Solar stops working when trailer wiring reconnected to battery

[firestation12]

Renogy absolutely states not to connect the solar wires until the battery wires have been connected to the solar controller. Whether or not this solves your problem, be sure to follow this connecting sequence as you look and probe. The install instructions clearly state the solar controller can be damaged if the solar panels are connected first.

[chapmast]

When you have multiple charging sources, in this case the vehicle connection and the charger they compete to charge. What happens in mine is the voltage from the vehicle is enough that my solar controller thinks the batteries are fully charged so it does not charge. When you remove the vehicle connection the solar controller sees the actually battery voltage and starts working again.

[JRTJH]

Originally Posted by chapmast

When you have multiple charging sources, in this case the vehicle connection and the charger they compete to charge. What happens in mine is the voltage from the vehicle is enough that my solar controller thinks the batteries are fully charged so it does not charge. When you remove the vehicle connection the solar controller sees the actually battery voltage and starts working again.

It's the same when you add a 4 amp (or a 10 amp) battery charger, clipped onto the battery terminals. It doesn't "add to the converter charger capacity" rather it causes the 55 amp converter/charger to go into "trickle charge' because the voltage from the 4 amp "add on charger" shuts off the 55 amp "main charger"....

There are circuits in "a well designed solar system" to compensate for this, but many people "add a solar panel, a stand alone battery controller and hope for the best. What they get is a system that's not compatible with the trailer system and one that only works when the trailer is "dry camping". Plug in a generator and you shut off the solar, plug into shore power and you shut off the solar. OR, you shut off the trailer charging system instead....

An "analogy" for this... Imagine connecting BOTH ends of a garden hose to faucets, turn on the water at both faucets and try to use that hose to fill your fresh water tank...... Unless you have "an extra device in the middle of the hose" you ain't gonna get water to flow... It's the same with a "stand alone, rudimentary solar system".....