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

unkel

I still don't understand how you paralleled them. Surely the JK BMS can only protect either the 16S4P or the EVE?

Sofar doesn't need any comms. No CAN, no RS485, no CT. Just use it as a glorified timed charger. Like my €70 rectifier on a €15 smart plug 😂

jasgrif11

So I didn't mention it, but I have 2 X JKBMS (1 each to protect each battery). I also have 14 solar panels connected to the Sofar. Do I need a CT for that? I presume the Sofar will then need to know about the battery.

SD_DRACULA

Why oh why didn't you go for the 12/14/16kw hybrid deye instead of the 8kw? Probably easiest/cleanest fix, not the cheapest, but you can also connect 6 strings to them.

I'm looking to bump up my import rates too and thinking about it as well.

graememk

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

CANbus is a multi node network, can easily have multiple things on it.

Also the esphome/jkbmscan only transmits, doesnt listen for anything having multiple inverters on the network will have no issue at all.

Having the CAN connected to both inverters will mean you dont have to run the sofar in default mode either.

Ive had 3 me3000's connected at once along with a monitor for the bms and a esp32 logger, no issues at all.

It may be designed to only talk to one inverter, but it can talk to many.

Id Keep it all as one big battery bank then you arent hassled with trying to figure out what battery to charge or discharge.

Do you have an inverter JK for the eve pack or just a standard JK?

jasgrif11

I have the standard JK for the Eve.

If i keep as one big battery then i’d have to split the CAN coming from the primary JK to goto both the Deye and Sofar correct? The JK on the Eve is purely for safety.

I can setup the Sofar to only charge from the grid between 2am and 6am and to not discharge as the Deye will manage the discharge.

Another option is to have one large battery with two JKs and just a standard CAN from the primary JK to the Deye. In this mode the Sofar is just a Grid tied system.

I would then need a rectifier to make up the shortfall charging at night time.

graememk

https://www.boards.ie/discussion/comment/121768186#Comment_121768186

Split the can it's what canbus is designed for, it's only the blue and blue/white wires are used

Dejvo

Thank you for the information, I ordered them cells too. They already arrived. I do not have the capacity tester and really want to use the cells for my home solar system. I think from your test results it is going to be fine. Right now I am waiting for the 2A active balancer on my JK bms to figure things out. But I am not worried too much, cause this is just second bank that I have and therefore I am not dependant on it right now, but it helps quite a lot to get through nights and mainly cloudy days. Hope yours will last for a long time and work great for your application. With kind regards David.

on_the_roots

https://www.boards.ie/discussion/comment/121767191#Comment_121767191

If another charger is in parallel, isn't it going to mess the voltage readings for the inverter?

My thinking, correct me if wrong: the second charger (either a standard one or another inverter) puts say 57V and the main inverter may stop the charging after triggering OV protection?

graememk

https://www.boards.ie/discussion/comment/121775738#Comment_121775738

The batteries will pull the charge voltage down to battery voltage.

Say battery voltage under charge is 52v and your charger(s) are aiming for 57, the voltage of the chargers will be pulled down to 52v. As the batterys fill up the battery voltage will rise until it reaches 57 v

jasgrif11

My ESS 72173207-305A cells arrived from Nkon. I plan to create a box for these in the next few months. However, in the meantime, I will compress them on a temporary shelf. Do these cells require the epoxy sheets in between or can I use 2mm arts and crafts foam (temporarily until they are in their new home).

I think they come with Aluminium busbars, and not enough to Top balance all 16 cells at once. I can do them in two batches. Alternatively, I have enough copper busbars from extra that I purchased with my Calb cells. Any issue using these? (once I don't mix them).

Lastly, there aren't any details in the box on the Torque level to apply to these cells, does anyone have this?

SD_DRACULA

https://www.boards.ie/discussion/comment/121789694#Comment_121789694

Save yourself some hassle and no need for epoxy sheets or compression or top balancing (if you have an active balancer on your BMS)

I lashed them in as is and never had any issues with the cells, I'd say each cell is easily 1kwh if not more.

I did get an email from nkon saying to torque them to 6nm

I'm looking to move mine to the shed shortly and won't have a need for the box I did for them, you can have it for whatever the plywood/plexiglass cost me 😉

For 32 cells

slave1

Why are you moving batteries and inverter? Is it inverter noise related?

SD_DRACULA

https://www.boards.ie/discussion/comment/121791371#Comment_121791371

Noise, peace of mind, heat, future expansion

slave1

Ha future expansion, PV is a path for a lot alright. I have my inverters in the house along with batteries and happy where they are but only because LifePO4 and no noise issues thankfully

Hakaman2

Hi there all. What a great thread!

I have been mulling over this idea to take advantage of cheap EV early morning charging rates. I have a few questions from those experienced around here.

Apologies if I am doubling up: I have read through a good amount of the thread, but not the whole thing!

I do not have solar. I am thinking of a DIY 14kwh setup controlled by a JKBMS (active balancing). I was thinking of running it through a Deye Hybrid inverter.

The idea is to minimise peak hours for charging and run the house off the battery.

I also have an EV to charge and a 4 hour charging window for the cheap rate.

Questions:

What size inverter would power the whole house off the battery? (I know this depends on how much I'm pulling down. I use 12kwh/day on average, but do have induction cooking which might influence things.)

I need to charge both the house battery and the car battery over this period from the grid. Car batt probably needing to charge 30kwh or so. Can this be done?

I assume the inverter would allow the grid to power some of the house if it can't provide enough wattage during a peak load?

I'm sure I'll have more questions, but this'll get me started!

I would love your thoughts and advice,

Cheers!

munsterfan2

On Energia, so 4 hour Window, get about 55KWh, Zappi gets approx 25, Leaf on granny gets about 8, battery gets about 11.5

Hakaman2

https://www.boards.ie/discussion/comment/121804435#Comment_121804435

That's great info. I am assuming the Zappi takes out 7kw, so the rest is just your normal house draw from the grid?

I was told by an installer today that you couldn't use a car charger and also draw down from the grid to charge a battery effectively... I guess that's wrong?

Can you tell me about the inverter setup you're using?

Thanks!

Newtown90

Great thread - so much info to take in...

Looking at picking up a Seplos Battery Pack - has anyone picked one recently?

I was looking at the below on Aliexpress:

https://www.aliexpress.com/item/1005006593463027.html?spm=a2g0o.productlist.main.3.cd327221Ww5FV7&algo_pvid=79b37e0d-f996-43e7-bb37-604bade94b3a&algo_exp_id=79b37e0d-f996-43e7-bb37-604bade94b3a-1&pdp_npi=4%40dis%21EUR%211039.06%21748.12%21%21%211098.14%21790.66%21%402103864c17092909518465208e1cb6%2112000037753749002%21sea%21IE%21119951720%21&curPageLogUid=q7yDnjldpbua&utparam-url=scene%3Asearch%7Cquery_from%3A

unkel

https://www.boards.ie/discussion/comment/121836572#Comment_121836572

Yeah it's a pretty sweet deal, €600

Add 16 cells from NKON at €60 + VAT and delivery and you have a good looking 15kWh system for very little money (less than most people paid for a 5kWh pre-made system in the last few years)

munsterfan2

https://www.boards.ie/discussion/comment/121810088#Comment_121810088

Hi,

My setup is a bit messy - when house was built we put in a 3kw hybrid Solis inverter with 8 x 380 panels on roof. I have since put in 12 x 380, 11x380 (lost one panel to hurricane and had to lower frame ) myself, connecting these to the 3kw hybrid. I bought an additional 2.5kw Solis inverter (on here) and connected it to the 8 panels on roof.

Battery is connected to the 3kw hybrid, Kona connected to the Zappi ( 7kw ) and the Leaf connected to an external socket / granny charger ( 2.15kw). The heat pump kicks in for hot water ( up to 2.5kw at top temp) and 1.5kw for heat.

Between the battery and the solar only used electricity at peak rate for one day this week. Red is consumed, green is solar/battery and yellow is exported solar

Here is my gaily usage of EV rate vs day rate usage from esbnetworks for 21st to 26th

The devils

Has anyone installed heating pads on there diy battery setup if using outdoor particularly for below 5 degrees in garage/shed/lean too ?

SD_DRACULA

I was watching this guy

https://www.youtube.com/watch?v=ZzKR6tYRlwM

do battery terminals the right way and he made a very valid point that when we add the bms sensor terminals to one of the battery terminals we're actually messing up the way the serrated nut "digs" into the bus bar, it can't do that anymore with the the bms terminal underneath, and potentially getting loose over time.

He just drills a new hole in the middle of the bus bar and puts the bms wires on that.

Did anyone go through the trouble of doing that?

unkel

https://www.boards.ie/discussion/comment/121991761#Comment_121991761

Is he still mentioning his fancy woman from AliBaba? 😂

But yeah we did that recently for my mate's battery setup

oaklands

https://www.boards.ie/discussion/comment/121991761#Comment_121991761

Yes, I just tapped an M3 hole close to the +ve side of each bus-bar & seems to be working fine.

on_the_roots

https://www.boards.ie/discussion/comment/121991761#Comment_121991761

How is the temp sensor going to accurately take the battery's terminal temperature if you screw it in the busbar?

SD_DRACULA

https://www.boards.ie/discussion/comment/121997506#Comment_121997506

Not 100% but that's just there to check voltages/current and balance, the temp sensors are standalone, at least in the jk bms that I have

graememk

https://www.boards.ie/discussion/comment/121997506#Comment_121997506

Battery + busbar will stay at very similar temperatures

SD_DRACULA

Depending on how secure the connection is and the type of busbar as Andy tested here (by forgetting a washer under one of them):

https://www.youtube.com/watch?v=EjBqng70ORc

I'd probably prefer a more secure connection on the terminal myself and move the bms wire to an m3 separate terminal.

championc

The terminals, bolts and busbars is one area where the CALB cells excel. Far superior to the EVE's imo.

SD_DRACULA

https://www.boards.ie/discussion/comment/121998160#Comment_121998160

Yeah but capacity wise they are very meh.

This type would actually be perfect with the two terminals, can easily use one terminal for the bms connection and also more area of contact with the bus bar, shame the nkon ones are not like this (the nicely priced ones that is)