@poor but proud - here is what I did in a nutshell
Bought one of these (as they were the cheapest at the time). I have the 200W model with the PWM controller
I made new Anderson leads but you could unscrew them from here and re-use them in a few steps from now.
Throw away this bit (keep the leads if you need them)
Buy one of these
* Make sure you get the SmartSolar model has it has Bluetooth built in. The BlueSolar model does NOT
** The 75 denotes 75v input from the panel (more than enough for 1 solar mat) - the number after the / is the number of Amps it can output. I would suggest the 75/15 as the 75/10 will be running flat out on a 200w blanket)
Attach the Anderson leads you either kept or made new to the Victron controller.
Connect the unit, follow instructions in the manual and open the app on your phone.
Configure the controller to match your batteries values (also don't forget to set the type of battery in there)
And thats it.
When you want to get more fancy, buy another Victron MPPT controller (I went the 100/20 so I could hook more panels up) and replace the unit in the van.
Throw away this
And replace it with the new Victron MPPT regulator. Setup the specs to match the battery again.
Grab one of these and attach it to the battery
Get the slightly more expensive blue model - it has better Bluetooth range than the black one and will reach your solar mat no matter where you lay it in the sun.
Then follow the manual and configure the battery sense and MPPT regulators into a network - see
This will prevent to portable mat and roof mounted panels "fighting" each other.