Hi figured I’d start new thread for this to show off the vruzend cap technology. They sent me v2.1 vruzend caps. The cells are lghg2, pack is 14s20p, 280 cells, 60ah, 3528wh, currently 37lbs. Still need to add the bus bars and the bms.
1 Like
One side of bus bars done. Takes longer then you would think to screw down 280 little nuts. Vruzend recommended doubling the bus bars on series connections if pulling over 12amps.
4 Likes
good job.
please keep posting your build process!
1 Like
Here’s couple updated photos. Have the bms connected now, but my dilemma is how to draw the power from the pack. The vruzend kit comes with these terminal ends, see pic, I used two of them on each end of the +/-, but vruzend said they would suggest using terminals at every second or third cell on the +/- ends with smaller wire leading to the larger 8gauge to take the power from pack. It’s a good idea but my question is how do I connect 10 16awg leads to two 8awg wire? Or does anyone have other suggestions as to how they would do this?
You should keep the main wiring as short as possible to reduce induction. Can you double up the nickel on each end and use only 4 of each?
Too bad that all of the negative wires have to funnel through the BMS and that all of the positive wires are at one end because the ideal placement of wires would be one positive and one negative at each corner going to each motor.
Yeah that’s what I’ve done, I’ve doubled up the nickel on every parallel group on the +- cells and connected 8awg wire to the top/bottom of the +/- cells. So two red and two black 8awg’s coming off the battery and connecting into the openppg. Vruzend suggests I use smaller wire and connect at ever second cell and join those smaller wires to the larger 8gauge. I’m tempted to just try it how I have it now and see how it is, since I’ve doubled up the bus bars. I could even triple the bus bars if needed, there is enough thread and I have plenty of extra bars left.
I wonder why they recommend connecting at every other cell as opposed to doubling or tripling the nickel. Does the BMS have thermal couples to measure heat throughout the pack? Perhaps you could measure the heat where the wires attach.
You could also increase nickel at the corners so that it starts with 2 in the middle, then 3, then 4 at the corners.
I’m not sure why they didn’t recommend just adding more bus bars. They said I need to double the bus bars for all series connections if pulling over 12amps per cell which I did. I’m leaning towards adding extra bus bars on the parallel +/- lines like you said and just testing it. Yes bms has four temp sensors I’ve already installed inside the pack as I built it.
Battery is up and running, there seems to be a password on the bluetooth connector to BMS, do you know what it is Etienne? I’m using the VBMS app that was given to me by the seller.
Nevermind password was 1234, app seems to work really well! Now time to build case and mount.
wouldn’t be a bus bar, like what I did, the way to go?
you have all the current, up to 360A going through those nickel strips only, plus only one 8AWG cable… I don’t remember all my calculations, but even with my setup, using the copper bus bar and 2x 8AWG I was at the minimum possible for 360A.
I am even thinking about adding a second smaller pack with another BMS, just to ease off my current battery…
1 Like
I actually have two 8AWG for + and - off the battery, taken off the top and bottom of the pack. I tripled the nickel strips on the ends so will see how it works, I would think this is the same as adding a copper bus bar, if I need more I could add 4 layers of nickel, or go with bus bar like you did. Case is coming together, there are long standoffs that go through the new Vruzend 2.1 connectors, they work perfectly for attaching the case, will also use them to install the T-bar connections to slide the battery onto the opening frame.
2 Likes
Looking great!
ladida, I have to write more than 15 characters 
1 Like
Vruzend was adamant I split power off the ends, they said if I just take power off the ends that it will create too much heat build up for the caps. So here’s what I did.
3 Likes
This is a great write up thanks for posting and showing another possibility , I thought Vruzend option was not capable of handling the power we need so its great to see a built unit … thanks for info and the work that went into making this pack
that was my assumption/guessing on my initial plan to build 13S15P only.
The less parallel groups you have, the more power each individual parallel group needs to handle.
One of the reasons why I increased my pack to 20P later on.
Finally got some decent time to finish up the battery. Almost done the box, next will be mounting the rails to the paramotor, then testing the pack!
2 Likes
Done the battery! Rail system works very well. Might use some quick disconnect pins so I can drop battery just in case, think it’s necessary? I ran it up and runs well with hardy any temp build up. But only ran for 10 min at about 150amps. Didn’t have time to charge it fully up as have to leave town for work now. It was about 50% charged. Pushed it to 300amps without issue. Although at the end the bms shut battery down due to hitting the low voltage cuttoff after revving it to 300amps. I had the discharge low voltage cutoff set to 44.8. I’ll have to change that to 35v. (14s x 2.5v). What is yours set to etienne?
I also used solderless rv pro plus 8mm connectors. They are super nice, they click together and are super easy to install.
9 Likes
Mine is set to 2.5V (I can only set the “per cell” low voltage cut off in the BMS-App), which is the minimum according to the spec sheet of the LG HG2
Thanks! I have same bms as you and there is a low discharge voltage setting for the pack. So for my 14s using 2.5v as minimum I would enter 35v. I’ve confirmed it works I set to 45v and it shut down the battery when it his this low voltage cuttoff during discharge.