Ecoflow delta reborn

PART1

Making a bigger powerstream: my plan was to open the powerstream, connect some cables to the cells and put some generic cells in parallel. this will fail. ecoflow measures the Coulombs coming at, and when the 2kWh came out, the battery shuts down. but when i sees still a full voltage, it will go in an alarm (battery capacity mismatch).

Project cancelled for a while...

PART2

I bought a broken ecoflow delta on the internet. time to do some testing. but had a problem: mine is lifepo4, the broken was is li-ion. and it had a dead pair of cells in it. The internal layout was also different.

The Dead cells of the delta. I removed 4 cells so i can go from a 52V to a 36V battery. this would work on my DIY home battery running ebike batteries.

Because i removed the BMS and complete logic, the display was also removed, and this is a bit sad. it had nice information on it. wouldn't it be usefull if we can get it working again? Time to take a good look at it...





This is nice. In the middle an NXS0104 level adapter. it adapts the 3,3V input (measured VCCa) to the 5V signals for the display (measured VCCb). The display controller is the Holtek HT1621B and now we are getting somewhere. there are 4 data pins coming from the display chip to the level switcher chip: CS/WR/RD/Data connected to B1-B2-B3-B4.
At the bottom is a 10wire connector J1. from top to bottom is connects to
-P10: LCD on wire
-P9: VCC 5C
-P8: not connected
-P7: data from A1 (CS)
-P6: data from A2 (WR)
-P5: data from A3 (RD)
-P4: data from A4 (Data)
-P3: connects to the onboard LED1
-P2: connects to the onboard button
-P1: GND

And this is all intresting, we can hook up an ESP and start bitbanging to see what lights up






Finally i got to this, all the RAMcodes and bits. it uses 29 ramcodes of 4bits each to light up all the segments.








Now, you have an ESP8266 in a delta, and it has wifi and nothing to do... time to make a webserver.
Top is the original delta from the ecoflow website, middle is my screen, bottom is the webserver interface. I can see the battery life whenever I want :-).

back to PART1 because we have learned a lot

I bought some 20Ah lifepo cells, they are not so expensive anymore.


and made a 52V battery out of it, add a BMS and ready to go. a 52V 1kWh battery for 91€




I said before, you can't connect it in parallel with the Ecoflow cells as it will see a battery mismatch, but here is the catch:
The BMS measures the coulombs coming in and out, what if we connect it AFTER this chip, so it doesn't see are battery current...
If you connect it on the busbar, you are connecting in parallel, but before the chips.
The battery connects to the powerstream, so they talk to eachother. and my battery is just in between them.
When the powerstream asks for 600W, 400W comes out of the delta2, 200W comes from my battery.
After delivering 600W for 3hours, the 2kWh would be empty. but because its only doing 400W, the battery will last for 5hours now. In the future I will build a even bigger one because this is only the test battery.

I have tested it for a few week. my battery normally delivers 150W from 20h tot 8h in the morning and it is at 30% then.
Now its delivering 200W and works just fine the whole night

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