timselectric
If I can do it, you can do it.
- Joined
- Feb 5, 2022
- Messages
- 18,720
Andy (off grid Garage) is currently raising his settings. He wasn't getting enough balancing on his cells.
So quick question, and maybe I missed it, but where d I find the most updated firmware and ShineBus downloads?
Thanks, I will give it a watch.As you are a fan of Andy's, then possibly you missed this video.
It's not so much about degradation. As it applies to available capacity.Great video. I am going to have to watch the ones that follow but my first impression is that charging to 54.5 absorption, 54 float is not so bad. It brings cells up to 3.4V but avoids run away cells. (probably not all of them, but I cant see that remotely on solar assistant, I wish they would add that feature).
Would love to hear more about why having cells that are not perfectly balanced could possible lead to greater degradation than charging at higher voltages? The lesser of two evils?
Thanks!!!
The pack voltage is the sum of cell voltage. Cells not balanced vary in SOC/voltage. Some still in the flat part of the charge/discharge curve, others into the knee areas at the top and bottom of the curve.Great video. I am going to have to watch the ones that follow but my first impression is that charging to 54.5 absorption, 54 float is not so bad. It brings cells up to 3.4V but avoids run away cells. (probably not all of them, but I cant see that remotely on solar assistant, I wish they would add that feature).
Would love to hear more about why having cells that are not perfectly balanced could possible lead to greater degradation than charging at higher voltages? The lesser of two evils?
Thanks!!!
I haven't watched his videos in some time. Last video I watched he was playing with some modified Heltec balancer.Andy (off grid Garage) is currently raising his settings. He wasn't getting enough balancing on his cells.
I would increase your bulk and float by about 0.5V minimum. 54.5V float will just get to 3.40V per cell and enable balancing. The problem with the Growatt not starting charging will probably go away also. The Growatt will charge in bulk until that voltage setting is hit, then it will let pack voltage drop to float and maintain it there.
If your cells have been run for a long period of time without adequate balancing, you probably will have a runner or two if you raise charging voltage. You could try raising by 0.1V per day for 5 days or 0.05V for 10 days. This will allow some balancing to occur.Thanks, I appreciate the input.
The charging algorithm will work as you describe as long battery voltage drops below float setpoint during T2 Float time. But if voltage stays above float then float times out and charging stops. If the the unit is set to follow loads, PV will supply the loads but no charging will occur, and the next day MPPT charging will not resume.
So I suspect you are right that raising absorption and float settings higher eliminates the issue. The tradeoff is closer to the knee of the curve, higher cell voltages and potential for cell to run to 3.65, which has happened to me.
- The charging algorithm ceases solar input if the battery voltage remains higher than the float voltage after absorption charging is complete.
If your cells have been run for a long period of time without adequate balancing, you probably will have a runner or two if you raise charging voltage. You could try raising by 0.1V per day for 5 days or 0.05V for 10 days. This will allow some balancing to occur.
If these cells won't balance well with passive balancing, then you will need to source an active balancer.
I don't use one but Andy has plenty of videos with his experience with them.Good suggestion; when I get back to the site and can monitor individual cell voltages will give it a try. If you have a recommendation for a good active balancer would be good to know.