hwy17's battery build


Anti-Solar Enthusiast
Nov 11, 2022
Santa Cruz, California
Rather than keep spamming new threads out as thoughts come up I'm starting a build thread now to share as I go.

16x EVE 304 from Ezeal
Orion JR2 BMS

Planning work in progress (polarity not detailed yet):

...1699473414237.png... would be the traditional symbol, but a TTL logic inverter symbol works for me :) - just don't connect 300V of PV to a 7404 TTL device!
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LOL... thought you meant Clive Sinclair for a moment, I exploded one of his amplifier chips in the 1980's (or was it 1970's... memory not so good at my age!)
Precharge circuit needs to get worked in there eventually. I wonder if I should precharge the main bus or just the load with the significant capacitors. Probably might as well do the whole thing.
My design so far is incorporating a lot of short bus bar connections between contactors and multi post bus bars.
At first I was thinking of using the Blue Sea Link bus part, but it looks like they're all 3/8ths and I need 5/16th's.

Anyone recommend any products or vendors?
I could use battery bus bars and drill them out, but I have trouble trusting the generic brands:

I have gazed into the depths of the manual again and the BMS is still hungry for more control. I will plan to serve it an AC power relay as well.
I like that the warning just says "whenever possible" turn off the power first. Because this is the wrench for when you gotta do what you gotta do.
Screenshot 2023-11-12 at 5.29.49 AM.png
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I'm considering whether to buy a bench supply for top balancing vs. just assembling and trying to passive balance it in action.

One one hand, I'm a bit skittish about top balancing all in a row before assembling the pack, because I would rather have compression on them before taking them up to full charge. If I assemble in pack form, then I won't easily be able to parallel them with bus bars.

For a while I was leaning towards no bench supply, but now I'm considering that even if I don't top balance at first, I might want to have the ability to do some individual cell charging.
I top balanced my cells while in the fixture.

See the below video at 4:40.

Instead of using temporary bus bars as shown in the video, I used wire to connect the cells in parallel. The amps passing through each connector wire was so low that I was able to use relatively low AWG wire leftover from a previous project.

EDIT: I installed my cells in the fixture in the same orientation I planned on using for the permanent series pack. By using temporary wires of equal length, I never had to remove the cells from the fixture to put them in series.
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That's sort of what I'm thinking with a cell tap lead adapter, I could make one that used those wires to put it in parallel for top balancing, and that might make it more convenient to periodically rebalance. It would still require going in to remove all the bus bars though.
Screenshot 2023-11-11 072154.png
Do you guys think these settings can provide charger hysteresis? I.e. Turn on charger relay if SOC below 20%, but stay on until 40% and then turn off again and stay off until below 20% again.

I think that's what it looks like to me.