Following up on user-reported cases of Battle Born LiFePO4 batteries displaying very hot positive terminals, [Will Prowse] decided to buy a brand new one of these LFP batteries for some controlled cycle testing.
Starting with 30 cycles with a charging current of 49 A and a discharge current of 99 A, this put it well within the 100 A continuous rating for the battery. There is also a surge current rating of 200 A for thirty seconds, but that was not tested here.
What’s interesting about the results here is that instead of the positive terminal getting visibly discolored as with the previous cases that we reported on, [Will] saw severe thermal effects on the side of the negative terminal to the point where the plastic enclosure was deforming due to severe internal heating.
During testing, the first two charge-discharge cycles showed full capacity, but after that the measured capacity became extremely erratic until the battery kept disconnecting randomly. After letting the battery cool down and trying again with 80 A discharge current the negative terminal side of the enclosure began to melt, which was a good hint to stop testing. After this the battery also couldn’t be charged any more by [Will]’s equipment, probably due to the sketchy contact inside the battery.
It’s clear that the plastic spacer inside the terminal bus bar was once again the primary cause, starting a cascade which resulted in not only the enclosure beginning to char and melt, but with heat damage visible throughout the battery. Considering that the battery was used as specified, without pushing its limits, it seems clear that nobody should be using these batteries for anything until Battle Born fixes what appears to be the sketchiest terminal and bus bar design ever seen in a high-current battery.
I really appreciate the folks who take the time to test batteries and the systems that rely on them. The battery market is sketchy, to say the least, and for people who depend on these systems to perform as advertised. often for the safety of their families and property. that work matters.
Most batteries are installed in places that are out of sight and out of mind. When they fail, the problem is often discovered too late, sometimes right before a catastrophic event.
I’m currently doing a bus-to-RV build, and this topic is very much front of mind for me.
Sounds like over-hyped “marketing” specs…. not uncommon in the battery world.
It’s not over hyped, it’s just lousy design. All the parts are capable, the people who put it together are not.
Mainly, if you want to make a high amp electrical connection you need sufficient clamping pressure to maintain that connection. Putting in nylocks or plastic washers will absolutely kill you since plastic under any appreciable compression or tension will creep and flow.
Adding a chunky strip of copper as a bus bar, this seems like this might be fixable, at least prior to first use. Although I’m still not convinced I’d like to trust it without considerable testing. The weight reduction sounds nice, but I think I’ll stick with good old Lead acid.
Yes, plastic does not belong in bolted joints, especially electrical ones. That’s just basic engineering.
Was that a ETL mark I saw on the label? Mark of the beast.