimo asked
Paul B answered ·

1 Answer

How to correct or repair a BlueSolar MPPT 150|35 that is reading battery voltage wrong

I have a working installation of a BlueSolar 150|35, v1.16, connected to 2 parallel series of 3 250W/24V panels. The battery bank consists of 5 pairs of 2 batteries, each battery a 110VA 12V stationary battery. The system has been working for almost 2 years without any problem. Four days ago, this changed:

- the system did not have power anymore to run a water pump

- because the battery voltage was too low, about 22.5 Volts

- the MPPT was stuck in 'float' mode really early in the day and because of this, never charged to batteries

Yesterday I managed to (re)connect the MPPT to a Linux machine using the VeDirect RS232 connector. Connecting using minicom, baudrate 19200 and 8bits, I got data frames from the MPPT, below a copy of one of them:

PID 0xA04B
FW 116
V 27320
I 300
VPV 101460
CS 5
H19 159940
H20 36
H21 723
H22 23
H23 400
HSDS 314

This tells me, that the MPPT thinks that the battery voltage is 27320 volts. One minute after seeing this, I measured the battery voltage using a multimeter. Battery voltage is 23,3 volts on the multimeter. The MPPT software seems to stay in float, because of the high voltage it measures.

What are my options ?

- is there a way to re-calibrate the voltage measurement of the batteries ?

- is it safe to re-configure the treshold voltage, set it to a higher value, like 30 or 32V, in the hope that it will go to float when the battery actually has 27 or 28 Volts ?

wiebe-ruiter asked
wiebe-ruiter commented ·

3 Answers

Victron MPPT 100/50 - Batteriespannung falsch angezeigt


Wir haben einen kleine Inselanlage mit 2x 100A 12V Batterien

Dabei mussten wir nun folgendes feststellen: es wird beim Regler eine viel niedrigere Batteriespannung angezeigt als tatsächlich auf der Batterie gemessen.

Dies hat meiner Meinung zur Folge, dass die Batterie obwohl voll immer weiter geladen wird. Bin ich richtig der annahme? Ausserdem hat die Batterie bereits stark Schwefelig gerochen, weshalb ich nun alles deaktiviert und abgesteckt habe.

Kann mir vielleicht jemand erklären, weshalb dieser wert falsch im Laderegler angezeigt wird? Die Batterien sind mit nem halben Meter Kabel verbunden

Ich sag schonmal danke



domsn asked
Matthias Lange - DE commented ·

3 Answers

10KVA Quattro Inverter -

Question. 1
My 10KVA inverter periodically changes over into inverting mode even though the mains
power supplying the inverter is not switched off? my supplier (installer) says this is because the
incoming AC supply from the municipality is 'Dirty'. AC waveform seems ok to me.
+- 220v to 240v continuous.

Has anyone had or seen this behavior before?


Question. 2
My batteries have also been giving me issues lately and the supplier replaced 2 of them last week
since they failed their load testing cycles
These are 8x 12v Victron AGM batteries. 2 x (4 x 12v) in Parallel with each other.

I noticed on one of the charging cycles after we had a municipal power failure the Batteries discharged to around 50v then the power came back on but the inverter tried charging the batteries at 52v this charge voltage should have surely been between 55v to 57v ?

Has anyone had this behavior before ?


Thanks in advance

shaunp asked
JohnC answered ·

2 Answers

Low battery voltage when not under load and low solar yield

Inverter Multiplus48/5000/70-100

4 batteries Victron AGM 12-230 Super cycle

12V210ah @10h rayte

12v230ah @20h rate

MPPT solar charge 250 I 100 - tr

20 solar panels @300w each.

The system worked great from May2019 till current where low voltage battery was becoming a problem even when not on load. Even a 300w load now when low solar yield cuts the battery to 46volts and shuts down. This never happened before. Only occurs when usage is greater than pv yield

Are the batteries the problem?

We have been having load shedding on a regular basis.

dhoodhat asked
JohnC answered ·

4 Answers

Battery voltage high & drops low under load!!

Hi all,

I’ve just installed a 300w solar panel and 100/20 MPPT smart to my van with a 12v 95ah class A AGM battery. I have, I guess two problems, one being the voltage seems very high (13.77) when not in use? See photos.

Second, when I first installed the system the battery seemed to sit at 12.8 but after loading the system for 30mins it dropped to 12.6 then by one hour 12.40 to which I turned the load off! X3 2w led lights and a fan vent. It said the current was 1.9amps be pulled. I turned them off as I heard dropping before 12.30 could damage the battery.

Not sure what I have done wrong or if I need to set the app up correctly?

I plan to add a second battery in parallel but don’t want to do so until this issue is sorted.

Kind regards





sampeett asked
Daniel answered ·

5 Answers

Multiplus II BMZ ESS Low Battery Shut down

Load shedding (South Africa) at times causes the battery SOC to drop to 10% and the system shuts down. When grid restores the system does not restart. A cold restart (power all down and restart) is then necessary to reset the system?

Any suggestions to overcome this? Maybe limit SOC not below 15%?

James Minnie asked
James Minnie commented ·

1 Answer

Battery voltage drops to 18,7V and up again on LiFePO4 24V system


I have 2 LiFePO4 12,8 V / 200 Ah Smart (series cabling) on Multiplus (via BMS and Ac detector).

When in the evening, I launch a dishwasher, suddenly the voltage which is arround 25,0 or 26,0 V, drop to 18,7V (2,33 per cells) and immediatly go up to 20,0 V, 21,0V... to reach 25,0 V again.

On multi-plus we can read : CA Input (2600W), CA Output (2600W), and state : "Main power assistance" or "Direct Capacity".

I just want to know if it's normal in this case (relay ot the battery, by the main current), and without consequences for the battery lifetime, or if we have to change parameters, knowing that multi-plus parameters and mppt parameters are fixed with the template for LiFePO4, proposed by the software interface.

Best Regards.

royer asked
royer answered ·

2 Answers

Smartsolar MPPT OPzS charge algorithm

I’ve looked but can’t find this answered anywhere.

I have a Smartsolar MPPT 250/100, hooked up to a 48v array of BAE Secura 6 OPzS cells.

I want to ensure I’m setting the charge voltages appropriately.

Looking at this - - it appears float is 2.23VPC, equalise is 2.4VPC, and absorption I’ve taken as 2.33VPC.

These voltages are more or less identical to those that victron list for their own OPzS cells -

So... why do all of the OPzS charge algorithms in the firmware seem to be a mile off these values?

The most conservative setting recommended for OPzS (Position 1) gives 2.3VPC for float, 2.68 for equalise, 2.38 for absorption. +0.07, +0.28, +0.05, respectively. It also limits equalise to 8% of charge current, although at 900Ah I should be able to do the full 100A until 2.4VPC at which point it drops to 45A (5A per 100Ah), so surely a setting of 45% would be safe?

Can anyone shed any light on why, and what I should do? I’m using the values from the data sheet currently, and doing the commissioning equalise at 2.4VPC - but the MPPT is limiting the charge current to 5A, when it could be delivering much more - there’s a 4kW array in direct sunlight right now.


Maxwell asked
Justin Cook - Bay Marine Supply USA answered ·

1 Answer

Is there any workaround to run a Victron system with dead batteries?

Hello, I think after two years batteries are gone. It was set up and configured by company for my father, but was not monitored or serviced either. After he noticed often low voltage alarm he asked me for help, as the company is not reachable anymore.

There are 10x panels (AS-6P30-260W),
BlueSolar Charger MPPT 150/70 firmware 1.46
MultiPlus 48/3000/35-50 firmware 4.30

4x 12V victron 110Ah Gel batteries (in series)

I've studied something, purchased cables updated firmware, installed venusOS on raspberry, changed to ESS (before there was some Hub system - preventing feeding to grid - no allowed in my country) but still voltage drops very quickly and almost 90% usage is from AC grid even on sunny day, though usual load is between 200-600Watts, so I suspect inverter shuts down due low voltage very often.

I've read in this forum system is not able to run without batteries (he do no want to invest in new batteries anymore) question is, is it possible to set it up that way it will use as much solar power as possible even with such "dead" batteries, if yes what is the best configuration.

Or is Multi 48/3000 capable running with smaller voltage e.g. 12V or 24 ? I could try to isolate broken battery and try to set it up with remaining good ones, or maybe use spare 12V car battery if it's necessary for system to run

babeny2001 asked
warwick commented ·

6 Answers

Victron 100/20 Load Output Settings

I work as a consultant providing RFID detection equipment for fish and wildlife services. Lately I have needed the what Victron 100/20 MPPT solar controller is marketed to provides - a cost effective, user friendly smart solar controller that will work in either 12 or 24 volt configurations. I mainly run 24v. Regarding the load output settings, which would be the best for a continuous load (antenna always running) but to still be able to disconnect the load when the batteries drop below say 22.5 and reconnect at 24? I have tried the user defined algorithm with the previous parameters but have heard heard feedback that the load will not reconnect and the yield in the history will show 0 from that point forward. I have tried to duplicate this scenario in my shop but was unable to do so. The reason I am asking now is I have heard from a second customer in an opposite solar region whom experienced this same issue. I have assumed the disconnect at 22.5 and reconnect at 24 will prevent the batteries from going totally dead.

billyblak asked
Justin Cook - Bay Marine Supply USA answered ·

1 Answer

Why is my off grid system shutting down overnight?
I have an off grid system consisting of 6 270W panels, 1 Victron Phoenix of 500VA / 48V, a Blue Solar 150/35 48V regulator and an 8x100Ah battery bank in two series of 48V each. The loads are luminaires of a corridor (210W installed) that must be turned on when the darkness of the afternoon starts and off at dawn, however they go out between 1 and 3 in the morning. 
I checked the sizing and it is fine, what I don't know, is if there is any voltage parameter that is incorrectly configured in the inverter or regulator, and that causes the system to shut down, due to low voltage maybe. As a background, the maximum battery voltage during the day reaches 57.5V and the minimum voltage, when the charges are switched off is 37.44V. 
I would appreciate comments to someone with more experience in this type of configuration, to see if I can solve it. 
Thanks in advance,

carlos-farfal asked
carlos-farfal commented ·

4 Answers

PV power to the battery/consumption from the battery

Hello guys!

I have a three-phase ve bus system with two PV chargers.

I think I have some problems with in/out power calculation on the VRM portal.

If I take one-day data from VRM its looks like the PV to battery power more than the battery to consumption power. So how it's happening? If I take from battery-less then I use where the excess power is going?

alperin asked
JohnC edited ·

1 Answer


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