24v 8s 230ah battery build-my first

[Diesel Pro]

I started looking at Big Battery but too many issues. Also considered Chins/Ampere time. Neither of these had decent monitoring or low temp charge protect so now I am looking at building my own. Given proper instruction I can build about anything. My hang up tends to be analysis paralysis so I am floating this out there in hopes that I get some good guidance. System specs at the bottom for reference. The system and capacity are far beyond what is needed but allows for increased demand.

Looking at building a 24v 230ah battery. Could potentially be swayed to or down a touch in ah rating based on bang for buck.

Looking at Eve cells from one of the China/USA suppliers highly regarded here

6000 cycle rating: Seems many are adopting this standard. I’ve tried to research this and it seems that there is no real change to the construction it’s being used more as a marketing ploy stating the best case scenario?

BMS suggestions: I’d like a good monitoring setup be it a heads up display or a Bluetooth. The Daly BMS seems to come up a lot in searches. I was looking at this one: https://www.amazon.com/gp/product/B09798DWWR/ref=ox_sc_saved_image_1?smid=A22QWF3YLLYB17&psc=1

Containment: I was thinking I would build into one of these Noco boxes: https://no.co/hm462
It’s a whole lot taller than I need but 2 groups of 4 cells in a block configuration should fit nicely.

Off Grid cabin unoccupied 350 days of the year. My system is much oversized for what we normally do. Has heat to keep from freezing, but standing pilot can go out so low temp charge cutoff on BMS would be required.

Magnum 4024 Inverter
Midnite Classic 150 charge controller
4x 320w Solarworld panels
430ah 24v wet battery bank-these are 4years old and now cooked


Parasitic draw for inverter, television, microwave, and a small fan in the partition wall that moves air from room to room. Amp draw of these loads does not show on the Magnum. The issue with wet batteries is not being there for weeks or months at a time and finding the right balance of sufficient charge voltages versus water cook off.

When we are there we run very little load 99% of the time. I have a small air conditioner that I run once a year to make sure it works. Otherwise it’s on standby. Microwave gets used here and there so that’s the most common large load. During maple syrup season I bring my Honda EU2000 generator so I can power my reverse osmosis. This is probably up around 1600-1800watts. On occasion I have run the R.O. on the battery system just to test and exercise it.

 

[Bvillebob]

Your plan sounds good, all good gear. At this moment I think you can get EVE 280 ah cells from Texas stock from Docan, I just got 16 of them a few days ago and they said they'd ship next week from Texas.

I'm running 3 of the Midnight Classic controllers, I love mine and they've been flawless for me. Northern Arizona has the best price and they're about $30 off for the next week or so.

The Magnum inverters are good. I like the Samlex EVO series, check out the prices on DonRowe.com, they beat everyone else by quite a bit.

I think you'll find the Overkill BMS are better thought of than the Daly, quite a few issues with those and pretty much zero with the Overkill, they have excellent bluetooth monitoring and proven low temp cutoff ability.

Good luck.

 

[wiseacre]

A big cheer for making Maple Syrup

I built two 24v batteries using Lishen 202Ah cells with JBD 8s 100a BMS. (400+AH)
Using 2 batteries in the bank allows each to share both load and charging and provides redundancy.
If one battery goes bad I still have some capacity.
The pair of 100a BMS isn't much more expensive that the single 200a you linked to. I also went with the JBD because I've seen a number of complaints about Daly. To be fair there are also a number of positive posts.

I suggest either Overkill or CurrentConnected if you decide to go with the JBD. I purchased from currentconnected.com
With low temp charging cut off you won't need to worry about charging during freezing temps.

Going from Gel to LiFePo4 was the best thing I have done for my system. I can draw down the battery and not have to worry about long periods of poor sun and resorting to alternative charging during the "dark days" of winter.

Considering fixing/compression the cells that battery box might not be ideal. See some builds posted.
With the aim of 230Ah I would suggest using lower capacity cells (100Ah) and making two batteries and wiring them in parallel. Although if I had the means I'd stick with the 230s to have a really nice capacity bank.

My battery bank basically just sits on a 2' foam board covered with 1/4" plywood and topped off with some rubber pond liner. For winter I built a take apart box using more 2" foam board and placed a seed starting heat mat on edge between the batteries. The box is about 4' long, 2' wide and long. The heating mat uses 20w and keeps the box toasty warm.

I build the system to use for my sugar shed, lights and a 1800w induction hot plate for finishing off the syrup. I only have 30 some odd taps and have a Leader 1/2 pint evaporator so it's much easier to finish off a day's run on the hot plate rather than keep boiling the same batch over and over until I have enough to draw off the evaporator. (makes some very good extra light syrup). On a sunny day there's no problem running the induction burner and now with the lithium batteries I have enough capacity to run a couple days without sun. (each day's run is boiled down to about 1/4" leaving a little over a gallon of sap to finish off. A bit of a pain being very careful to stop stoking the fire at just the right time and letting the sap level slowly lower)

 

[Diesel Pro]

I will look at the Overkill BMS. I was looking at 200 amp capability, but that's pretty "overkill" in my setup.

I wish my Magnum had less parasitic and better frequency control for clocks.

 

[jamiegreen]

Personally I'd go for something else other than a Daly BMS, once you get inside them their construction really isn't too great.
I'll give my 2 cents on what to buy.

I bought my LF280K (6k cycles) from Amy Wan at Shenzhen Luyuan Technology
You do pay a bit more, but the packaging is amazing and the cells are perfectly matched grade A.

I bought a JK BMS 200a from here.
If you haven't checked out "OffGridGarage" on YouTube he's well worth a watch and goes into good detail on this BMS.
I have also heard good things about the JBD BMS too, but have no personal experience.

About containment, mine is static, but I used 2 sheets of ply, threaded rod, and 4 valve springs to maintain pressure on the 8 cells sandwiched within.

 

[Diesel Pro]

280 6k in USA or shipped from China?

Haven't heard any commentary on the 6k versus 4k other than the assumption that more is better which may or may not be the case.

 

[jamiegreen]

280 6k in USA or shipped from China?

Haven't heard any commentary on the 6k versus 4k other than the assumption that more is better which may or may not be the case.i

I believe I've read about a seller in Texas who imports them. Mine are straight from china, depends if you mind waiting, mine took roughly 80 days to the UK.

I think the 6k cycles may be a slight marketing ploy.. If I recall they are only rated at 6k at 0.5c discharge, at 1c discharge they will obviously have less cycles.. but how often are people discharging more than 0.5c in a solar setup..?
Also only rated for those cycles with cell compression, hence my rods and springs.
But even so, after all those cycles you still have 80% capacity.

 

[Diesel Pro]

OK I managed to order my JK BMS today B2A8S20P so I have a start.

Debating 230ah vs 280ah cells. Bang for buck goes to the 230's