I dont understand how it can be ignored- especially for someone with a RV setup, with a large battery bank capacity to cover zero sunshine days, usage of 60%-70% of capacity max, but more normally only 30% of capacity cycling, solar charging only, at less than 0.1C and wishing no further checking/testing of the bank over the next ten years use. When i buy a car, i dont expect to check the battery every year. It simply works for the 10 years i have the car. If a house bank is installed in a RV, i expect it to simply function as normal after the initial comissioning or top balancing. What seems to be the prevailing thought amongst electrically minded folks, is that they will babysit them every 6-12 months....full charges to wipe memory effects/recheck balancing.......that is the fud.
It is all fine and dandy for 'battery manufacturer' (no ref to upnorth) guys to bluster 'for goodness sake' its a battery etc, just use it, but if something can be done to increase life expectancy of a battery bank from 10 years to 12 years, then it is worth it for the DIY'er. We dont all have several thousand £/$ to throw at battery banks. They just need to work.
So far, no one has really intimated the perfect way to commission once and run trouble/maintainance free thereafter for ten years....imo.
Are these batteries only for nerds, that have nothing better to do with their time that run meters over their cells and constantly monitor outputs and data.....what happened to fit and forget?
Two years ago I plugged in a 12V battery string into bank,
And I plugged a 24V battery string into bank.
On 7-Jan 2019, and on 7-Jan 2020 I pulled both strings out and did a full charge, full discharge, and full recharge on the meters to figure out EXACTLY how much those LiFePo4 batteries and degraded over first 1 year, then 2 years of fairly hard use.
That's exactly 1 each 100% guaranteed charge every year.
I'm sure the panels/charge controller/BMS got them 100% charged during the summer months, I'm also equally sure they did NOT get 100% charged in the winter months.
Call me a 'FUD' if you want to, but I'm learning about LFP and BMS's, so I'm watching & learning from top quality battery manufacturers and what they do with BMS paired with their cells.
Batteries in the parallel 12V string had degraded ON AVERAGE 1.5% in 2 years,
Batteries in the Series/Parallel string had degraded ON AVERAGE 1.25% in 2 years.
I'm sure they will degrade FASTER as they get older, but that puts them right on track with the 10 year or more time frame many LFP battery makers say they can live and still work at better than 80%...
With On Board BMS, the cells were all within 0.07V of each other after 2 years.
These batteries were fully charged 'Stand By' units for at least a year before I acquired them,
And I didn't cut them open to check cells the first year, They were too new and I didn't want to damage them.
Now I have a pile of cells and BMS units that match the cells.
Probably a good thing I didn't cut them open the first year or I wouldn't have had an idea of what to look/test for in a BMS.
I'm still using them, the cases simply aren't sealed anymore.
I charge/discharged cycled each cell, recharged and connected BMS and put the entire mess back into the cases.
After sitting at least a year at full SoC (BMS Controlled),
And after two years of 50% to 85% discharge/recharge in my hands, 0.07V (7/100 of a Volt) is all the cells were out, from highest to lowest.
I'd say a good BMS is a requirement, but no one wants to talk management, they would rather talk, and talk, and talk, and talk about what *Could*, *Possibly*, *Might* happen...
The CHARGE CONTROLLER isn't anywhere nearly as important as the BMS.
Buy $3k or $4k worth of cells, then hang a $20 BMS on it, you get what you paid for and probably deserve...
Buy a BMS that both top and bottom controls, has both charge & discharge balancing, has a cut off at high/low voltage, and the cells live.
It's about that simple...
Like anything else, the more features, the more you pay, but it's a 10+ year investment, which can go on the next battery string, assuming something better than LFP comes along in those next 10+ years...
And that's assuming someone doesn't make a better BMS in the next few years, you can always switch out BMS fairly easily on battery strings you built, and BMSs aren't hateful expensive.
You can continue to loose sleep and get wound up, or you can take it from someone that's running large battery banks already and check on things from time to time, just in case...
LFP is not subject to Memory Effect, your spinning tires for no reason, that's a left over from the days of NimHi, NiCad and all those other nasties of the past.
Steve bought a BMS that cuts off charging, and cuts the battery off when it reaches his preset discharge threshold, Done & Done.
The $2,800 12V batteries I got surplus do the same thing inside the BMS, the battery has to drop 1/2 volt before charging will resume, and it cuts off completely until the battery is 1/4 charged on the low end,
But then again, these were $2,800 when new and are used in no-fail medical devices.
I'd say Steve installing relays to cut off high/low charging was the most cost effective way to go in his home system.
Steve didn't pay $1,000 for a BMS that does those things inside the case of a 12V battery...
As for RV guys, they are on their own.
Sealed batteries, BMS inside, I'd go with someone that has a 10 year warranty like BB instead of loosing sleep about what *Might* happen, just cover my ass with a warranty...
Is that a reliable source of information? I mean, I was almost decided to go for a lithium battery bank for a solar system I intend to build, mainly because I was pretty much convinced that any lithium variants (including LiFePo4) were not vulnerable to memory effects. The information on that article just rocked my world...
