Ronski's Solar & battery DIY build with whole house backup

[Ron-ski]

So when the battery full and grid down and you cant turn on your oven what happens. Where does the solar kW go ?

The turning on of the oven part was to drain the battery a bit, as I needed to verify what was supposed to happen, happened, which it did, and I wanted to watch it happen. Once the battery was down to 90% I turned off all the extra loads including the oven to allow the battery to charge.

When the grid is down, the battery is full, and there isn't enough AC load the Victron system will do two things:

1. It will reduce the power generated by the MPPT charge controllers - it did this, you can see this in the last picture above, the red and blue lines are the two strings directly connected to the Victron system.
2. The Quattro will increase the AC frequency to 52Hz (this setting can be changed), most (not all though) solar inverters will then shut down at this frequency, the SolarEdge inverter that I have shuts down at 51.6Hz - you can also see that it shut down in the picture above.

So you can see that the amount of power generated can be controlled, if the above two didn't happen then the power would be dumped into the batteries until the BMS turned them off to protect them from being overcharged, at that point as I understand it the Quattro would shut down.

Newer inverters can be set to gradually restrict their power, as the frequency rises above 50Hz they will reduce their output, the Victron can be set as required to control this.

 

[Ron-ski]

I've done some more to the second battery over the weekend, not a lot to show picture wise though, so no pictures. Made up the negative cable from the breaker down to the tray, made up a splitter for the T class fuse holder, made up the battery heat spreader, and did some other odds and ends.

I've also been modifying my scheduled discharge routine for Node Red, going to need this from tomorrow.

The discharge timers are currently embedded in the flow, but its very easy to change them should I need to.

From the dashboard I can turn the schedule on or off, set how much battery power to discharge, and a minimum SOC of charge to stop discharging at.

It now takes into account AC loads and PV power, the aim being to set how much the batteries are discharging at - so the figure "Grid set point to use on the schedule" updates depending on PV production and house loads.

 

[Ron-ski]

Just need to cut the end plates, drill them, cut and tap the spacer rods next weekend and the second battery tray will be ready. Need to 3D print some covers as well.

Next batch of cells should arrive in the next two weeks hopefully.

 

[Ron-ski]

Made up the last two 120mm cables and fitted them, the battery rack busbar is now live.

Need to print some covers for various parts, and also some cable clips, but I've stripped down my 3D printer hot end as it kept leaking, turns out the thread that the heat break screws in to has stripped, so when I tighten the nozzle it eventually pushes the heat break out a bit, and hence leaks again.

Once I get my printer working again, I'll print some cable clips just to tidy the cables up.

 

[Ron-ski]

@Troop no, not yet.

@Oldman2 have you heard anything from Fogstar, wonder if your rack batteries in the same shipment?

 

[Ron-ski]

@Troop Thanks for the heads up, I emailed them yesterday, but haven't yet had a reply back. That's a shame, would have been nice to have them over the bank holiday weekends, oh well it is what it is.

 

[Ron-ski]

@Troop thanks, you've a better line of communication than me, they've not replied to my email yet, although if I hadn't of heard from you I would probably ping Ben a message.

 

[Ron-ski]

I just replied to the one my order confirmation came through on, which I've used previously and got replies.

 

[Ron-ski]

Not much to update for the last couple of weekends.

Finished off and tidied up the rack busbar cabling, which is now all operational. Also cut and tapped the bars I use for connecting the balance leads, so they are ready. Bit of luck the new cells will arrive this week, I think I'm ready although bound to be something I haven't got or done.

Designed and 3D printed a cover for the cable connections to the Lynx shunt

Designed and 3D printer busbar covers.

 

[Ron-ski]

@Troop Any news on the cells, the Fogstar website has dates of end of April and end of May depending on if you're looking at retail or wholesale site?

Also seems grade B 280Ah are in stock, perhaps grade A just hasn't been updated, but that doesn't explain the May date, unless thats the next batch.

 

[Ron-ski]

@Troop yes makes sense, they've had my money since February.

Just a little concerned with the timing, I've regularly been checking the dates and it's only today I noticed they have changed.

 

[Ron-ski]

@Troop just had confirmation that my grade A cells are being dispatched today, so hopefully yours are on their way to you as well.

 

[Ron-ski]

It doesn't look like mine have been shipped yet either, all the DPD app says is they have received order details and awaiting my parcel, so will hopefully ship today for delivery tomorrow. I ordered late February and had to pay in full, at some point later I noticed they were taking deposits.

 

[Ron-ski]

DPD still haven't received my shipment, just phoned Fogstar, and he said they've got so many orders to go out he thinks they've overloaded DPD, he said hopefully they will go out today, but can't be certain.

 

[Ron-ski]

@Troop always the way.

 

[Ron-ski]

DPD have mine, due for delivery Monday, so a job for next weekend, and I can check the cells during the week.

 

[Ron-ski]

Mine are also being delivered to work, so no one there on a Saturday, not that DPD will know this.

Hope your Kitchen and battery install goes well.

 

[Ron-ski]

Just received my cells

 

[Ron-ski]

Checked and labelled the cells last night, checked internal resistance and voltage today, all cells were made in February this year.

B1 0.19m ohms 3.2941v
B2 0.19m ohms 3.2941v
B3 0.19m ohms 3.2941v
B4 0.19m ohms 3.2942v
B5 0.19m ohms 3.2943v
B6 0.19m ohms 3.2941v
B7 0.19m ohms 3.2942v
B8 0.19m ohms 3.2941v
B9 0.19m ohms 3.2941v
B10 0.19m ohms 3.294v
B11 0.19m ohms 3.2941v
B12 0.19m ohms 3.294v
B13 0.19m ohms 3.2943v
B14 0.19m ohms 3.2942v
B15 0.18m ohms 3.2943v
B16 0.18m ohms 3.2943v

Average Ah according to the EVE spreadsheet is 296.27Ah (last years batch was 291.8), minimum is 295.392 and the maximum is 297.272.

 

[Ron-ski]

Its a job for the weekend.