Wow this is a huge thread related to LiFePO4
for stationary energy storage
I wish the same level of interest will exist in the OffGrid House community.
Almost all still use the expensive and inefficient Lead Acid.
I live Offgrid since last year is somewhere in the middle of Canada
I build an energy efficient house and decided energy storage
will be done with LiFePO4. I got the batteries about two years ago 2012.
The house uses between 60 and 90kWh/month mostly closer to 90kWh.
I have 3x 240W solar panels and a small 300W wind
turbine storing the energy in a 24V 8s cells of 100Ah from GBS so just 2.5kWh of storage around 2kWh useful.
Since battery is still the most expensive /kWh of used energy during the lifetime I wanted to keep the battery size to a minimum.
I have the advantage of both good sun and good wind
resources in my area and that helps a lot with the battery size.
Most of the power I use is during the day where is used directly form the solar PV panels as it is produced and the small difference only from the battery.
Over 60% of what I use is during the day and mostly for food
The kitchen is the only one with an AC outlet provided by a 2400W power inverter form Tripp-lite around 92% efficient.
The rest of the house is powered directly with 24V DC. Since most electronics
like laptops use little energy is not a great idea to use AC (loss on conversion and even standby) and then form AC back to DC another loss.
I use DC-DC converters like Battery 24 - 28V down to 19V for laptops.
is also 24V DC with LED's. And heat recovery unit will be custom made also with 24V DC fans.
Power generation is 60kWh/month in December worst month and up to over 100kWh in the rest of the months 3x 240W PV
And from the wind turbine (300W) about 40kWh/month in winter and less around 30kWh/month in summer.
I needed to design a Solar BMS charge controller that works with 3 up to 8 series connected Lithium cells (any type of Lithium cells) so 12V and 24V max possible for small systems.
It can do up to 40A charging from solar PV and 80A discharging this is ideal for my offgrid house since I have less than 40A 1000W of panels and under 2000W load that is why I went for this numbers.
Is now on Kickstarter just a few days left is quite close to making the minimum goal but I expected way more interest in LiFePO4 solar charging so I'm a bit disappointed.
If it makes the minimum goal that is set quite low just about 50 units then it will become Open Source and hopefully someone will take this and build more products around my design.
If you are curios about the Solar BMS or my offgrid house just follow the link in my signature and from there you get to Kickstarter where when you push on the photo with my house will send you to my youtube channel where you find more videos with battery tests both GBS and A123.
Most technical stuff is there but if you want to ask anything else about LiFePO4 or Solar BMS you ca do so here.