I've yet to finalise plans, but suffice to say, I've been perplexed by some peoples unwillingness, or anxiety about changing out their existing battery setups when they realise they need more storage. There's been a few threads where people have a WECO 5kWh battery and are asking about running a DIY kit with it, rather than just getting a DIY and selling the WECO, effectively doing a straight cost swap for triple the storage and a bit of assembly/setup. Some have just been afraid to make the leap and end up paying way too much for another WECO battery to increase their storage.
I get it. I nearly bought 2 x 5kWh WECO batteries when getting solar. I now have nearly 5 times the storage for about the same cost. The guys on here convinced me to go DIY and the kits were as far as I was willing to go. They're great and I highly recommend them. They're also very neat and relatively compact. The next stage is more about being flexible and optimising space and a small increase in storage without necessarily losing your wallet in the process. You can both save people money and hassle, while doing the same for yourself. Changing doesn't always have to mean you're breaking the bank. I'll document the whole process and hopefully I learn a little and can share that with others considering their options.
Hi ghost, sounds exciting, as you know I have 2 WECOs and Seplos on one property and 2 Seplos in another property, Solis inverters in both properties, replaced both of them once and due another swap on the apartment as the replacement is faulty, but that's another story.
There's no problem keeping your existing batteries and adding some self built or custom battery to it. In fact I have talked several people through doing just that in the last few months. A major benefit is that very likely they don't have to make any changes to their current setup, not even any changes in the settings, and can just parallel the new battery in
The new battery "piggy backs" onto the existing system, keep all settings, keep all comms as is. It simply adds capacity
Main issue is trying to shift the wecos 😂. Speaking from experience when I originally built my DIY set up I tried to sell the wecos. Had them up on adverts for over a year with only small interest despite several price drops. They're running now alongside my existing set up. Figured I may as well be getting some use out of them. I estimate at the price they cost me it'll take about 8 years to pay themselves off. Over double what the DIY set up will take. If anyone is interested in 2 Weco 4Klt's let me know, I'd happily do a boardsie a very good deal.
There's no problem keeping them (if you have the space), but I know if I had one, or two WECOs, I would sell them off. Even at a nice discount to the second owner, you can double or triple your capacity for the same money with a DIY battery build. You're partly to blame for this upgrade Unkel 😂. I'm looking away from Seplos and toward JK. As yet, undecided.
Everything has a market and a price to sell. Batteries aren't sexy, but I think with some effort and the right price, they will find a seller.
I've had a bunch of people asking to buy mine since they were installed, but I had no intention of selling for a small profit after the trouble of getting them in place and I didn't want to start building and selling them. I've built batteries for my inlaws and a boardsie, but I wouldn't be into it as a side hustle. I enjoy doing it and i'd like to keep it that way. Bonus points if it helps others do the same.
Thanks for that I'll have a look at them. I wouldn't mind having a go at building them myself. Would also make it easier to get them into the attic if it was in kit form.
@insular1 look at selling via the Irish Solar FB group. Should be plenty of takers in there I would have thought
Any sign of the battery? Keen to pull the trigger during tehe black friday sale
No according to my tracking it is in Cologne Germay so no update
Saw this on HUKD: https://www.fogstar.co.uk/products/fogstar-energy-seplos-48v-16-1kwh-solar-battery?variant=55202924757369
£1399 for fully assembled Fogstar 16.1kWh battery. It's pre-order, not sure about delivery cost.
There's a DIY kit version as well, approximately €1300 + delivery.
https://www.fogstar.co.uk/collections/seplos-mason-kits/products/seplos-v4-kit-and-x16-cornex-314ah-grade-a-bundle
Very decent prices. Unfortunately they have the **** Seplos BMS. They know themselves they are crap as they now provide a JK balancer as well 😂
They must have some contractual deal with Seplos or this whole venture is a joint venture with Seplos or something. It would cost less in parts to just have a JK BMS rather than a Seplos BMS + JK balancer
I guess you could just rip out the Seplos BMS and install a JK BMS yourself, but that defeats the purpose of the prebuilt kit and you might as well build your own
I have three Seplos batteries, a second hand 280L with Seplos BMS passive balancer only, 1 x V4 with Seplos BMS active and passive balancer and 1 x V4 with Seplos BMS and JK active balancer.
They all perform similar in terms of cell spread under charge and discharge, I've never seen the JK balancer active or the Seplos BMS balancer active on either of the V4's.
The 280L is off line at the moment with a dodgy cell (it was second hand to me) waiting for a couple of new ones to arrive from Fogstar, now this one did get over 100mV spread in the charge and discharge cycles but seemed fine up until one cell just gave up completely no matter what I did with it, hence the replacement.
At what voltage is the difference measured at. If at 3.4/3.5+ is where it actually shows up
Around the 57v so 3.5x per cell on the V4 JK this goes to 100% soc as its just the one battery at the moment.
And 54V on the V4 non JK but this is one of 3 batteries (2 x WECO) so it never reaches 100% soc in the 4 hour EV window even with a 3Kw rectifier along side the 5K Solis.
Would I be better letting it get to 100% soc every week or so, by switching one of the WECO's off or using the PV?
Fogstar 16.1 kwh Battery £1399 delivered up north .
https://www.fogstar.co.uk/products/fogstar-energy-seplos-48v-16-1kwh-solar-battery?selling_plan=711643169145&variant=55202924724601
Get it sent here and then pick it up ! Happy Days
https://www.borderparcelmotel.com/
This Deligreencs kit is the cheapest I've ever seen these go. €1160 delivered to your door (paired with LiShen cells, 17kWh total).
https://deligreencs.com/products/jk-51-2v-300ah-battery-pack-diy-kits-with-jk-bms-and-active-balancer?variant=55738907492732
Is it too good to be true?
FYI: in one photo they show flexible busbars for main connections and in another what look like very thin doubled-up wires.
Looks like a JK BMS too. Very good price if real and indeed includes all duties, taxes and shipment to Ireland
32kg for that size of battery.
Weight (kg)
32kg
Possibly a mistake but needs clarifying along with a few issues on that website, open 15 years and only a handful of reviews all in the past 6 odd months on their website.
That's what our AI buddy reckons. Anyone in here brave enough to buy from this crowd?
Same basically but longer from Google Gemini.
TLDR:More or less saying they're probably ok for small purchases, but be very weary if using them for LiFePO4 cells
Based on user reports from solar enthusiast communities and available data, here is a detailed breakdown of the safety and reputation of deligreencs.com (Changsha Deligreen Power Co., Ltd.).
Deligreen is a legitimate company, not a fake "scam" site that will take your money and disappear. However, they have a mixed reputation in the DIY solar community. While they are a real manufacturer and distributor, many users report receiving products that do not match the description (e.g., "new" batteries that arrive used or bulging) and poor customer service when things go wrong.
Better Alternatives for Batteries:If you are looking for reliable LiFePO4 cells, the community generally recommends vendors with a verified track record of honesty, such as:
If you do buy from Deligreen, video record yourself opening the package and testing the voltage/capacity immediately. You will need this evidence if you have to file a dispute.
Zoom_cool is expecting a delivery from deligreenmc. Waiting to see how it goes.
I did the tracking says the consignment is in DHL Ireland may have it today. I paid with Paypal so hopefully if a problem I will be ok.
Results of today's research:
Looks like the Fogstar kit might be the best value when trying to compare like with like, I've left out aliexpress for now, because my minds melted enough.
I'd be competent enough to build a kit, once I knew parts were compatible (thanks @...Ghost... for the videos)
Is there anything glaringly obviously wrong, or a supplier with major savings I should check out
I've 7kWp, and hybrid Solis inverter mounted on external wall of garage, battery will be going on internal wall
From
What
Dispatch
Subtotal
Shipping
Total
€
Parcel motel
Drive
Fogstar Kit
SEPLOS V4 Kit and x16 Cornex 314Ah Bundle
21/12/2025
£ 1,140
£ 60
£ 1,200
£ 1,371
€75
€30
€ 1,476
Fogstar Prebuilt
Fogstar Energy ECO 48V 16.1kWh Solar Battery
18/12/2025
£ 1,400
£ 1,460
£ 1,668
€ 1,773
NKON Prebuilt
NKON ESS Pro - 51.2V 16.1kWh Home Battery
15/01/2026
£ 1,900
€ 238
€ 2,138
NKON DIY
Cornex PF173-314A 314Ah LiFePO4 3.2V - Grade A-
16
£ 57
£ 919
NKON ESS Cable Set – 2.5m 50mm²
1
Seplos 3.0 - 48V +13.44kWh Home Battery DIY Kit
£ 570
11/12/2025
£ 1,549
£ 238
£ 1,787
€ 1,787
AliBaba is always cheapest. Cut out the middle man. But if your head is melted from gently surfing AliExpress, you will probably want to avoid negotiating 24/7 with Chinese representatives, with dodgy western names, who don't have the best English, from 30 different factories, in a very different time zone 😂
No shipping charge on the prebuilt unit. Looks like they have added in the £60 on the others to claw a few quid back - I don't believe it was there at the start of the week.
You're welcome. Are you using the DIYSOLAR10 discount code with Fogstar?
No longer valid either!
What? I'll get onto them!
I have a diy fogstar v4 set up the last year or more.
I've ordered another.
Do I need to do anything with the BMS on the second one or will it just be a slave to the first.
Honestly haven't changed a setting on the first one since day one so can't remember anything at all 🫣
