I’ve been running this system for a couple of weeks now, in my garage, attached to my home and about 13 meters from my electrical panel.
JK BMS SOC isn’t the best; I’m using the smart shunt for SOC measurement.
I had two Victron Energymeters (VM-3P75CT**)**, one for grid metering, one for PV metering. But I decided to remove them and use the Victron itself for metering grid. This works fine because it’s directly connected to the grid. The PV (SolarEdge Wave HD4000 1 phase) is connected via modbus (Sunspec) and communicates directly to the Cerbo fine.
The backboard is Fermacell for better heat protection, and I’ve also installed a fire alarm. DC is connected with 70mm² cables, and PV is connected to AC OUT on L1. Charging the EV is done on L3 (using a normal socket connection). I’m a bit uncertain whether it’s better to move the EV socket to L1 for direct PV usage. The batteries have a custom 7” screen, with 3D print from Robbert DIY channel, very nice.
Open questions:
emergency shutdown in the electrical panel using the green remote (on/off) control.
emergency disconnect on the batteries, I have circuitbreakers in each battery itself which fully disconnect the battery DC; is this enough? Or should I install a DC breaker on the busbar positive output? what about length of the cable(s) then…
EV charger, I could buy one, but there is no real need, the socket works, for charging the car (currently 2000W/hour, which is enough for charging over night 19.7kWh car battery).
Current still 2000kWh used, 1000kWh returned to grid, in doubt if I should already move to dynamic energy contract or not…
Any tips, hints, or comments would be greatly appreciated.
Could make sense for your PV, but I believe your vendor doesn’t fully agree:
20.2.6. Q6: I see incorrect current (amps) or power readings on my EGX
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The general answer is: the Multi and Quattros are not measurement instruments, they are inverter/chargers, and the measurements shown are a best effort delivery.
Placing your ev charger on L1 will be more efficient during daytime, but if you charge only at night it doesnt matter
i also have an emergency stop system, two emergency stop buttons, one near the install another in the house near the powerboard, they shutdown the multiplusses and my pylontech batteries (pylontech batteries have a remote shutdown contact)
I would add fuses to the Lynx. As your whole battery stack is on one port I would use an Adler EF3 fuse. The Lynx Power-in can be converted to a Distributor without fuse monitoring.
Please change one battery cable on the stack to connect diagonally. E.g. ref on top m, black on bottom. This will distribute charge and discharge equally to your batteries.
Thanks,
The lynx has a 200A(or 250A can’t remember ) mega fuse on the red, so that is covered, next to the smartshunt on black. Isn’t that covering the whole stack engouh?
Hmmm, nice thing on the battery, I understand the note, will look into that. Eel (my battery boxes) shows also the same, curious why would you do that different?
Nice, and also nice to know other people think about the emergency shutdown. I already have an unused CAT6 cable which I can use for the remote shutdown I think.
So that each battery has the same total amount of cable length and connection points.
In the example above, the battery on the top right is closest to the inverter, it only has ~2m of cable and two connection points (its own terminals). The battery on the lower left is at the end of the chain, it has ~10m of cable length and 18 connection points (its own plus every other battery terminal along the way) to the inverter. The “starting” battery will therefore charge higher and discharge lower both in terms of voltage and power, the “end” battery will contribute/receive much less.
If you start the positive at one end and the negative at the other, you will equalise both the connection points and cable length. Each of the batteries in the chain will then see ~6m of cable and 10 connection points back to the inverter.
Cabling has been explained by chrigu. It‘s also documented in Victron variable „Wiring Unlimited”.
With a stack of 20kWh LFP batteries, the internal resistance get very low, resulting in short circuit current higher than 2,000A. Mega fuses are rated 2,000A. If the short circuit current is (significantly), than there might be an arc and current continues.
The Adler EF3 fit into normal Lynx, have sand inside and can clear currents up to 50,000A .
There might be new ceramic Mega fuses with higher arc clearance, but I haven’t seen them.
Thank you for your response, i’ve watched both videos. I have 3 boxen, all three connected with a 200A/80V/10k AIC per box. From the top (for now) they are connected with 80V/250A (2000 AIC?) MEGA fuse.
Am I correct to say the boxes are protected correctly with the installed circuit breaker?
I am a little unclear on if there is still a chance that the can be a short circuit with >2000A when the boxen trip at +/- 200A and are protected at 10k AIC.
so my question: do i still need (or better/more safe) a Adler EF3 250A on the the connection to the busbar?
If each box has a 10kA AIC would consider it save.
On the other hand, I replaced all Mega-fuses for each of my 14,5kWh boxes by Adler EF3 to have good feeling
Door het diagonaal aan te sluiten, zien alle batterijen dezelfde weerstand. In jouw opstelling ziet de bovenste batterij de laagste weerstand en zal het meeste werk verzetten. De onderste batterij ziet een langere kabel en alle overgangs weerstanden.
Als je gaat laden of ontladen met 150A verdeelt de stroom dus niet gelijk met 50 ampere per batterij. Bij het laden is de bovenste eerder vol en andersom. Als je kort pieken trekt wordt daarna de bovenste batterij weer geladen uit de onderste batterijen.
Diagonaal heb je dat niet/minder en blijven de batterijen in ‘balans’ onderling.
Nice setup. Caution: you will be upgrading continiously on every part.. About the EV charger, I swapped the (chinese) 3phase charger to a Victron EV Charging Station 32A. There a some known dislikes, but the main advantige is it communicates well with VRM, so the overload PV or cheap grid power is pushed in the EV.
Haha, jep. Already thinking of additional things (next to EV Charger) like additional PV etc. We’ll see, everything when the time is right… (now? )
@EvSC / @termeerh Dank voor de reactie, ik ga kijken of ik diagonaal voor elkaar kan krijgen en dan snel door naar de EV oplossing kijken. Maar heb net Dynamische contract afgesloten, dus ook daar gaat wat tijd in zitten verwacht ik. Allemaal leuke dingen! Betreft klankborden; prima maar vind het ook wel leuk om dit openbaar te doen, zodat anderen ook mee kunnen lezen (ik lees ook met hen mee)…
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) mega fuse on the red, so that is covered, next to the smartshunt on black. Isn’t that covering the whole stack engouh?
About the EV charger, I swapped the (chinese) 3phase charger to a Victron EV Charging Station 32A. There a some known dislikes, but the main advantige is it communicates well with VRM, so the overload PV or cheap grid power is pushed in the EV.