Search results

I did notice it wasn't BigBattery, but it just bumped that whole sad story back to life. Plus there was a link in this thread to the "banned" post by MrGreen, which triggered me and reminded me among other things of how unsuitable those products are for marine use, in spite of claims.

Curved busbars are pretty common but it looks to me like they will still transfer plenty of load to the terminals. Some have used braided copper cable, but there are concerns about less reliable electrical contact and increased corrosion. Firmly fixing the top and bottom of the cell while...

I would say you are exceptionally well qualified to comment on the question. What I got from your detailed reply is, mechanical stability is the only real issue and even a beefy circuit board is not enough. So next question: what would be enough, if one insisted on using a circuit board? I...

It's related in the sense that it removes all doubt about whether leaking electrolyte is caustic and dangerous.

Recall for sure If this were the auto industry instead of batteries, probably sharp teethed lawyers circling around also. But it isn't the auto industry, it's the wild west.

Until your post, that was about the only part of the design I actually liked. My interest being primarily marine, I am concerned about motion, vibration and shock loading. I wonder what needs to be done for a circuit board to perform satisfactorily as part of the mechanical structure like this...

What don't you like about it, insufficient ampacity? I had a nagging doubt about that, it just doesn't look like a whole lot of metal compared to a copper busbar, but maybe it is enough. It does tidy the wires.

Can we definitely rule out the possibility that they "augment" their supply of new cells with recycled/refurbished ones? Maybe a few that don't have dents and hold a decent charge. After all they started as a recycling depot. As I recall, the video also shows stacks of recycled materials. Does...

I think he meant, don't orient the cells on their side. Do lay the Bigbattery pack on its back, which orients the cells upright and gives you a drip catcher should that ever be needed. Quick take: I'm not liking that vertical standing concept at all. It appears to be entirely for looks and not...

...and don't stand them vertically, lay them on their backs to catch the drips, maybe even prevent the issue.

For now I will stick with my theory that the 11 (is that the right number?) leaking cells they claimed to have "discovered" in their inventory were actually all discovered in the field by customers. This theory would seem to fit the data better than what they implied they had done, that is...

Understood. The question I raised is, would a solar controller make a decent substitute for a dedicated dc/dc converter for this particular use case, and maybe have advantages, such as a familiar interface, maybe manufactured in higher volume, therefore cheaper, more featureful and perhaps even...

Going back and rereading this informative thread... my reason for suggesting MPPT is that they use an efficient buck converter as opposed to inefficient pwm for a cheap controller that generated extra heat and eats watt hours. Caveat: I am not an EE so my free advice is worth what you paid for it.

Which makes Big Battery's eensy weensy extinguisher look like the safety theater it really is. Good thing LFP thermal runaway usually stays below electrolyte ignition temperature, unlike Tesla's NMC cells.

You may be getting close to the truth. It might not take much of a bump. As I recall, Will's leaky cell was second from the bottom, so the two cells lying above are a hefty 7kg. Set the assembly down on its end with even slight momentum and bang, pop, squirt. Maybe. Each cell is fixed to the...

Hmm, I would not call the thread hostile. Justifiably skeptical perhaps. There is the matter of living down the white grease claim. I can understand some discomfort there. As things stand I will forevermore associate Big Battery with "white grease eats your battery". Then there is the claim...

To avoid possibly endangering a cargo aircraft?

Oh well. I've got the sense that that's the end of the line for trustworthy reports. I would love to be proved wrong but believe I've detected a pattern.

Would you be so kind as to get on some nitrile gloves and open the main compartment now? More than a bit curious about what happened inside.

In my humble opinion, Lishen may need to revisit that advice. I hope they are already in the loop re your recent issues.

Actual white grease. Not known to dry out to granular/powdery like in your photos.

Looks like heavy corrosion on that header.

I seem to recall a voltage reading of 7 volts?

How about a photo of the box? I'm interested in whether it says "this side up" anywhere on it.

Wow, what a mess. I was wondering where the cell pics were, then realized you've got a "void the warranty" situation here. It's up to Bigbattery to do the forensics, which I sincerely hope they will, including posting photos. IMHO you are now a Bigbattery business partner... because you're on...

The whole statement is pretty slim pickings, information wise. Really does not sound like an engineer speaking. Good point. And now I see what you meant by "properly sealed valve will not leak". You mean a valve that only vents under catastrophic pressure. Whereas I imagined a vent that vents...

Twisting the pressure vent off of a pressurized cell... step one should be "put on your goggles".

Comment now unpinned, so harder to find. You're not kidding, Bigbattery's response is beyond tone deaf, that's being charitable. Also does Will know he is a "business partner" according to Bigbattery?

An Eve representative said it is normal. "During the charge & discharge process of battery, the cell will “breath” like people does- swell & shrink effect." Never mind that this kind of breathing is nothing like respiration, they say it's normal. Granted, this does not actually say the cell...

I haven't seen another one, but that's just me. Few are using prismatic cells for that matter. I found this line by Lynx, looks like DIY in the wild, complete with Daly BMS, cells zip tied, no case. And all currently unavailable on Amazon, what does that mean? They also have prismatic builds...

I wonder if "discovered" really means "got report from customer". They may need to update that guidance. One thing they can't do is stay silent on the question. It can leak fluid when gas vents, or else it relies on some hitherto unknown physical principle. And it's not just Lishen and...

Assuming Seth Rooney is a real person and the report is accurate... Does the box say "this side up"? It should, and that direction should be up with respect to the cells, not the case. Was it shipped by ground or air? If the latter then does pressure change plus horizontal or inverted cell...

But does this take into account the effect of a sustained ignition source such as an internal or external short? Also what about the electrochemistry? I would appreciate some information about how state of charge relates to fire hazard.

The point is, the demonstration does away with the popular wisdom that lifepo4 is immune to thermal runaway and can't self-ignite. So the question becomes: what exactly are the conditions that cause thermal runaway or self ignition? Needs further research. We have a lot of this out on the web...