This site is now in read-only archive mode. Please move all discussion, and create a new account at the new Victron Community site.
Hi,
Here are my settings :
the voltage is atm 53V and the Multi states low battery BUT it's in Inverting mode which i don't understand. First the battery is not low and from what i can tell i have set the switch correct from the BMS so right now the Aux 1 is Open but never the less the Multi states low battery and more bizarre it is in Inverting mode whereas if it was really low battery then it should be in Charge only mode. I don't understand. Could somebody explain what am i missing ?
/peter
What voltage is the "DC input low pre-alarm" set to (in Inverter tab in VE Configure 3)?
Your 0.005C cutt off voltage is too high at 52V. For a 16 cell LiFePO4 battery, that would mean 3.25V per cell (on average).
First the battery is not low and from what i can tell i have set the switch correct from the BMS so right now the Aux 1 is Open but never the less the Multi states low battery and more bizarre it is in Inverting mode whereas if it was really low battery then it should be in Charge only mode. I don't understand. Could somebody explain what am i missing ?
It goes in charger only mode when Aux 1 is closed. Right now you say it is not closed.
Low battery does not mean empty battery.
@Seb71 thank you for replying. I only used the default values. Can you suggest what the value should be for LiFePo4 ?
Here are my settings :
Those values are way too low for LiFePO4. But when using ESS the shutdown voltages should be the ones set in the ESS assistant (the dynamic cut-off voltages).
Just in case you remove the ESS, set the "DC input low shut-down" to 48V.
I have my "DC input low pre-alarm" set at 50.4V (that's 3.15V per cell).
I am using ESS and i left everything default, have i selected something wrong ? It states during the ESS wizard that the Dynamic cut off voltage should rarely be changes since they are set correctly for the chosen battery type which i did select to LiFePo4, so what exactly should i change ?
This is the default in the assistant :
So i don't understand, does the DC-input low pre alarm get used when setting the Dynamic cut-off ?
One is just an alarm (that your battery is getting low), the other shuts down the inverter.
This is your problem - I think.
This is conflicting with your BMS onAux1.
Uncheck this box, should solve your problem.
Not sure why that would create a low battery warning ? I can't uncheck it since I need a password.
I have also spotted another problem.
You have chosen "Two signal BMS", but you have chosen both signals (Full and Empty) on the same input.
Why not put the battery full signal on Aux2 and the battery empty signal on Temp Sense Input (if you have no temp sensor there). Then that leaves Aux 1 available to the Grid Feed disable signal.
You are right that i chose to do that. I can easily change it without any issues but i still not sure it will solve the problem. Until now i had Grid turned off so i could learn how things are working. Now i have turned on the Grid and the low battery dissapeared but i am unsure how to configure the charger for LiFePo4 and the 2 wire bms.
My problem is that in my BMS i have following :
The last two checkboxes on the right are my relays that are connected to the multi but i only use the last one at the moment. Relays on the BMS are connected with Multiplus with Normal Closed eg. On means open circuit and Off means the circuit is closed. The relay is set default to be On. I am in doubt what this means in Victron because the Ve.Config states :
How does this correspond to ESS messages :
In my case right now it shows this :
and the relay on Aux 1 is On in the BMS meaning it's Open circuit eg. means the battery is full but the charging specs in VE Config says this :
so it should not float yet but i guess it's because the BMS told it it's full it goas into float as specified in ESS. Maybe all problems are here because i configure the BMS wrongly and the BMS should only interfear with the charging if the voltage goes really high or very low whatever that must be for LiFePo4 which i don't know yet. As you can hear i am confused but i am certain all problems can be solved if i configure BMS correct and the way 2 wire BMS works in Victron.
So BMS on means that it is open circuit.
In ESS Assistant Aux 1 open circuit means battery is full - charging must be disabled, ES code #3.
You also have ESS Assistant Aux 1 closed means battery is empty - charing must be disabled. So as soon as you BMS allows charging and the relay closes, then discharge will be disabled straight away.
Battery is full and battery is empty need to be on separate inputs of the MultiPlus.
You have chosen Aux 1 for both, try to choose a different input for the battery is empty signal. If you are not using the battery is empty for now, then set i to closed, but they can't both use Aux1.
Two signal BMS means two signals into two inputs of the MultiPlus.
great so i have now changed it to following :
Relay 3 is Temp Sensor and Relay 4 is Aux 2. Default relay state is Off (eg. means Closed circuit).
In Ve.Config i have it as following :
So this means BMS does not do anything at the moment since no rules are fullfiled and that means the current state is :
I don't know why there is a usage of 51W atm, have no idea what consumes that, no loads are there at the moment. The setpoint is set to 50W, no Energy Mounted yet. Maybe it means something else, i must read the ESS manual again. So all in all i guess this is correct, now i need to put the correct data for LiFePo4 in BMS, do you know those ?
Good, that looks good to me. It is good to have relays go open when rules are met. If there is a fault with the wiring then it also goes open circuit and stops charge /discharge to be safe.
Kind of strange where it thinks it is putting 50W.
Sorry, no advice to give on BMS settings. I don't know your BMS or what cells you have.
ok so you suggest to invert the logic so if the bms loses power the ,ulti stops charging ?
I am using LiFePo4 16s of 160Ah.
I don't know why there is a usage of 51W atm, have no idea what consumes that, no loads are there at the moment. The setpoint is set to 50W, no Energy Mounted yet. Maybe it means something else, i must read the ESS manual again. So all in all i guess this is correct, now i need to put the correct data for LiFePo4 in BMS, do you know those ?
Atm battery consums 16W and Multiplus the rest from 51W
Hi, I can answer the simple part of your question. (Luckily others have sorted out your more serious problems!) If you read the manual carefully, in ESS low battery warning is given when voltage drops below the dynamic cut-off value PLUS the offset ( ie the restart offset) which is 1.2V for a 48V nominal lithium system. So....anything below 53.2 V with your current settings will give that low battery warning at no or low load. Personally I think the 52V cut off is too high. I use 50.8 on my similar system, so the low battery warning does not start till low load voltage drops below 52V.
Cheers, Leslie
