The description about feeling like the trailer brakes are so strong that they’re stopping the truck, does not sound safe to me.
It's actually quite the opposite. Having the trailer stop the tow vehicle is a dynamically superior condition.
Think of the trailer as a mass on the end of a stick, a lollipop shaped pendulum if you will. If the braking force is coming from the tip of the handle of that pendulum you are essentially trying to balance the pendulum on the tip, and the only thing keeping the trailer behind you is the relatively low lateral forces, and the tires adhesion to the pavement. If you need to both turn AND stop at the same time, the tow vehicles greater braking capability, combined with an offset direction on the pendulum will tend to force the trailer to the side, and most likely create an oscillation. This is the same as if you're balancing that lollipop on your finger, then move the finger purposefully to the side.
Now, lets consider the same lollipop style pendulum, but hold it from center of the mass, not from the tip. The tip of the handle will naturally fall straight down, and return to straight down if you move your hand. There is no active balancing, or other interaction required, the system returns to it's naturally lowest energy state, and remains stable. This is analogous to the trailer creating more braking force than the tow vehicle. It quite literally "yanks the rig straight". A well tuned electric actuated system (full electric or EOH) will create just a touch of additional force than the tow vehicle, with it tending toward stopping it's own weight plus a small small fraction (2-3%) of the tow vehicles weight. Additionally, gain modulating brake controllers that are based on inertial measurement units (Accelerometers and gyroscopes) can help tune that balance in real time based on what is happening in the tow vehicle.
The ideal condition is that both vehicles, the trailer and the tow vehicle, brake and slow their own weight. A WELL TUNED (which I think Shorelander's is pretty well tuned) surge system will do this somewhat automatically. There is no gain to set, no testing and checking based on load. The braking force is modulated with spring in the tongue actuator, adding or removing braking force as needed. If that spring fails, or is improperly sized for the load at hand then you will either get too much or too little brake application. Also, the nature of a system with a spring, a mass, and a disturbance is to oscillate. This is when you hit the brakes hard and get a surge/release/surge/release cycle, the worse the tuning of the system, the more distinct this effect.
For me, with several years of towing experience with both surge, electric, and EOH systems. The surge is my last pick. It's the least proactive system, and has very little ability to adjust for varied loads, or driving conditions. So when I am going to choose a new system, or an upgrade to an existing system, it's at the bottom of my list and becomes an "Only if I can't work out something else". I've personally avoided accidents by having the ability to reach over and "fan the brakes" on a trailer during an emergency stop. Kept a 22ft enclosed trailer BEHIND ME when I popped over a hill at 60mph with traffic stopping and dodging into the median ahead of me. I grabbed a handful of trailer brake with a light foot on the vehicle brakes, and steered myself and the trailer into the grass and avoided a collision. That kind of proactive capability is what really makes any type of cab controlled electric system superior.
With all that said, I have no intention of downplaying the effectiveness of a surge system. Given the choice of no brakes versus surge, surge is better. Well tuned surge systems (such as those we find on Yamaha factory trailers) are actually quite good. They are well tuned, somewhat easy to maintain, and perform well in general. The reverse light lockout features is a nice touch as well, that makes it a well rounded system. If you have a good functioning surge system, there is no immediate reason to go out and replace it, especially if your tows are short and/or infrequent. Those guys that are making annual pilgrimages to FL from NY, or towing over the "big mountains" out west would see a benefit of moving to an electrically actuated system.
Again, hoping this is a general info type post, not intending to react out against
@seanmclean I included his post as a quote only for context.
