Budget 90ah 48v lifepo4 battery build (under a grand)

[augiedoggy]

Originally Posted by Pat911

Once the pack is balanced you should remove/turn off the active balancer.

At the risk of telling you something that you already know, make sure your bus bars/links are torqued correctly and evenly. Any difference in terminal resistances can show up as unbalanced cells, but this would be more noticeable at higher charge/discharge currents.

Thanks.
Thats what ive been doing although Ive been experimenting with things such as turning on the balancer for a bit after charging has been stopped and the cells have settled to see if that would have a better impact on the "runner",
the thing with the runner cell is when its charging in constant voltage mode it doesnt spike,(and the voltages all climb within balance) only when the higher current is going into the pack.
And as you might remember reading I put a lot of effort into making sure my buss bar connections are clean and protected from oxidation with noalox.

I was working on the cart yesterday and got the old batteries removed and the 2awg wiring in along with the 48v solenoid. I also got the rust converting primer and paint on the battery grid work. I also got my overhead console installed with the battery meter/bms interface an other wiring such as lights and radio. I hope to get this battery installed and get some actual testing on this pack to see how it really charges after being drawn down vs being topped off after the minimal draw from the bms every few days which isnt really much of a charge at all.

[Pat911]

Originally Posted by augiedoggy

the thing with the runner cell is when its charging in constant voltage mode it doesnt spike,(and the voltages all climb within balance) only when the higher current is going into the pack.
And as you might remember reading I put a lot of effort into making sure my buss bar connections are clean and protected from oxidation with noalox.

Not 100% conclusive but that points to a resistance issue. Make sure your bus bars a flat. Even the slightest curvature on the surface can prevent full surface contact from the bus bar to the terminal. I’ve not experienced it but there have been reports of slightly curved bars, especially aluminium ones. The fix is to sand them flat at the ends using a piece of glass and sandpaper.

If you have access to a thermal camera you can check to see if you have terminals hotter than others when pushing higher currents. This would indicate higher resistance on those terminals.