My 2P16S LF280K Battery Build

[cods4]

Thought I'd share some pics of my battery build. Happy to hear any constructive criticism.

I modelled it off Andy's (Off Grid Garage) battery rack.


My old bank (~40kWh of lead acid that was now only good for about 8kWh)


Removing the old batteries (each cell weighs about 12kg)


New cells arrive


Made up some end plates from 8mm thick steel for compressing the cells.


I designed a laser cut panel to hold my BMS, active balancer and terminals


Cells in position ready to be be compressed a little


Wiring up balancer and BMS


Series connections installed (yes I should install dual wall heatshrink on the lugs, but I didn't have enough and that stuff is expensive.)


Mid-string class T fuse (I soon found that this added quite a lot of resistance and messed up my BMS voltage sense readings for cell 9 under heavy load, fortunately Seplos have an extra sense wire for cell 9- which I originally just connected up to cell 8+. Once I moved this over to the negative side of cell 9, my voltage readings came right).

 

[cods4]

Battery all done


I also had to make some changes upstream at the inverters. This included replacing the old 40A DC MCBs with 125A DC MCCBs and redoing some of the DC cabling.


Mostly complete


I didn't have to do much in here, but here's a peak inside the battery isolation panel. It is ready for a future second 2p16s bank.


The finished product (for now)

 

[cods4]

3

 

[NCislander]

Nice looking upgrade from your Lead Acid. Gets me excited. Picking up my LF280K cells next week. How do like the Seplos BMS? That is Seplos, correct?

 

[cods4]

Nice looking upgrade from your Lead Acid. Gets me excited. Picking up my LF280K cells next week. How do like the Seplos BMS? That is Seplos, correct?

Yeh Seplos 200A 10E BMS.
I am pretty happy with it. I like that you configure it via pc software rather than a mobile app using bluetooth. It just seems a bit more industrial.

Most of the settings are very difficult to understand becuase of the poor translation from chinese to english. So be prepared to do some research into what all of the functions mean. But on the plus side there are lots of options.

Comms to my Deye inverters has worked well.

 

[googdot]

Love it...Build looks awesome, mate.

 

[42OhmsPA]

Very nice build and clean install!
My only question / advice, if those are particle/pressed board shelves I'd be concerned with them bowing / collapsing; especially if they ever got wet. I see there is plenty of support in the framework but the shelves caught my eye.
Nice work on the steel plate and front cover. I just got a 3d printer last week, I see a laser in the future.

 

[NCislander]

Can I ask where you purchased your Seplos 10E from? Also delivery time?

 

[cods4]

Very nice build and clean install!
My only question / advice, if those are particle/pressed board shelves I'd be concerned with them bowing / collapsing; especially if they ever got wet. I see there is plenty of support in the framework but the shelves caught my eye.
Nice work on the steel plate and front cover. I just got a 3d printer last week, I see a laser in the future.

Thanks, yeh that was a thought. It looks pretty flimsy, but the shelf is rated for 500kG so it should be fine unless it gets wet as you say. Fortunately the shed is very dry and warm and it's off the ground so I decided it wasnt work spending $200ish on another sheet of aluminium.

 

[cods4]

Can I ask where you purchased your Seplos 10E from? Also delivery time?

Ordered it directly from Seplos, arrived within a couple of weeks via DHL or fedex I think. Shipping wasn't cheap to New Zealand though.

 

[NCislander]

Ordered it directly from Seplos, arrived within a couple of weeks via DHL or fedex I think. Shipping wasn't cheap to New Zealand though.

I appreciate the Seplos shipping/purchasing info. I was considering JK BMS. 1st time DIY battery builds. I need to make a decision this week.
Anything specific on the Seplos BMS features you prefer to other BMS units?

 

[cods4]

I appreciate the Seplos shipping/purchasing info. I was considering JK BMS. 1st time DIY battery builds. I need to make a decision this week.
Anything specific on the Seplos BMS features you prefer to other BMS units?

I have an 8s Heltec BMS for another mini build I am doing, and the quality, size and weight of the Seplos BMS seems way better than the Heltec.

Basically I bought the Seplos because I wanted something that supported comms to my inverters, but I would buy it again (or something similar like a Pace BMS) simply because it seems a lot more solid and well built than the cheaper options.
Unfortunately I can't do any side by side comparison of them, but I wouldn't be surprised if the Seplos runs a lot cooler than the JK or heltec under 190A of load.

 

[NCislander]

I have an 8s Heltec BMS for another mini build I am doing, and the quality, size and weight of the Seplos BMS seems way better than the Heltec.

Basically I bought the Seplos because I wanted something that supported comms to my inverters, but I would buy it again (or something similar like a Pace BMS) simply because it seems a lot more solid and well built than the cheaper options.
Unfortunately I can't do any side by side comparison of them, but I wouldn't be surprised if the Seplos runs a lot cooler than the JK or heltec under 190A of load.

The build quality looks really good from photos. Beefy heatsink as well. I will contact Seplos for pricing/shipping details to my location.

 

[Whats_per_question]

Great looking install - shows some real thought has been put into the design work, especially your rack and compression system for the cells.

 

[740GLE]

Thanks, yeh that was a thought. It looks pretty flimsy, but the shelf is rated for 500kG so it should be fine unless it gets wet as you say. Fortunately the shed is very dry and warm and it's off the ground so I decided it wasnt work spending $200ish on another sheet of aluminium.

what is it 1/2” or 3/4”?? Keep an eye on it. IMO that particle board will fail just in a matter of time with that load on it. If it fails hopefully it’s a slow failure and you catch it. You may get lucky. . .

One thing about having that cover over the bank is you won’t be able to see any issues developing with that particle board until it’s too late.

 

[ChrisG]

Any issues with this 2p16s build? Considering doing the same with 32 105ah Eve cells. Have a 200amp JK with 2a balancer for the BMS.