When I see that my car battery isn't in top condition (hard starting, lights fadeing during start, etc) I connect it to one of my (semi)intelligent chargers and let it on overnight. In the morning I see the charger turned off or just showing the charging current = 0 A (these chargers automatically stop charging when the voltage rises over xx Volts).
What I would like to see is a number showing Amper hours that the charger pushed to the battery - this way I would see when the battery capacity is decreasing and it's time to buy a new one.
Even better would be graphs showing the voltage and current, either on the charger display or via an app connected via Bluetooth.-- slovakmartin, Jan 15 2017 Not a bad idea. It would also be nice if something similar were built into the car, to monitor battery health continuously. Or is that what you meant?-- MaxwellBuchanan, Jan 15 2017 These things are already available for most types of battery, especially LiPos which are particularly sensitive.
I bought, for £4, a "usb charger doctor" which intercepts any usb charging cable, and displays the voltage, current and the time and mAh delivered since you last pressed the reset button.-- mitxela, Jan 15 2017 Do you think USB is a practical method of charging a car battery?-- pocmloc, Jan 15 2017 Well the U stands for Universal, so I expect it would work swimmingly.-- mitxela, Jan 15 2017 No, it's only "universal" for a series of buses.-- MaxwellBuchanan, Jan 15 2017 Well, if it can charge a bus battery, it should easily be able to charge a car battery ... buses are much bigger, although they're probably on a 24V system.-- 8th of 7, Jan 15 2017 //Do you think USB is a practical method of charging a car battery?//
Well, considering USB is 5V @ (IIRC) 0.5A and car batteries charge at 14V and hold 60-80AH, you'd need a voltage converter... and it's going to take awhile.-- FlyingToaster, Jan 15 2017 Agreed, but there is a certain beauty in having part in hand when asking for the replacement.-- normzone, Jan 16 2017 random, halfbakery