did anyone get a good setup of the DIYBMS with Venus?
For me, it is discharging around full charge, charging again and doing so at high power.... instead of pulling the current at sufficient PV power from the MPPTs.

Dynamic cut-off is an option only available on systems running as ESS, i.e. the ESS assistant has been installed and configured on the inverter device, and there is a GX gateway present on the system.

AFAIK, dynamic cut-off exists so as we can set a lower cut-off voltage for when there is a large current coming from the battery, since the battery has not actually been discharged, but all that's happening is extra voltage drop due to internal resistance and such, i.e. when the load is lifted, the voltage wire rise considerably.

So, I guess dynamic cut-off makes perfect sense for lead batteries, where -for example- you could safely pull a 12V lead down to 10V when there is a 2C load on it.

However, in my opinion, dynamic cut-off doesn't make any sense for Lithium batteries. Why? Because Lithium batteries have a build-in BMS that will block discharging when the battery's minimum threshold (or a cell's) is reached. This will definitely happen when there is a hard load on the battery. So, it doesn't make any sense to adjust dynamic cut-off for a lithium battery at a lower value than the battery's BMS minimum voltage setting. That said, it doesn't make any sense to enter a higher value, either.

So, what's the point of dynamic cut-off for Lithium batteries? Please elaborate.

The Multiplus should switch of the charger when Charge Current Limit (CCL) is 0 and should switch of the inverter when Discharge Current Limit (DCL) is zero, to really ensure, that there is not forbidden charging or discharging.

Currently Mulitiplus is still charging and discharging inspite of zero limits so driving a battery into overvoltage or draining a battery which already signalled discharge limit zero.

There is an issue on githib and also code which seems to solve the problem, but it has not been integrated: https://github.com/victronenergy/venus/issues/736

Also the Multiplus II is not behaving like it is documented in https://www.victronenergy.com/live/ess:ess_mode_2_and_3#running_software_on_the_ccgx_and_using_dbus_paths

It is not possible to disable charging via Modbus register 38.

Hi,

I have a Victron MP2 setup with attached DIY battery (16S, 280Ah). In the ESS assistant, I have set the low values to stop discharging to 46V when discharging slowly and to 45V when discharging above 0.1C. I have not set any value to 47V - at least not any I remember :-)

The BMS is configured to even lower numbers (44.5V).

However, the battery stops discharging in Mode 1 without battery life setting at 32%, 47V. I wonder why it does that and what I have to change to drain it to lower values.

Best regards,

Roger

Je mèn en ce moment des recherches pour évaluer la capacité résiduelle de mes vieilels batteries (OpzS installées en 2012). Pour vérifier SOC dont je ne comprend pas le calcul par BMV, je voudrais mesurer la densité de l'électrolyte. Je cherche un système qui:

• prélève automatiquement l'électrolyte,
• si possible sur plusieurs unités de batteries,
• transmette le résultat via internet

Mon installation:

• Alpes du sud de la France
• 1710m d'altitude
• 2kWc sur le toit (SSE, pente 8/10)
• 30kWh batteries (12 OpzS 1250Ah)
• Gestion entièrement Victron

Vos suggestions sont bien évidemment bienvenues

What's the quietest Victron inverter? thxs

I have a 24kwh battery built from a Nissan leaf. I have added a Batrium BMS system. My battery will not discharge beyond 65%. The settings in the ess are set to 20% in the discharge setting.

Anyone help. It's rather frustrating.i have been over and over the settings

Hello all,

Would be grateful for any help.

Off grid system for my tiny house. I have 2x 380W solar panels in series, 60A Victron MPPT charge controller, and 2x 140ah Sterling AGM deep cycle batteries in parallel.

Its been horrible and misty for weeks now. I moved out a couple of days ago because the charge controller hadn't gotten past Bulk charge for about 5 days. Today I went back at about noon to disconnect the fusebox incase there was any slight power draw. Victron app at this point reported a bulk charge and a battery voltage of about 13.8. I went back just now about about 4 hrs later and now the app reports battery voltage of about 12.8V. Having never left Bulk charge.

Why has the battery voltage dropped when there has been no power draw? It has been a horrible rainy day but I thought it would still manage to put something in the batteries?

Second question. I would like to know how to tell the DOD of my batteries. I came across images like this:

[image]

Which I thought might be useful. But then I noticed that when my batteries are being charged to Float state by my panels, the Victron app reports the max voltage as being about 14.5V, and min as 12.7/12.8. Does this mean min voltage is the more useful data point? This makes no sense to me because this is what the victron app is reporting now even though my batteries haven't made it beyond bulk charge for days.

Some screenshots incase this is helpful.

Today:

[image]

Less miserable weather:

[image]

Thank you all for any help offered,

Jodie

[image]

Hi all

In my setups with a color control connected to a multiplus 12/2000, Victron AGM super cycle 230, MPPT 100/50, i noticed some werid changes in soc. While i only have inverter as load i use the multiplus build in battery monitor . No BMV or smart shunt connected because no need to.

Now and then my SOC seems to change.

While i can control the system by VRM sometimes i have to switch of the inverter to protect from battery drain. While it seems when i set the inverter to off i cant see voltage and amp-usage, i tebd to switch to "charger only" while above mentioned seems visible.

For example:

My battery SOC is 100 % while i charged by generator and solar panel. During midnight battery voltage is.12,9 volts and no amps drawn except multiplus standby amps, around 1 amp.

So SOC seems to be correct. I Leave multiplus on because i need power and slowly battery is draining because of ther is not too much sun and i use more power then solar can breng up.

Battery soc seems to be ok and calculations seem to be in order. After a few days battery SOC reacties 65 percent, Voltage around12,25. While i dont like to damage the batteries and i it is not completely nesacery i turn of inverter and switch to "charger only".

After one hour battery voltage has dropped a bit (also because solar power is less) to 12,15 and battery SOC jumped to 85 percents. 85 percents never matches 12,15 volts, even not without knowing amps drawing.

Build in battery monitor is setup correct with 230 Ah.

Above mentioned happens when i turn inverter off , or to charger only. It seems like build in battery monitor is confused after i switch off inverter?

Is there a solution to this problem?

Best regards and thanks in advance.

Bonjour,

Mon questionnement est certainement basique mais je rame encore un peu sur le fonctionnement de mon installation. Ma maison n'est pas reliée au réseau électrique, elle est complètement autonome. Les anciens propriétaires ont fait l'installation photovoltaïque (en 2015/2016?). 2 PV 250w, 2 régulateurs MPPT 100/15, 4 batteries AGM BTL12/200 (qui ont déjà 5 ou 6 ans mais très bien entretenues), un onduleur Multiplus Compact 24v/1200va/25a, et un contrôleur de charge. Au départ, chaque PV était branché sur un régulateur. J'ai rajouté deux PV 280w car la production était trop insuffisante pour les longues périodes nuageuses. Et j'ai aussi un petit groupe électrogène de 2kw. J'ai mis les PV en série branchés par deux à un régulateur par série (les deux anciens sur un régulateur et les deux nouveaux sur l'autre, soit 2×250w et 2×280w). Alors oui, les régulateurs sont sous-dimensionnés pour absorber toute l'énergie produite par les panneaux mais le vendeur des derniers PV m'a dit que ça ne gênait pas le fonctionnement, l'installation n'était simplement pas optimisée. Il me faut redimensionner tout ça mais je n'en suis pas encore là (d'ailleurs tous vos conseils pour dimensionner une installation sont les bienvenus). Et jusqu'ici tout fonctionne. Mais ce weekend, les fusibles des régulateurs m'ont fait faux-bon. L'un a grillé, et l'autre était en partie mal connecté. Je n'ai pas établi la cause, je n'étais pas là ce weekend mais une erreur de manipulation de la part des personnes présentes pourraient bien être l'origine. Toujours est-il que personne ne s'est rendu compte que les fusibles étaient grillés. Les régulateurs n'ont pas rechargés les batteries qui se sont déchargées progressivement (le frigo est branché en permanence) jusqu'à ce que l'onduleur se mette en sécurité pour éviter une décharge profonde. En rentrant dimanche soir, je réalise qu'il n'y a plus de courant, les batteries sont à 10v, je trouve la panne, je règle le problème, je fais tourner le groupe 2h pour recharger un minimum vu qu'il fait nuit et que le frigo va redémarrer. Lundi, pas de soleil, les PV rechargent très peu, le frigo consomme toujours, hier, pas de soleil, les batteries rechargent très peu, le frigo consomme toujours, en rentrant hier soir : pas de courant, onduleur en sécu, les batteries sont aux alentours de 7,5v! Il est trop tard pour démarrer le groupe (j'ai des voisins). Ce matin, nuageux, les PV produisent peu, je démarre le groupe. Maintenant j'essaye de comprendre.

1) Est-ce que lorsque le groupe recharge, les panneaux produisent toujours ? Les deux modes de productions sont-ils en simultanés ou est-ce que le groupe prend le relais et les panneaux "tournent dans le vide"?

2) À partir de tous les éléments de puissance décrits plus hauts, combien de temps dois-je faire tourner le groupe pour recharger les batteries ? Quelqu'un peut-il m'expliquer quel est le calcul ?

3) Les batteries sont descendus à 7,5v, elles ont passé la nuit comme ça (environ 8h). C'est des batteries AGM. Quel impact sur leur durée de vie ? Dois-je envisager de les changer rapidement ? À quel point peuvent-elles supporter ce genre de décharge profonde (sachant que c'est la première fois) ?

Merci pour vos réponses. Je ne suis pas hyper au point sur toute cette technologie mais j'essaie de comprendre et je progresse doucement.

We have recently installed a BMV712 on a syndicate owned boat and I am trying to understand what it is telling me. The boat has two 12 v Victron 220Ah batteries wired in parallel. He last discharge and average discharge have been showing 0Ah, so I have just changed the Charged Voltage setting from the default 13.2 v to 13.5 v hoping that this will give more information before resetting.

The thing that really puzzles me is that the Deepest discharge is shown as -543Ah and min battery voltage 4.17v, although the number of full discharges is showing as 0.

I don’t know what other syndicate owners have been doing with he boat but can these readings be right? I don’t understand how the deepest discharge can be -543Ah when I understand the maximum battery capacity to be 440Ah. Also, how the min battery voltage can have got to 4.17v when there is no indication of no full discharge.

Can anyone please advise if I am misinterpreting the data and, if not, whether I need to have serious words with the other syndicate members bout how they are treating the batteries?

Hi, i have a off-grid system build from a SmartSolar 100/20, a SmartShunt, a Phoenix 24/2400 and 16x Hawker SBS40 as 8P2S.

These are connected to a VenusOS-Raspberry via Original USB adapters and everything basic works as expected.

Now i search for a way to tell the Phoenix to only switch on, if the SOC is above 50%, to keep my batteries safe.
But I cant find any Option for doing so, only for using cutoff voltage, which feels a bit stupid to use when there is a known SoC% aviable to the system.

Best regards
Miriam Schwarz

Hi,

I’ve installed a phoenix inverter 12/3000 that is connected to a 100ah lithium superpack in my RV.

I would like to connect a 2nd 100ah lithium superpack in parallel, but this one has a max discharge rate of 50ah instead of 100ah max discharge as on the first battery.

Would that be a problem, as the 2nd battery will discharge much faster & they will have two very different voltages for charging?

Is there a way to mitigate this problem by adding a standalone charger to the 2nd battery or is there another solution I haven’t thought of?

I realize I need to charge both batteries to the fullest before connecting them in parallel so that they will have minimal difference between their voltage.

Thanks in advance!

Eli

Hello Victron Community,

We have the Lynx Smart BMS connected to one 12,8V / 200Ah Lithium battery. I think usually the battery capacity used with the Lynx Smart BMS 500 is bigger. Therefore the capacity reserve after going into hibernation mode is also bigger.

In our case the Lynx Smart BMS discharges the battery down to 8,5V before it powers completely off. Power consumption in hibernate mode 12V system is 0.25mA - 0.35mA .

MY QUESTION:

Will it be possible to self adjust the discharge floor for smaller battery capacities & switching Bluetooth off to lower the Power consumption in hibernate mode?

The best option would be that the user could self adjust the discharge floor parameter higher than 15% himself. For safety reasons the minimum discharge floor parameter can be 15%.

Relavant passages from the manual:

"Discharge floor The “Discharge floor” parameter is used in the time remaining calculation. The battery monitor calculates the time it takes until the set “discharge floor” has been reached. It is also used to set the state of charge alarm defaults. The discharge floor parameter is fixed at 15%."

"9.3.7. System in sleep or hibernate mode This is indicated by the status LED off and the Bluetooth LED flashing every 3 seconds. The Lynx Smart BMS goes into sleep or hibernation mode once the battery or a battery cell has been deeply discharged. The Lynx Smart BMS will conserve as much power as possible, to not discharge the battery much further. Bluetooth is still active, but other non-essential circuits are turned off, including the power to the Lynx Distributor(s). Check the voltages of the connected batteries and if they are low, charge the batteries. As soon as the Lynx Smart BMS sees a charge voltage it will automatically re-activate and close its contactor to allow for battery charging."

"Hibernation mode The Lynx Smart BMS is in hibernation mode when the Lynx Smart BMS has turned itself off because of a low battery event or when it has been turned off via the remote on/off switch. In hibernation mode, the contactor and most of the electronic circuits are turned off and the power consumption is very low (0.8mA). The status LED is off. The power to the Lynx distributor(s) is turned off. Bluetooth is still active during hibernation mode. The blue Bluetooth LED is either flashing every 3 seconds or is on, depending on whether there is an active Bluetooth connection with the VictronConnect app. The Lynx Smart BMS will come out of hibernation mode when the remote on/off switch is switched on or the batteries are charged."

Hi,

I want to make a 12v battery system, charged from PV via MPPT (two Panels in series 400W each).

The idea is to use is in case of a blackout for home appliances like fridge, TV ....

The system is based on folowing components:

- Victron LYNX Dist.

- Enclosed DC 16A Switch - DC Disconnect (PV Disconnect from MPPT)

- Victron smart shunt

- Victron MPPT 150/70 charge conntroller

- Victron 100A smart BP.

- Victron ON/OFF Master Battery Switch (275A)

- DIY lifepo4 batteries with BMS (JBD or JK BMS)

- 2000W DC-AC(230V) Inverter with remote switch (non Victron)

Can I use the BP in that constellation ? Or should I avoid using the component ?

Generally, the BMS has the role of keeping the battery status under the eye (all 4 cells individually with balance option) so in case of any under voltage of any cell it will cut off the "-" wire which then leads to a system shutdown (load disconnect).

My question are:

- what happens with the MPPT controller if the battery gets disconnected and the Solar PV are still providing power to the component ?

- how to connect the BP in such a system - schematic would be great !?

- should I connect the Inverter directly to the battery via LYNX Dist (with fuse of course)?

I have read some posts on the internet which say that the BP should not be connected directly to the inverter (inline) because of an inrush current. Can someone please explain how should this be done properly !

If this is the case the BP is just useless in my case or am I missing here something ?

regards

Andrzej