Battery Best Practices

[Al Skierkiewicz]

Originally Posted by Superllama12

Some major advice: if the battery drops below 10.5 volts, it will get damaged! I would advise to check the batteries pretty frequently, and make sure they don't go below 11v. Also, when they charge, their max is 14.4v, but it will drop to 13.8v (its max rest charge) afterwards, so don't freak out if they seem to charge and then drop again!

Brandon,
These batteries can and do regularly drop down below 7 volts without damage. Testing with simply a voltmeter is not enough to determine if a battery is good enough for competition. Only a load tester of some type will give you an indication that the battery can actually supply power. A voltmeter reading of 13 to 14.5 volts is normal for a battery that has just been removed from the charger. This battery, however, is nominally 12 volts under load and that is the reading that will show on your dashboard when communicating with the robot. That reading comes from the battery connection on the analog module of the Crio through the jumper to port one. That is actual battery volts as measured at the PD. Without a true load tester, using the robot and dashboard while running the drivetrain may give you a pretty good idea of battery health. You can expect to see a voltage drop when starting but it should return to near 12 volts after one second. I highly recommend the West Mountain Radio CBAII or III USB battery tester. These devices will fully test batteries for AMP HR ratings taking an hour or two to perform the test. The results are available in graph form and can be saved in order to perform annual tests on batteries and compare the results. Please remember that our batteries are specified for about 400 charge/discharge cycles maximum. Our use causes that number to drop as a match will draw far more current than the battery was designed to deliver. I would expect life to be in the 300-350 cycle range.