@venquessa , welcome to the forum. I have followed your posts on the other forum simply because of the paucity of comments there, not because I am interested in the dialogue you were having there. I think you will find the quality of input much greater here and the knowledge base is far deeper, especially with regard to experience with LFP chemistry.
Let me explain where I am right now and how I got here, which may explain some of my tone and I agree it may be out of place.
I've been using and abusing batteries since I was a child. I'm 48. I set fire to my first lipo cell in 2007, thankfully outdoors in a speed controller fault. I nearly had one detonate beside me on the bench when the current sense lead "desoldered" itself from the load mosfet. Luckily a little tiny pack the size of a match box, but it was at that stage rolling across the desk the size of a cricket ball. That went into the sink, under water, then got transferred to a bucket and placed outdoors until it cooled down. These were the LiPo high discharge pouch cell days.
I've been running a completely DIY, bespoke 12VDC nano-system for the past 5 years? First on lead acid backed up by the LiPos and now LFP.
I find charging and discharging batteries bizarrely cathartic, or maybe it just passes time nicely with something to keep checking on. Shrug.
At the same time my main hobby outside of work is electronics and embedded software. It was in the former that I was bitten many, many times until it finally sunk in that the voltage is never the same at any two points in a circuit and solid, ideal schematic lines don't exist. Believe GND is GND is GND at your own peril.
YouTube. YouTube has identified my interest in lithium LFP and solar. So it has started recommending videos and channels to me. Additionally I have genuine questions which I don't see answers to.
What's the problem? The first problem is, and decide if this applies to you or not, people haven't the faintest idea how to measure anything. Seriously I can't watch half the videos because it's completely wrong from the start to finish. I get frustrated when commentors and creators make incorrect claims, I get even more frustrated when they then devise an experiment to prove themselves correct. Sigh. I get even MORE frustrated when you look at the comments and the forum threads with all the disciples parroting along and telling the OP how great they are for figuring all this out for them and they can just follow to the letter and even buy the snake oil garbage the person is pushing (in the extreme cases).
Now, I understand in "some" cases they are actually genuinely "lying to the children" and do actually know what they are doing. Sometimes the audience is not "you".
Units and measuring is my absolute bug bear with a lot of DIY battery and solar content online. I know it sounds "pedantic", but when someone can't even get the difference between "kilo-watt-hour" and "kilo-watt" the right way round in their head, what use is it listening to another word they have to say on the topic of solar energy? It's like claiming to be a profresional driver and not understand what a steering wheel is! It's not pedantry it's being convinced the source is worth listening to at all.
On measuring. The number of people who quote ohms law, do their little song and dance version of how to explain it to kids and then promptly throw it clean out the window in their very next measurement ... makes my mind growl.
No names, but I watched a popular YouTube channel and battery manufacturer "capacity test" a customer return. They charged the pack blunt with 14.40V 50A until it was terminated by the BMS. Where did they measure this fictional "the voltage" ... on the charger. They then did the same thing with the discharge side. Stuck the pack on a fixed current 10A load and again let the BMS hit LVC to end it. Where did they measure this fictional "the voltage" this time? The load. They came up with a capacity of something like 88Ah and claimed this was because of the small dent in the side of one cell caused in shipping, the customer has used the battery for months, but wants it replaced. They confirm that it has lost capacity. I mean... maybe... maybe if that's EXACTLY how you tested it before you shipped it. However the whole test from start to finish is just wrong. Several commentors on the video said they have had AliExpress and others refuse to accept a return based on "this equipments" test results. I do wonder why....
On LFP, my frustrations with that side of things is these voltages people keep floating around. They are almost entirely made up. People talking about "rest voltage". People talking about 14.00V charge voltage. People talking about charge termination parameters, balancers, float voltage, oh.. yes... low current overcharge. Almost never do these figures come with the required qualifiers. Where is the voltage measured? Why what? What is the current flowing at that point in the circuit? If there is any, where are the other measurements to calibrate the first?
Look, it's fine, I'll get over myself, it will stop annoying me in a while and I'll just accept it. Do keep raising it with me if I seem to have an attitude from time to time.
In this thread I confess I had a bit of my tongue in cheek because Amp-Hour is a classic thread on every electronics or electrics related forum. It never ends well because it's a unit which "depends" on so much other stuff that unless you specify those parameters it's next to meaningless.
At least people aren't going the other way and telling people to charge their LFP's on LiPo mode to 4.2Vpc to get another 2% capacity. However, there are safety aspects to this. Not understanding that voltage measurements made in a circuit underload MUST, 100% of the time be backed up by other measurements including, but especially the current.
If could strive for one thing to come out of any of my rants is for people to start reading the voltages on ALL the meters they have. To start asking why is this voltage different to this voltage? "Why do the cells add up to 14.00V but the battery is reading 14.20V and the charger is reading 14.40V?"
The safety aspect is this. If you can't answer that, or if you assume it is just "meters diverging", then you have to consider that "your" voltage measurements are not accurate to much less than 1 volt. 1 volt accuracy is NOT enough to understand what you are doing in a LFP system.
I know I'm preaching the choir here for a lot of you. I would place myself, in terms of electronics, probably nearing the bottom of my descent of mount-stupid, the point you realise compared to what you do know, what you don't know is the next, never ending mountain to climb. So do correct me when needed, but I will argue pedant points, just because that's fun.
As to measurements. I have the voltage reading of every cell, the pack, the MPPT, the panels and dozens of other readings taken every 5 seconds 24 hours a day, 7 days a week. In some cases I have this data stretching back years.
![when-youre-arguing-with-a-fool-make-sure-he-isnt-doing-the-same-thing-quote-1[1].jpg](https://diysolarforum.com/data/attachments/145/145156-831d1b2f146f44da1ceaeaa06339a06e.jpg "when-youre-arguing-with-a-fool-make-sure-he-isnt-doing-the-same-thing-quote-1[1].jpg")
