24 volt Battery build. Looking for advice

Mark_B

New Member
Joined
Nov 28, 2020
Messages
51
Hi All. I'm building a 24 volt Lifepo4 battery and have a question or two.
The pictures below illustrate my questions.
I bought copper and made my own busbars. I didn't think it through well and ended up unable to stack busbars due to thickness.
So I am thinking I can use 6 awg wire to jump pos to net.
Any issues with this? My inverter is 3000/6000. I currently have no expectation of ever exceeding the 3k, probably more like 2k.
But I am wondering if the 6 awg jumper wires from pos to neg on my battery build are going to be an issue carrying the necessary amps/voltage?

Nextly, I have a crimper, maybe not the best. So I am wondering if soldering is a good option after crimping? Heat shrinked on both ends as well.
Thanks for having a look!

(If the pic of my battery is confusing, I am using a long bar at the end to connect the two sets. I just haven't got it drilled yet)

NavitasBattSetup-1.jpgjumpwire-1.jpgjumpwire-2.jpg

NavitasBattSetup-2.jpg
 
Last edited:

NVS

Solar Addict
Joined
Sep 14, 2021
Messages
323
I think I would drill a hole in the bus bars and put a bolt in it for your jumpers. Because it doesn't look like your current studs are long enough.
 

esouthard

New Member
Joined
Mar 11, 2021
Messages
14
Maybe not for this build, but it would be nice in the future to use the thick busbars for the pos-neg connections and the less thick wire for the parallel connections, as the parallel connection current should be relatively small.
 

Mark_B

New Member
Joined
Nov 28, 2020
Messages
51
Maybe not for this build, but it would be nice in the future to use the thick busbars for the pos-neg connections and the less thick wire for the parallel connections, as the parallel connection current should be relatively small.
You gave me a much more accurate way to view the current flow. Thank you.
I don't mind changing my plan here.
I have plenty of copper pipe I could make bars out of to use on the 4p part of the battery. Does it make sense to do this and use the thicker bar for the 8S part? I can mill down the thickness for the bolt connection if need be so it will fit on top of the pipe bars.
 

Mark_B

New Member
Joined
Nov 28, 2020
Messages
51
Quite a bit of extra work I have made for myself, but this should be pretty robust. Yes/No?

jumper-1.jpgjumper-2.jpg
 

esouthard

New Member
Joined
Mar 11, 2021
Messages
14
It would be a bit of work, but I'd recommend using two of those for each of the positive/negative connections. That should avoid current crowding and equalize the voltage on the cells as much as possible.
 

Mark_B

New Member
Joined
Nov 28, 2020
Messages
51
It would be a bit of work, but I'd recommend using two of those for each of the positive/negative connections. That should avoid current crowding and equalize the voltage on the cells as much as possible.
I appreciate hearing this. It helps me understand the battery mechanics better.
But ultimately I just ordered new thinner bars that are wide enough to make the parallel and serious connections in one bar.
My work time is worth more to me than the cost of the new bars.
Cost me a bit, but I am learning from my mistake. :)
I'll post a photo in the next few days.
 

Mark_B

New Member
Joined
Nov 28, 2020
Messages
51
I got the battery all built and all seems well. I'm topping off the charge with my new desktop variable power supply.

Thanks everyone for all your help with this. It has been quite a learning experience. Next I'll be building out the power wall with inverter and MPPT charger (Victron). Debating whether to use 2 or 4 385Watt Solar Panels. Not sure how hard I am going to be using this setup and might want a panel or two to mess with another build.

Pics.
BuiltBattery-1.jpgBuiltBattery-2.jpgBuiltBattery-4.jpgBuiltBattery-5.jpgBuiltBattery-6.jpg
 

Mark_B

New Member
Joined
Nov 28, 2020
Messages
51
This is a little 4 cell 12v box I built for learning and for phone charging, camping and what-not.

12VoltBattBuild-1.jpg12VoltBattBuild-2.jpg12VoltBattBuild-3.jpg12VoltBattBuild-4.jpg
 

esouthard

New Member
Joined
Mar 11, 2021
Messages
14
Looks great, and I'm really digging the new busbars. The BMS ground connections are a little on the long side, but I'm not sure what you could do differently with your cell arrangement
 

Mark_B

New Member
Joined
Nov 28, 2020
Messages
51
Looks great, and I'm really digging the new busbars. The BMS ground connections are a little on the long side, but I'm not sure what you could do differently with your cell arrangement
Thank you! The wires are long as they came this way from Overkill. A good problem I guess.
 

Mark_B

New Member
Joined
Nov 28, 2020
Messages
51
I do have a question. Is there much to be gained or lost in tinning the bars where they connect to the batteries?
I'm thinking to prevent oxidation of the copper over time?
 
Top