Chassis Battery Charging

[cmillsap]

If you’re considering adding an on-board battery charger to your chassis battery bank, just be aware that there’s a bit more to the job than just hooking-up a charger to the positive and negative battery cables. The chassis battery bank wiring on a Prevost is fairly complicated and requires a 2 bank 12/24V battery charger to correctly keep each of the 4 batteries equally charged. Therefore, it is imperative that the charger gets connected properly.

First, to determine the proper size charger, the rule of thumb is 10% of the amp hour rating of the batteries. For example, batteries sized at 100 amp/hrs would require a charger that is sized at 20A or 10A on each of the 2 legs. A parasitic draw of more than 3 amps may require an increase in the charger size to compensate.

The charger needs to be located in a ventilated area and upright to allow it to cool properly. There weren’t many placement options on my Marathon. I ended up building a frame for it and attaching it to the floor in my engine bay and plugging it into my engine bay 120V outlet. That outlet is powered through its own circuit breaker in the 120V electrical panel. I just have to remember to flip the breaker off before I run the engine/24v alternator to prevent any damage the charger.

I installed this charger: http://www.amazon.com/Marinco-Charger-Ba...r+%2328220

David Brady was kind enough to help me determine how the chassis battery bank was wired and how to connect the proper battery charger leads to the correct connection points. Without David’s direction, odds are that I probably would have installed it incorrectly. Although Marathon routinely retrofits a chassis battery bank charger in older Prevosts, they were unwilling to give me any direction on the matter. They probably had a liability issue.

This is how I installed my battery charger with a lot of direction from David who is an electrical engineer. I am not suggesting anyone follow my lead. If you aren’t sure, have a professional install it for you.


  Chassis Batteries Schematic Final 2.pdf (Size: 113.9 KB / Downloads: 39)