Recommended Battery Size for Breakaway Brake System

Published 11/13/2014

Question:

We have a 10,000 lbs trailer which has a electric/hydraulic brake system. The breakaway brake supplied with the trailer is only 5 amp/hours. Is that sufficient?

asked by: John P

Expert Reply:

The battery you use for a break away system needs to be able to power the trailer brakes on full for 15 minutes. A 12 volt battery rated for 5 amp hours is normally used, unless you have 3 axles each with brakes, then you would benefit more from a 9 amp hour battery. However a battery this large would not charge up through the 12 volt circuit coming through the trailer connector.

The replacement batteries we carry, # HM20008 and # TK2023 are both rated for 5 amp hours.

You can add a charger designed for a break away battery like # 20011.

expert reply by: Chris O