One morning it wouldn't start so I jumped it and lately I've noticed it has been starting slow. I took my 2003 Highlander to Advance to get the battery tested and they were not exactly definitive on what the issue was. Battery measured 305 CCA and 650 was expected. Alternator tested good (according to the tool) BUT the charging system results perplexed the tech so he asked someone else and she said based on the squiggles on the graph she thought a diode on the alternator was bad. No load measured 13.69 volts and loaded measured 13.43 volts. And something about the charge spiking after I let go of the accelerator when revving it. Anyway should I replace the alternator and try to trickle charge the battery back to health? Or just replace the battery since it is the stock one from 7 years ago. Is it possible to test with a multimeter?