BigBattery 24V Breaker Replacement and 100A Re-Test, Problem Solved!

I reviewed these 24V 100Ah batteries a few weeks back and found the circuit breaker was heating up to 150C! WAY TOO HOT. In this video, I took apart the unit and found the actual cause was not the circuit breaker itself, but went ahead with a replacement anyway as a test exercise. I then re-tested the battery at 100A, comparing the results to my original tests.

*WARNING:* Lithium batteries are dangerous and can result in fire! This video is NOT intended to be instructional or a "how-to" lesson. I am not a professional. Do not attempt anything you see here without first contacting a certified and/or licensed professional.

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00:00 Introduction
01:30 Removing Old Breaker
03:00 The Problem Discovered
05:03 Installing New Breaker
06:55 The Testing Setup
10:00 Beginning of 1st Test
14:00 Beginning of 2nd Test
15:20 Conclusions

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*Disclaimers and Statements:*
► I receive a small commission on purchases made using my affiliated links shared the video description and comments section. The views and opinions expressed here are my own, unbiased, and not influenced by this commission in any way.
► My videos are in no way intended to be instructional "how-to" lessons. I am simply documenting my project for informational purposes. Property damage, personal injury, or death may result, even when following manufacturer's instructions. I cannot be held liable for such damage or injury. It is YOUR OBLIGATION to ensure that you are complying with any local and federal laws as well as code and permit requirements.

[LithiumSolar]

Hey guys, I'm happy to let you know that I have spoken with BigBattery this evening regarding the problem(s) I have experienced. We are all in agreement that the problem is not the way the breaker is wired, but rather the torque of the bolts and the quality of the breaker overall. They have had many internal discussions since the posting of these two videos, and will no longer be using these breakers going forward. For them, it's a matter of reducing the potential points of failure. They will be redesigning the product to feature a user-serviceable fuse with an on-off switch rather than a breaker. Despite my disappointment in having experienced this problem, I strongly appreciate knowing BigBattery is willing to listen to customer feedback and make changes for the better of everyone.

[Erik-jpkk]

I think I can say we really appreciate the time you took doing this test. Knowing this could save someone’s house, rv, well-being.

[largepimping]

The loose connections to the original breaker are concerning. But from the way big battery seems to interact with reviewers on youtube, I'd bet they will take steps to address those issues. What worries me even more is the original breaker that wouldn't shut off... or didn't shut off fully... or something like that. Even when it was switched off, it stayed on!!?? That scares the hell out of me.

[robertgee]

In the future if you should encounter the same type of situation with loose connections - redo the test after tightening the connections then proceed to cut connectors and test with new parts. That will give you 3 options to compare to and eliminate any guesswork.
JMO

[pulesjet]

I'm with you on the double breaker idea. Those are meant to be used on two pole power configurations. Here it's just more to go wrong.

[michaelmadison]

Dude, I wish I knew half as much as you on this stuff. Enjoy your channel a bunch. I watch pretty much everything start to finish. Great editing.

[rpsmith]

In addition to redesigning the breaker, they also need to up the wire size of those wires that were getting excessively hot. If for no other reason then to reduce the voltage drop that was causing all that unnecessary heat!

[pjhalchemy]

Seems you nailed the issue being loose screws, however breaker 2 getting stuck in the interim position is indicative of pour manufacture and QA IMHO, plus you indicated no certification markings. Personally I'd change them both out for a quality (CE, UA) single unit. The one thing that comes to mind is the additional heat build up when the unit top is on, in use and unattended, high loads and depending on the ambient. Not a risk worth taking after what you've seen, again IMHO. Additionally I'd probably go through both units and check all fasteners and connections after what you found. As always a pretty thorough reckoning with good details. Nice job on the LCD in the camera close frame!

[RichCompMan]

I received 2 batteries from them this week and had the Anderson plug on 1 of them not even bolted down in the enclosure. They claimed that it came loose during shipping but when I opened mine up there were zero bolts or nuts to be found. I was ready to send it back but was asked if I can add the bolts myself to save on the time that it would take for me to receive a replacement. Looks like their quality control team is non existent. I’m hoping that’s the only problem I have with my batteries after spending $1600 on them. Thanks for holding them accountable with this video!

[DCGULL]

Well, I'm glad you re-tested, but- I think the lack of a lock washer, and, general looseness was the REAL problem. At the value price listed, I would do a little disassembly, add a lock washer if needed, and tighten (Think Will Prowse saying tighTen) the bolt firmly. 70 C doesn't throw me off @ 98% of max capacity with a double copper pole 63A working breaker. Overall, I thought it was well put together, but that lack of lock washer, and subsequent loosen of the bolt is actually concerning.

[AndyMcBlane]

Exactly why I wouldn’t personally get into selling a product like this. 150°C is scary hot. Great video as always

[ariahann]

My boyfriend keeps using my YouTube to watch these videos, he literally subscribed and turned of notifications for this channel, like am I supposed to hand him my phone when y’all drop a new video? Anyways, I appreciate your content because it makes my boyfriend seem like a genius super hero because I can’t do any of this shit <3 <3

[mondotv]

I agree - a lock washer should be used in that design (remember these batteries are likely to be used in mobile situations). And they need torque specs during assembly to ensure proper connection. Mechanically you would need to ensure those breaker clamps are designed to exert enough force on a solid copper buss bar as well.

[SylwerDragon]

Yes As you said problem was for sure in missing washer and also loose cables. ..also as you also stated that braker looked a bit cheap and also had issue ..and ofc that is on new item..who knows how it will work in 5 years ..

[SedatedByLife]

Flow some solder on the positive leads before you put them into the breaker. It'll help give a more solid connection and less chance of them coming out in a vibration scenario. One of the tricks when working with stranded wire

[HzuZazu]

Those Clamp down Connectors are actually made for Solid or semi-solid wires, you should use a Ferule (no soldering thats not as relihable as a crimped therminal) around those two Wires and also use a Torque wrench or torque screwdriver, most Manufactures have Torque ratings in the Datasheet, bc under and over tightening are both bad.

[ooklaa]

They are out of stock on these batteries. Do you know if the 2021 restock will use the fuse? I assume also what you did voided your warranty? Are they allowing it to be modified with the better breaker, or to be sent it so they can modify it?

[BobHannent]

There's a German study that I can't get to right now, it showed that lock washers didn't actually affect nut stability over time.

[pmeschultz]

Putting a 2-pole breaker in parallel is fine, but the one in the video is polarized, so it was not put into parallel correctly. The current will only be flowing correctly through one of the sides creating the potential for a runaway arc if the breaker is shut off under load

[roger]

Given that there were 2 wires on the input to the breaker, I have to wonder if the original plan was to have them connected independently, but they found in testing the current from the two leads wasn’t balanced and chose this solution rather than redesign the case for a single breaker.