Which simply isn't a thing with LTO chemistry. You can see videos of them being drilled, cut in half with an angle grinder, being run over by a forklift, over-charged, whatever. These aren't like LiPo which can have the dangerous failures.
Sure, running without balancing probably isn't optimum but again, even if they only last a quarter of their advertised life expectancy I'm happy enough and about 1/3 of the cost I have into my banks is just the copper, hardware, tools and time into busssing. I was probably the first guy in the USA using those for car audio so there really wasn't even anything on the market to balance 6s banks anyway. Wasn't worried then, not worried now.
Building a small bank the only other thing to consider is "C rating". That is, how many times the rated amp hours of curerrent you can charge or discharge safely. Some of these cells (like the YingLong) are "rated" 10C which means you could charge a 40AH bank at 400A or pull 400A under load. If you look at the performance specs and cycle life specs they'll be some fraction of that max rating for best performance and whatever max rating you see published should definitely be considered "NEVER EXCEED". So for example, if you have 280A alternator you are going to need 28AH of a 10C rated cell to be safe, but if you double your amp hour capacity you'll get better performance and extend the life of that bank by about double.
Again, these are rated to last 20 years or 20,000 or more cycles so I'm going to guess that even with some abuse they'll outlast anything we could have used prior to their invent. Some of the car audio branded battery companies are even selling tailor-made banks which they claim are fine to run along with stock or AGM, which is flat out ******** but they are likely going by the assumption that even with that sort of install they'll still outlast whatever warranty they're offering.
Anyway, counter-sinking the bars is an option but an awful lot of work if you don't have access to a real metal shop.
Congrats on the pending new job. Hope you're staying out of trouble.
Ok, I was concerned about safety/longevity of the bank without balancing. I'm currently writing a research paper on microbattery technology, and some of the new lithium chemistries that perform great are unstable/dangerous. Not an ideal quality for powering wireless earbuds to say the least. I just started the paper two weeks ago, so I haven't dug into all the different lithium chemistries yet.
I know a decent bit about AGM batteries, but my knowledge of lithium cells is limited. I would like to know more. When you say 5S or 6S, does that mean a 5 cell bank or 6 cell bank?
The Lishen cells are rated at 15C/50C. 15C being the maximum recommended continuous pull (270A), and 50C being the absolute maximum rated draw (900A). The Wilson Audio Labs test showed the smart 3 drawing 277A at 1 ohm, 288A at 1.3 ohms, and 334A at 2 ohms. After watching the video, I definitely learned a lot about the smart 3, assuming their information is accurate. If I'm wired to 1 ohm nominal, my minimal box rise *may* be somewhere around 1.3 ohms. I know there are a TON of factors with this, and it is theoretically possible my minimum box rise could be around 2 ohms. The amp establishes a maximum voltage output based on the load, and isn't "constantly correcting" (making a constant power over a range of impedance) like I had incorrectly assumed it would do.
That being said, if we assume the amp draws 300A for extended durations of time, it's a bit out of the comfort range of one bank. If I add a second bank, it should be well within the usable daily range, even factoring in the 4 channel amp and vehicle's draw. My stock alt is something like 75A. I'm thinking about trying 2 banks on the stock alt first, and then deciding between the 240A and 300A alt based on voltage drop severity. Likely, I'll end up going with the 300A, because I don't like to skimp.
I'd like to test my skills with the bus bars. I have some mill bits for my drill press at home. Otherwise, I have access to the metal fabrication shop on campus. As long as I'm bringing in my own aluminum stock, I can work on personal projects. Worst case, they turn out bad and I have the local metal shop (which I know the owner of) make some bus bars with the remaining aluminum bars I haven't messed up, haha. Otherwise, I saw some for sale online.
Thanks! I wouldn't say I'm staying out of trouble completely, but I'm still kickin'. I bought my first house in 2019. I had my uncle who is a partner at a construction company check it out. It's solid, and not a fixer-upper. 2 bed, one bath. Single car detached garage with a huge fenced in backyard that has a gate for alley access. Had a new roof put on a month before I bought it. I ordered new windows in August, and they just arrived last weekend. Going to install the new windows before I get too far on this build. Based on my last 2 years' financial statements, I could pay off my house in under 4 years if I don't change my spending habits too much after starting the new job. Life isn't all good, but I know it could be worse. One thing I've learned in life so far is that things can always get worse.
I appreciate the time you're taking to advise me about the batteries. Thanks
