I run a Trimetric Monitor from BestCoverter.com. Once you set the battery capacity, it will show you volts, charge/discharge rate (A), and % full. Simple 4 wire hookup and a shunt in the ground wire just before the battery. More than you, I was worried about battery usage until I installed the monitor. Then I realized just how frugal I was and started having a blast.
I didn't go with the kit, but did go with the Renogy 100W panel with a PWM control similar. Max I have seen is just over 4A, but the battery was mostly recharged before the sun was high over head. The one panel will easily give me 20A recharge on my single battery which is all I need.