Cheap (timer) vs Quality (proportional) brake controllers
I'm just copying and pasting this here from another forum I help manage for the benefit of everyone here as well. I wrote it with those hauling things other than horses in mind, but IMHO it's even more important for those hauling livestock, so I thought I'd post it up here as well.
I often see threads all over the net where people report difficult (trailer pulls and yanks their tow vehicle), jerky (too much) or soft (too little) brakes, and one of my first questions is "What trailer brake controller do you use". Sometimes the results tell the story.
Many people report their model of brake controller only to discover that their controller is a "Time" based model. PROBLEM.
Myself, and many others who understand these controllers, and their failings, consider timer based electric brake controllers to be dangerous - virtually an accident waiting to happen.
I'll explain why.
Contemplate the following. You're cruising down the interstate at 70 MPH with thousands (or tens of thousands) of pounds of trailer behind you. All is well in the world.
Suddenly, there's an accident on the road in front of you. Cars go everywhere, smoke from locked tires, people smacking into the guardrails, cars spinning everywhere....and you're heading right for it with nowhere to go.
Instinctively, you mash your brake pedal....and the trailer braking reaction begins. Now, you go down one of two paths depending on if your tow vehicle is equipped with a good proportional electric brake controller, or a cheap (and arguably, dangerous) timer based controller:
Proportional Electric Brake Controller: The second you touch the brake pedal the brake controller wakes up. Immediately it senses massive deceleration of your tow vehicle due to the controllers built in inertial sensors. Since it detects rapid (emergency) stopping effort is being called for, it instantly answers the call and provides the same (maximum) braking effort to your trailer. Setup correctly, the trailer will provide the maximum physical braking effort it can provide just short of wheel lockup.
You stop rapidly and safely without becoming involved in the accident yourself. Whew!
Timer Based Electric Brake Controller: Since the setup of a timer based controller is based on maximum braking effort, and time delay to get there, you are very limited in functionality. You can't set the controller for more then the maximum amount of braking effort that provides a "comfortable" amount of braking from the trailer without causing the trailer to drag the tow vehicle uncomfortably hard during normal stops. Most people subsequently adjust the "delay" fairly long so that driving in stop and go traffic doesn't result in herky-jerky braking effort. Some people NEVER get them setup correctly and tend to favour setting the controller to provide very low braking effort in order to avoid herky-jerky or wheel-screeching stops.
What MUST be remembered is the following:
- The "Maximum" brake power you setup will NEVER be exceeded. If you set the controller to provide only 6 Volts (~50% braking effort) to the trailer brakes, the controller will NEVER exceed 50% braking effort unless you manually apply the controller.
- The "Delay" never changes. The controller doesn't care if you're making a gingerly stop in town, or an emergency stop on the interstate - it'll still act according to how you set it up. If you set it to provide a 6 second delay to reach maximum braking effort (which, as per the last setting, may actually only be 50% braking effort at that!), it'll always take 6 seconds to reach the maximum braking effort. Simple math says that at 3 seconds it may only be providing a mere 25% braking effort. You see where I'm going with this?
So, back to our accident scenario.
Your'e cruising along, the accident happens. You mash your brake pedal. What happens next with the timer based brake controller? Very little!
The controller is "Dumb". It has no inertial sensors that allow the controller to be able to see that you are in the midst of a critical emergency stop. It has no idea whatsoever, so it treats this stop as any other - a gentle, ramped application of the trailer brakes....but ONLY to the maximum you set it to!
So, the trailer begins to push you...HARD. You push the brake pedal in your truck harder and harder, but the trailer is only 2 seconds into it's "Ramp" up of the trailer brakes, and the trailer is still only providing perhaps <20% braking effort. A second later, maybe 30%. Did you set the controller for 40% maximum braking effort? Yep, a few second later you reach 40%, and that's it - the trailer brakes won't apply any further, no matter what.
The trailer continues to PUSH...PUSH...and PUSH...providing totally inadequate braking effort...and SMASH..you become part of the accident due to your inability to stop. The trailer just didn't provide enough braking effort since the controller had no idea it was an emergency.
For all the controller cares you were still in stop and go traffic just tapping the brake pedal, not trying to push it through the floor board moments before an impending accident.
Ask yourself...what scenario do you want to be in?
If you have a timer based controller, they are DANGEROUS. Yes, they are better than nothing, but once you understand their failings you understand why they really should be replaced by a proper inertial based controller.
An inertial based controller has "brains" that knows how fast you are trying to stop - a gingerly stop at a stop sign, or an emergency stop on the interstate at high speed, and it acts accordingly. A "timer" controller is dumb - it has no idea what's going on aside from the fact that you're stopping. Set it aggressively and every (attempted) gentle stop at a stop sign is knocking your horses off their feet and nearly locking your trailer wheels. Set it gently to avoid that and that emergency stop someday could result in a wreck with devastating consequences.
Hopefully the example above will help you understand the situation better.
Questions, comments? Discuss below. I'm happy to answer questions.