Basic understanding of the battery pack is fairly straight forward. The battery pack is made of up of a lot of batteries connected in series and parallel to form a package with the correct amount of voltage and amps needed for a specific task. In our case to provide power for an electric bicycle.
The two measures of power for your battery pack are volts and amps. They are inner related to give performance to a motor. Volts tend to effect speed and Amps tend to effect range. In theory you just need to match the volts and amps to the rating on your bike's motor. Some of us tend to push the envelope a bit, but that isn't what this is about.
Batteries and volts.....
Most classic batteries (lead acid, alkaline, carbon) produce 1.5 volts per cell. Most, of the modern cells (Nicad, Nimh, lithium) produce 1.2 volts. Voltage can be increased by stringing (connecting) cells in series to increase the required voltage. The series connection will increase volts, but not amps. So if your pack needs 36V and your cells are 1.2v you would divide big V by little v. In this case a pack made of modern materials would need 30 batteries to get the amp rating of a single battery but in 36v. You would need 25 of the more vintage cells to get 36V.
At this point let me say when you buy a lead acid battery, the cells are combine inside the battery case so it in effect is a battery pack. The same is true of your laptop and cell phone batteries. The basic construction of the battery pack is the same.
Batteries and amps....
So lets say we have combined 30 modern chemistry cells to get one 36v string and each cell is 10,000mah or 10 amh. So the pack reading would be 36v 10ah, Cool but not really enough ah for us. Heck we want to ride to the park to have a picnic now and then.
So we need more amps in our pack. Amps are increased by parallel connections. We just have to build more 36v strings and hook them together with a Parallel connection to increase the amps. Two strings of 10ah each would be 20ah... three strings of 10ah would be 30ah. To figure the number of batteries we need it is total AH needed by the ah of a single cell. or 30AH divided by 10ah equals 3 cells. So for a 36Vs and 30AHs in our pack we need 90cells all together.
Whether my project works or not the math and the practice is the same. The controversy is in the recharging properties of the battery pack. That remains to be seen. But this is about the basics of battery packs.
I do hope those who have a better knowledge of the subject join in on this.
The two measures of power for your battery pack are volts and amps. They are inner related to give performance to a motor. Volts tend to effect speed and Amps tend to effect range. In theory you just need to match the volts and amps to the rating on your bike's motor. Some of us tend to push the envelope a bit, but that isn't what this is about.
Batteries and volts.....
Most classic batteries (lead acid, alkaline, carbon) produce 1.5 volts per cell. Most, of the modern cells (Nicad, Nimh, lithium) produce 1.2 volts. Voltage can be increased by stringing (connecting) cells in series to increase the required voltage. The series connection will increase volts, but not amps. So if your pack needs 36V and your cells are 1.2v you would divide big V by little v. In this case a pack made of modern materials would need 30 batteries to get the amp rating of a single battery but in 36v. You would need 25 of the more vintage cells to get 36V.
At this point let me say when you buy a lead acid battery, the cells are combine inside the battery case so it in effect is a battery pack. The same is true of your laptop and cell phone batteries. The basic construction of the battery pack is the same.
Batteries and amps....
So lets say we have combined 30 modern chemistry cells to get one 36v string and each cell is 10,000mah or 10 amh. So the pack reading would be 36v 10ah, Cool but not really enough ah for us. Heck we want to ride to the park to have a picnic now and then.
So we need more amps in our pack. Amps are increased by parallel connections. We just have to build more 36v strings and hook them together with a Parallel connection to increase the amps. Two strings of 10ah each would be 20ah... three strings of 10ah would be 30ah. To figure the number of batteries we need it is total AH needed by the ah of a single cell. or 30AH divided by 10ah equals 3 cells. So for a 36Vs and 30AHs in our pack we need 90cells all together.
Whether my project works or not the math and the practice is the same. The controversy is in the recharging properties of the battery pack. That remains to be seen. But this is about the basics of battery packs.
I do hope those who have a better knowledge of the subject join in on this.
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