absorption Image


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

Absorption and float value

Hi all,

Apologies if this has been asked before, I have 12v batteries in series to give 24v and using a Multi 24/5000/120 , my query is, do i configure absorption and float values as per individual battery ( 12v ) or as per the series 24v ? Thanks!

cmez asked
cmez commented ·

1 Answer

EasyPlus Compact 12/1600/70 sudden restart during end of battery charging during Absorption

I am running firmware v485, and my EasyPlus is attached to a 200Ah LiFeP04 battery with on board BMS.

I am testing the system in lab before final installation and I noticed this behaviour.

I lightly discharge the battery using the inverter, let's say to 13.09V


The I attach the mains and the charging starts. First the bulk phase kicks in at 50A


Then it soon enter the absorption phase and current decreases:


Suddenly the Inverter and Charger switches off without any warning or errors. It comes back online after few seconds.


It then enter again insto absorption phase where it stays permanently at 98% drawing 0A


I have tried the above with and without AC loads connected but it's alway the same. The EasyPlus kind of "restart" during the current ramp down of the absorption charge and reconnect staying in absorption at 0A and 98% forever.

Any idea?


amidships asked
amidships commented ·

1 Answer

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

Reenter absorption ?


In cloudy weather i see that the charger get's out of the Absorption before the battery is charged fully. I see the battery at 85% then the absorption ends and later during the day i might get sun but the charger won't get into Absorption until it get's back in Bulk is after 0,8V lower than Float so therefore the system would send the overflow of energy to the Grid which is wasted since i could charge my battery instead. I know i can enter Absorption using dbus and i tried it few times and it worked but i am not around to do that every time. Is there a way to configure the system to reenable absorption when the SOC is still not 100% and there is more energy that is not beeing used ?

I have a Multiplus II and a SmartSolar together with a Cerbo GX.


peternielsen asked

0 Answers

Absorption Vs State Of Charge

Hi there.

A few disclaimers firstly:

I appreciate that SoC is not an exact science, depends a lot on chemistry and settings.

I have also ensured that the settings are such that the SoC doesn't switch to 100% too early

I have a 560aH flooded lead acid batteries (less than 6 months old) with 3 X MPPTs, SmartShunt and a Multiplus.

So heres my question:

I have read a number of Victron litterateur that absorption should start when the batteries are about 85-90% full. Where as on my SmartShunt, the SoC is often at 97-99% when Absorption starts. To put it into context, my usage is such that when my solar chargers start in the morning, I have used about 75aH overnight which is approximately 15% of capacity (again, I know there's no way of know that without testing). My SoC reads 87%. Perfect, about what you'd expect. The batteries are then charged during the day at about 7amps per hour for 10 hours. They then switch to absorption for the last 3 hours when SoC is is about 98% and go to float after 3 hours absorption. (3 hours absorption based on adaptive charging on my MPPTs).

So based on the above, I would assume that the SoC is working as expected, and my interpretation of "SoC=90% when absorption starts" is incorrect? Any ideas?


lawrence-craig asked
pwfarnell commented ·

3 Answers

2 x MPPT Controllers - 1 goes onto absorption earlier than the other, HOW TO STOP THIS?

I have two of the same MPPT 75/15 Controllers, one of them goes to absorption mode way before the other, which means I get to my batteries being full at a slower pace.

The settings are both on factory default.

Is there a reason why this is happening and is there a solution to have them both keep running until my batteries are full.

**One controller has 2 panels conected in series

**The other controller has 2 panels connected in parallel

andrew84 asked
pwfarnell answered ·

2 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

Repeat Absorption Interval

Multiplus and Skylla Chargers: Is the repeat absorption interval re-set when power to the charger is disconnected or does charger continue to time the current interval even if power is cycled?

Lithium batteries on a sailboat. Want to control when bats are pushed into bulk/absorption voltage to reduce un-necessary wear. Plan to enable "Watch function" on Skylla (start-up in storage if battery voltage >=13 V.). And set repeat absorption interval to 15 days (to allow cells to re-balance). Want to avoided charger from entering bulk/absorb voltages when charger is plugged back in if batteries are at or above float/storage voltage. Concern is the repeat absorption interval will re-set every time the boat is unplugged from the dock and not go into repeat absorption mode if power is regularly cycled inside of 15 days. Charger will always start in storage mode if voltage above 13v. Therefore Bulk/absorption voltage never reached for cell balancing.

tx-sail asked

0 Answers

Lithium - Repeated Absorption

Hi All

Is it bad for Lithium batteries to be going in to bulk / absorption daily - when they probably don't need to ?

Situation is....

  • yacht in marina
  • connected shore power
  • the Multiplus has the batteries in float
  • small 12v loads are being covered by the Multiplus
  • Sun rises everyday - and the MPPTs go to Bulk, then Absorption
  • The multi reduces the Amps as the MPPTs start to provide
  • the result in the batteries are full
  • and the MPPTs are going in to Bulk, then Absorption, every day



miya asked
rslifkin answered ·

2 Answers

Absorption time should be settable to less than 1 hour with lithium

Currently my Quattro (and multi) only allows a minimum of one hour of absorption time on initial charge (even though it allows .25 hours on repeated absorption).

My (and arguably most) lithium batteries require very little absorption time. So forcing them into a 1 hour absorption is both unnecessary and potentially causes extra wear on lithium batteries.

I would like to see the base absorption time settable to, at the very least, the same levels as with repeated absorption, or to even smaller window sizes.

Ideally I'd put my batteries in 10 minutes of absorption.

geomz asked
carl-n commented ·

4 Answers

Does VictronConnect show when my Multiplus is in "forced" Repeated Absorption mode?

When my Mulitplus goes into Repeated Absorption mode, does the VictronConnect app tell me?

Similarly, does the Mulitplus itself tell me when it is in Repeated Absorption mode, via certain lit LED's?

From a search of the Manual, the answer appears to be "no."

So then a Feature Request, asking for an indication when the Mutliplus is in Repeated Absorption mode, so that I don't think it is in a "runaway" condition when I find it charging my battery to Absorption, even though my voltage (or setting) doesn't call for a recharge.

pmikep asked
pmikep edited ·

0 Answers

New victron agm battery accurate solar charging parameters
Hello I just bought a victron deep cycle 110 ah agm to replace the old battery after 3 years.
I would like to ask a Victron technician for the correct parameters.
I only use a solar charge with a fully configurable 30A mppt regulator.
Every day the solar energy is more than enuff to charge completely the battery. 
I discharge the battery every night on average about 20 ah.
I would like to know the correct absorption voltage and the correct duration of the absorption for my use (daily discharge of 20 ah).
Currently I have set 14.5v and absorption duration of 120 minutes with temperature compensation of - 4mV / C / cell. Floating 13.7v.
Today for example after the end of the absorption, the battery absorbed 0.8A in floating at 13.7V.
But trying to increase the floating to 14.5v, I saw that it went up to 2.6A. These is strange for me... 
Does that mean it wasn't fully charged? Or is it due to gas generation?
Then disconnecting the solar panel, after an hour the battery was at 13.5v, so it would appear to be fully charged.

The old agm, at the end of absorption, absorbed 0.8a for both 13.7v and 14.5v.
Why these difference on new battery? 
I can see all these parameters on the victronenergy smartshuunt.

francesco asked
francesco commented ·

2 Answers

Soc 100% at absorbtion beginning

Hi folks!

On my system, SOC reaches 100% about 1 hour before the end of Bulk while full sun at 10:00. I thought that Bulk could only fill 80% of the battery capacity and that absorption was designed to fill in the remaining 20% and reach fuil SOC. I set BMV with the C20 Ah capacité Where am I wrong?

Lionel SEYDOUX asked
michelg edited ·

5 Answers

Voltage Spikes, System Failure, MultiPlus Absorption Transition During Charging LiFePO4

System Design:

I have 3 Lion Energy UT1300 LiFePO4 105Ah batteries. They each have an internal BMS and are the 'drop in' replacements for deep cycle Lead Acid batteries. They are rated for maximum 100A charge / 150A discharge each and are connected in parallel using 4/0 AWG cables. On the negative terminal I have 12" 4 AWG cable to a BMV 500A shunt and then 24" 4 AWG cable to a Lynx Shunt. On the positive side I have 24" 4 AWG between the battery bank and a BlueSea m6000 disconnect switch, then 12" 4 AWG from the switch to the Lynx Shunt. The Lynx Shunt is connected to a Lynx Distributor. Then I have a MultiPlus 12/3000/120 connected to the Lynx Distributor via (2) 36" 4 AWG cables and a 400A Mega Fuse. The Lynx Shunt has a 800A CNN fuse. The MultiPlus has the voltage sense connected using a fused 20 AWG wire to the battery terminals. I know the 4 AWG wiring is not ideal, I will replace with larger wire in my final installation, I don't know if it is the source of my issue. Here is a crude wiring diagram



I can discharge the batteries fine, the problem occurs during charging. When the MultiPlus transitions from Bulk to Absorption problems occur. They range from interrupted charging (Absorption voltage set to 13.9 - 14.1) to complete shutdown of the MultiPlus (Absorption voltage set to 14.4 - 14.6).

Here is a picture of the PV during charging showing the transition between bulk and absorption. The absorption voltage is set to 13.9, the unit seems to stop charging after the transition to absorption.


Here is the picture of PV when the MultiPlus absorption voltage is set to 14.4 Volts. The drops during the absorption mode represent when the MultiPlus shuts down and then resets itself. During the shutdown all lights are off and AC1 is off. NOTE: The voltage spikes seem to follow the current peaks. The MultiPlus will continue this interrupt cycle indefinitely until I intervene.



1. Has anyone else seen this behavior?

2. Could this be caused by the BMS shutting down during charging?

3. Could this be caused by using 4 AWG cable?

4. Could the MultiPlus design be causing the voltage spike?

5. What would a normal PV chart look like during absorption mode? I have read absorption mode is a constant voltage with reducing current until charging is complete.

Thanks in advance for any help.

mtnscott asked
davesnothere commented ·

4 Answers

Nach Update auf V1.50; Warum lädt der MPPT 75/15 Laderegler nur noch in Erhaltungsspannung (Bulk) ?

Hallo, wir haben einen Smart Solar MPPT 75/15 an einem 110 Watt Solar Panel und einer 225 Amp/h Batterie installiert.

Vor dem Software Update auf V.1.50 hat das System toll funktioniert.

Bulk und Float alles ok. Siehe bitte Foto.

Nach dem Update auf V1.50 kennt das System nur noch Bulk - Ladung.

In den Tagen vor und nach dem Software Update waren keine Stromverbraucher aktiv. Auch sonst wurde nichts am System verändert.

Wir haben nun seit 3 Tagen Verbraucher hinzugeschaltet. Das System lädt weiterhin nur in Erhaltungsladung - Bulk weiter. Die Sonneneinstrahlung ist in den Tagen vergleichbar.

Warum lädt der MPPT 75/15 nur noch in Erhaltungsspannung (Bulk) ?

Gibt es ein neues Softwareupdate? Oder kann man auf die alte Software Version zurück wechseln?

Vielen Dank schon einmal im voraus für die Informationen.


wesso asked
harald-tedesco answered ·

3 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-II 48/3000/35-32 with LiFePO4 and DalyBMS not doing correct absorption cycles

I have a Multiplus with 16 cells of LiFePO4 batteries (48V setup), hooked up to a Daly SmartBMS.


Currently it is setup as a UPS. Following settings are used:


And on the panel ESS mode is active with following settings:


Scheduled charging is on at 24/7.

I have not put it on 'keep batteries charged' because that gives very strange errors, hence it is on 'Optimized' with minimum SOC 100%.


Now I see the following when the system gets to 100% SOC, when it does the trickle charging as set above, however it exceeds the 55V and runs to 56V (goes above the absorption voltage?) and that is the moment the Daly BMS over voltage protection disconnects the battery which results in a short blackout until the entire system restarts:


In detail:


Anyone any ideas on how to solve this? Thanks!

frefre82 asked

0 Answers

Blue Smart IP67 12A Charger - Firmware


Has there been a firmware update to the Blue Smart IP67 12A charger or the VictronConnect app so I can set the aqbsorb time to less than an hour? Not being able to set this to less than an hour does not make any sense unless this was a coding error. I am in the process of commissioning some SimpliPhi 24VDC 3.8 batteries and the absorb is to be set to 6 minutes. The minimum I can seem to set this to is 1 hour.

Any workarounds for this on the SimpliPhi batteries?



bdimambro asked
bdimambro 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

SmartSolar MPPT 100/30 Absorption Settings Behaviour

Can anyone please clarify what the expected absorption behaviour is when set this way?

Will this result in getting 4 hours of absorption time unless current drops to 3 amps with voltage at set absorption voltage?

I have read through many posts, many are getting old and changes in firmware may have occurred.


lehrling asked
lehrling commented ·

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

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

Multiplus stays in absorbtion mode for over 12 hours with high voltage and 0 or low current

On a sailboat, we came to a marina and plugged in. Batteries were pretty full already, but started topping off. Multiplus running latest firmware stayed in absorbtion mode, and we started getting high voltage alerts.

The system has lifepo4 batteries and was set to 14.4.v and on the bmv was seeing 14.5 and higher bounces. I was set for 3hr absorbtion and after 10 hours, was still in absorbtion mode. I was seeing 0-2A of charge. I finally reconfigured the mutilplus to drop the absorbtion volaltage to 13.61 so I wouldn't worry about it overnight.

What would cause this to occur? Both the high voltage, as well as it staying in absorbtion?

Other notes: upgraded firmware about 3 weeks ago, we do have solar and those were showing float and 0 current. Bmv showed 100%. Tried resetting the multiplus (power off and on) and it stayed in absorbtion.

svenjoy asked
jwfrary commented ·

4 Answers

Mppt 100//20 equalization won’t exceed absorption voltage

When starting my equalization, the voltage won’t go above absorption limit. EQ should be as 16.2, absorption is at 14.8. Once it starts it won’t go above 14.8, unless I change the absorption limit in the settings. Thoughts? (Yes, these are the correct voltages per battery manufacturer support)

Firmware v1.53



darkwroth asked
Alexandra commented ·

0 Answers

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

Why is bluesolar mppt skipping absorbtion

Mppt is going strait from bulk into float? This is the first time I have seen this. It was charging at around 16A then went strait into float and down to 2A ? It has now done it several times today


robin asked
Alexandra answered ·

1 Answer

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

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

re-bulking and absorption questions

Good day all, i have a couple of questions i hope someone can enlighten me on, i have 4 smartsolar 100/20's on a VE network charging a 600ah vrla battery, bmv-712 also on the network, currently the chargers all have the same settings, float voltage is set at 55.2v, Re bulking should commence at 54.8v after 1 minute, this does not happen, currently the battery is at 54.1v and dropping, charge power is 500w in float at this point, any reason why the controllers won't re bulk? the units never achieve absorption voltage (58.6v) they always cut to float at 57.8v by mid to late morning (lowest morning voltage is 48.75v but is going down every day, lower highs and lower lows). Absorption mode is set to adaptive. Has anyone had similar issues? all firmware is up to date. Cheers, Maxx.

maxxpwr asked
maxxpwr answered ·

2 Answers

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