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Why does float voltage end after 2 hours?

I have a Victron 100/30 smart mppt charger on a 400 watt system feeding a 200ah LifePo4 battery. The last few charge cycles the float voltage (set at 13.5 volts) is truncated and drops below float after 2 hours. Full sunshine and good current should maintain float during sunsine hours. Correct? No clouds in the sky during this phenomena. Any good thoughts on why this occurs?

orvh asked
klim8skeptic commented ·

0 Answers

MPPT 250/70 with 32 Volt Modules

I would like to run 32V Modules with the MPPT 250/70 that is build into SmartSolar 2 GX.

Which Systeme Voltage do I have to select in the MPPT Calculator? 24V, 36V or 48V?


I want to use it with a Pylontech US5000 48V

Thanks for your help

timaios2000 asked
klim8skeptic commented ·

2 Answers

SMARTSOLAR MPPT 75/10 solar panel output started to be 0 V


160W PV panel, 100Ah battery, battery voltage >12V when having issues below.

Suddenly voltage at solar panel output started to be 0 V and battery loading is over (0W). I cleaned the panel, this caused panel for 10-15 minutes to generate voltage >0V but then again 0V. Sometimes in the morning for some 20-30 minutes generation is happening (voltage is >0) and then stops generating. I even measured voltage at the contacts of PV panel - 0V. I can understand that controller can disconnect panel from loading, but is in this case voltage will be 0V?

I have some doubts about battery being too old - can this be reason for PV panel voltage to be 0V?

Is there a way to definitely find out using this SMARTSOLAR MPPT 75/10 that battery are too old? Or any other means to check viability of battery?

eugenijus asked
ingo21 answered ·

1 Answer

AC current limit

Does reducing the AC current limit effect the ability for AC connected solar on the system output to push back to the grid? Is it bi directional whereby causing over charge issues?

paul-ham asked
sharpener answered ·

1 Answer

3 phase ESS BYD high voltage Alarms

Having issues with a new system. All firmware up to date.

Has 5 RS 450/200 and a grid tied inverter on output. Batteries go into high voltage alarm and shut down the system.

Looking at battery CCL showing 0amps the Victron continues to charge also when trying to reduce charged voltage through DVCC it has no effect and doesn't follow the value set. Help needed

paul-ham asked
paul-ham answered ·

1 Answer

Victron ESS low output voltage when grid voltage low

I have a Victron ESS system with MultiPlus-II inverters and a Cerbo GX, and I live in a country with unreliable grid power. Today the grid voltage has been 103-109V, and I noticed that the ESS system has also been outputting 103-109V. This is with batteries full and power coming from the batteries/panels and nothing being drawn from the grid. If I switch off the breaker that disconnects my system from the grid, the voltage immediately stabilizes to 120V (still coming from the batteries).

I was expecting the Victron system to regulate voltage to 120V, especially when drawing from the batteries and not the grid. But it looks like as long as the grid is physically connected, the Victron system outputs the same low voltage that's present on the grid. Is this expected behavior? If so, is there anything we can configure to avoid this situation (maybe setting a limit to auto-disconnect the grid at 110V or so)?

sahkovirta asked
Matthias Lange - DE commented ·

2 Answers

victron centaur 12/30 no green light 2v maximum charge output

my victron centaur 12/30 is dead. no green led and charger output ranges from mv up to 2v depending on the battery type. voltage gradually increases from mv to 2v. I have got dc 200v coming out of the rectifier and no shorted transistors also have check the temp sensors, and fuses and checked the yellow transformer has resistance and no shorts... any ideas on what i should check next? thank you. cheers, Aran.

ivan56140 asked
kevgermany answered ·

1 Answer

High difference of battery voltage between multiplus and MPPT on Easysolar 48/5000/70 MPPT 150/100

My Easysolar has not been charging the batteries correctly (48V 24xA600 OPzV system) for some time. After investigations, it turns out that the battery voltage recognized by the MPPT is very much above the real voltage (+6.5V approximately). The batteries are therefore never fully charged by the MPPT.

I checked the wiring (it's OK) and the voltages at the various terminals with a multimeter and I always find the same voltage as at the battery terminals as well as that indicated by the Multiplus, never that indicated by the MPPT.

I strongly suspect an internal failure of the MPPT but would like your opinion before replacing it.

help-conkouati asked
Gustavo G answered ·

3 Answers

Voltage limit on MPPT

Hi Folks,

I'm looking to understand the MPPT max voltage limit a bit more, for example the 250/100 MPPT.

Max voltage being 250v. Say I have panels with VoC of 49.5, and put 5 in series. (Awfully close to 250v)

VoC is technically under 250v however in practice, in the scenario cloud -> sun with battery disconnected for whatever reason I suspect 250v would be breached even if for a short period of time.

Is the 250v limit on MPPT based on VoC (ie likely has a buffer for the niche scenario described above), or is 250v a hard limit and installers/system designer should add a buffer themselves to ensure the 250v is never breached or is VoC * number in string sufficient.


matt1309 asked
matt1309 commented ·

1 Answer

Usb low voltage problem - Bluesolar Pwm

Hello I have solar panel connected to car battery through Pwm, everything works fine, but after I started engine with a bit low battery, on Pwm started blinking U 0.2v, which means voltage on usb output is only 0.2 volts. Normally it shows around 5 volts. It happened me once before and after a while it went back to normal, but now it always stays the same.

Pwm is working normally, only usb is not working.

I haven't found any relevant info on this, do you have any idea what can be causing this and how can it be restored?

P.S: I tried disconnecting the module, but didn't help.

Thank you


kubick asked
jurisvarpins answered ·

1 Answer

Lithium 160Ah - Battery Voltage versus Depth of Discharge

I have a new 160Ah smart lithium battery and it's my first lithium battery installed on my boat. I'd like to know if somebody has the correspondence between the battery voltage and the depth of discharge in order to check if my smartshunt is working well.

In the manual I have seen the attached graph: is it possible to have detailed values?


Many thanks and best regards.


giuliocanale asked
giuliocanale commented ·

1 Answer

Pylontech - shut down 40% SOC - impossible de descendre plus bas ?


J'ai installé un Multiplus II 48/300/35-32 et deux Pylontech US2000C. Je viens de m'apercevoir que je ne peux pas descendre en dessous de 40% SOC et je souhaiterai descendre à 20% SOC de décharge. J'ai utilisé les réglages recommandés, DC input low shut-down 44V, peut-on descendre ce paramètres et si oui jusqu'à combien ?

Ce serait occasionnel de descendre entre 20 et 40% SOC mais cela me permettrai d'avoir une marge de sécurité, je suis en food truck et j'ai peur qu'avec les fortes chaleur à venir ma consommation explose.

ked asked
yann answered ·

3 Answers

PV voltage never goes above 12.0-12.6 never charges.

Hello I have a 160W panel and a MPPT 75/15. The PV voltage never goes higher than 12 plus volts. It never charges. I have tested on a meter the battery and solar voltage. I have had the camper in different spots. One thing I can not explain is when I charge the batteries I see the PV voltage go up as the battery charge goes up.

Thank you for the help.

Jared Baker asked
Jared Baker answered ·

5 Answers

Multiplus II charger voltage inaccurate

I just installed a MP2 in my RV. The charger is set up according to the setting recommended by the battery manufacture: Absorption 14.4V and Float of 13.8. Most of the time the MP shows appropriate DC voltage in this range but only produces around 13.1 to 13.5 V verified by a multi meter. This low voltage allows the battery to discharge even while plugged into shore power. If I change a setting by even .01 V on the MP, it quickly displaces it current produced voltage and then jumps back up the appropriate charge voltage and charges the battery. This however only stays this way for a short time and then the voltage being produced drops back down in the 13.2-13.5 range while the display still shows a voltage in the 13.9-14.2 range. I have updated the firmware, but that did not seem to make a difference. Both picture were taken at the same time. Any suggestions?



pilotchuckles asked
gjohnson commented ·

4 Answers

Autotransformer voltage outputs are different

I am having an issue with the Autotransformer output voltages - 114V on L1 and 120V on L2 (with no load)

120V current is supplied by a Quattro 48V / 10000 / 140-100/100 to the 100A Autotransformer. I'm using the AT to provide a split-phase 120/240v supply to the 50A main break panel in my RV

I have wired the AT connections according to the diagram #3 shown on the system schematics page from the Victron website: (https://www.victronenergy.com/upload/documents/AT-3-split-phase-120V-to-120-240V-with-Quattro-120V.pdf)

The Ground Relay in the Quattro is set to ON and is correctly grounding the Neutral to earth.

Here are the voltages I read at the terminals:


The problem I have with this is that the voltage on L1 decreases a lot with load, and when occurs equipment will pull more current to compensate for the lower voltage.

Here is a pic of my RV control panel, showing the disparity in voltage between L1 and L2. Even though there are 2 air conditioners on Line2 it has only dropped 2 volts - Line1 dropped from 114v to 105v. This can't be good.


Questions: 1) - Is this method of wiring correct, and 2) what is causing the voltage discrepancy?


Aug-31: Editing this in an attempt to make the question visible again. I'm thinking of sending this AutoTransformer back to Victron as it is not performing to expectations. I have seen voltages as low as 96 volts on L1, at which point my UPS shuts down my computer, and various other circuits shut down. Not happy...

I'd appreciate a comment from anyone who has had experience with an AutoTransformer.


Pete MacLachlan asked
gutzpowers commented ·

6 Answers

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