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diy solar

diy solar

I must be doing something wrong.

Mattb4

Solar turkey
Joined
Jul 15, 2022
Messages
5,534
Location
Far far away
Almost 2 years back I decided to try out these new fangled LiFePO4 batteries. Because I am cheap, and distrustful of things that are new to me, I bought the lowest cost liFePO4 battery I could find. No communication, no uploads to the 'Net, no fancy apps to monitor individual cells, no internal resistance gauges. At first I had some weird behavior from it that by dint of study on the Forum here I came to realize that I needed a lower voltage to charge at than the default one from my AIO with lithium battery type. So after a week or more things settled in and better operation happened.

I added another battery in parallel and it after a week or so established itself and things moved along. Another and another were added. My last two I went crazy and decide to build my own 2 batteries from cheap cells. That seemed to work out and they are all working together with my other batteries.

Now here is the problem. I don't seem to be having one. I read Thread after thread about people with all kinds of strange issues that keeps them busy with graphs and displays of individual cells voltage and capacities. It seems that LiFePO4 batteries are nothing but problems. So why is it I am getting good results?

Hard to figure.
 
Well, - giggling laugh - More often than not, people try to squeeze more than the spec allows for.... Charging too high, disconnecting to low or even pushing the limit of Charging Amps. Now all Premades are equal either... IE a 100AH Pack with 4 100AH cells or 8 50AH cells etc etc... the combos & variations can make one nuts.

Reality is, if everything is "moderate & gentle" you can get the max out of the packs provided "only the working voltage range is used", step beyond that and troubles come along to make life interesting.
 
No communication
I spent too much time believing that closed-loop control with the EG4-LLs was important and critical to running an efficient system, and spent lots of time fighting over voltage warnings. Once I got the cells reasonably balanced, I went back to open loop. I make sure the SoC gets reset to 100% by charging to 56V for 30 minutes (once weekly).

Life is good, batteries charge, batteries discharge, no warnings.
I'll check the cell voltages every 3-4 months to make sure nothing is out of whack.

If I eventually DIY build some batteries, I'll probably be more hyper-focused on cell voltage.
 
I compare this to the diesel forums. They complain all the time about the truck breaking down. If you go read other posts they've put tuners on uped HP bigger tires and don't understand why they're $100k truck doesn't run. I just laugh. By more than you need and don't run it hard!
 
Almost 2 years back I decided to try out these new fangled LiFePO4 batteries. Because I am cheap, and distrustful of things that are new to me, I bought the lowest cost liFePO4 battery I could find. No communication, no uploads to the 'Net, no fancy apps to monitor individual cells, no internal resistance gauges. At first I had some weird behavior from it that by dint of study on the Forum here I came to realize that I needed a lower voltage to charge at than the default one from my AIO with lithium battery type. So after a week or more things settled in and better operation happened.

I added another battery in parallel and it after a week or so established itself and things moved along. Another and another were added. My last two I went crazy and decide to build my own 2 batteries from cheap cells. That seemed to work out and they are all working together with my other batteries.

Now here is the problem. I don't seem to be having one. I read Thread after thread about people with all kinds of strange issues that keeps them busy with graphs and displays of individual cells voltage and capacities. It seems that LiFePO4 batteries are nothing but problems. So why is it I am getting good results?

Hard to figure.
Yeah, I'm in the "why is my inexpensive stuff working so good?" group. Everything just keeps on keepin' on.
With product names like Kepworth, Pionergy, SunGoldPower and no-name-at-all, it's a mystery.
 
Getting the most out of what you pay for is important, but I never understood fretting over 2, 3, 4 percent discrepancies.

As long as you're occasionally checking things to make sure your batteries are within a row of assholes then I truthfully believe your time is better spent doing other things.

Rather than have a potentially expensive (upfront cost of buying parts that can communicate) and annoying data collection polling rate of 20ms and constantly worriedly checking up on it, why not manual quick data collection polling rate of 20 days?

If your system is so fragile that you need near constant data collection and to be warned of mere percentages of differences, then you're doing it wrong in my opinion.

Set it and forget it.


As long as you are sure that your equipment is set up correctly to stop discharging at an appropriate voltage and to only charge to the voltage that you desire, then you're fine.

😵‍💫😵‍💫😵‍💫
 
Now here is the problem. I don't seem to be having one.
That you know of. #YouCan'tControlWhatYouCan'tMeasure

Don't get me wrong, I'm hoping your batteries have a long unstressed life, and I'm hoping for Set-And-Forget with my EG4 ESS, but I'm all about sensing, measuring, logging, graphing, and understanding what's going on, so that I can get comfortable with 'normal', and then keep an occasional eye on things. I get around 4 dozen emails every day, mostly around midnight from various Raspberry Pis and other computers telling me what's going on, and I've gotten to the point where I can glance at them and delete them. Or catch issues early, and not have the power go out (or the water treatment fail, or the Internet go down, or the cistern go dry, or the freezers fail, or ...)
 
That you know of. #YouCan'tControlWhatYouCan'tMeasure

...
Needing to know if the Black hole containment field is beginning to go into uncontrolled oscillation is important immediately. It could destroy half of our solar system. Luckily we maintain strict 2 man round the clock Watch with alarms piped to my day room in case of this. More mundane things I catch during my daily inspection tours. Things that happen at midnight are someone else's problem.

Edit: I will admit failure of the coffee pot is a General Quarters condition. That is Life Support.
 
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failure of the coffee pot
In fact, along with one of the dishwashers (everyone has two, yes?) the coffee grinder failed yesterday, so we had to send my son (who had sourced the water valve that afternoon) back out to Walmart before his early morning trip to visit us.

#RedundancyIsYourFriend.
 
One of my main attractions to Lifepo4 is that as long as you're not trying to max out the 'allowable' C-rates you can be sort of sloppy with things and it will still work. "Buy more than you need and don't run it hard" is a great way to put it.
 
In the control industry we have a saying

"To many alarms is no alarms after 6 months!"

The operator ignores everything after that time period.

On the other hand:

If one is unaware of an unpleasant fact or situation one cannot be troubled by it.

"Ignorance is bliss" :p

Some people get by and don't need to know how or why something works, it just does, and that's fine.

I've been off-grid for 18 years, and now I do like to have the fancy graphs and alarms because I like to know what's going on and understand things, and get notified if there's a problem so I can fix it proactively rather than reactively. I definitely don't want to get spammed by the BMS's sending me multiple emails every night though!

I do have a peek at Victron's VRM every so often out of interest (probably more than I should) but I don't think I've ever had an actual critical alarm yet, apart from false alarms whilst updating or changing settings.

Because I know I can leave it do it's thing with all the graphs and shunt, safety mechanisms etc I can just get on with life not worrying about it as it's fairly self automated. That's how I get on and it's also fine.

Some people are just lucky b*stards though, and get by without issues, it's kinda sods law, if you spend time and money making something as good as possible it can still go to sh*t, others spend no time or money and everything's fine.
 
...

Some people get by and don't need to know how or why something works, it just does, and that's fine.

....
I try and have a good understanding of how everything works, it helps to ensure that it just does. Probably why machines like me so much. Machines can sense when you dislike, ignore or are afraid of them. That's when they tend to screw you over. Bit like cats.
 
Edit: I will admit failure of the coffee pot is a General Quarters condition. That is Life Support.
I had a cadet do a complete system trace and write-up on the HT Caffinate System once for extra credit at his academy. 😁

In other news, I have an old metal PowMr MPPT that's been in service for 6 years now.
 
Well, this wouldn't be a hobby if it worked flawlessly all the time. I mean everything does work quite nicely now, BUT that's a good reason to add new things to my system. I'm pretty sure that my latest acquisitions will make this hobby again. It helps that I have no clue how to make them work so need to learn new things to be able DIY everything.
 
Needing to know if the Black hole containment field is beginning to go into uncontrolled oscillation is important immediately. It could destroy half of our solar system. Luckily we maintain strict 2 man round the clock Watch with alarms piped to my day room in case of this. More mundane things I catch during my daily inspection tours. Things that happen at midnight are someone else's problem.

Edit: I will admit failure of the coffee pot is a General Quarters condition. That is Life Support.
Which half of the solar system? The half on the other side of the sun, I hope.
We keep a secondary coffee pot on standby. It's a shame my cardiologist just forbade me from drinking coffee any more. I swear, on my deathbed I'm going to ask for a cup of coffee, no cream no sugar.
 

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