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MPPT 75/15 charging voltage below 13v

My question is about something I do not understand.


My setup is an MPPT 75/15 connected to 2 Sunpower spr e flex solarpanels. It's feeding a bank of 2 x105Ah lead acid batteries. Charger settings are standard for lead acid. Everything worked fine for about 2 years, voltages and current correspond to sun position, strength and cloud conditions.

Now, since 2 weeks charging voltage does not exceed 13v. even with the app showing healthy PV conditions. I have to add that I have disconnected any load, and only 1 of the 105Ah batteries connected, to make the screenshot. I will add the csv from the last 30 days as well. (no I won't, the csv file is not an accpted filetype, other possibilities?)

On the screenshot there is a load drawing some current, switching between 0.1 and 0.3 amps. But... the load output of the MPPT 75/15 is disconnected... Before the low charging voltage problem, the load visible in the app was null as it is supposed to be without connected loads.

What do you think the problem can be? Is it reasonable to assume the readings on the app are absolute and should add up to a correct charging profile, or am I missing something?

Dear answerer, I'm hoping you can help..

mark-volt asked
kevgermany edited ·

8 Answers

Victron Blue Smart IP22 Charger 12V 30A Battery Compatibility with Renogy 50A 12V DC to DC In Vehicle Battery Charger W/ MPPT Solar Lithium


I am deciding to purchase

Victron Blue Smart IP22 SLA/LiFePO4 Charger 12V 30A

Victron Blue Smart IP22 Charger 12V 30A Battery Compatibility with Renogy 50A 12V DC to DC In Vehicle Battery Charger W/ MPPT Solar Lithium

in particular when I am on shore supply connected to 240V and the Victron charger is doing its thing overnight AND then the sun starts shining in the morning what happens ?

Ideally Id like to add the Renogy ~50A of solar charge to the Victron ~30A of 240v charge. Is this possible ?

How do you set which item has precedence ? Im assuming its internal settings on one of the devices to cutout near the max voltage of the batteries an allow the other device to finish off.

How do you stop them cycling or turning each other off as thresholds are reached ?

My preference would be for the Renogy Solar to have precedence with the Victron charger being an additional source. Ideally the Victron 30A helping the solar get the Lithium batteries (2x250AH) to near full charge then cutting off to let the solar take the last bit.

The reason being when I park up overnight I can have shore supply on for 10-18 hours BUT I don't intend to connect shore supply unless I have to. Thereby meaning I wont be using the Victron charger often. As such I wouldn't want to 'decrease' any of the Renogy Solar charger characteristics as the Solar and Alternator Driving are my main source of charge for 99% of occasions.

I also don't want to have to 'just switch XYZ or just turn off XYZ' when you connect shore supply as human intervention is the worst type of system (that's code for i will forget to do XYZ ! :) )

Is it possible to program custom modes into this Victron Charger:

mode 1 - I am parked up for 18 hours overnight undercover with no solar - 100% Charger

mode 2 - I am in sorta bad weather parked outside - split charger/solar

Any explanations welcomed !

Other random info:



2x250AH Lithium batteries in parallel

Victron Blue Smart IP22 SLA/LiFePO4 Charger 12V 30A

Renogy 50A 12V DC to DC In Vehicle Battery Charger W/ MPPT Solar Lithium

700W solar panels

plipaus asked
scubadoo commented ·

2 Answers

DVCC questions

DVCC questions

I’m designing an external BMS for a Victron Smart Li battery. I’m incorporating a SmartSolar MPPT 100/50 for charging the battery, and a Cerbo GX to monitor that device and others. I know I can use a Cyrix Li to enable the BMS to disconnect the charger if necessary, but I’m reluctant to do that because it’s my understanding that disconnecting a battery from a charger, while it’s charging, can damage the charger. A better scenario would be to turn off the charger if required and I know that I can use the single VE.Direct connector with a VE.Direct non inverting remote on/off cable to do that, but then I am unable to connect the MPPT to a Cerbo GX.

So here are my two questions…

  1. Is the SmartSolar MPPT 100/50 “DVCC capable”? Can a Lynx Smart BMS (or a VE.Bus BMS) turn off the charging current of the MPPT 100/50 if both devices are connected to a Cerbo GX with DVCC enabled? The MPPT 100/50 manual makes no mention of DVCC that I can find, but the GX Device manual states that DVCC can be used to control VE.Direct MPPTs with firmware v1.46, or beyond.
  2. If this is possible, can I still use the Cerbo GX to monitor other VE.Direct devices that are connected to it? The GX manual states that “Enabling DVCC changes a GX device from a passive monitor into an active controller”. Is this an either or feature? If the GX device is changed into an active controller is it no longer able to monitor other devices as well”. I would think it would still have that capability, but would like confirmation.

Thank you

pcg asked

0 Answers

Possible to control charge state of BlueSolar/SmartSolar MPPT charge controller using MultiPlus & two-signal BMS?

Hi everyone,

Is it possible to control the charging state of a BlueSolar/SmartSolar MPPT charge controller if I use a two-signal BMS setup connected to a MultiPlus II?

ie. if my BMS detects that one of the cells hits a pre-configured high voltage state and sends a signal to the MultiPlus to stop charging, is it possible to also tell the MPPT charge controller to also stop charging the battery?

gyrex asked
gyrex answered ·

2 Answers

Can I repair in Panama

My solar controller gave me a heat warning and never worked again right. It is just out of warentee. It stays stuck in bulk mode and completely turns off at night and I cant access it.

bluesphere asked

0 Answers

MPPT, Multiplus and buck boost parallel

Maybe a silly question….

I have a Multiplus 2000 and a Buck boost in my RV (connected to cerbo). I now plan to install solar with an MPPT.

Do I have to use any diodes, to prevent the Chargers from voltage backflow?

Or can I easily put them in parallels?

What happens when solar is charging and buck boost or the Multiplus charger kicks in?

Is there any problem, when float voltage and absorption of the mppt is set a little lower as in buck boost and victron? (Lithium batt)

thanks for your help!

bitcrusher asked
bitcrusher answered ·

2 Answers

No amps, high Voltage as soon as over 15ish Amps

Hello Victron Community,

I have a problem with my setup, and I am very confused how it happened. We live in a trailer and have been using the MPPT 100|50 charge controller, the BMV-712 Smart with 4 batteries (24v/250amp in total, those AGM batteries), 4 12v solar panels (wired to be 24v), a 3500W pure sine inverter (which still works) and we have not run into problems for almost 2 years!

All of a sudden we are reading 38V and 0A!

But not all the time. In the morning it does charge the battery, but then it shuts down as soon as it reaches maybe 15-20amps (25 is our max, so I believe it is more to the lower end).

If there is no hidden fuse in one of the building parts (is there?) I can rule out a fuse being the issue.

We did have a very rushed wire connection that was hit with wet snow the other day, but I since rewired the whole thing, and the issue persists.

We are totally off grid and need help! Thank you so, so much!

Attached are a few pictures that hopefully help.

I am certainly not an expert (as evident) so if you need more information, please ask.




Philipp Czakert asked
Philipp Czakert answered ·

4 Answers

Problem mit MPPT 100/50

Ich habe seit einigen Monaten eine Solaranlage installiert. Bis jetzt hat alles gut funktioniert. Aber seit ein paar Tagen ha die App den Solarregler nicht mehr angezeigt. Ich habe dann alle Kabel vom Regler genommen und neu angeschlossen. nun findet die App den Regler wieder aber die Batterien werden nicht geladen. Hat jemand eine Idee woran es liegen könnte ?


frankych asked
Mike Dorsett answered ·

1 Answer

SmartSolar 150/70 VE.Can current fluctuate

I have a SmartSolar 150/70 synced setup (1 only 1 VE.Can/ for 2 different arrays. They are both attached with to GX Cerbo, SmartShunt, Smartbattery (historical before GX Cerbo)

Just a couple of days ago 7 or 8 after firmware update (v3.07) the VE.Can device has fluctuating current. From 0 to max availble and back. The other SmartSolar (v1.59) does not have any issue

Did all sort of troubleshooting already (downgrades to 3.05 and 3.06, beta's (GX), unplugging, wiring checks (including all connectors), disabled DVDC, disabling bluetooth network) It looks ok for a couple of seconds and then it going up and down again in just seconds.

Both arrays are close in total config so the difference is easy to spot during the day. See Roof (SmartSolar with issue) is far behind last days (today system is been out for a while so stages are not right anymore)


1980 Watt (3 x 6 x 110W)


1640 Watt (2 x 2 x 410W)

When I disconnected the batteries (450A/24V (4 x AGM)) and only used Solar power mid day during some time, the VE.Can took over as primary and stabilised (as long as there was enough light for the load), which was what I expected at all. After switching battery power on again it began all over again.

270920121: Did exchange arrays today. Same SmartSolar VE.can went grazy on other solar array also, the other SmartSolar kept stable. This exclude there is an issue on solar panels and related wiring.

Saw other questions, mostly regarding 1 MPPT only with comparable issues.

Hope anyone has an idea as the short days are coming and desperately need stable power.

macelly asked
macelly answered ·

1 Answer

multiplus 2 en ess et mppt 150/100 rev 2 qui charge très irrégulièrement voire pas du tout

bonjour voici mon problème avec un mppt 150/100 Rev 2 ve can qui charge très irrégulièrement voire pas du tout

description installation :

4 batteries ultracell 200a

un cerbo gx,

un bmv 712

un multiplus 2 est un 48 v 5000va ( il fonctionne en ess)

2 mmpt un 150/100 rev2 avec 6 panneaux longi 320 w et un mppt 150 /60 avec 9 panneaux URE 335w

j'avais exposé mon problème sur ce lien : pourquoi le mppt 150 100 ne charge pas mes batteries en 48 volts mais les charge en 36 ou en 24 volt?

depuis j'ai reçu un autre appareil en rma. mais j'ai toujours le même souci : le mppt 150/100 rev2 charge de manière très irrégulière voire pas du tout alors que les batteries sont en demande.

il y un autre mppt, un 150/60 sur le cerbo lui fonctionne très bien et en permanence

solutions essayées sans succès

mise à jour de toute l'installation

j’ai tout réinitialisé sur ce régulateur mppt 150/100, je l’ai complètement débranché , supprimé de la liste des appareils et remis en ligne
j’ai arrêté l'autre mppt 150/60 je l’ai débranchét pour que le 150/100 reste seul en ligne
j’ai tout rechargé les batteries avec le réseau pour bien réinitialiser le soc,
j’ai tout remis ensuite sur batterylife
Tous les paramétrages de tension sont identiques sur les mppt et le multiplus
mais j’ai toujours 5 w maxi…sur le mppt 150/100 avec 119 volt sur la ligne je ne comprends pas

jean-paul asked
jean-paul answered ·

12 Answers

MPPT 75/10 charging only in low light

Hello, the following setup to the question: motorhome, semi-flexible, monocrystalline 100W module, SmartSolar controller 75/10, offgridtec gel battery 100Ah. The panel provides power even in low light. If the voltage is 5V above the battery voltage, the regulator turns on. If it then becomes sunnier, the controller switches off again, for example in the low 2-digit range. Then the PV voltage always remains slightly below the battery voltage - switching on impossible. When driving, the following has happened: in a shady forest, the controller suddenly switches on, charging current immediately there and, out of the shadows, over 40W. Since I like to be self-sufficient, the system should of course supply as much electricity as possible, especially in the sun. Can anyone tell me anything about that? Thank you in advance.

mrjo asked
Alexandra commented ·

0 Answers

MPPT 75/10 lädt nicht trotz Sonne


folgendes Setup zur Frage: Wohnmobil, Semiflexibles, monokristallines 100W Modul, SmartSolar Regler 75/10, Offgridtec Gel Batterie 100Ah. Das Panel liefert schon bei geringem Licht Strom. Ist die Spannung 5V über der Batteriespannung schaltet sich er Regler ein. Wird es dann sonniger schaltet der Regler wieder ab, so etwa im niedrigen 2-stelligen Bereich. Dann bleibt die PV Spannung immer leicht unter der Batteriespannung - einschalten unmöglich. Beim fahren ist nun folgendes passiert: in einem schattigen Waldstück schaltet der Regler plötzlich an, Ladestrom sofort da und, aus dem Schatten heraus, über 40W. Da ich gerne autark stehe soll die Anlage natürlich gerade bei Sonne soviel Strom wie möglich liefern.

Kann mir jemand etwas dazu sagen?

Vielen Dank im Voraus.


mrjo asked

0 Answers

2 smart solar 75/15 on a 24 volt system

Is it possible to use the above mentioned hardware to charge 2 12 volt batteries individually. And have 2 batteries wired in series for a 24 volt system. Thank you for any comments.

1deadmanwalking asked
wkirby answered ·

1 Answer

Why Float so early

My 75/15 solar charger seems to go to Float too early, the BMV is telling me 80% SOC.

Could the battery be fully charged already & the BMV is not correct?

I should add, the battery is 300AH LifeP04 & charger settings to suit.


nelsonpk asked
nelsonpk commented ·

3 Answers

MPPT 75/15 - Consumption - why is consumption high when there is no load?

Hi all,

I am new to solar and need some help. I have a simple solar set up two 300w panels, victron MPPT 7/15, victron phoenix 24v 250 inverter and two 140ah AGM batteries in series. Attached to the MPPT load I have a USB charger to power a mobile phone. I also have a blue tooth dongle attached to the inverter to link to the phone / app.

I have a breaker in between the panels and the MPPT and fuses between the MPPT and batteries and between batteries and inverter - all on the live wire.

When everything is off - no load on either the USB or inverter (inverter is switched off) the Victron app is showing consumption of 50Wh.



The system ahs been running for around 2 months. Initially consumption was no more than 40wh but in last week or so it has been over 100wh (but with load - laptop / two monitors c100w - 140w).

Questions I have are:

1. Is this normal / typical?

2. If not normal what could be causing it? Problem with MPPT / batteries / connections / panels / fuses?

Any help / advice greatly appreciated.

andrew-aikman asked
tomwarden commented ·

3 Answers

Rebulk Settings for Victron 220ah AGM Batteries

HI All,

My batteries go into bulk charging twice a day - (last 2 days) i have 6 Victron 220ah AGM Batteries.

They aren't in any type of load during the day so cant see why they need to restart the cycle. I checked and the rebulk setting is set to 0.40v and it says:

''Resulting Voltage at which the charge cycle will restart: 13.4v''

At that voltage the batteries are actually close to full so would it be a bad idea to drop this to restart at 12.8 to avoid over charging?


abrgrg asked

0 Answers

Tail current setting with multiple MPPT and BMV

I have two MPPT 75/15, a BMV 712 smart and a smart battery sense all connected via networking. The lead MPPT shows Voltage/Current reception from the BMV and Temperatur Value from the battery sense. I use the tailcurrent setting (with adaptive time) in the MPPT for the switch over from absorption to float. Now the question: if I enter 2,5A as tail current in the settings of each MPPT does the switch from absorption to float happens when the BMV shows 2.5A or at 5A?

nrickert asked
gyzko answered ·

1 Answer

Quiz. Time needed to full charge

How long should it take to charge 24v 250ah flooded tubular battery using mppt100/50. Consider 1400w at the mppt input from pv. Charging from cutoff voltage. Tested results would be nice.

bloudan asked
bloudan commented ·

3 Answers

How to force more bulk charging in day time?

I have 2 Hollandia carbon batteries HP 12-200CA connected as 24v, during the day i have about 1100 watts from PV and the load is about 600 watts but since the Victron 150/60 MPPT goes into bulk early morning when the PV watts still low it does not seems to go full charge even with zero load on inverter for couple of days the batteries SOC still below 30%. My smartshunt and MPPT battery setting attached below



hjazeeri asked
klim8skeptic commented ·

1 Answer

BlueSolar 75/10 MPPT shuts down when I plug in VE-Direct Cable

I typically leave the VE-Direct USB cable plugged into my charge controller so I can easily plug it into my Android phone and monitor the battery and charge when I'm camping. This weekend I tried to plug in the phone and couldn't get it to find the device. I also was not getting any power out of the battery.

When I unplug the cable from the charge controller, I get power out of the battery again and the lights on the charger show that it is charging. But as soon as I plug the cable back in, I lose power and both (blue and yellow) lights on the charger illuminate solid.

Any ideas on what is wrong?

daineric asked
helios-harvester answered ·

1 Answer

Smart Solar 250/70 at 49 Degrees

My smart solar 250/70 sits at exactly 49 degrees for the duration of charging. It is not fully loaded and the battery charge current sits at no higher than 50A during Bulking. Is the charger supposed to get this hot?

The heatsink is only warm to the touch but the front of unit is panful to the touch. I will upload some graphs below of current and voltage of the MPPT in question. I just want to make sure that the charger is not undersized in some way which is causing the extreme heat. I thought that I had oversized the charger more than required.


basil katakuzinos asked

0 Answers

MPPT100/50 and Victron Lithium Smart Batteries

Hi what is the correct float voltage when using Lithium Smart Batteries 2x 12V in series, charged by 1.7kW PV feeding MPPT100/50?

Section 6.2 of the MPPT manual; Default Settings for LiFePO4 batteries recommends 26.4V float, but section 4.2 of the battery manual recommends 27V float.


abegweit asked
klim8skeptic answered ·

1 Answer

mppt and b2b chargers what is the difference

Forgive my naive question.

What is actual difference between mppt and b2b chargers, both getting current from the source and processing according to the charging profile?

markmoto asked
markmoto answered ·

1 Answer

100/30 with 3 x100w panels in series has max charging amps of 2.5 in bulk?

I have a pair of 12v 100ah deep cycle AGM's under my van with 3 x 100w panels in series connected to a 100/30. Camping for 3 days in total shade depleted 50AH from my 80AH self imposed limit. Using the BT app I'm seeing almost 60v solar but only 1.6A solar and the battery amps are only 2.5A with no load. If I turn on my Dometic 50qt fridge, the BT app shows voltage dropping from mid 50s to 30s with solar amps going from .3A to 1.6A. Is this normal behavior? Three days later in bulk for 11+ hours daily I've only recovered 40ah of my depletion.

quigleylad asked
quigleylad answered ·

1 Answer

MPPT 30/100 battery reading full when not.

I am having a problem with my charge controller reading my battery bank as 13-14V when my battery is reading on my multimeter much lower. from 9V-12V. I have unplugged (uninstalled) everything and plugged it all back in twice now. letting it rest between. I have checked the connections for continuity and replaced wires just in case. But its still reading them as full. This is a 12V system with 240 watts of solar filling 2 deep cycle batteries in parrallel in a conversion van. I hope someone can help me figure this out. I haven't had solar for 6 days now. Luckily im house sitting for a week but I usually live in my van full time. Does anyone have any suggestions for how to protect the solar charger form the alternator current (if you think thats part of the problem) which also charges the batteries when I drive? Ive got a 100 amp circuit breaker but ive realized thats probably way too big to protect anything. Ive been going thru batteries like crazy in the rear and i think its because the alternator dumps out whatever it wants for voltage to charge and that is maybe killing my batteries. so i guess really this is two questions. the solar charger question and a is my alternator damaging my solar charger or batteries?

owlmedicine asked
Alexandra edited ·

1 Answer

MPPT100/15 not working

MPPT 100/15...Been working fine up to 2 days ago...even with 12.4v battery it remains off...19v from Panel but only showing 13v on App...tried reboot, reinstalled stumped..

jumar asked
klim8skeptic answered ·

1 Answer

Which Controller?? Help please:-)

Hi all

I have a 12v system they are 2 x 12v @ 220ah so total of 440 ah on my boat.

I have been looking at the following panels and would like to install 2 or 3


Even after quite a bit of research and attempting to understand how to calculate it. I always end up with an extra unsure thought..

I have come to the conclusion that a reputable MPPT controller is key there for I decided on victron

So which MPPT controller would I need for 2 x these panels

And which if I get 3 of the above panels

Or is there a better scenario you could recommend.

Your help is greatly appreciated

leigh asked
leigh commented ·

1 Answer

MPPT 100/20 doesn't charge to the right float voltage

Good afternoon,

I am using MPPT controllers in a streetlight application.

5 units of smart MPPT 20A and 3 units of smart MPPT 10A are used.

4 units of 20/100 mppts and 2 units of 10A mppt seems not working properly anymore. The float voltage doesn't reach the right value.

It happened studently last 10 to 15 days and it has been working properly for more than six months. We changed only the operation mode yesterday from batterylife to Conv. Algo 1. Streetlight mode was always active. The lights are programmed to switch ON for 7h per night.

The float voltage is now approx. 24Vdc for 24V system and 12V for 12V system. We don't have problem with the meteo, it's sunny all the time.

You can find screenshot from the Victron APP for one of the signage, We can see the same phenomena for almost all the site.












We updated and restarted the MPPTs 4 days ago for some of them but no change happened.

Thank you for your help. Fist time I am facing this issue.

julienmathurin asked
julienmathurin answered ·

1 Answer

Charge voltage setting MPPT 450/100 running ESS

Hello, I have been having issues with the voltage settings on the MPPT 450/100 running ESS. Switched from VE Can to VE direct ....



Turned on DVCC to a setting of 47.70V .

However the MPPT shows 48.40 charge voltage but no clue where he gets it from



at the victron connect App the voltage settings are set to 48V


So where does the system get the 48.40V from ?

Carlos Carvalho asked
klim8skeptic commented ·

4 Answers

Mppt 75/15 not charging


Hi just wondering if anyone can help me as im a newbie have a 120w solar panel on caravan wich generates 21.4 volt at the wires going in to in to mppt when disconected measjred with fluke multi meter, battery shows 12.5v however charger says its off and also shows in blue tooth app solar lower than the battery volts,

Could this mppt be faulty?


keith5637 asked
offroadflow commented ·

2 Answers


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