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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

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
alham answered ·

5 Answers

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

Multiplus-II Absorption and Float - discharging to grid


I have an ESS installation with a Multiplus-II 5000/48, an MPPT 150/85 with 4Kw solar system and a 48V 200Ah LifePo4 battery system (currently no BMS). Absoprtion voltages are 56.4 on the Multi and 56.8 on the MPPT - float at 54.4. There is some behaviour that is concerning me in that during absoprtion and float, the Multi seems to be continuously switching between charging and inverting, this happens during the day where the data logs look more complex due to varying AC loads and MPPT but it also happens during scheduled charging overnight, see plot below. You can see the half-hour absoprtion phase from around 00:20 to 00:50 where amps oscillate between +5A and -10A, then folllowed by a large amp spike (selling to the grid) at 00:50 when it switches to float (I believe this is caused by the drop in voltage - hence the battery needs to discharge current to achieve that. In float mode (from 00:50), the same behaviour continues, going from charging to the discharging.

I feel this is neither good for the batteries nor for the Multiplus - am I doing something wrong or areany of my settings wrong? I am running Mode 1 ESS self optimised.




tkrull75 asked
Jaco Reinecke answered ·

1 Answer

MPPT Controllers Going to Float Too Early

I have a Cerbo GX, BMV-712, and 4 x SmartSolar 75/15 MPPT controllers.

Controller Settings:

Bulk/Absorption Voltage: 14.4
Float Voltage: 13.4

Max Absorption time: 6 hours

Tail Current: 6.0A

Some of the controllers (sometimes one, sometimes two or three) often go into float before the 6.0A tail current is reached (as recommended for my battery bank), while the others stay in absorption mode. The controllers in absorption mode cannot finish the charge cycle (because they cannot maintain 14.4V until tail current is < 6.0A) and the controllers in "Float" mode are not producing (0W) because they are waiting for the voltage to drop to 13.4.

I was under the impression the the Cerbo would coordinate the controllers so they would act in unison. Perhaps I missed a setting?

I am running firmware 2.54 on the Cerbo GX and cannot upgrade yet because I am waiting to get a question answered about using a powered hub since I will lose one USB port currently in use with firmware greater than 2.57. I have read the release notes for later firmware and it does not seem to mention this issue.

Any thoughts on what to look for would be greatly appreciated.

svsimple asked
JohnC commented ·

5 Answers

Float voltage LiFePo4 battery


I have a LiFePo4 12V battery and a Victron smartsolar MPPT 100/50 regulator.

battery présents recommends 14.6V. However default setting of LiFePo4 is at 14.2V for absorption voltage and 13.5V for float voltage. Should I change both absorption and float voltage to 14.6V? Appreciate in advance your help. Friendly regards


amajor asked
amajor commented ·

2 Answers

Low battery in float HELP!

Last night i was awoken by low battery alarm from inverter. Turned it off and looking on the CC app theres only 3 or 4w and my batteries are showing almost empty and its stuck in float. How do i fix this?

Im very new to this and only been in my camper 2 weeks having bought it 2nd hand i didnt install the electronics. Running 300w panel and 3x 120ah batteries. cc is victron smart solar mppt 100 1 20.

Can anyone help im totally lost

borkthebasher asked
Vance Mitchell answered ·

1 Answer

How would i know if my battery charge.

I have a Multiplus II. How would i find out if my battery charge. What is the difference between float & absorbtion.

dina asked
Justin Cook - Bay Marine Supply USA answered ·

1 Answer

Batteries slowly discharging after absorption although there is plenty of solar energy to keep them charged


I have an off-grid system with a Multiplus 24/5000, MPPT 100/35 and a fronius primo 3.0 on the ac out. After the batteries have charged at 100% and the absorption is finished, they begin to slightly discharge althoug there is a lot of solar power to manage the loads and keep them charged. In detail the mppt 100/35 turns of and does not provide power.

The system is working with an ess assistant with "keep batteries charged" enabled. Any ideas?

Vangelis Beligiannis asked
Vangelis Beligiannis commented ·

2 Answers

SOC jumps or stuck


In few last weeks, there jumps up some problems in two of our installation.


1) 2phase - 2x Multi II 5000VA 48V, 9,6 kWh Lead-Carbon battery, 4,92 kWp, Smart Solar MPPT 150/85, Venus Gx

2) 3phase - 3x Multi II 3000AV 48V, 17,2 kWh Lead-Carbon battery, 7,2 kWp, Smart Solar MPPT 150/100, Venus Gx

these are not only installation with these batteries and we have no other problems, so I am certain, that the batteries parameters are set well.

there are 2 problems:

1) there are high jumps in SOC

2) once per 2-3 weeks the SOC stucks at some point and ESS stuck in float and system needs to be restarted to correct the SOC.

With our clients I have found out, that there is some weird behaviour, when the water pump or water level sensor (1) client doesn’t have water level sensor so it looks like, there is problem in water pump (230 V) which causing energy to returning to the system (it runs with the grid disconnecte). At the other client (2) I didn’t found problem in Water pump, but it looks like, the energy returns is caused by Water Level sensor.

Excuse my English please, I am better in reading then writing.

Thank You!

Stanislav Vávra asked
Stanislav Vávra commented ·

0 Answers

Float mode drops down below configured value


Suddenly my Smart Solar MPPT 100/15 has the following problem

The batteries goes up to 28.8V (Bulk voltage) goes to absorption (1A)

(2x12V lead acid batteries)

but applications shows me that goes only 0.2A to battery after some minutes goes to float which should be 27.2 but drops down to about 26.6 because the current for load comes from the battery... and after some second goes again to initial load and so on...

This is strange because the current for the load before came from the solar panel...

I have a 280W solar panel and load is only 85W when charging batteries 130W ....

So what could be the problem?

Defect batteries?

Batteries are normal auto batteries 75Ah each acid, calcium

Should I initialize an equalization cycle? (Never done until yet, they are about 4 month with this setup and 1 year in total use...

tkmbe asked

0 Answers

250/85 going to float 150/70 x 2 still in absorb

I just expanded an existing installation by adding a 250/85 to an existing system with 2 x 150/70 charge controllers . All wired up this afternoon, but the new charge controller is just sitting in float rather than charging as well. The old chargers are in absorb and the new addition goes straight to float, meaning the new array is not doing anything . Is there a fix for this ? One thought I had is the the 150/70s are using the adaptive charging ( which I cant change) and the new one I have set to fixed absorb time . The 250/85 didn't even run through its full absorb time before going to float

thanks in advance

jdm asked
jdm edited ·

2 Answers

How do you change the float voltage on an EasyPlus Compact?


The default float voltage on my EasyPlus Compact (12 volt, 1600 watts, 70 amp) is 13.8. This is too high for my LifeLine AGM batteries which require a float of 13.4 volts.

The float voltage can't be changed using the dip switches and the VE Configuration tools for VE.Bus Products software download that is available on the victronenergy.com web site only runs on Windows and I have a Mac.

Given the above, how do I change the float voltage?

Thank you

Allan Fraser

allan-fraser asked
Justin Cook - Bay Marine Supply USA commented ·

2 Answers


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