Connecting a 100 watt solar panel to Zamp port

You've given a lot of very sound counsel here, WillThrill. I would like to add that it is beneficial that your volt meter is accurate to 2 decimal places. Measuring to the 1/10th volt is usually very approximate if measuring battery state of charge. Most often the final digit at the end is plus or minus 1 digit. With 2 digits (1/100) the measured state of charge (SOC) is more accurate.  

It's best that the battery is neither being charged or discharged when taking the voltage measurement - the rest voltage. This chart gives the SOC at rest.

Voltage also varies with temperature and flow of current into or out of the battery. The following link gives a good discussion of SOC when the battery is not at rest:

With all the variables in play, measurement of state of charge is not exact. But it can be of some use nonetheless.

First, the primary purpose for my solar installation is to remove the need to supply 120v from my house during the summer when the Pod sits in my yard.  There will be infrequent need for power resources mostly limited to the parasitic draw.  Occasionally the fan, radio or lights might be used for a short period of time when in my yard.   We do not intend on doing a lot of off the grid, dry camping.  In fact, we we will probably never go more than 48 hours relying solely on Pod power.  So it's requirements on the road are, at this point minimal.

So, the installation includes a flexible HQST monocrystaline 12V 100watt flexible panel

https://www.amazon.com/gp/product/B017OMTAV6/ref=od_aui_detailpages03?ie=UTF8&psc=1

The panel is being attached to the Pod using 1" wide Extreme Industrial Velcro (brand) tape.  The original intent was to have 3 configurations I could mount the panel depending on the angle of the sun.   There was a Major fail with this.  The velcro sticks against the two tapes extremely well, the adhesive against the Pod vinyl fails when the tape is wet!

So, I am now augmenting the 1" velcro with 1/2" VHB tape.  The tape is helping secure the Velcro to the Pod vinyl.   I'll keep an eye on this as I thing the real problem is the vinyl on the Pod itself and it's being a poor recipient of the glue.

I have also put 1/2" foam insulation tape surrounding the panel mounting.  The intent is to reduce any air that might try to get under the panel by wind.  It may also reduce water to the velcro, but that would be a plus and beyond the original requirement.

The panel is wired into a Morning Star Sun Saver charge controller.

https://www.amazon.com/gp/product/B017OA5DH8/ref=oh_aui_detailpage_o05_s01?ie=UTF8&psc=1

The charge controller is capable of managing a second 100 watt solar panel if that's what I need in the future.  It looks like a good fit and so far seems to be performing well. 

The charge controller is mounted in the battery box.  I needed to get a larger box for this, but it only cost about $8.00.  Connectors cost more than that!

I also installed a voltmeter/ammeter to measure the charge between the charge controller and the battery.  This is more flash than function but it will help acknowledge the suns yield.

Am I correct in my assumption that the charge controller will maintain the battery charge and provide whatever solar energy is available towards any load demand?

Or conversely will all available solar power go to the load and any excess be used to maintain the battery?

Clarification on the 'load' side of the charge controller.  This option only works if there is a battery present, presumably to avoid the issue you mention and assure adequate power (assuming the battery is capable of supplying what the sun can't)

I am not using the load terminals.  They'd probably only be of use for a utility light or some other low power appliance.  The Pod already has a light.

I've also been thinking about the unused Zamp wiring.  I may rig up a 12 volt adapter to it.  Should be simple since it's wired directly to the battery.  All I'd need is a fuse and either an SAE to 12v adapter or replace the existing SAE on the side of the pod.   I really don't like making any physical changes to the Pods exterior so I'd approach that option with reservation.  

An alternative would be in the event I wanted to add a suit case panel in addition to the semi-permanent panel on the roof.  I could re-wire the Zamp wires from their current mount on the battery and run them through the charge controller with the other panel (parallel).  Then I could use the Zamp connection on the rear as intended without the need for an additional charge controller.

Of course, neither of these modifications are necessary or even practical now.  I just can't help but think about this sh*t.

Thanks again.