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Hi all, A few months ago I made a post about my 3D printed battery design based on EVE 304ah cells. The project was completed a month ago but I have been very busy with work since then. I just managed to find some time to push the design to Github...

This is a 210ah (105x2) battery I built for my 16-foot trailer. I purchased most of the components prior to discovering this forum, had I read this forum first, I probably would go with 280ah cells, much cheaper and requires just 1 BMS. With that out of the way. I hope my experience would be...

OK, just finished designing of this battery case, I named it '300', as it's 300ah and fairly spartan :) Waiting for a couple of components to arrive before I kick off printing. If all works well, I will put the design on github. Wish me luck :) Cells: EVE 304ah BMS: JBD 200A

Wow, this is it! all make sense now. After I read your comment I went to check my connection (previously I did use multimeter on busbars) and I discovered one of the terminal has a small piece insulation squeezed by crimper got between washer and bus bar. after I fixed this everything seems...

Just want to give a quick update on my progress. The printed parts (4 cell sections, 2 end caps, 1 top cover and 4 mounting feet) are completed, with 4 3/8" steel rods the case is very strong. The 4mm wall thickness seems to be a bit overkill, 3mm probably is enough. So the overall design is...

@JG51Ogg Sorry to hear the bad experience you had :(. But seriously. 8 420ah Grade A cells for $1186, What else were you expecting other than a scam? Did you seriously expecting this seller, not only willing to sell you something at loss, but also had an R&D that blow away all battery companies...

One aspect that has not being discussed is the energy density - in my application I have very limited space for LiFePo4 battery - for the space I can place 210-280ah battery, while only 100ah Battleborn. This was deal breaker for me for Battleborn. I have watched Will's video he cut open a BB...

Without specialized welding tool it's PITA to connect these cells, and why? the prismatic cells are smaller in volume, easy to work with.

I am not sure where you picked up I was defending the scammer. If you are going the DIY route, you need to have some basic understanding of the technology - understand 420ah with the same dimension of 280ah is not possible doesn't require anywhere near 100% researched.

I want to give an update on this, it's very likely the BMS app was reporting wrong SOC since I just connected everything together and there was no charging/discharging cycle for it to give it more information. After I top balance and fully charged it, the cells worked as expected.

For functional parts, I use 15-20% honeycomb almost exclusively. it offers far better strength than the default one. For critical parts involves fasteners, I also use different infill at point of contact (in Pusaslicer), but in most case this is not necessary. I found counter sink screw holes...

The mounting option is where this design truly shines, with a bit longer rod at the bottom, I could add a printed clamp at the end, even hold down 2 batteries side by side. or if I am length constrained, I can put a tab with screw hole on the side, the possibility is endless :) My slicer says...

@bryn I was waiting for copper bar and 1 awg wire to arrive for fitting verification. I will start the printing tomorrow, and I would take a few days to complete. Definitely will post update here, no matter the result is.

Thank you, the video is very helpful. I will definitely wire the 3 panels in parallel, looks like PV2 in above diagram would be more impacted than Pv1 and Pv3 as multiple cells would be entirely in shade of the AC unit.

Very nice work, @bryn I can definitely appreciate the hard work behind this, as I went through this process just a couple of years ago. Some feedbacks - 1. I noticed the section of rod tunnel is square, there are 2 downsides of this - a) it uses more material, takes longer to print, without...

Thanks for your comment and glad to hear your setup works well for you - I am pretty confident the modest sized panels (rigid or foldable) would work well for me as well. We made conscious chose not to go big rig, our small trailer give us access to some very best camp in PNW that bigger rig...

In my case it was a faulty unit as I have another unit which didn't have the problem when connected to the same cells. I have just ordered 2 4s 200A one from Alibaba, I only need one and I am ok if one of them is faulty, it's about $70 a piece.

Can the 'Charge' connector of the 7-way plug be disconnected from trailer, so the trailer battery will be charged by either shore power or solar? I can't think of any reason why I would need towing vehicle to charge my trailer's battery. I prefer they stay isolated even without the alternator...

That's a good point. likely.

That's my main/house battery. is it illegal not to have the charge connector connected and no 'secondary/backup' battery? Breakaway is not a common event, and I just need to make sure I don't drain the main battery before start towing. The solar will top it off right? Wait, dang - I see the...

Thanks! I will likely use one of the brokers on this forum to get the cells, not sure if they supply BMS as well. I have purchased many things from aliexpress and I have to say I'd rather pay a little more to have a good mood :D

About to order a few 304ah cells from Jenny, anyone knows what's the difference between the 302ah and the 304ah cells? I don't really care about the 2ah difference, are they similar quality wise? Thanks!

I want to give an update on this. as I promised when I started this thread. First I did make a mistake, I thought 2 4awg wires = 1 2awg wire. I probably got this wrong idea from nail gauges, for which the width is what matters, but for wires, it's the area and 2 4awg wires are equivalent to a...

Many people do that (disconnect charging wire from 7-way connector) once they have decent solar. However you need to be mindful about leaving enough juice in battery for breakaway brake and fridge

I also received my EVE 304ah cells last Friday. Have not fully tested them yet but they look great. Thanks @Jenny Wu

Haha, that's cool, are you are software engineer? can't imagine folks of other occupation would use open/close bracket :D

@Tgmontague @HRTKD Not according to this post: https://diysolarforum.com/threads/how-to-quickly-kill-a-lfp-battery-part-2.3703/ Most charger float at 3.4v, according to varies voltage -> SOC table thats somewhere between 90% and 99%

Thank you @MisterSandals, that's what I plan to do, I was planning on using breaker as switch, but I have changed mind and added 2 marine switches (1 for battery disconnect, 1 for pv disconnect) for easier access.

Just want to give an update on this. Today I received a very cheap inverter that I ordered a few days back, just for testing batteries. the only thing in my house that draws high current is a electrical water boiler, the my battery put out about 75A total for 20 minutes, I used an IR gun on...

See this post for link to the project's github page Thank you all for being very patient with this https://diysolarforum.com/threads/battery-300-design-open-sourced.34832/