First post. Throwing out a puzzle, to me anyway,.
I built a 10S-5P pack out of old Panasonic 22P's. Originally rated 2200 mah,, Six years old. Tested around 2100 ah on a Liitokala 500S @ 500A. IR around .038 ohms on a YR1035. Spot welded. Series nickel was double layer of .15mm and .10mm, ,60 inch wide, more than enough for 5A per cell.
I only had 48 cells. I made 9 rows with the 22P's. The last one was three 22P's and two LG MH1's, also used but tested at 3100 mah and ,032 ohms IR.
While I didn't go into the details of a repackr selection, I arranged the nine rows to be at least 10.4ah each with the last one at 12AH, I expected to get 7-8AH out of the battery on an ebike,
Next, I ran the battery on my ebike. From past experience, I know 20 miles will take about 5Ah at 12 mph. At 19.3 miles, the battery voltage was down to 35.7, about half way down. Half of a nominal 10Ah is 5Ah. Looking OK,. Then the BMS shut down the battery. Uh oh. it's unbalanced.
I went home on my backup battery and then checked the balance voltages. The first nine averaged 3.61 volts, low of 3.59, high of 3,62, but the tenth row was only 3.3V. I took the tenth row cells out, and all of them were 3.31 volts, so no broken spot welds, I tested the three 22P's from row 10. Discharge capacity was 2040-2090 mah, so nothing different. The two MH1's were above 3100 mah.
I surmise that the tenth row supplied 5AH like the other nine before going flat,. It should had at least 3-4 AH left, Where did the power go?
My plan is to make the tenth row all MH1's, as that's all I have left,
I built a 10S-5P pack out of old Panasonic 22P's. Originally rated 2200 mah,, Six years old. Tested around 2100 ah on a Liitokala 500S @ 500A. IR around .038 ohms on a YR1035. Spot welded. Series nickel was double layer of .15mm and .10mm, ,60 inch wide, more than enough for 5A per cell.
I only had 48 cells. I made 9 rows with the 22P's. The last one was three 22P's and two LG MH1's, also used but tested at 3100 mah and ,032 ohms IR.
While I didn't go into the details of a repackr selection, I arranged the nine rows to be at least 10.4ah each with the last one at 12AH, I expected to get 7-8AH out of the battery on an ebike,
Next, I ran the battery on my ebike. From past experience, I know 20 miles will take about 5Ah at 12 mph. At 19.3 miles, the battery voltage was down to 35.7, about half way down. Half of a nominal 10Ah is 5Ah. Looking OK,. Then the BMS shut down the battery. Uh oh. it's unbalanced.
I went home on my backup battery and then checked the balance voltages. The first nine averaged 3.61 volts, low of 3.59, high of 3,62, but the tenth row was only 3.3V. I took the tenth row cells out, and all of them were 3.31 volts, so no broken spot welds, I tested the three 22P's from row 10. Discharge capacity was 2040-2090 mah, so nothing different. The two MH1's were above 3100 mah.
I surmise that the tenth row supplied 5AH like the other nine before going flat,. It should had at least 3-4 AH left, Where did the power go?
My plan is to make the tenth row all MH1's, as that's all I have left,