Build Thread - 120Ah LifePo4 - 40 mile range for less than $1200?

[AussieInSeattle]

Thanks for the comments so far. A bit more progress on wiring up Sergio's black box circuit design. Am waiting on cell balancing ring connectors before I can make more progress. I hope to top balance this weekend via a bulk charge and then a parallel charge.

Pictures are:
1. Layout of black box with the terminal blocks for the bms balance wires located under the bms - I changed the relay locations - swapped the bottom two relays which made more sense
2. Innards of the UY600 charger from amazon - black V on pot - turned counter clockwise to desired voltage
3+4. Wiring done except for the BMS balance wires
5. top view of wiring showing renogy shunt

Only thing I would have done different so far is making the black wire from the LED longer as its a bit tight when you tilt the bms up to get to the green terminal block that the balance wires will go into from BMS side and pack side. I anticipate needing to get to this block at certain times to measure individual cell voltages instead of having to take the cover I plan on building for the top of the cells.
.
.

[NCPW]

Looks good!

[simicrintz]

Very clean work

[AussieInSeattle]

Got the 16 cells wired up in series with the provided busbars and wired in the cell taps to the terminal block located under the BMS. Hardest thing was concentrating on not shorting any of the cells during that process with the BMS wires or any of the tools (which I wrapped in electrical tape). I'm using 20mm M6 studs instead of the supplied bolts in the soft aluminum threaded cells to eliminate the risk of stripping during disassembly since they will always stay in.

Always a bit scary when you first power on something like this - I "jumped" when the relays clicked thinking it was a short but all is well. On my first attempt to charge the pack, the BMS kept shutting off the charger and then it would turn back on again after a couple of seconds - traced it back to nuts on my terminals not being tightened down and creating a poor connection for the cell taps. Had not tightened them fully as I am planning on disassembling after a bulk charge at 48 volts and paralleling the cells for a top balance.

I only have 45 minutes of charge on the pack and its at 53.1 volts - am figuring it is about 70% charged already as they seem to ship at about 60% charged. Cells range from 3.315v-3.322 so only .008V difference between high and low so far.

[Mike from Texas]

Looks great. I like your battery box idea.


Sent from my iPad using Tapatalk Pro

[Drumstick]

I am curious to hear how long it will take to fully charge your pack - I am assuming your UY600 is 10 amp, right? These chargers seem to get to about 90% quickly then slow to a crawl for the last 10%.

[mattkovo]

Looking good. Where did you get your battery terminals and green terminal blocks? Do you have any links?

[AussieInSeattle]

Originally Posted by Drumstick

I am curious to hear how long it will take to fully charge your pack - I am assuming your UY600 is 10 amp, right? These chargers seem to get to about 90% quickly then slow to a crawl for the last 10%.

Took about 6.5 hrs to push 48Ah into the pack on the first charge - I dont really know what my pack percentage is though - am thinking it is 85%-90% charged at this point. Still some more research/testing to do.

[AussieInSeattle]

Originally Posted by mattkovo

Looking good. Where did you get your battery terminals and green terminal blocks? Do you have any links?

I assume you mean the through wall Battery Terminals and the covers (pic coming soon) - those were from here:
https://www.vtewarehouse.com/content...ower_posts.php
I also bought their big *** fuse holder but didnt use it - I did use one of the spacers that came with it though.

Green Terminal Blocks from here:
https://www.environmentallights.com/...sult?q=phoenix
Thanks to Sergio in his thread for pointing me towards "phoenix" connectors - that's how I found these.

[mattkovo]

That's perfect. Thanks!