Smartshunt and Peukert coefficent?? Doubts...

Goodmorning everyone.

I bought victronenergy Smartshunt.

I must say that I am extremely satisfied with the accuracy of all the measurements.

Comparing the readings from TracerAn 3210 Epever and Smartshunt, they are surprisingly nearly identical, in both current and voltage.

They differ only by 0.02A and 0.02V. That is practically zero.


However, I am not convinced that the Peukert coefficient works.

In theory, by increasing the coefficient, the remaining runtime should shorten as the discharge current increases.

But it's the other way around:

for example, with a discharge current of 3 amperes, if I put coefficient 1.5 there is more time remaining, compared to coefficient 1.0.


The percentage of SOC also increases as the Peukert coefficient increases. I expected the opposite.


In my case, the statistics with default coefficient 1.25, seem too optimistic and less realistic than coefficient 1.0 or 1.1.

Can anyone clarify this for me?

francesco asked
francesco commented ·

3 Answers

Synchronize VE.Bus SOC with battery? Select on loss of communication source for genset

Synchronize VE.Bus SOC with battery

Has this item been rolled into dvcc? After some digging here it seems its been removed yet its still in the manual. The last mention of it in the changelog is in the v2.02 – 30 January 2017 Venus Os

Are you guys working on an update to the manual to remove redundant settings to avoid confusion?


loss of communication source for genset

I have a few systems I setup and support with auto start gensets, after a couple of weeks of bad weather one went into LVD during a sustained load at a low SOC. Voltage start timing settings were a bit too long to catch the voltage crash. LA batteries.

I had set start on loss of communication as a third fail safe to start the genset, and had the BMV as the source for genset SOC. However the genset didn't start as the BMV was still active yet the multi had shutdown. I had assumed that it would start on loss of comms to anything on the VE.bus. After rereading the manual, it's loss of communication to the SOC source.

Normally I disable the battery monitor in the multi to avoid the user accidentally changing the source.

I have now reenabled the monitor in the multi, which seems to be tracking the BMV and set the genset SOC source to the multi.

However Synchronize VE.Bus SOC with battery is completely missing so the only indication the SOC is being read by the BMV to the system is that its the same as the BMV.


Seems a rather complicated method, could we simply have this changed so we could select the loss of communication source?


This now raised another question, when performing remote configs through the portal the multi/quattro drops communications to the venus device for a moment. Will this cause a genset start?


alan asked
JohnC commented ·

1 Answer

State of Charge

We bought a used T@b400 with a victron 712 already installed. It does not seem that the state of charge is reading correctly. I shut off the battery and let it sit a few hours - the hand volt meter we are using says 14 volts which is similar to what the victron says for volts but the SOC is saying 27%.

The battery is a C235 so we did set the battery capacity at 235 instead of the default of 200 and we set the full charge V at 13.7

We are not able to see that any power is coming in to the batter either even on a sunny day- it does have the factory solar

We are a little lost with all the technical info on all this but it does not seem that the SOC Is correct or are we not testing that correctly? My husband is putting the volt meter on the leads going from the battery to the converter not directly on the battery - is that ok or should it be right on the battery like you read your car batter?


karent asked
karent commented ·

2 Answers

SOC DRIFT lithium with multi ii, mppt & cerbo

Hello,

I have tried seemingly everything but am obviously missing something.

I have a multiplus ii, cerbo gx and a 150/35 mppt.

The SOC drops by about 0.5V/hour until the alternator is connected.

I have followed all the lithium battery manufacturers suggestions and set the mppt voltage 0.03V above the multi voltage.

The system is going into float every dayand the current falls right off at that point so it's clear that the battery is charged.

There is 1 x 4000Wh lithium self managed battery and 6 x 400W solar so it's more than enough.

Can someone please assist

[image]

elysium asked

0 Answers

Grid SetPoint and SoC

Hey guys,

Very Quick quesiton. If I set grid setpoint as a -ve to discharge battery when spot price is high, can I rely on the SoC setting to stop discharging when the batteries get too low?

What one takes precidence?

Mike

mike-casey asked
Alexandra answered ·

1 Answer

Optimise BMV SOC detection with ESS

I have a BMV712 connected to 4 x 220AH Victron Gel batteries in series, an MP2 3kVA and a 150/45 MPPT using ESS.

I put the bmv in when it became obvious that the MP2 was useless at accurately reporting SOC.

I have tuned the BMV as per docs and some guidance from victron (charge voltage midway between float and absorption, extended the time needed to sync to 8 minutes and reduced the tail current to 1.9%).

This works most of the time, the SOC gets to around 98% and then syncs.


Where it falls apart is if when there are bad PV days and the charge voltage is closer to float, the batteries don't sync. after a couple of days you end up with charged batteries but with a decreasing SOC reported.

When batteries discharge you now hit the ESS SOC limit too quickly (only use top 30%) which means the batteries never discharge far enough to hit bulk/absorption.

You're now get stuck in this float/discharge cycle, with battersafe increasing limits making it worse.

Being unable to force a remote sync means it is a real problem to break this cycle without having to start changing the ESS schedules and limits.


Is there a better way to setup the BMV?

For those doing partial discharge of batteries it isn't difficult to end up in this loop.


nickdb asked
alan answered ·

1 Answer

Bmv 712 readings out of whack

[image]

Hi guys, so I'm scratching my head at the moment for a few things that have been showing on my bmv-712.


1) tonight when I checked via Bluetooth on my battery, it was showing 63% soc, but 11.9V. It is a lead acid battery, 75ah, under bonnet. I double checked voltage, as 11.9V is 40%,not 63%. It was 11.9V. The only thing running is my fridge, and the car was taken out today for a run, which was about 30 mins drive total (2 x 15mins trips) yesterday it wasn't run, and fridge was off. I now have that battery on trickle charge to top it up.

2) when I'm driving I monitor the battery, and the most the bcdc1225d is putting in, even when low voltage is 5A. I've not seen anything above 5A. It goes from say 73% straight to 100%.

3) battery is a century 75ah deep cycle lead, prob 4 months old.


My questions are, should the bcdc be putting in more than 5a when discharged down to say 70%? How do I realign the bmv and battery soc?

System has been wired properly, only battery on battery side of shunt, everything else on load side. Has been running fine for a while, now just seems out of whack.


hairyhaggis asked
michelg edited ·

2 Answers

SOC no longer going below 40% in ESS

Hi,

since a few days,I recognized that my MPII (cerbo + 3xUS3000) does not discharge the battery below 40% even the battery was charged during the day to 100%.

I cannot remember that I changed any settings but I had installed the v2.62~4 and v2.62~5, but went back to 2.60.


Does anybody can help?


hansbaer asked
Izak (Victron Energy Staff) answered ·

1 Answer

bmv712 does not update SoC after manual Loading

Hi

loaded the battery manually.

SoC not updated?


What am I missing?


Thanks T

riker1 asked
riker1 commented ·

1 Answer

Cant sync batteries and soc not accurate pls help

Hi i have a set up that consist of this


quattro 15kva

2x smartsola mppt 150/100

Ccgx

Lynx shunt and lynx distributor

Old 800ah lead acid battery 48v (16pcs 12v 200ah)


Can someone help me? I will be replacing the lead acid batteries with pylontech, but for now i have to use the lead acid batteries while waiting for the pylontech. Cant seem to get accurate soc and sync batteries


running on ESS, battery monitor is lynx shunt

gabo asked
hummingbear commented ·

0 Answers

SOC way to optimistic

I have a challenge with my BMV-700 SOC. It displays to high SOC.


I have a 24V battery made of 12 x 2V 1100Ah AGM cells.They are 10 years old, so they are most likely not any longer 1100Ah of capasity, so I have downgreaded them to 1000Ah in the BMV settings. However that is not the problem (I think)

For the last six days the consumption has been net 8.7Kwh (Very little sun in Norway right now, but we do get a white Xmas)

[image]


The SOC of charge however only drops from 99% to 86.5% indicating a consumption of 12,% of (24Vx1000Ah) = 2.88Kwh - that's clearly incorrect.


What do I do wrong?


[image]

Snapshot right now: 13% <> 250Ah - Does the BMV think I have a 12V system?

[image]







Anders asked
francesco edited ·

2 Answers

Hilfe, mein SOC wird nicht richtig berechnet.

Hallo,

Kann mir jemand erklären wie und wo bei Victron der Ladezustand der Batterien gemessen wird:

[image]


Bei mir ist es so das beim entladen der SOC richtig gemessen wird und beim Aufladen der SOC stehen bleibt, obwohl die Spannung steigt.

Grüße

LayesP

layesp asked

0 Answers

SOC keeps decreasing and remains at 0%

Hello everybody,

My experimental installation is composed of :

  • 1x SmartSolar charge controller MPPT 150-60
  • 1x 60Ah 12.8V Battery from Victron energy
  • 1x Venus GX
  • 1x BMV 712 Smart

[image]

I have an issue with the SOC that keep decreasing and now remains at 0%, even if the charge controller is in “bulk” mode. In facts, I tried to let the battery charging for a long time and I synchronized the SOC at 100% but it decreased just after slowly to 0%. I also checked that my shunt was correctly wired and there are no other wires than the battery on the “only battery” side of the shunt. So I guess that the shunt is not the problem.

Does anyone know how could I keep the SOC synchronized? I tried to modify the Tail current, Peukert exponent and the charge time detection as followed :

[image]

Do you think that I have to re-adjust those parmaters ?

Here is the SOC remains at 0% :

[image]

Thanks a lot for your help !

Have a good day !

Justin


justinp asked
jwfrary commented ·

2 Answers

SOC = 0% on a full charged battery.

My question is, should I move the sending unit wire from the Magnasine from the battery to the load side of the shunt to get an accurate SOC reading

david-brooks asked
Justin Cook - Bay Marine Supply USA answered ·

1 Answer

multiplus SoC not syncing to 100% (mains backup system)

Hello,

I have a system with:

1 x MultiPlus 24/3000/70-50 firmware 476 (but problem predates this firmware too)

4 x Trojan SAGM 06 375

for mains backup.

----------------

Edit 2020-11-24

Having clarified a few things since first opening this post I'm listing here the key points as I see them:

The system is not triggering a bulk/abs cycle after anything except a very deep discharge. I.e. it returns straight to float after small to medium discharges.

This means that over time, with several small/medium discharges the SoC indication gradually drops off, when really it should return to 100% once mains returns after such discharges.

I have been told that, by design, the bulk/abs cycle is triggered when the battery voltage drops below 26.2V (2.6V, for 24V systems, below the set absorption voltage of 28.8V). This is happening here, yet the bulk/abs cycle is not activating.

----------------

Original post:

The SoC indicated by the system will not sync to full for long periods of time, which results in the system always showing well less than 100% even when in float. Please see the VRM screenshot below.

I raised this issue somewhere on Victron community/disqus a good while back, but can't find it anymore! We never got a resolution, but I recall it was discussed that the reason was:

i) the battery voltage doesn't drop low enough under the brief discharges/small loads to trigger a full bulk/abs cycle (the SoC does reset to 100% on the rare occasions this does happen).

ii) the repeated absorption feature (which is set at every 7 days on this system) does not trigger a SoC reset on completion

I'd be very grateful for any ideas on how to resolve this, especially now as the system is using the new "shut-down on SOC" feature, which means the batteries will be cut off sooner than necessary due to starting with an already low SoC.

Many thanks

[image]

Edit 2020-11-02

I've added vrm screenshot to compare charts for the same mains failure event for this system and another very similar system (only differences I can think of are 48Vnom/375Ah vs 24Vnom/375Ah and CCGX vs venus GX). This system goes straight back to float, other system goes through bulk/abs cycle.

[image]

Edit 2020-11-24

Just adding another screenshot here as we've had some interesting events over the last three days. Of note is how a bulk/abs cycle was triggered by the full discharge to 40%. However, the most recent discharge to 80% didn't trigger a bulk/abs cycle. I'm wondering if perhaps somehow this system has the bulk/abs cycle voltage level trigger of a 48V system even though it is a 24V system?

[image]

colin asked
colin edited ·

1 Answer

MultiPlus SOC dropping when charger in Storage mode and inverter is off

Hi

I recently set up a small UPS using a MultiPlus 12/800 and a 105AhC20 AGM battery. Everything works as expected and I'm also running Venus OS on a Rpi 3B to be able to monitor the system.

The MultiPlus is working as standby UPS (no ignore AC settings), so it only uses the battery/inverter if AC goes down or misbehaves.

Battery Monitor on Venus is set to MultiPlus on VE Bus.

I noticed that SOC keeps dropping about 0.5% every day. This should not happen as the battery voltage is 13.4V (temp. comp.) and no load is applied. I also see a strange random load of 1A being drawn from battery. This is probably related.

I was able to catch one, see below...

[image]

I been thinking...

Is this maybe caused by temperature compensation? (temp raising so charger lowers the voltage maybe causing false current readings?) If so, this can also confuse SOC calculation?


Any thoughts and help would be very much appreciated.


UPDATE:

So, if we had solar/external chargers or loads connected we shouldn't use the MultiPlus to calculate SOC, but if we have a basic setup like mine, with no external charger/loads, I think that would be a good idea that internal calculation could hold SOC at 100% after entering storage mode and if inverter was not being used, so it would ignore 'noise' readings like the ones I get that I think are caused by temperature compensation adjusting voltage.

[image]


moonlightrider asked
richardp63 answered ·

2 Answers

BMV-712 - How to keep SOC between restarts

Hello,

I have a system powered by a Li-Ion battery and I installed a BMV-712 to monitor the SOC, current consumption and voltage.

If I leave the battery always on, I have no problem - the monitor will detect everything, goes through charge cycles correctly, etc.

However, when I power the system down (i.e., turn off the battery) and power it up again, the voltage output of the battery is bellow the set "charged voltage" but the SOC reads 100%. If I uncheck the "battery starts synchronized" setting, it shows ---.

Via the manual, I know this is the default behavior, but is there a way to preserve SOC between resets? The load system has safety equipment that must be always on when in operation and must be connected directly to the power supply (sourced by the battery) and that consumes a lot of current, so leaving the battery always on is not an option.

Can I achieve this via VE.direct? I have an embedded controller that could store the SOC and be used to set last known SOC through the VE.direct port when powered up.

Thank you for your time

danielfz asked
klim8skeptic answered ·

1 Answer

Victron bmv 12 reading nanm

Last night my victron system shut down. Today I have charged the two 100ah lithium batteries. The BMV is showing 12.8v in the batteries but will not show any SOC information and in the time to go section it says nanm I can't find anything about this in the manual. The system is still working as I have power at the moment but I am.still concered I have damaged the batteries.

Many thanks for any information


oldelbow asked
danielfz commented ·

0 Answers

Unexpected relay behaviour - Multiplus 48/500 controlling generator switching on/off at minimum run duration

Hi, very confused, appreciate any views...

have a Multipus 48/5000 configured to close relay to start generator at defined SOC. Which it does.


However rather than running until SOC condition met, it runs for the configured "Minimum Run Time", stops, then 2 or 3 minutes later starts again...and so on until the SOC condition is met.

Maybe I have misunderstood, but I expected the "Minimum Run Time" to set a lower run limit in case the condition which initiated the start was resolved faster? Not to turn off the relay after that time, then re-assess all the conditions again?

Thanks!

energetic61 asked
energetic61 answered ·

2 Answers

Wrong battery percentage on the BMV712?

I've just bought my first sailboat, with a fancy bluethoot system for reading the stats of the battery and solarpanel.

But my question: The panel (BMV712) shows a battery percentage, and its dropping when there is laod on the batteries - still all good. But the percentage keep dropping even if I connect the shorepower and the batterycharger. This weekend I tried to watch it, and shut down all power when we left the boat for aproximately half an hour. During that time of the boat, the percetage raised from around 44/45% to 100%. The charger gives up to 30A, and the batteries are 2 x 100Ah, so it is not possible that the charger should be able to fill up the batteries so quickly...


What could be the problem?

eirik-stabell-rodsand asked

0 Answers

Within 2-3 days SOC dropped from 90% to 7%
Hi,
As you can see from the attached graph SOC dropped from 90% to 7% in the span of 2-3 days.  The system has been up and running since June and nothing like this have happened before. The consumption has been more or less constant for a long time (25W) and the only thing that draws power directly from the battery is the CCGX.

Could this drop be a result of some “maintenance” routine initiated from the CCGX or the BYD BMU/BMS?

The system consists of the following components:

•Color Control GX
•MultiPlus-II 48/5000/70-48
•BYD B-Box Pro 7.5
•SmartSolar Charger MPPT 250/60
•
Regards
Sveinung

[image]

sveinung asked
sveinung commented ·

2 Answers

ESS assistant charges and discharges the battery continuously when there is not enugh PV, why?

I know that my question pretty much describes what the ESS Assistant should do.

But is there a way to prevent continuous charging and discharging?

My AC loads are mutch higher then what my PV is generating, this is why the ESS Assistant draws current from the battery until my desired SOC is reached but then it swiches of the inverter and is slowly charging the battery with PV and after charging 5% above minimum SOC the inverter turns on and quicky emtys the battery down to minimum SOC. Since my AC load is always greater than what I can generate with PV. It would make much more sense to feed the generated energy directly into the grid to help power AC loads. There is no ecess power, so why always charging 5% of the battery and then quickly emtiy the 5% at maximum current.

I would prefer a constant output power when the AC Loads are higher then what i can get from the PV and then only store excess power in the battery.

Thank you for your Help.

felix-vt asked
layesp answered ·

5 Answers

BMV-712 capacity discrepancies

Hello, Group. I'm using a BMV-712 with a Relion 100AHr LiFePO4 battery that I purchased a couple of months ago. Both are in an emergency power battery box I built as a pandemic project. I mostly power computers, phones, and other electronics from it. I also recently acquired a Blue Smart IP67 12/25 charger to charge at 25A, and previously used a West Mountain Radio Epic PWRgate to charge at 10A.

The BMV-712 is configured per recommended LiFePO4 settings: 100Ah, Peukert exponent 1.05, charge efficiency 99%, charged voltage 14.2. What I'm confused by is the following:

Last discharge I hit 11% SOC, and voltage was 11.24 with 4.75A draw. Consumed Ah was reported as 94.5A, however. 5.5A remaining is certainly not 11% of 100Ah. From the low voltage, I'm inclined to believe that 5.5Ah was left, so why is the SOC saying 11%, and how can I align that with actual capacity?

Also, on recharge, SOC reached 100% some time (maybe 20 mins) before the charger output dropped down below tail current. The Blue Smart charger was still charging like gangbusters at 24.37A when SOC hit 100%, with voltage only at 13.92. I think there was around a 3A draw at the time. How can I set this up so SOC is more accurate?

Thanks,

Abe

abeness asked
abeness commented ·

1 Answer

BMV 712 wrong soc

Hi, my battery system has 920ah. After discharging 20% (184ah) bmv shows 87% soc instead of 80%. What settings do I have to tweak in order to get close to the correct soc?

Before all batterys were full and I synced manually. Thanks

[image]

skykay asked
Vangelis Beligiannis answered ·

1 Answer

BMV-702 wont SYNC - LiFeYPO4

First - Sorry
I know it has been asked before, but I can’t seem to find a solution to the earlier posts from other users. So, therefore, I allowed myself to ask.

Setup: My battery is a DIY (Winston 200AHA) project, a 12V system. 8cells in total. Two parallel and series.

From the last cell, the negative terminal is connected to the shunt for the BMV-702 (on the battery side of the shunt), from the load side of the shunt there is a 100A copper bar connected with all the negative connections to loads.

So that must be correct.

Problem: The BMV-702 won’t do the regular automatic synchronization.

Settings of the BMV-702:
01. 400Ah
02. 13.90V (.30 under the absorptions as recommended)
03. 02.0%
04. 01

I know that 03 and 04 normally are 4% and 3 minutes, it didn’t work, so I tried to make them smaller.

Have tried to sync when the battery is fully charged manually, it hasn’t helped.

Here are some screenshots from the settings:

[image]

[image]

sebastian-w asked
sebastian-w answered ·

3 Answers

CCGX menu : Use solar charger current to improve soc

Dear,

Tanks everyone to help me concerning my last topic ( Johon, Alexandra , All others ..

After reading the CCGX Manual and all interrogations concerning the SOC value on this forum, I loocking for this :

(B) Battery with Multi or Quattro and MPPT Solar Chargers -ALSO- An EasySolar with CCGX built-in

No battery monitor is required, as long as all MPPT Solar Chargers are Victron products and are connected to the CCGX. The CCGX will continuously read the actual charge current from all solar chargers, and send the total to the Multi (or Quattro) which then uses that information in its SOC calculations.

Configuration:

  1. Enable and configure the Battery Monitor in VEConfigure.
  2. On the CCGX, in Settings → System setup, verify the selected Battery Monitor. It should be the Multi or Quattro.
  3. In the same menu, verify that the option 'Use solar charger current to improve VE.Bus SOC' is enabled. Note that this is not a setting - it just an indicator of an automatic process.

Note that this feature requires recent firmware versions in both the Multis or Quattros (402 minimum), and the CCGX (v2.06 minimum).


After tcheck my Multiplus firmware ( version 413 and the CCGX version 2.60 ) I find the selected battery monitor but I haven't option to improve VE.Bus SOC ! ?


Do you know why ?

Thanks a lot, Michaël

mika2a asked
mika2a commented ·

1 Answer

How to reset SOC to 100%?

There is one past thread about this issue in which I participated, but it seems the recipes mentioned (and that I've been using) for some reason don't work anymore:

https://community.victronenergy.com/questions/39650/how-do-i-get-soc-to-show-100.html

For the last weeks I never got my system to show 100% again (or 85% for that matter). I've set MPPTs to have absorve voltage higher than what is set on Multiplus, I also made sure the absorption time was higher, but nothing seems to work. Never get to the 85% or whatever is set on the Multi.

I have run out of ideas...

My system is Venus based, no BMV, but no DC loads or charges.

Current Multi Settings are like this:

[image]

[image]

MPPT vales are what you wish.. tried even with 28.8V in absorption today.

See graph:

[image]


Why can't the SOC be recognized as 90% ?

Venus is running 2.60, not since too long ago. Could be something within Venus OS?

I also tried Multi connecting to GRID -> Goes straight to FLOAT, SOC continues at ~30%

This is an old issue... but for the moment, besides trying to figure out the root cause for the system not resetting every day to 85/90%, what I would like to ask now - as a workaround - is how to manually force the system to reset to 100% ?

I used to do the trick of commanding the Multi to Equalize from Grid and then Interrupt -> go to absorption / Float. It used to reset to 85% (that was at the time set). But now even this is not working.


elimac asked
rubas commented ·

6 Answers

Feature request: Dynamic Grid-Setpoint in ESS, based on top SOC.

Currently the Grid-Setpoint in ESS is a static number (in watts) that controls how much system power is allowed from grid, with the remaining load being served by incoming solar and/or battery capacity, down to a tolerable SOC. While that works great in the assumption of keeping batteries @100%, every day, it’s not so good for long-term health and maintenance of lithium batteries, in a (stable) grid-tied system.

I would like to suggest an upper limit to the SOC (other than default 100%), at which point the ESS would dynamically shift the load more/less (by changing Grid Setpoint) to charge the batteries when they’re below the high mark, and otherwise running the load off of solar or battery capacity, down to the existing minimum SOC (as normal)... or similar type of functionality.

Currently, I’m constantly changing the Grid Setpoint down, to serve the system loads from the incoming solar preferentially, as much as possible. Then resetting it up again at night, to keep the batteries above a reasonable SOC. While workable, it is way more manual than it needs to be.
I believe adding a simple top SOC to the algorithm that controls when to shift to using solar would greatly simplify and automate this process.

geomz asked
lucode commented ·

0 Answers

SOC measurement issues

With a BMV712, shunt that is correctly wired and an ESS MP2/Smart solar MPPT setup (victron gel batteries), I have continuous issues with reported SOC and what it does with system performance.

I only use the top 30% of battery for use overnight.

On a good day, SOC gets to around 97/98% when the shunt will sync the SOC to 100% (my shunt charge voltage is midpoint between float and absorb at 55.4V).

The problem comes in if there has been a bad light day, or like now in warm temps (31C) the inverter decides to not do a bulk/aborb cycle as the voltage is at a temperature adjusted float voltage and can't trigger the sync. The only change in the environment is temperature and with increased cooling loads ESS hits the minimum SOC threshold very early in the morning.

The inverter stays permanently in float. Unless I manually sync the SOC, it will continue to slowly leak, which means there is less discharge by night.

I have several installs all doing the same thing where before the increase in power required at night and the increase in temps it worked fine.

Trying to get assistance with this is near impossible.

The shunt should be able to do a better job of measuring the SOC.


nickdb asked
JohnC commented ·

1 Answer

Defined high/low state of charge limits

I have a victron 48V bank (4x200Ah smart), bms, smartshunt, cerbo, BlueSolar Charger MPPT 150/45, batteryprotect, li-charge and multiplusII (yes, all in on victron stuff :) )

Goal is to have it autonomous as much as possible.

Currently when charging, the systems always tries to charge to 100% where the bms is shutting down multiplus and the li-charge relay where the solarcharger is connected. As I don't want the batteries to sit at 100% for long (which they then will do during summer months when we have plenty of sun) in order to keep battery lifetime as good as possible, I'd like to define a upper limit like 75% SoC perhaps. The system should then try to charge to 75% and at that level only add energy (via solarcharger and/or multiplus) as needed in case of load to keep it at 75%. And yes, I would need to now and then charge up to 100% so the SoC measure isn't drifting off. The manuals suggests once per month so can be a manual thing todo, perhaps with some notifier via VRM...

Similar for the lower limit... instead of bms shutting down load at battery protection level, would be nice with a definable lower level like 35% SoC. Have not so much experience of this part of the energy envelope as the system so far coped good with load :)

This would also allow one to test and make sure the protection mechanisms will work, without having to actually be at the edge of safe SoC range.

Haven't found howto do this, or should it be possible?
If no, perhaps add as a enhancement request?

saxofon asked
saxofon commented ·

1 Answer