Why do Trailer Electric Over Hydraulic Brakes only Operate if Break-Away Battery is Fully Charged

Question:

I have this Dexter brake controller on a Myco boat trailer operating electric over hydraulic disc brakes. We tow with a 1998 Dodge 3500 Duallie using the P2 controller. With this set up the brakes will only operate if the break-away battery is fully charged. On a recent trip from Virginia to Florida we had to purchase and use a total of 4 batteries to keep the brakes operational. I thought the purpose of the battery was to operate the brakes if the trailer came disconnected from the tow vehicle and was not in use while the trailer is connected to the tow vehicle. Shouldnt the power to activate the brakes come from the tow vehicle and not be reliant on the power in the battery?

asked by: Charlie H

Expert Reply:

Your Dexter Electric Over Hydraulic Actuator # K71-651 will need your breakaway battery to be fully charged to operate as you've figured out I'm sure. It sounds like the problem is that your 12 volt power circuit on your 7-way is no longer functioning and its not charging the battery so its dying.

Most likely there is a blown fuse on your 12 volt trailer circuit and because of that the breakaway battery is dead and your electric over hydraulic actuator is no longer working.

The amperage draw of the actuator is greater than what the 12 volt circuit on your trailer connector can provide, that is why a separate battery is required. You need to make sure you are using the correct rated battery like what is in the Dexter Breakaway Kit # 34-285. Your system requires a 9 amp per hour battery like the # 34-285.

expert reply by: Jameson C