Batteries

[eugenebrooks]

Originally Posted by Al Skierkiewicz

This is pretty unusual for batteries to be bad out of the box. Although I can't open the file (I will try from work tomorrow) it would appear that the battery might not have fully charged. This can occur when there is a high resistance connection to the charger. I would double check all electrical connections, charge it up and try it again.
It is interesting to note here that an 18 AH battery cannot supply 18 amps for one hour. The spec sheet lists the test parameters and the final test voltage vs. time but it should be noted that the battery changes output with temperature as well.

We finally got our current regulated capacity tester running, and have tested two ES-18 batteries from 2004, and the two EX-18 batteries that arrived in the KOP for 2005. Given a constant load current of 20 amps, and a cutoff voltage of 11 volts, the two 2004 batteries lasted 32 minutes, while the two 2005 batteries lasted 22 minutes.

The capacity of the EX-18 batteries does appear to be 50% lower.
If your robot will have high current draw you need to pay careful
attention to this issue...