Setting ANT BMS to work with reject 32700 LiFePO4 cells when using 60v AGM charger скачать в хорошем качестве

Setting ANT BMS to work with reject 32700 LiFePO4 cells when using 60v AGM charger

Working with reject cells adds a level of difficulty for the BMS, and LiFePO4 cells are notoriously whacky to begin with. If you paid $3/cell for these 6ah cells, they are definitely reject cells not intended for sale to the general public. Then an unscrupulous Chinese seller goes around buying up all these cells that cant be sold as legit by the manufacturer. These cels are then rewrapped to appear to be brand new legit cells. But brand new legit cells aren’t different from each other. If you buy 120x legit cells, you can make a 20s6p pack blindfolded. Because all the cells are tested, graded and matched. So the steps we take to make a decent battery from 💩cells is first test all cells for capacity, then group them with Repackr.com website, then set the SMART BMS to protect the pack while avoiding problem areas. In this case the cell groups aren’t stable until voltage is abour 3.38v/cell. So the ANT is programmed to balance when over 3.35v, anytime cell dfferential is more than 0.001v. And it will run unti cell differential is 0.000v. Balance current shoulb be set as low as possible that atill allows it to achieve balance. A healthy battery only needs 20 milliamp bleed current . A pack with a self discharging cell might need max current and longer sessions 0:00 Reject cells failed QA and have different characteristics than other reject cells. 0:09 of you buy 10 reject cells and charge them all to 3.65v, then connect in series and discharge them, the voltages will be significantly different 0:16 most people will use active balance and mask this problem, but you can also avoid it by setting max voltage close to 90% SOC 0:20 the charger is the original Lead Acid 60v charger, so the ANT will be telling it when it can charge 0:56 OVP is set at 3.38v and OVP release is set at 3.35v. This opens and closes the charge port which determines if the chargers can charge. 1:18 typical LiFePO4 SOC curve. But it varies depending on the manufacturer and temperature. 1:21 most of the energy is between 3.20v and 3.35v, very flat SOC curve, so it should never be balanced in this range should be above 3.35v 1:25 if using reject cells, don’t balance it at 3.65v either. 3.35-3.40c is a good place to balance. 1:40 mine is set to only start autobalance when above 3.35v, and it will run until differential drops to 0.000v. 1:56 as soon as i plug in the charger you see the light turn red and the ANT app shows -2.80a (charging is shown as negative values) 2:08 you can see it already started autobalance automatically because of the settings I gave it. 2:15 The ANT has a red LED that lights up for each cell group that is being bled to balance the pack. 2:29 this balancing is false balance based on voltage surge of reject cells being so different. But it will fix it later 2:37 watch cell #1 (the highest voltage cell group). Once it reaches 3.38v the charge port will close and the voltage surge will subside. 2:44 The app shows UnitOverVoltageProtect has kicked in and closed the charge port. No charging or regen will be allowed in if this is closed. 6:08 balance current can be set higher to speed up balancing but it should be set as low as possible that still achieves balance. 20ma ideally 8:24 the balance resistors make a lot of heat if current is set high, this is why you want it as low as possible but still does its job. 9:14 fully balanced so all bleeding stops.