question

On https://www.victronenergy.com/live/ess:design-installation-manual

I retrive the good chapter wich is 4.3.4

4.3.4 Feed-in excess solar charger power
Set to 'On' to make the Solar Charger always operates at its maximum power point. The first priority is powering the loads, and the second priority is to charge the battery. If more power is available when those two priorities are met, then that power will be fed to the utility grid. 

Is there any value on Dbus to know how GX calculate the "more power avaible" ?

Many thanks in advance.

I already have developed MPPT Chargers HW/SW by my self and made many thoughuts about exaktly that problem. In my opinion there is no good calculation methode on a running/working MPPT for it. Thats why no mppt on the market do that. Normaly in bigger systems we simple take a referencial shortcuted micro modul on which ISC is permantly messured. That value you have to set in correlation to devliered pv power. This will make it possible to calculate exaktly the non used pv power. Thats the most easiest and really exakt way.

@mvader (Victron Energy Staff) Maybe you will offer sometimes such a small very Basic Plug in box, with an simple HAL and a communication port. I think there would be a potential Market for it for all mppt users who wants to know real possible power on there Systems.

@Peter Polz thank you for your reply. According to me Victron have yet developed a very similar function. With activation "Feed-in excess solarcharger power " on a GX system, the MPPT excess power is feed-in into the grid. It works great on my system with SmartMPPT + GX + BMV + Multi.

But with this GX function, the output is only a grid feed-in. You're right, any solution permiting to an extra system to know the current unused power seems to have some happy market issue.

@mvader (Victron Energy Staff) I understand it could be quite difficult to add feature each time users ask for a new one. But could you explain the current computation (output of the "Feed-in excess solarcharger power" function), it could permit to do the computation in the extra computation system you usualy have in TBM ?

Thank

@amrane Feed into grid is a completly other kind of system, tha works just voltage based as an "i" regulation such system will not work in any kind of offgrid sitauation where you want to know how many fix definied loads you can start. You just can try to higher loads until you chargers fall out from absorbtion

If you just want to dump into water you can take a look on ELWA-E System from MYPV. This system already works in combination with Victron and has a seemless power regulation

@Peter Polz Yes, i agree and feed-in don't intresting me a lot, my current goal is to manage load redarless to the the unused MPPT power mainly in asbobtion and float stage ;)

But I hope you will be agree to say that to feed-in an "MPPT excess", the system have to cumpute an "MPPT excess". If the system knows how to compute the excess, my propositions/question to Victron are :

- Is there a resgistry or MQTT topic where the excess is store and could be retrieve

- If not, please put the current output of the internal GX computation into a MQQT topic or any simple way to use it

- If you could not create a new registry, please describe you current algorithm

Thank to send the ELWA-E, i don't know these products and in case of ongrid installation it could be a very interresting solution.

@amrane ELWA E already works AC based in a offgrid System and direct communicate with VENUS/CCGX.. it has seamless powerregulation without any kind of phase control.. thats why perfekt for offgrid inverter systems

I'm working on the same problem. Except I have taken a different approach. Rather than trying to figure out the potential power of a solar array from available system information, I decided to use an irradiance sensor that returns Watts per square meter and panel temperature data. If the sensor is mounted with the array and, has the same orientation as the array, the data should be accurate. Given the Watts M/2 and the panel temperature, and with the specifications of the panels, I should be able to calculate the potential power of the array for any given sun condition.

Just in the planning stages now but looking forward to the project.

Below is a data sheet for the sensor I plan to use.

Pat

Si-Sensor_2017_E.pdf

What happened with this topic? Is there a way provided by Victron to know the excess power? I’m interested to find out how to implement a smart power out for extra load consumption.

Also, I have a EV charger station that I don’t know how it’s working in auto mode. Victron is saying that PV excess power is total pv production- load power and needs to be more that 1.3KW. Not sure what means total PV production and how they are calculated

@amrane, do you have a resolution here?