Old bikes: voltmeter where you can see it while riding.
Brilliant

I keep one on a 3' sae cord, plug it into the battery tender pigtail and check charging in the garage and on the road, one of the early things I do on any new to me bike
Brilliant

I keep one on a 3' sae cord, plug it into the battery tender pigtail and check charging in the garage and on the road, one of the early things I do on any new to me bike