]Let me first say - DO NOT DO THIS AT HOME....
Every EBike battery has some common characteristics. Most people who buy a fully assembled battery have several connectors coming from it. There should be one for the charger (3 pin, round), one for the motor (2 connectors, rectangular, red and black)
3- Other Connecto&.jpg
and maybe one more - this is sortof rectangular and white. It may have one red pin, or it may have one black pin. This is called a Balancing Connector and it has a connection to every cell in the battery. It looks like this:
Balancing..jpg
So, I have built two cables that can be used with a balancing charger - or CellLog - or both at the same time. These cables can be used to charge a bank of 6 cells at a time, or a single cell.
1- 6pin connector&.jpg2- 2Pin Connector&#.jpg
Now, the common issues that are found with batteries:
4- Ping Disassemb&#.jpg
1. It was left on the shelf over winter and it won't charge.
Prevention: A balancing charger has a mode called "storage". If you don't have one of these, then charge the cells halfway and get a CellLog so you can check them periodically. If a cell drops below a certain voltage, you will likely get a balloon - if you are lucky. Keep them above 2.0 volts. They do discharge over time, and do so slower when cooler. Do not freeze them.
Solution: See the solutions below.
2. The pack won't charge, a charge doesn't last, etc...
Prevention: Keep the pack balanced and make sure that a cell never goes below 1.8v or above 4.2v If you got this far, you never let them go below 2.9v or use more than 80% of the stored energy. Balanced means that they are within 2% of each others' charge state. It's a tricky thing to get to if you don't know how. If you have CellLogs (or similar devices) you will hear an alarm. If not, then the LVC (Low Voltage Cutoff) of the controller may be kicking in.
Solution: A cell has gotten out of balance or will not charge. This can only be tested for and solved on a per-cell basis. You need to be able to verify each cell voltage - please, get a cell monitor.
3. A cell has gone below 1.8v
Prevention: Never deplete a cell
Solution: Use the "Bucket Solution"
4. A cell is charged over 4.2v
Prevention: Never overcharge a cell. Have the means to test and verify the battery and each cell's state to ensure this never happens - get a CellLog or use a multimeter.
Solution: Run!!!! No fire extinguisher can help you. You should have used the bucket solution.
The "Bucket Solution"
5- Bucket..JPG
More on this the next post....