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

on_the_roots

https://www.boards.ie/discussion/comment/121595843#Comment_121595843

This is not RS485->USB but Ethernet->USB, not the same protocol. If this is used on a RS485 connector this is fatal for the BMS interface, as Ethernet works with 48~52V signals, way above 5V for RS485/RS232.

https://www.boards.ie/discussion/comment/121595883#Comment_121595883

You mean that is the same hardware Seplos sells on this one?

championc

No. When you buy a Seplos BMS, you can add the USB interface, and it is very similar to the one I linked

Ints

Can you tell me which wires on rj45 cable need to be connected to this plug?

SD_DRACULA

The busbars don't work great with this setup it seems.

Should I just drill through and stick the cells together or is more room better for airflow/temps anyway?

graememk

https://www.boards.ie/discussion/comment/121600830#Comment_121600830

You don't need the double bus bars, though

SD_DRACULA

https://www.boards.ie/discussion/comment/121601053#Comment_121601053

Yeah I know but I had ordered extra so I was like might as well

championc

Does anyone still have the foam packaging from the CALB cells, that they want to dispose of ? If so, could you please PM me.

Just looking to reuse to insulate my cells. Used them on another set already

unkel

https://www.boards.ie/discussion/comment/121610583#Comment_121610583

We might get the boxes and insulation on our incoming second hand cells. Will know in about a week or so. Sit tight, you might have all you need (I don't need mine)

johndoe11

Planning on adding a 15kw DIY battery to my existing setup of 3 x 5.12kw server rack batteries. See pic below. These are connected via 125a fuses, using the busbar setup pictured, to a Solis 6kw inverter and communicate using Pylon LV protocol. There is also a DC breaker between the inverter and the batteries. Will probably pick up the 300ah cells from NKON.

I'm thinking using the new JK inverter BMS as the primary BMS to control charging/discharging on the new battery and just leaving other 3 to themselves, on the assumption the won't communicate with the JK. Any foreseeable issues with this setup given the different battery sizes or anything else I may need to pick up?

unkel

I've had something similar for a while, @johndoe11 . Except my DIY battery was 10 times as big as the server rack battery. The DIY battery JK BMS was talking to the inverter and the server rack battery was in parallel, just helping out a bit 😂 its own BMS was of course protecting it

KaseLieberKase

How do you charge 30kwh+ exclusively on the three hour EV rate? My inverter is limited to 60A so realistically I'm looking at about 9kwh at most. Even if my inverter could do 100A would that not be bad for the batteries charging at such a high C rate?

slave1

EV(s), washing machine, dishwasher, dryer, immersion along with house load

SD_DRACULA

https://www.boards.ie/discussion/comment/121642620#Comment_121642620

Easy answer you don't/can't with one inverter, even the 8kw inverters can only max out about 23ish kwh in 3 hours, max of around 140a.

Not bad for the batteries at all, for example if you have 4 batteries that can sustain 50a each, then even at 100a each pack would get 25a which is nothing.

Depends on the amount of batteries of course.

munsterfan2

Anyone looked at Sodium Batteries yet https://www.alibaba.com/product-detail/Grade-A-220Ah-3-1V-210Ah_1601015664977.html?spm=a2700.pcdrm.0.0.53399NjC9NjCeH&s=p - do any of the BMS support ?

graememk

BMS should support it fine, it's it's huge voltage range (1.5-4.3) with a 16s, inverters usually only go down to 40v (2.5/ cell and )

Max voltage is usually is 60v (solis is 42-58!) 60v is 3.75v.

unkel

https://www.boards.ie/discussion/comment/121644670#Comment_121644670

Way more expensive than LiFePO4. What's the point even thinking about them? It will be years before they are cheaper.

And you better start saving for a new inverter because none of our current inverters can handle them 😁

unkel

https://www.boards.ie/discussion/comment/121643376#Comment_121643376

Not entirely true. Charging your battery from your inverter is not the only way you could charge your battery. You could have a separate charger, charging the battery at the same time, directly from the grid (a socket)

That's what I do. I can use a 3kW rectifier with a fixed voltage output. And I can use a powersupply that I made by putting 4 * HP 750W server power supply (cheap, plentiful, reliable, safe to run 24/7) in series after modifying them

Now if only I had a 16kVA connection to the grid, I could charge my battery at 18-19kW 🤪

SD_DRACULA

https://www.boards.ie/discussion/comment/121645591#Comment_121645591

Yeah well it's safe to assume the usual solar user will not be doing any of that hence why it was left out.

You can use multiple inverters in parallel, throw a sofar charger (or any other) into the mix, or just get an inverter than can draw more from the grid, the Deyes single phase hybrids can go up to 16kw 😉

The devils

https://www.boards.ie/discussion/comment/121645591#Comment_121645591

👍,

dermotx

https://www.boards.ie/discussion/comment/121580089#Comment_121580089

Hi Dejvo. I've all 16 cells tested now. They are 305Ah grade "B" cells. The following are the capacities:

305, 298, 302, 302,294, 298, 302, 300, 300, 301, 299, 300, 297, 297, 298, 297.

unkel

I don't think people need to bother capacity checking any EVE type cells. They seem to all pull stated amp hours or thereabouts!

jasgrif11

What is the recommended Torque for CALB and EVE Cells?

Right now, I'm using a torque of 7nm in securing by busbars to my CALB cells. I have also compressed the cells together with threaded bars, but this is more for just keeping this together and away from the kids. I haven't set a particular torgue value as my understanding is that this isn;t important for CALB cells, but is for EVE.

I'm planning to purchase 16 EVE to run in parallel and want to understand to torque requirements.

SD_DRACULA

Nkon sent me an email and said to not go over 6nm

jasgrif11

https://www.boards.ie/discussion/comment/121739877#Comment_121739877

That's for EVE, correct? What is the default for EVE?

hexosan

I done 4nm and had no issues

slave1

No need to compress CALB cells

SD_DRACULA

https://www.boards.ie/discussion/comment/121739910#Comment_121739910

Envision ESS cells, so I would say google the model number and find the spec sheet, it might have it there.

jasgrif11

Hi All,

I currently have two batteries connected in parallel (CALB 40kwh (64 cells) and EVE 14kWh (16 cells). There is one JKBMS, and I do Grid charging during my 4-hour EV rate. Needless to say, I can't fully charge the battery even with my 8kw Deye inverter.

I have a second Sofar 6000HYDEP that I could use to add an additional charge to the battery. However, researching this online, BMS CAN is designed to connect only to one inverter. If I want to use more than one inverter, I would have to use an inverter that can support parallel inverters; Deye does, but only with its inverters. So I'm not sure if this is an option, and I would like to hear others' thoughts and if you have a similar setup.

Alternatively, I could get a second JKBMS and set up the 16 cells as a standalone battery, directly connected to the Sofar inverter. This would mean I have 2 batteries and 2 inverters connected to my home. Again any thoughts on this approach?

unkel

https://www.boards.ie/discussion/comment/121766983#Comment_121766983

Just use your Deye as is talking to the JK BMS. Then use the Sofar inverter as a dumb battery charger, no need to connect a CT even, just program it to also charge the battery during the night slot. The BMS will prevent it from overcharging the battery.

I'm not sure what way you have your batteries in parallel though?

jasgrif11

My 40kWh setup is 16s4P and the EVE is standard 16S and I connected the battery cables to a combined 350A rated busbar, then to JKBMS and onto the Deye.

Do I need to reconfigure the sofar to act as a dump charger? If I do this it will still need a CAN connection to know there is a battery connect correct or no?