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150/70 Switching back to Bulk less than 10 mins after being in Float

Installed my new Victron 150/70 and programmed the battery manufacturers settings. Turned on the panels to charge the batteries and the MPPT started to charge in bulk for 5hrs as it should than went to absorption for 1hrs than float. After less than 10 mins in float the MPPT went back into bulk, but was not producing any current. There was no load on the batteries and it was early afternoon. Have I missed a setting or is there something wrong with the MPPT?




islander-off-grid asked
islander-off-grid commented ·

1 Answer

ESS bulk restart voltage causing stuck in float

I try not to be too hard on my Lifepo4 batteries so I charge to 56v and float at 53.6v. This worked fine with the MPPT charge controllers, but once I added ESS the problems began. The issue is the bulk reset voltage. On the charge controllers this is float -0.4v so bulk restarted at 53.2v, or around 80% battery capacity which was fine.

With the ESS system, Victron in their wisdom have chosen to set the bulk reset at float -0.8v

Why different ?

This means bulk does not restart until 52.8v. With the flat profile of Lifepo4 this is around 63% battery capacity, which is way too low. Until this point it just sits in float. If you heavily load the system to drop the voltage then it changes over to bulk without any problems, but sitting with a low load you lose a lot of charge time.

Does anyone know a way to adjust this bulk reset voltage ? I know I could float at a higher voltage but this seems a poor solution to the problem.

muddy1 asked
Leslieanne commented ·

0 Answers

DC to DC 12/12 30 entering float mode too early on my Ford transit conversion...HELP!

I have a Victron Orion tr 12/12-30 connected to the starter battery in my Ford Transit camper. It seems to be working, but keeps going into absorption and float way too early.

When I start the engine and drive away, the unit goes into absorption for approx 10 mins and then floats. It does keep my battery % at whatever it was when we left but wont increase the %.

I have 1 x 260ah agm battery. I use a victron MPPT, a BMV and a battery protect.

I have attached screen shots, and would love to know why it doesn't seem to be working properly!

I am in Scotland and could do with the power. There is f'all sun!







peevichpc asked
kevgermany answered ·

1 Answer

Bluesolar 75/50 gets to float voltage too early.

Seen some with similar problem but not seeing many answers. Please help. Trying to improve SOC during daylight hours. Have Smartshunt onto 600Ah Lithium. Po4. Come the afternoon, solar producing close to 50Amps. The voltage moves increasingly higher and then goes into Float. Float set at 14.2v. Trying to keep voltage low and Amps high to increase SOC. Is the charger regulating the max. Output by increasing the charge voltage? When I turn the charger off for a few minutes, voltage regulates to below 13.8 and charger goes into Bulk mode with higher charging current obviously. Running VE Bluetooth dongle and Smartshunt networked

wisey asked
klim8skeptic commented ·

5 Answers

Boondocking with BMV-712: SOC error? Best practices?

I have the following setup: smaller 2015 Lance travel trailer with 2ea 12V lead acid flooded batteries in parallel, BMV-712 and the standard Honda 2kW generator. The trailer's battery charger seems modern (3-stage charging, lots of amps, etc.).

I plan to boon dock (no shore power) regularly and would like to tune the BMV-712 to help keep the batteries charged, healthy, and to know when and how long I should run the generator.

From research, I know I should always keep the batteries above 50% capacity to avoid premature replacement costs. Also, without many hours of charging (e.g., plugged in or on solar), I cannot expect battery capacity to rise above 90% while boon docking.

When charging from, for example, ~60%, the charger will be in the "bulk" mode with high current, and rising voltage. This charge mode is the quickest, but only gets to 80% capacity.

Then the charge mode changes to "absorption" where the charger voltage is held high (14.6v in my case) and then the amps fall off toward ~2amps (in my case) when the charge mode changes to "float" at which the battery capacity is at 90%. To charge from 90% to 100% capacity would take many hours and isn't reasonable while boon docking.

Therefore, while boon docking, I should expect to cycle the battery between 50% and 90% depending on loads and generator run-times.

However, AFAIK, the BMV-712 is designed to treat the 90% charge state as "100% SOC" (?) The BMV-712 decides that when the voltage is the high "absorption" mode, and then the current drops below a "tail current", it proclaims SOC = 100%. But in reality, the battery is at 90% capacity at that moment (i.e., at the end of the "absorption" mode).

If starting from a full-charge (i.e., batteries have been plugged in for a day), the SOC value will be fairly accurate. However, if not starting from a true full-charge (allowing the BMV-712 to auto-sync the 100% SOC value at the end of the absorption mode), the reported SOC value will be 10% lower than reality. So the accuracy of the reported SOC value depends on whether the previous charge completed the float mode? Is this true?

If that's true, then I must tweak other settings to make the SOC value match reality or add-in some fudge-factor or work-around.

I could:

  • tell the BMV-712 that the "battery capacity" is 10% lower than the battery specification.
  • set my "SOC relay (charge floor)" to 60% instead of 50%, and mentally never let the reported SOC value fall below 60%

Is this a known problem with the BMV-712 SOC value? What do others do to work-around this inaccuracy?

Do other boon dockers have tips on using the BMV-712 to stay confident that the generator is running for the right amount of time?


goodguy5000hd asked
captn-mike answered ·

2 Answers

Battery is not charging anymore?!


I am not sure if it's connected to an update I did, but my Battery is not charging anymore. The Smartsolar is showing me Volt from the solarpanel but no Watt is coming in. In the history the battery minimum is always 0... After reconnecting everything and checking the cables it stays on bulk for 2 Seconds and changing to floating. I will ad some Screenshots, maybe someone can help me???

jonny asked
jonny commented ·

1 Answer

SmartSolar MPPT 150/45 don't go into Float


I got myself a SmartSolar MPPT 150/45 - TR with the Display option. I switched from my 100/20 to the 150/45 because the smaller one was on its limit.

The problem that I encountering now: The new MPPT doesn't go into float.

It's connected via VE. Smart Network to a SmartBMV 712 and a SmartBatterySense. On the app, the MPPT says it's using external voltage and external Battery current sense from the BMV and Battery Temperature from Battery Sense.

Its also connected to a Raspberry Pi running VenusOS.

Right now, the MPPT is set to a maximum absorption time of 6h and an Absorption Tail Current of 4A. The MPPT as I'm writing this is charging the Battery with 3.1A (MPPT Reading) where 2A go to Battery (BMV Reading)

From my understanding, the MPPT should go into Float if the Absportion time is at max 6h or the Battery Current goes under 4A for one Minute.

Today it started charging with 11.8V and is in absorption for 4 hours.

Typical days are, charging bulk over the day, going to Absorption, Battery Current falls under 4A, and MPPT still in absorption. Then, when I come home and using the energy, it goes back to bulk if the sun is going down. Or if I'm not using Power, the MPPT going straight from Absortion to off.

2 Days ago it once was in float for 20 Minutes then the Sun gone down.

I think it is not good for the battery if it's continuing this. Does someone know an answer to this?






Daniel asked
maxs commented ·

5 Answers

MPPT 100/30 float issue

Hi all,

I've had a look through the masses of previous questions and unfortunately couldn't find any that were quite the same as mine.

Recently I have noticed that my SmartSolar 100/30 completes it's bulk and absorption stages and enters float mode. When in float it will match any current draw from the battery for roughly an hour and then will suddenly no longer keep matching the battery and it will then start dropping down from 100%.
It says it is in float mode, there is plenty of sunlight and panel voltage present, however it doesn't output any charge to the battery. No other chargers connected to the battery.

I have the float voltage set to 15.8V and even when the loads connected to the battery increases it does not kick it back into bulk.

I then have to reset the controller by disconnecting the solar, then battery and reconnecting, which it will then it go back into bulk mode, absorption mode and then eventually into float again.

Has anyone else experienced this issue? Is it potentially a firmware issue?






ksmith asked
patrickvanneck answered ·

8 Answers

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

MPPT remains in float


I've two Smart Solar MPPT 10/75, which are connected to a Life4po battery with builtin bms. A compressor fridge is connected to the battery. Normally everything works fine. But when it's a warm, the battery bms seems to stop charging. I'm in discussion with the battery manufacturer because of this.

When the battery stops charging the MPPT change to float state. This seems to be okay and it's understandable for me. But I don't understand, why it remains in float state, even when the fridge starts and drains the battery? Only in the evening, the MPPT change back to bulk state.

Do you've any idea, why the mppt remains in float and how could I fix it?

Thank you!


markusg asked
solardude answered ·

2 Answers

High current in float mode MPPT 100/30

Hi everyone,

The MPPT in float is charging the battery with 9.3A. How is it possible ? It is a 100/30 smartsolar. He is connected to 2 175W pannels en series with battery voltage of 12V.

Here are some more information :



eliot asked
eliot commented ·

1 Answer

Recommended Bulk, Absorption, float voltages for LiFePo4 3.2V nominal cell by Victron.

I am using 57.6V pack ( 18s of 3.2V nominal LifePo4 cells). Please recommend the above voltages to configure.

Nikhil Valiveti asked
wkirby answered ·

1 Answer

How to configure Absorption Voltage and / Time ?


I am using 3 x 3000 Multiplus II and 2xMPPT 250/100 and 1xMPPT 250/60 on 20 kWh LTO batteries that I want to operate between 50 and 60V.

Unfortunately I do not really understand the absorption and floating parameters in the VE Configure Charget Tab.

Could you please verify and correct my understanding ?


Absorption Voltage is on 59.5 V

Float Voltage is on 59.5 V as well

That means that the Charger fills the batterie up to 59.5 V in "bulk" mode (withouth any amps limitation). At 59.5 it stops filling it and now I tries to stay as close to 59.5V as possible.

The difference between float voltage and absoption voltage is not clear to me.


Repeated Absorption Time is on 0.5hrs, absorption intervall is on 1 day, absoption time is on 2 hr.

That means that after 2 hours of absoprtion ... what happens ? I have no idea .... same for the 0.5V parameter.

Please help me to understand these seetings :)



gawan asked
alham edited ·

2 Answers

Blue solar mppt 100/30 going to float too early

Hi I’m very new to this so please bear with me, I have been reading a lot of this forum to try and learn but hoping someone can help me put my unit to the right settings to make it work!

I have 3x120w mono panels

connected in parallel to my blue solar mppt100/30

Charging 2x numax xdc27mf 95ah batteries

Batteries currently reading 11.7v and charger is on float! How do I make it charge. Unit is currently on setting 2 which I believe is correct for my batteries... help please!

markpostles asked
christopher-maric answered ·

1 Answer

Float and absorb voltages

Have some supersafe 2T1000MJ batteries wired for 24v. They only publish recommended float charge voltage 2.280Vpc at 20℃ or 2.265Vpc at 25℃

Setting configuration on Bluesolar 100/50 (easysolar 1600) I would assume a float of 27.18v @25degrees c. Can anyone tell me what I should be aiming for with absorption? Assuming keep equalise turned off?

Anything else I should be looking at changing?


michael211 asked
JohnC answered ·

1 Answer

Spike in charge voltage and float voltage to high?


Hi all,

Connected to a multiplus 12-2000 are 2 x victron agm 230 super cycle in parallel.

Since yesterday i suddenly had a spike in charge voltage up to 15,61 Volts. After that the multiplus went into float stage and for 24 hours now wont be under 13,99 Volts (around 0,5 amps) , wich seems to high for me. Also, storage mode want kick in. Storage voltage is set at 13,35

What happend here?is this something due to adaptive charginf? Batteries are new so i am careful with it.

Best regards and thanks in advance.

piet-hein-van-asselen asked
piet-hein-van-asselen answered ·

1 Answer

Is 13.7 float voltage too high

I have recently changed to a Lithium Super Pack 12v/200Ah. My MPPT controller does not have a setting for lithium and the float rate is 13.7v. Is this too high?

mike-lewis asked
Stefanie answered ·

1 Answer

Load goes on/off on full batteries, system wiring ok, (after connecting load to the batteries directly, Load port still keeps tripping on/off even when nothing is plugged to it....

UPDATE : Connected load directly to the batteries, And the load port keeps tripping ON/OFF every second or less. :( it makes me think maybe my Victron MPPT needs servicing...

Hi everyone,

So I'm still with no load on full batteries, load is pretty small (5 led lights and 2 water pumps) NO FRIDGE (on gaz), also there is an inverter connected, but straight to the batteries without going trough the load of the MPPT, and it's most of the time off anyways, (I use it only to charge my laptop once every 2 days). and until few days ago everything was running perfect :(

So the problem is : Batteries show fully charged, but load doesn't give load.
Can anyone tell me where look for the problem ? I changed the settings only in favor of better preserving the lead acid batteries with the charging infos i got from VARTA... so i changed the "absorbtion", "float", and "equalization"
(absorbtion 14.4V Float 13.4V equalization 15V)... also I selected conventional alghorithm 1 to turn power off when it's 11.1, and back on when 13.1.
both batteries are on 13.6 right now and both yellow and green lights are constantly ON.

My system :
200W 24V solar panel
Victron MPPT blue solar 75/15

2 Varta LFD90 (90Ah) Lead acid batteries in parallel.

Phoenix inverter 12/375

Any Ideas ?

leonman247 asked
leonman247 edited ·

0 Answers

SmartSolar 150/70 showing float when in absorption


I recently updated firmware of my SmartSolar 150/70-tr and now it's doing weird things. It goes into absorption for a few minutes and then jumps to float. However what is being reported and what it's doing are not the same. It's clearly still operating as if it's in absorption but showing float. The load when I took the screen shots was 150W.

Any help/instructions would ve very much appreciated. We live off-grid and depend entirely on our solar setup.

Many thanks,







onechanet asked
onechanet commented ·

3 Answers

MultiPlus 12/3000/120-16 - Low Power on absorbtion/float


i have a Multiplus 12/3000/120 setup inside my van. Everything works fine. The System is connected to shore. The Battery is fully charged.

Now i connected an electrical heater (2000W) to the system. The heater is the only thing connected.

Usually the Heater should consume around 2100W. Connected to the Multiplus it doesn't use more then 1700W and the heater isn't getting warm as usual. The Multiplus is in Absorption mode. If i disconnect my shore cable, the consumption is around 2300W and the heater is getting warmer and blows faster. The MultiPlus show inverting and the Battery gets empty (as expected ;) )

Any Ideas why the heater is getting less power on shore connection?

Max. shore Current Limit is set to 16A/230V. Charging the Battery (additionally to the heater) with 1200W works fine. All in all providing at least 3200W from shore is working fine. VRM shows 8A usage when heater is connected.

But the heater is working with less power.

Does someone has any good idea belonging to this strange behavior?


f00b4r asked
f00b4r answered ·

2 Answers

Orion-Tr DC-DC Converter Settings

I just got my Orion-Tr DC-DC Converter Isolated 12/24 V 15A charger, and what to configure setting for my environment.

I have limited understanding so my questions may be lacking. I will elaborate when needed. Also will appreciate advice and direction to concepts I missed here.

I have multiple 24V batteries in parallel all connected to busbars. Do I run the Output wires to the busbars?

I know my battery's voltage range is 21V – 29.4V. What do I set Bulk and Float to?

My alternator has a fixed voltage of 14.2V.

Absorption Voltage: 29.2?

Float Voltage: 27.6?

Caveat, I plan on limiting my driving to less that six hours a day when I do drive.

What are the Bulk time limit and Re-bulk Voltage Offset?

Oh - and Adaptive Absorption?

Lock-out I assume has to do with chassis batteries. I never want them to drop below 11V. Is it here that I input that setting? (12.3 - 12.9)

Engine shutdown detection, do I set this something like 12v - 13.8v?

Thank you.


Voltage: 24V

Voltage Range: 21V – 29.4V

Capacity: 95Ah (2.3kWh)

Power (Amp): 100A Continuous, 200A Peak

Configuration: 7S 20P


Prestolite A0014949PA

Output 270 amp

Fixed Voltage 14.2V

ajaja asked
marvs answered ·

1 Answer

How long must battery voltage be at at Bulk trigger level before Bulk is activated

AS stated elesewhere the trigger level for Lithium battery 48V system to go from float toBulk is 0.8V below float set value. What I'd like to know how long must this value be valid before Multiplus accepts it. It seems to be around 3 or so minutes but its difficult to to work out

merlepeter asked

0 Answers

My BMS tells MultiPlus-II not to charge or discharge but MultiPlus-II ignors it.

MP-II has the proper assistant loaded.

BMS indicates that is telling MP-II not to charge o discharge, but I see current going back and forth on the battery.


Is keeping the battery at "Float" voltage not considered charging or discharging?


marekp asked
marekp commented ·

2 Answers

Quattro: are we charging long enough?

We just bought a widebeam narrow boat which had a new Quattro fitted a few weeks ago. We understood that we would need to run the engine an hour or so twice a day to top up the Trojan T105 80ah 12v 4x battery bank which is our main source of power. We were briefly shown the bulk - absorption - float process and I’m sure we we’re told that we should turn the engine off when the float light comes on as it means the batteries are full and we could damage them by continuing to charge in float. When we turn the engine off, we have about 12.2-12.4v reading. However, over a period of several hours, running 12v fridge and freezer, watching Tv or charging devices, that goes down to about 11.4/6. Overnight, this causes an issue as our webasto heating system won’t start, presumably to avoid a flat battery.

Are we turning the engine off too early - Should we leave the engine running while in float for longer? And do we need to check that the Quattro was set up specifically for our battery bank - if so, how?

ducksinarow asked
JohnC commented ·

5 Answers

Best float voltage and absorption time ("Energy Unlimited book)
  1. good morning, I have read (not all given my difficulties with English ....) the book "energy Unlimited", and I have a couple of questions.
    I live in a camper with a 300 watt PV system, 30 A mppt regulator and 2 service batteries (1 + 1 or in parallel, Agm 100 ah and cheap start battery 100 ah) and an engine battery.
    The AGM is almost 3 years old and 900 cycles and still works almost at 100%, the start battery for the services was replaced after 2 years and 700 cycles with another similar one.
    I think I use them in the best way:
    Absorption at 14.4v and floating at 13.7v, with temperature compensation with sensor on the battery.
    The average working temperature is 25 degrees Celsius in the Canary Islands.
    My Tracer 3210 regulator is great but has an adjustable but fixed absorption time. Default to 120 minutes.
    However, I copy the algorithm of the victronenergy regulators.
    If I discharge the batteries in the evening, for example Vb> 12.6, I set 1 hour of absorption.
    If 12.2 <Vb <12.6, I imposed 2 h of absorption, etc ...
    The average discharge each night is at 12.55 v.
    However, while reading the book, I had some doubts about the float voltage.
    The book says that a 13.8v float for a long time damages the batteries due to excessive gasification ... especially the VRLA batteries.
    My batteries on average float from 12.00 / 13.00 to 17.00 / 18.00 (more time in summer, less time in winter).
    The alternator supplies 14.2 v and I connect it to the service batteries with victronenergy cyrix, almost only at night while traveling or traveling in the rain, for the fridge etc. So it's not a problem.
    In your opinion, what is the best absorption voltage compared to the usage data I have provided?
    For now I have lowered from 13.8 default to 13.65.
    If I took it to 13.2 / 13.4 v would I get some advantages in battery life or some disadvantages?
    Thanks and I apologize for the length.

francesco asked

0 Answers

Quattro: Question regarding Battery charging

hi new to victron.

I have a quattro 5000. on a narrowboat uk

how long does it stay in float for should the led be lit constantly. my batteries are saying fully charged. there is no draw on the system at the moment but the float led has been on for 16hrs. should there be any noise. it is making a humming noise not the fans.

seddygina asked
tony-c answered ·

2 Answers

multiplus stuck on float (again)

Having sorted SOC reporting (mostly) my ESS setup that reliably kicks into bulk/absorb overnight after battery usage, now will not do so.

Temperatures have increased from the mid 20's to lower 30's and I use DVCC.

My float is set to 54.4V.

Originally I thought that temps had improved the batteries storing of charge, so I increased the overnight discharge level to try force a bulk cycle.

Battery voltage hit 48.8V which is more than 5V below float, so it should change to bulk but it doesn't.

Is temperature compensation lowering the float voltage and the system needs to be 5V below this?

Any suggestions for what to do about this.

I have multiple multis in a similar config behaving the same.

nickdb asked
Mark commented ·

1 Answer

Victron Inverter chargers and float voltages ? why do they not retain ...

Good day all . A question thats been burning me for a while .. given that ive installed alot of lead acid and lithium systems i have been evaluating the charge and float profiles and their results ... i find this alot in systems with Standby application no solar .. and alot with No comms to batteries no canbus or DVCC enabled.. Just a plain backup ..
So Scenarios are such inverter charging battery from the grid and battery permanently connected to the inverter as should be.
the inverter charges up to 100% and reaches 55.7v (16s Lifepo4)
then the system switches to float where is should retain voltage --- NOT HAPPENING
then a rebulk or re absorb should take place in 7 days .. ---NOT HAPPENING

technically a 0.2v per 12v method is used meaning in a 48v system we should get a drop on float voltage of 0.8v to get a reabsorb ... ---- NOT HAPPENING.

Alot of battery systems use contactors and Bms systems internally which account for internal draw from the battery cells . and in which case means that the battery does take some load to retain the voltage from the inverter ..
We get to point where the SOC falls and falls and battery is never recharged with lithium ticked ...

But why would this not take place on the inverter with a predefined float value is my question and why does the deviation value not kick in the recharge .. when lower then 0.8v below float ?

A little more details i feel should be added in .
Two different inverter units, one multiplus 3000va 48v unit
the other multiplus 5000va 48v unit.
Both when set to a float voltage of 50.6 to 50.7 charge the battery to 100% Lifepo4 . 15s configuration .. after this process they dont retain the float voltage of 50.7 ... the battery has bms and circuitry internally that uses power.
Storage Not ticked .
Lithium batteries Ticked on
Both units are used only for power back up purposes and both units have Venus GX connected .. Pulling my hair out .
Please can some one chime in .. I dont want to have to run with DVCC as this is not 100% working and surely the default profile to Float maintain voltage should do its job unless i am missing something often after two weeks or so the voltage of the batteries drops to around 48v .. Not good .

nismoboy34 asked
Guy Stewart (Victron Community Manager) commented ·

0 Answers


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