10kWh LifePO4 DIY Battery Addition..... Here is my write up.

poker--addict

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poker--addict

Heat pump going now so discharging is working....

in terms of charging, is there a certain amount excess before it will trickle charge? As I saw some going to grid before the load came on house from heat pump?

unkel

Set the balancing voltage much higher. Something like 3.47-3.50V or so

In other news, unexpectedly got my next lot of 16 CALBs yesterday afternoon so built my 16S4P last night, proper job, JK BMS also working on it. The lot neatly inside that old cabinet. So with the server rack pack I rescued I'm up to 45kWh now 😁

poker--addict

Sorry unkel, which setting to 3.47?

poker--addict

550w max charge rate?

unkel

"550w max charge rate?"

LOL, no, you're simply not producing much PV from that graph

"Sorry unkel, which setting to 3.47?"

Start Balance Volt

poker--addict

Plenty of sun now and it's going to grid (mostly), battery BMS showing 71% charged

unkel

Probably a setting on your Solis inverter. Not sure why it states CAN Null when you've selected a generic battery type (so not using CAN). You'd be better off asking in the dedicated Solis inverters thread.

poker--addict

ok, so the BMS is low energy Bluetooth, so can't see BMS data on the app when I leave the proximate area or the battery. Slightly annoying, at least until I get some confidence it will stop and start charge and discharge at the right times

championc

Imo, the Bluetooth is a gimmick. If you want to track it, just connect the RS485 to USB adapter into your Ha or Node-Red device and get all the data you want that way.

If you are seriously interested in data, you want to have all data in one place, under one app.

Get info from your inverter, the MyEnergi API, and this COM port, and amalgamate everything under one app

poker--addict

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BMS view.

slave1

Large voltage difference in cells there

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championc

Are you trying to have a perfect system with a non-connected to inverter BMS ? If so, expect a world of pain as an inverter guesstimates the battery SOC% from just the voltage. And it will base this on the discharge profile of Lead-Acid which is quite different to LiFePO4

munsterfan2

Hi,

Anyone have a spare NEEY balancer to sell or can recommend where to buy, HANKORBMS not selling at the moment ( https://www.aliexpress.com/item/1005003125644284.html )

Thanks

poker--addict

I realise I was spamming the thread a little with screenshots. I have deleted several posts and will start fresh. Mods, feel free to tidy.

Championc, essentially yes. My understanding is it can work fine - I am not trying to automate too much at this point, just set up a basic system. The only "automation" really is a desire to charge from the grid at night rate.

I understand that I need to get the inverter settings/limits to a place where they are not achieving anything and let the BMS switch the circuit on and off, let the BMS decide what the SOC is, and try to limit (fool) the inverter logic.

I have not top balanced with a desktop charger (did not have one), so I suppose first priority is getting them charged to 100% and balanced.

unkel

https://www.boards.ie/discussion/comment/120242853#Comment_120242853

You're a few hours late. I decommissioned mine yesterday morning. But I have already promised it to a friend. Great piece of kit for very little money.

graememk

https://www.boards.ie/discussion/comment/120242853#Comment_120242853

I think they are coming back in stock soon, send them a message

unkel

https://www.boards.ie/discussion/comment/120243818#Comment_120243818

And iirc, it didn't take that long to arrive. Mind I did pay for shipping.

graememk

https://www.boards.ie/discussion/comment/120243006#Comment_120243006

What is your current settings? Your charge voltage needs to be 55-58v (start at 55 and edge upwards as the cells balance out)

Mr Q

https://www.boards.ie/discussion/comment/120242666#Comment_120242666

My current setup has a BMS that does not connect to my Sofar. What you say about a world of pain is correct.

The two units never have close to the same SOC. It works currently but is far from ideal as some nights it doesn't charge the battery enough as it thinks it's reached the desired percentage.

A BMS that can communicate with the inverter is on my list of changes to make.

Mr Q

https://www.boards.ie/discussion/comment/120242853#Comment_120242853

I have one that is new in the packaging they sent it in. Never got around to fitting it, PM if interested.

yankinlk

https://www.boards.ie/discussion/comment/120243006#Comment_120243006

im glued to your posts becuase i have the same Solis inverter and I am worried about adding a DIY battery and losing the simple easy to use setup i have with my Dyness. Hoping you get this all figured out and i can copy you!

poker--addict

https://www.boards.ie/discussion/comment/120244045#Comment_120244045

Could the battery size inputted into the inverter be set artificially high, so it never senses/reaches SOC of 80 or 100%?

poker--addict

https://www.boards.ie/discussion/comment/120244075#Comment_120244075

I will do a full write up - if I can get it working at the most basic level then anyone can!