PM4 is known to drop voltage to a trickle at about 3/4 charged. PD or IOTA hold the voltage up for an extended period and may have been a better choice. However the solar will be perfect to fill in the gap.
Controller close to the battery is always best. Good controller with adjustable set points is also very helpful to get back to full charge.
There are battery monitors to count amp/hours and let you know when to charge and when you are full. I get by fine with just a voltmeter and I recommend adding two more batteries before you get a monitor. Although people that have the monitors really seem to love them.
