Connecting one or two Weco 5.3 kwh batteries to an existing system

k123456 · 15-08-2025 10:01AM #1

I have one Solis inverter

14 panels

1 Weco 5.3 kwh battery

I am considering getting one or two Weco 5.3 kwh batteries

or one 10kwh , but probably ;

two Weco 5.3 kwh batteries

Apparently to daisy chain the new batteries

you connect in this way

Is there anything else I need to consider apart from the weight 2 x 60kg

weco wifi to update using bluetooth, so that the new batteries have the same firmware as old (this is optional I guess)

cable from old battery plus to plus and neg to neg

old can b to new can a

ratracer · 15-08-2025 10:13AM

I had a second Weko 5.3kW battery added to my system last year, after a year of operation, and have had no issues with either battery.

k123456 · 15-08-2025 10:20AM

Thanks and did you self install it, and is the process above correct

ratracer · 15-08-2025 06:22PM

No, I left it to the original installer to install it. It sounds about right though.

Ha Long Bay · 15-08-2025 06:26PM

https://www.boards.ie/discussion/2058422017/connecting-one-or-two-weco-5-3-kwh-batteries-to-an-existing-system

Not familiar with Weco batteries but I imagine the can bus needs to also be linked between them using a cat5 cable.

mjatkey · 17-08-2025 08:00AM

https://www.boards.ie/discussion/2058422017/connecting-one-or-two-weco-5-3-kwh-batteries-to-an-existing-system

Hi, yeah I had two WECO's installed originally, was going to add a third but went DIY Seplos instead, you get 3x capacity of one 5K Weco for similar price (I was quoted €2200 to install third Weco) paid £1500 for the Seplos.

If you do add the Weco yourself I'd say its handy enough just need to reconfigure the dip switches on the batteries so they all act as one.

The App lets you add the Weco's to your LAN updating firmware is fine.

hhm · 03-11-2025 04:22PM

Hello Mjatkey,

Disclaimer: I have very little electrical knowledge and am looking to educate myself a bit and am looking to increase my solar setup battery capacity from the 1 x Weco 5K3 which I have currently connected to a Solis inverter which has been installed in Spring of this year..

Could you link me the specific link where you ordered your Seplos battery from?

Does the Seplos battery cell voltage match the Weco battery voltage (51.2V?) or is there a differential i.e. Seplos 48V? The reason I ask is when I check Fogstar.co.uk I can only seem to see 48V circa 15kWh battery systems for sale.

mjatkey · 03-11-2025 07:32PM

Hi, yeah both Seplos came from Fogstar and voltage wise you are fine 48V-54V is like the working range of most LV solar batteries.

Fogstar will only deliver to Northern Ireland but there are a few companies that will onward transport or collect yourself.

Plenty of videos on assembly and set up from our own ghost, plus of course the guys on here are spot on with any help/advice that is needed.

I run the house inverter as WECO battery still as when I was running User Defined on the Solis it (not necessarily connected) stopped working correctly and had to be swapped out.

billy_beckham · 05-11-2025 09:51PM

Hi Folks,

current setup has 1 battery, looking to add a second. Is it Diy'able? Anyone got experience or tips?

Thanks

graememk · 05-11-2025 09:57PM

Moved to existing thread with related info

billy_beckham · 06-11-2025 06:06PM

Anyone done this before? Add a second weco 5.3kwh battery?

graememk · 06-11-2025 07:10PM

@mjatkey had 2 before got the 15kWh one.

It should be a straight forward thing

mjatkey · 07-11-2025 12:45AM

https://www.boards.ie/discussion/comment/123965710#Comment_123965710

Thanks graememk, yeah I added a 15Kwh Seplos to two existing WECO's no real issues, to add a WECO would be very straight forward, just connect DC from new to existing (additional connections are already on batteries) try to use same length cables or even add a couple of bus bars, (probably bit of over kill) then CAN cable (RJ45 (LAN cable)) the two together, probably need to change the dip switches on both batteries but mail WECO and they'll tell you what way they go.

I can check mine but out the country till next week end.

Thanks

billy_beckham · 07-11-2025 01:27PM

Hi, Thanks for replying, it'll have to be cables. existing battery is wall mounted. Won't be stacking them. From research I've done so far I have 2 questions,

Can the + & - cables just be daisy chained? As per attached image.
20251107_132536.jpg

2. Do I need to check voltages on both before connecting in parallel?

mjatkey · 08-11-2025 12:42AM

https://www.boards.ie/discussion/comment/123969506#Comment_123969506

Yes, thats fine mine were originally connected like that and yes ideally the voltages should be similar (which they should be unless one is very discharged) but once connected they will balance out with the higher passing current to the lower.

k123456 · 09-11-2025 10:44AM

If you ring Weco or whatsapp them (there is a number on their website), they will give some guidance and send online docs on how to , you will need to explain what type of inverter you have (Solis etc)

billy_beckham · 29-11-2025 08:41PM

Hi Folks, so I have connected up the second battery, all ok. Just wondering if I need to change anything on the inverter (Solis) ??

Thanks

Connecting one or two Weco 5.3 kwh batteries to an existing system

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