I was thinking of buying a Topdon BT200 to check batteries and alternators on my family’s many cars. However, I was wondering why I can’t use a Cen-Tech 61593 multimeter that I already have just as well
You can’t just measure the voltage of the battery (which a multimeter would do) and assume the battery is healthy. That’s good for checking the charging system so still important to measure the voltage. But the battery itself also needs to be tested with proper loads - which a multimeter cannot provide. Now, which is the best battery load tester? That’s a good question.
no. A multimeter won't tell you anything about the internal resistance of the battery.
I use an Autool BT-460 tester that Scotty demonstrated in one of his videos some time ago. Seems to work well. I also have an old-school resistance-type load tester.
https://www.amazon.com/AUTOOL-BT-460-Auto-Battery-Tester/dp/B07PM5JMCF
https://www.amazon.com/Bastex-Battery-Insulated-Carrying-Automotive/dp/B01N75BLH5
