Hi Allan, All LFP batteries can be charged to a much higher voltage than we will ever use. Some as high as 4.2Vpc. A disconnect voltage of 3.8 Vpc is typical protection voltage for LFP batteries which is below the well maximum charge voltage. Some recommend charging to 3.65Vpc, others a little less. 56.4 is low at 3.52V. Our cell balancers don’t even start to function until 3.5 volts and above. Using a low voltage can also cause a problem with the SoC calculations.
Using a Trimetric is easy if you use a high enough charge voltage of 3.55Vpc or higher and charge at .5C or less. You can use L1 settings only, P7 Off. Simply setup the reset parameter P1 voltage about 0.2V below charge voltage. Leave P2 Charge Amps off. Set P3 AH to match actual capacity. When voltage parameter is met, you are close enough and it resets to 100%. This is due to internal resistance. Your voltage will not go high until you are at about 98% or so. FWIW, if your concern is about harming the Li cells, we have never had a single cell failure. We have had several ruined cells from neglect caused by over discharging when people did not follow EMS assembly instructions. With 4 cells in a 12 volt battery pack, I am talking about thousands of cells we have sold in the last 5 years. LFP is rugged, very fast to charge and will last a long time with little care. When I read things about Li batteries on the internet, it makes my head spin from all the folklore, falsehoods and fear-born myths. Careful what you read. Larry Crutcher Starlight Solar Power Systems On Aug 21, 2018, at 12:26 PM, Sindelar Solar <[email protected]> wrote: Yes, I just did. Ralph retired last year and I spoke with the new owner. In short, little change - use 2% of capacity for amp threshold and set CEF to 98% from default 94%. I was also told to stick with the default 14.1V voltage threshold, but that equates to 56.4V for a 48V system, which is above the normal range of these batteries, so I'm reluctant to take that advice. I'm working with Kyle Bolger of Blue Planet on this first installation, and will post to the list what I learn that will benefit others. Thank you, Allan
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