LiFePO4 Install
- Thread starter dreadlocks
- Start date
luthj
Engineer In Residence
The good news is that if the BB BMS fails, you can rewire with your own if needed. Some minor hacking with a cutting tool needed.
Looking at some teardown reports of that model BMS (made by many suppliers). There is a pretty big range of quality. The biggest issue is the soldering on the FETs, and the short copper bus bars which are typically soldered onto the fets back plane to carry the current. If the fets aren't placed flat they either won't carry current, or they will overheat.
This is probably what happened with Dreadlocks unit. Quality escape (or just poor MFG in general). This type of issue should show up with a full load test at the factory, but who knows what they do for quality, either at the factory, or at BB.
Looking at some teardown reports of that model BMS (made by many suppliers). There is a pretty big range of quality. The biggest issue is the soldering on the FETs, and the short copper bus bars which are typically soldered onto the fets back plane to carry the current. If the fets aren't placed flat they either won't carry current, or they will overheat.
This is probably what happened with Dreadlocks unit. Quality escape (or just poor MFG in general). This type of issue should show up with a full load test at the factory, but who knows what they do for quality, either at the factory, or at BB.
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dreadlocks
Well-known member
I feel alot better after seeing the inside of one of these, thanks for that video..
yeah I think my OG unit shoulda failed some QC checks seeing the day 1 difference between that failed one and the new one.. but I dunno, if I was building these I think most of the QC would go down before it was sealed up so tightly so mebe it was something that happened after that.. was early enough in production that often you dont have that forsight then.. but yay for the warranty, however now I'm kinda torn.. I'd love to cut some holes in it and get access to the BMS, but not after such a good warranty experience.. which is not a normal reaction for me, I love voiding warranties usually..
yeah I think my OG unit shoulda failed some QC checks seeing the day 1 difference between that failed one and the new one.. but I dunno, if I was building these I think most of the QC would go down before it was sealed up so tightly so mebe it was something that happened after that.. was early enough in production that often you dont have that forsight then.. but yay for the warranty, however now I'm kinda torn.. I'd love to cut some holes in it and get access to the BMS, but not after such a good warranty experience.. which is not a normal reaction for me, I love voiding warranties usually..
dreadlocks
Well-known member
I think second hand ones still are warranty covered, I never provided any purchase detail, when/where.. I coulda been 3rd owner for all they knew, my wife bought it off Amazon w/0% Financing, that was main reason why I went BB, we needed a battery asap at the time because the one that came w/my trailer was like a 60AH interstate piece of garbage.. in 2 months of use it lost 10AH of capacity because I was discharging it so hard and we were running the genset almost non-stop.
Once you get to that level, just throw the whole so called "drop-in" concept out the window.
Start with known-good top-quality cells, that as long as you don't screw up could last 6000 cycles or more.
Cheaper **and** better!
Then look at how you want to protect them - does **not** necessarily mean relying on "a BMS".
That term is a collection of functionalities, and I have yet to see one at reasonable cost:
does them all right, user configurability
excellent genuine components
robust consistent build quality.
Many LFP bank failures, even fires, are **caused** by crappy all-in-one BMSs, and that includes many costing hundreds of dollars.
Learning how to / getting the gear to LVC / SoC, balance cells, safely charge, test capacity, etc properly is a much better value proposition than just handing over profits to a middleman that adds hardly any value and uses sub-par components.
Yes, **if** the company survives and continues to service all their customers the way they did you
that is indeed the BB value proposition for those not willing to DIY getting started.
But for me, that's a big If, and 10 years is a fraction of what I expect.
shade
Well-known member
I hope he doesn't blow a finger off while hacking into cases. Seeing him pry against screwdrivers with all his might makes me cringe.Will's a YouTuber, been learning a fair bit but started out as an arrogant Dunning-Kruger.
As did we all
His videos are good for noobs, but caveat emptor, not canon by any means.
I'll give him credit for looking deeper into his past recommendations and publishing his mea culpa.
shade
Well-known member
His second video on that battery is sad, but not a surprise. That company may throw whatever they can find into the same box and sells it as the same product, and/or they crank out special review units to deceive people like Will. Nothing new about either, but I don't think he's been around long enough to know those are common practices by shady companies.
I'd like to see him tear down some more expensive batteries.
shade
Well-known member
From his videos, they changed cells, BMS module, and wiring gauge. At least the box and label stayed the same.
luthj
Engineer In Residence
With distributor sourced parts, many times the easiest way to spot check for counterfeits is by weighing the shipment. Copper, steel, batteries. Inevitably all of them get lighter when someone starts cheating. The key is to not let anyone know you are doing this...
You might end up with something like this on occasion... Its and external "hard drive"
Or this...
You might end up with something like this on occasion... Its and external "hard drive"
Or this...
shade
Well-known member
Nothing wrong there. It's just spare parts storage.
If it's heavy, you know it's high quality stuff, right? I've seen that done with suspiciously heavy heat sinks that looked ok from the exterior, only to find no thermal contact inside the device to the finned chunks of metal. In firearms, the Hi-Point brand is notorious for making very heavy things that may function better as clubs or hammers than guns.
Even top-notch cell makers buy their lithium chemical slurry in bulk from specialist suppliers.
Less pure batches can slip through QA processes, but hopefully get caught later on downstream.
The factories have clearly marked Grade A vs Grade B etc cells, and the lower grade stuff gets sold off by the fly-by-night sellers as if top quality.
Chinese military being top customers (owners) of the companies don't have such risks in their supply chain.
Vendors like Battle Born sure do though.
Less pure batches can slip through QA processes, but hopefully get caught later on downstream.
The factories have clearly marked Grade A vs Grade B etc cells, and the lower grade stuff gets sold off by the fly-by-night sellers as if top quality.
Chinese military being top customers (owners) of the companies don't have such risks in their supply chain.
Vendors like Battle Born sure do though.
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