I have a AGM 48V 80Ah Battery on my MultiPlus 2.
Every day when there is not enough sun and the battery is empty, I get an alarm. The Cebro beeps until the voltage is higher again.
What shoud I have to do?
asked
Every Day 3-5 Undervoltage Alarms, what did I wrong?
Are you using ESS? Grid attached?
You should consider raising the minimums if you are, so the battery isn't drained so far.
What are the battery specs? How is the multi configured?
If your settings are right for the battery, you either need to reduce loads or improve charging.
45V is low.
Yes ESS is enabled. Here are my settings:
I use 4x 12V 80AH lead battery from Sonnenschein.
You're discharging it quite deep for a lead acid, it won't last long with the voltages you are going down to.
I would raise the ESS minimum SOC closer to 60% and consider using batterylife so ESS can adjust the discharge level when poor solar becomes a problem.
Do you have a shunt to track SOC accurately? The built in multiplus monitor is inaccurate in an ESS environment, so this may be contributing.
hi nickdb, thank you for your answer!
Where should I set the 60%? In the Multiplus or in the ESS menu in the Cerbo?
Are the other settings in the Multiplus ok?
i have a victron smartshunt here a the settings off the shunt and the MPPT:
ESS changes can be made on the GX, though you can now also do it via the VRM portal assuming the system is online.
I was trying to find the spec sheet for your batteries but my German is non-existant.
You really want to make sure you have followed what the manufacturer has put in their spec sheet and has been set on the multis charger tab.
Here is the battery datasheet:
Shoud i activatet Battery life?
Here and in english:
Ok. There is a mismatch of settings between the mppt and the multi - float is not the same.
The multi is using the preset default.
I am not convinced using the upper and lower limits for absorption and float is the best idea, personally I would aim a little lower for absorption and a little higher for float, but both devices do need to have the same settings.
You should also have DVCC enabled on the GX so the mppt and multi can coordinate and limit their charging. This allows you to set a shared temperature sensor for temp compensation etc.
https://www.victronenergy.com/media/pg/CCGX/en/dvcc---distributed-voltage-and-current-control.html
Your shunt isn't optimally set, it may struggle to synchronise with that voltage and tail current.
It requires some tuning to get it right and there are others way more experienced at setting them. There is a good video here:
https://www.youtube.com/watch?v=mEN15Z_S4kE
For ESS it is usually suggested to start with a voltage that is midway between float and absorb and with a lower tail current than you have and perhaps a longer time window.
Basically if the shunt sees that voltage and current for that duration it knows the battery is full and will synchronise. If it can't get that right you can end up with some serious drift over time.
As mentioned, raise your minimum discharge SOC, it is way too low (and possibly inaccurate) and use batterylife so there is some automatic management.
Hallo Martin !
Dein Akku ist meiner Meinung nach für den MP2 5000 viel zu klein. Laut Aufkleber hat er seine 80 Ah nur, wenn Du ihn mit maximal 0,2 C belastest (C5). 0,2 C einer 80 Ah Batterie sind aber mal gerade 16 Ampere. Der MP2 5000 kann aber kurzzeitig Ströme bis zu 200 Ampere ziehen (nominal nur 100 Ampere). Deine Settings werden den Akku ziemlich schnell zerstören. Die maximal Nutzbare Kapazität Deines Akkus liegt bei 50% -> 40 Ah. Das entspricht dann etwa 1,9 kWh. Also nicht mal eine halbe Stunde Volllast bei dem MP2 5000. Das ist alles viel zu klein bemessen für das Gerät.
Das weiteren geht man bei Blei Akkus meistens von einer maximalen Ladeleistung von C10 aus. Das bedeutet bei Dir: 8 Ampere. Du hast 100 Ampere konfiguriert. Woher genau hast Du denn diese Werte ? Bei 4 Akkus in Serie hast Du bestimmt auch einen Balancer installiert ?
Viele Grüße
Jens
Hallo Jens und danke fü deine antwort,
habe den Ladestrom auf 8A geändert, das Problem ist dann das der MPPT nur noch 8A produiziert. Er soll aber soviel wie möglich Produzieren und den alles über 8A in Netz einspeisen.
Wo kann man die 16A Belastungsgrenze einstellen?
gruß Martin
Hallo Jens und danke fü deine antwort,
habe den Ladestrom auf 8A geändert, das Problem ist dann das der MPPT nur noch 8A produiziert. Er soll aber soviel wie möglich Produzieren und den alles über 8A in Netz einspeisen.
Wo kann man die 16A Belastungsgrenze einstellen?
gruß Martin
