Hello, I am planning to build my first 18650 7s battery pack for my small home which uses roughly 2kWh per day. Currently im running on two 150Watts solar panels in series and two 40Ah Lead acid batteries with a 24v Inverter which has solar charge controller built in. Im not running the house off-grid but I want to if I can with these 18650s
I have collected 47 dead laptop batteries and from these I got 183 18650 cells which had 2.9-3.6 volts in them. currently im charging them all with 10 TP4056 all of them are beign powered with a 5V 5Amp power supply and capacity testing them with 2 Keiweisi usb testers with 1Amp load on them. I cant use opus and liitokala chargers as banggood dont ships them to my address also I dont have much money for fancy battery charger and testers. I will be expanding my pack as a found more laptop batteries.
My Questions are
1. Some of my 18650 cells doesnt charge up to 4.20V, they only go to like 4.08-4.16. Are these bad cells? or I can use them in my pack.
2. How much voltage drop is acceptable in 2 weeks. Like if I charge them to 4.20V and store them for 2 weeks then test their voltages and I get 4.15V can I use them?
3. Can Sanyo heaters be fixed? I have searched for the thread but seems like it has been deleted.
4. Can I use my pack without a BMS? Because the Daly BMS on banggood which will ship to me will take almost 2 months to reach and is a bit high on price for me. So, im thinking of building and using the pack until I save the money for the Daly BMS. I will be monitoring the voltages everyday.
5. Is self discharging an issue as I will charge them and discharge them everyday.
If Im doing something wrong please guide me through the steps to cells harvesting and pack building.
Thank You.
I have collected 47 dead laptop batteries and from these I got 183 18650 cells which had 2.9-3.6 volts in them. currently im charging them all with 10 TP4056 all of them are beign powered with a 5V 5Amp power supply and capacity testing them with 2 Keiweisi usb testers with 1Amp load on them. I cant use opus and liitokala chargers as banggood dont ships them to my address also I dont have much money for fancy battery charger and testers. I will be expanding my pack as a found more laptop batteries.
My Questions are
1. Some of my 18650 cells doesnt charge up to 4.20V, they only go to like 4.08-4.16. Are these bad cells? or I can use them in my pack.
2. How much voltage drop is acceptable in 2 weeks. Like if I charge them to 4.20V and store them for 2 weeks then test their voltages and I get 4.15V can I use them?
3. Can Sanyo heaters be fixed? I have searched for the thread but seems like it has been deleted.
4. Can I use my pack without a BMS? Because the Daly BMS on banggood which will ship to me will take almost 2 months to reach and is a bit high on price for me. So, im thinking of building and using the pack until I save the money for the Daly BMS. I will be monitoring the voltages everyday.
5. Is self discharging an issue as I will charge them and discharge them everyday.
If Im doing something wrong please guide me through the steps to cells harvesting and pack building.
Thank You.