My dashboard has two voltmeters with voltage sense leads on battery terminals.
It also has an ammeter that at one point measured total alternator output, but now measures only amperage into or out of house battery.
But my house battery is also my engine battery since June 2015, so one of those dashboard voltmeter sense lines is on the OEM wiring rather than a battery terminal.
I have an AH counter tiesd to my solar controller. It displays total solar input and output, and amps into or out of battery.
My 40 amp plug in adjustable voltage charging source has an inline Wattmeter installed on the output terminals, modified with 8awg. 45 amp anderson powerpoles are widespread. I have a few of these same wattmeters I can employ inline on any circuit under 45 amps.
These wattmeters read :
Amps
Volts
Watts
Amp peak
Watt peak
Voltage minimum
Amp hours
Watt hours
I'd estimate they are about 92 to 95% accurate in the 0.6amp to 40 amp range . Below 0.6 amps they read low, but it varies unit to unit. I had one which was accurate down to 0.06 amps.
I cannot imagine not knowing how many amps my battery is accepting at X voltage or how many volts it is maintaining under X amount of load for X AH removed from full.
Voltage readings alone are nearly useless in comparison, but better than nothing.
