solar charging unstable charger 2

Why are I getting weak and unstable solar charging through my charger 2?
I am pairing the charger 2 with the Elite 200v2 but cannot get a stable solar input through the charger 2. I have bypassed the charger2 to confirm the solar panel and wiring is ok and it gave me good strong stable charge then wired back through the charger 2 and back to weak unstable charge. I suspect a fault with the charger 2? Charging from the car alternator is excellent just need to rectify the PV solar charge. I have double checked connections are good and as should be in the manual.