I’ve been running it for a few years like this, just expanded and added the third MPPT a few months back. It’s rock solid with no SD card failures. I do make an image of the SD card and write it to a spare SD card just in case but I haven’t needed it yet. I also use the SanDisk Ultra cards and have never had a failure personally.
I power my Pi from the batteries, I bought this buck converter to step down the voltage, but I see they are out of stock:
I have eight Pylons in my bank.
Setup is very easy, you can have a look at:
And both the CAN HAT and the above scripts both work on the Pi4, I have one configured as a backup.
As mentioned, the Cerbo has all this integrated but you are already more than half way there. Personally, I like to tinker so the Pi works for me.
It’s definitely a little more pricy than the option @Thaelian gave you but I recently bought one of these to keep a Pi Venus going, I could not find a cheaper alternative in stock anywhere.
It should be. The CAN hats are usually MCP2551 transceivers with a MCP2515 CAN controller, connected to the PI using SPI (serial pheripheral interface). If you know the pin-out of your Pi (and it is readily available, and I believe standard on all boards), you can even pin it yourself with a cheap board like this.
If you already have the Pi with the MK3 running VenusOS then just keep that. Buy the USB->Ve.Direct cable for your MPPT and the CANhat for the battery. Then just make sure you have good DC power and you are set.
I two have been running the Pi (3B, 3B+ and also Pi Zero 2) with VenusOS for a few years now. I used an old 4Gb SD card first, but that gave some issues. Replaced with SanDisk SD and no issues since.
I have a 4 port USB hub to expand the USB ports. On that is:
1x USB->MK3
2x USB->Ve.Direct (for the 2 MPPTs)
2x USB->RS485 (batteries)
1x USB->TTL (batteries)
Only issues I had was when using a 2A only psu. You do need to use 3A psu.
Ok, so I bit the bullet and acquired a Multiplus-II 48/3000/35-32 and BlueNova RacPower. Managed to get it all setup this afternoon just before loadshedding kicked in at 18:00.
Overview of the setup:
Multi II; no assistants installed - no solar at the moment, waiting for delivery of panels
Cerbo GX
BlueNova Racpower
BMS CAN cable made up according to BN spec; pin 7 CANH, pin 8 CANL all others not connected
BN CAN terminator in 2nd battery CAN port
Victron CAN terminator in 2nd Cerbo CAN port
The Multi seems to charge the battery and now as I type this it is inverting without issue. Only issue I have is that I cannot see any battery details and if I look at the BMS-Can network it shows that the port is stopped and there doesn’t seem to be any comms
A few questions if anyone can assist:
should I be able to see the battery details? I assume that I should be able
do I need install ESS?
Any other insights or assistance greatly appreciated.
So, the quest continues. I still cannot get the Cerbo to “see” the Blue Nova battery. The Victron instructions state the following:
"After properly wiring and setting up, the BlueNova Energy will be visible as a battery in the device list:
"
I don’t see it in my devices list:
But after a reboot I do see that the CAN-Port has gone to error status:
I was thinking of trying the second Victron terminator in the BN battery, or alternatively the BN terminator in the 2nd Cerbo port. As far as I know the Victron terminator is just a 120 ohm resistor on pins 7 & 8. This is what the BN CAN terminator looks like, it has a small pc board with connections to pins 4 & 5, and 7 & 8, I assume this is also a resistor, can anybody confirm this? Why are pins 4 & 5 also connected? Is this an option or do I risk magic smoke?
Hi jacksdad - I am experiencing EXACTLY what you had. Please can you clarify - firstly was it the small DIP switches on the front of the battery? If yes, how were they configured please. I have #5 on and the rest off. Your help would be greatly appreciated.
Other things to look out for is to make sure that you have the correct cable config, i.e. pin 7-7 and 8-8 with none of the others connected, and make sure the terminations are in place.
I would shut down the battery before changing the DIP switch for safety’s sake. The Cerbo shouldn’t need a restart but it won’t do any harm if you do.
If there is currently no comms, or comms but at the wrong board rate, you will have the state as “STOPPED”, as in post #27 above. Once they are talking, you will have the state as in post #28, “ERROR-ACTIVE”.
Thanks jacksdad - problem fixed. Looks like the dip switch fixed it (I also added a terminator to the battery) and the battery BMS is in control and now communicating effectively with the Cerbo GX. One thing I notice is that the battery only seems to charge to 99% and stays in Absorption mode - before it would finally go to Float. Battery health is 100% and charging at recommended 25A. I read that the difference between Absorption and Float is only about 0.2v so probably not a biggie.
Ja, I had the same issue and it bugged me enough to get hold of Blue Nova (long saga trying to get anything out of those clowns). Eventually one of their tech guys came back and said it is by design and not to stress too much about it, if it bothered me I could take/send the battery to them and they could tweak it. This was during stage 6-8 LS so needless to say I didn’t take them up on the offer. Have learnt to live with it.
Most of the clever guys here on the forum agree that 99% or 100% is neither here nor there as SoC is not an exact science and is more just an estimation, the important thing is that health is good and the cells are in balance; I just listen to them
Thanks - good to know. And yes the Blue Nova tech support is pathetic. I questioned the two rather contradictory illustrations for the RJ45 cable #7and#8 pin outs and they were rather arrogant in response. The LHS illustration is viewing from the cable side but looks like it is from the front but no label on either! Also no proper clear reference to the DIP switch configuration - hence our issue that others have also had. Anyway all working fine at present.
Ja, I only got a response from them once I had ripped them on HelloPeter and on their own Facebook page, their CEO happened to see it and then I had all kinds of people helping me.
No, mine has mains and either Bulk(most of the time) and occasionally Absorption for a short while, also never goes to Float. I’m not sure how the indicator lights are controlled on the MP, whether the parameters that are set in VE Configure, or directly by the battery now that there are CAN comms.
I very rarely charge from Eskom, mostly done through solar. How is yours setup, inverter and battery, or have you also got an MPPT and solar?
