Seplos mason battery build [Should I get 2 x 5kWh or a 10kWh battery?]

DC999 · 30-09-2024 12:05pm

https://www.boards.ie/discussion/comment/122667409#Comment_122667409

You've 1 more sub :) I love a good auld solar 'how to'

nimrod86 · 01-10-2024 6:51pm

Very interested in going down the DIY battery route, especially as I have the same inverter as …Ghost… does so following along should be handy (I hope!).

The link Ghost sent months back to the Battery Cells gives a 404 now, but on the NKON site they have 280Ah cells available in the coming weeks. I'm wondering can anyone tell me what the difference is with prismatic cells, and more importantly should "non-prismatic" cells be avoided when building a Seplos 280L Mason battery?

As it stands, I'm looking at getting these cells, and this Seplos kit when Fogstar has them back in stock.

KaseLieberKase · 01-10-2024 7:38pm

Similar to you Nimrod I'm about to take the plunge on a Yixiang DIY Case and 16x 280Ah REPT cells for about €1,450 after payment processing fees. Seems like a good deal, but hoping someone wiser can let me know if I'm making any glaring mistake with this order.

For context I have a SAJ H1-4K-S2 hybrid inverter and 4.4kWp solar array to go with this.

Case Link (https://www.alibaba.com/product-detail/YIXIANG-DIY-16S-48V-51-2V_1601258989869.html)

Apologies if spam as I did post similar in another thread!

...Ghost... · 01-10-2024 8:35pm

https://www.boards.ie/discussion/comment/122673417#Comment_122673417

The B Grade cells are all you need for home storage. The 315Ah cells will be a better buy than the 280Ah.

https://eu.nkon.nl/rechargeable/lifepo4/prismatisch/envision-hc-l315a-3-2v-315ah-1008wh.html

I'm also waiting for these to come back into stock, as well as the Fogstar Seplos Case. Be sure to pick the correct grade case to match the cells. The cases are setup for A and B grade, so you need to get the right one.

nimrod86 · 01-10-2024 10:29pm

https://www.boards.ie/discussion/comment/122673834#Comment_122673834

Thanks for the reply! Good to know about the different battery grades, will keep in mind. I've subscribed to be notified when the batteries are back in stock, and sent a message to fogstar to see when the cases might be back in stock too.

Have you had any issues getting the battery cells shipped here? Looks like NKON are only charging around €75 for shipping which seems great considering the weight.

GarlicBed · 01-10-2024 10:29pm

https://www.boards.ie/discussion/comment/122673834#Comment_122673834

"The cases are setup for A and B grade"

Whats the difference in the setups ?

KaseLieberKase · 01-10-2024 11:00pm

https://www.boards.ie/discussion/comment/122674354#Comment_122674354

There are different terminals on Grade A and B EVE LF280K cells.

...Ghost... · 01-10-2024 11:35pm

https://www.boards.ie/discussion/comment/122674349#Comment_122674349

My first lot was delivered no problem. The second lot I collected when driving to Germany.

Likewise on the case from Fogstar, except the delivery is to NI and needs collecting from there.

On a side note, I thought 20kWh of storage would be more than enough for me. It's not. I have 26kWh useable and have run out of juice near enough to midnight on a couple of occasions….notably when people are home and using appliances.

It's near enough midnight now and I have 78% remaining in my cells. That's still more than 20kWh! So, I will have used only 6kWh from battery because:

My house imported 40kWh to charge the car, top up the batteries and compensate for higher loads during the day (if any).

Solar generated 16kWh and exported 7 of those to the grid.

The battery discharged 12kWh today.

A few variables to consider. I'd rather have it than need it, so will get the extra battery.

...Ghost... · 01-10-2024 11:38pm

https://www.boards.ie/discussion/comment/122674354#Comment_122674354

Busbars are different sizes for A or B to connect the cells.

Fogstar did give me the wrong accessories kit for my second pack, so mistakes can be made. It was only because I had built one previously that I realised I got the wrong kit…the one without the active balancer. They were quick at sorting it out and I would have no problem recommending them.

nimrod86 · 02-10-2024 3:08pm

Fogstar replied to me, they're hoping to have the Seplos Mason 280L back in stock on Oct 11th. They also recommended their kit for £1499 which includes 305Ah Grade B cells but I think it's still slightly cheaper to get the NKON 315Ah cells you recommended and pair them with the case. Extra bit of power too along with the small cost saving!

...Ghost... · 02-10-2024 8:27pm

https://www.boards.ie/discussion/comment/122676543#Comment_122676543

Good to know they are soon to be back in stock, thanks.

My other 2 batteries are 305Ah, but NKON don't seem to have the exact ones I ordered previously, so 315Ah will do when they are in stock.

I think the reason I wouldn't be as keen to order a pre-built battery is having to collect it from NI. They are HEAVY!!! A good 130(ish)kg.

nimrod86 · 02-10-2024 9:58pm

Possibly a stupid question, but will the BMS in the Seplos kit work with 315Ah cells? I assume like you showed in your video you would need to connect to the BMS to tell it they are 315Ah rather than the 280Ah it's default for, but otherwise it shouldn't care?

Another question, do you use an Eddi and if so was there any issue with Eddi trying to drain the battery to heat water?

mjatkey · 02-10-2024 10:01pm

Hi Ghost, hopefully getting the inverter install done soon so looking at what way the Seplos dip switches should be set for the CAN to work with the Solis inverter (same that you have), currently the first from left is in the ON position?

Also what size DC breaker/isolator do you use between the two, only using the one 280L?

Thanks

...Ghost... · 02-10-2024 11:37pm

https://www.boards.ie/discussion/comment/122678194#Comment_122678194

Not a stupid question. Setting the correct capacity in the BMS studio will let the BMS do its thing. Even if you had several pack with different capacities, a long as each BMS knows the capacity of the pack it is managing, it should be fine.

I don't use an Eddi, but that can be setup to use only excess solar.

graememk · 02-10-2024 11:41pm

as for the eddi, you may need to set a export margin of 50w to stop it from pulling from the battery, (or grabbing the excess before the battery does)

...Ghost... · 02-10-2024 11:51pm

https://www.boards.ie/discussion/comment/122678211#Comment_122678211

If using V3 BMS, set all DIP switches to OFF position. The BMS will manage without them. This can be seen about 10 minutes into the video where I connect the second battery.

I have yet to install the breakers. Pretty sure I have 250A DC breakers ready to go. I will have a breaker separating each pack before it connects to the main busbar.

mjatkey · 03-10-2024 9:28am

https://www.boards.ie/discussion/comment/122678540#Comment_122678540

Thanks Ghost, and BMS set for Ginlong_CAN and inverter battery setting for Aobo or User defined?

Calahonda52 · 03-10-2024 9:39am

OP: great stuff here, maybe think about putting some of it in a separate thread with a relevant title as this "gold" will be lost under the current thread title

...Ghost... · 03-10-2024 4:23pm

https://www.boards.ie/discussion/comment/122679022#Comment_122679022

I am set as user defined. AoBo behaved strangely.

https://www.boards.ie/discussion/comment/122679061#Comment_122679061

I suppose I could do that. Thread title isn't exactly appropriate for where the thread is now.

con747 · 03-10-2024 4:28pm

https://www.boards.ie/discussion/comment/122680603#Comment_122680603

Maybe work with a Mod and get the relevant posts on a sticky on the main page with the other stickies. @graememk @Jonathan if you think it's ok.

mjatkey · 03-10-2024 5:18pm

Thanks again Ghost.

Muahahaha · 06-10-2024 2:38pm

Very interesting thread. Can I ask whats the approx cost of a DIY 10kw battery? Im tempted but not sure if Im a good candidate for it as more than 60% of my electricity usage is now at night rates anyway with all the heavy loads like dishwasher, washing machine and hot water heating done on the lower unit rates.

Can I ask with these set ups is there any software you can get that dictates the flow of power. Like for example can make your solar panels fill the battery rather than power the house/export to the grid?

graememk · 06-10-2024 2:47pm

https://www.boards.ie/discussion/comment/122690307#Comment_122690307

Generally it's 14-16kWh now as the cells are 280-300ah each.

Cost could be about 1500ish. Can get box and BMS for 4-500 and cells are currently under 1k.

Or a all in one kit from fogstar at 1500 GBP (but will only deliver to NI )

As for power flow, house will always get first use. Normally without external control the battery gets the rest until it's full. Then it's exported.

What some people are doing, especially with oversized arrays is restricting the charge of the battery to export more and when the inverter reaches its ac limit it puts the "excess" into the battery

...Ghost... · 06-10-2024 3:10pm

https://www.boards.ie/discussion/comment/122690307#Comment_122690307

What graememk said^

I would add that 60% of my use was at night too, but we use around 15,000kWh per year in our house.

The DIY battery route will be €1500 to €2,000 depending on whether you get a diy case or not. The Seplos is what I went for and you have about 13kWh useable is a pack.

My excess solar goes to battery and only then to the grid.

Muahahaha · 06-10-2024 4:21pm

€1500ish for 13kw is terrific value, I remember getting a quote about 18 months back from a company who quoted €3k to install a small 5kw battery.

@Ghost Id be a pretty low user of electricity, usually only about 3,000kwh per year. And at the moment my small 3.3kw solar system is generating about 2,400kwh of that annually. But next year Im thinking of getting an EV and if I do Id need 82kwh extra a week to run it the 550km I drive weekly. Annual electricity usage from the EV would be 4,260kwh bringing me up to about a total usage of 7,260kwh annually.

But just looking at my annual consumption and doing calculations off that. I currently use 3,000kwh charged by Flogas at 25c day/12.5c night units and at a 40/60 day/night split it costs me €525 a year. If I had a battery and moved to an EV rate of 7 cents to fill it every night for use to run the house those 3,000 annual units would cost €210, which is a 60% saving over what Im currently paying. At a saving of €315 a year it would give a €1500 DIY battery slightly over a 5 year payback period. Definitely food for thought.

...Ghost... · 06-10-2024 5:39pm

https://www.boards.ie/discussion/comment/122690742#Comment_122690742

Looks even better if you draw all your energy from the grid at 7c and use the battery during the day to run the house. If you can do that, then you could be exporting the solar and would see payback much sooner. My batteries will pay me back in a year!

nimrod86 · 09-10-2024 8:49pm

Putting together my shopping list for building this pack, and one thing that occurred to me is the installers who put in my inverter took away all the boxes/manuals/etc with them and left me with nothing. Did Solis provide the battery cables with the inverter or do I need to source these myself now? Can't find information about if the Seplos kit comes with them but I see on NKON I can get 2m cables and the RJ45 for €20.95.

Not sure if that's good enough though as when I searched for Seplos battery cables I found Ali-Express shops selling them as 50mm² cable but the NKON cables are only 25mm²… I think ideally I'd like to try buy cable and the connectors myself to make up my own as the location I want to position the battery means I'd need maybe 4m to 5m of cables to be able to keep it routed tidy.

...Ghost... · 09-10-2024 11:24pm

https://www.boards.ie/discussion/comment/122702423#Comment_122702423

If you got a solis hybrid inverter, it comes with the battery cables. Installers should have left these, as well as all the manuals which they are required to do.

NKON sell the cables (25mm) or you can make your own if you need longer runs. I would think it might be easier to get NKON cables with the plugs already connected. Cut these and connect between inverter and an MCB. And make your own cable to go from the MCB to the battery. Don't forget to ground the battery case for safety.

You need to supply your own comms cable. I just picked mine up in powercity.

olympicweights · 10-10-2024 5:15pm

https://www.boards.ie/discussion/comment/122702423#Comment_122702423

I used that set of cables on my Seplos Mason battery, no issues.

nimrod86 · 12-10-2024 3:42pm

https://www.boards.ie/discussion/comment/122702882#Comment_122702882

Yeah, crowd who installed my panels and inverter didn't leave them... They also left covers loose, cables without strain relief, and incorrectly wired the check meters in the consumer unit... I corrected all these issues myself but still dragged them out to see what they didn't wrong and apologise for it.

I've emailed them now anyway requesting the return or replacement of all the parts which should have been left with me but worst case I'll buy those cables from NKON. In good news, NKON told me they hope to have the 315Ah batteries in stock around the end of the month.