NOCO charging system guidelines

Information on the design and performance of the Noco charging systems and how to maintain performance while at home and off grid.

The Noco system is not specifically designed to charge batteries and service 12V loads at the same time, but it can work well doing so.  The charger can provide at most 20 amps of charging. With the fridge using up to 10 amps and the fan 5 amps, you must manage your available power.

The older Noco Genius GEN2 chargers are appropriately wired in parallel to the batteries – one Noco bank to each battery. The batteries are of course 12V each, and wired in parallel to supply 12V nominal.

The later Noco Genius GENPRO chargers are not designed to charge the batteries in parallel, but the system is still wired this way. This is because field experience has shown that issues with the batteries are not common if care is taken to keep the system charged.

How do you keep the system charged?  

You need to always understand where you are.  At rest when neither charging nor servicing any loads some rough guidelines for the charge state of 12V deep cycle batteries are as follows:

12.6 volts = 100%           12.5 volts = 70%           12.3 volts = 50%           11.4 volts = 20%.

The batteries should never be allowed to get below 50% charge state. There are 80 amp hours in each battery, 160 total - which means that there are 80 amp hours of capacity available.  The only way to determine how fast your batteries will discharge is to do an experiment with your loads - ie: set up the trailer the way you're plan on using it, start with the battery fully charged, and measure the working time you get until the batteries are still at or above 12.3 volts.

As an example, one may suppose that the fridge uses only 6 amps.   This is truly dependent on temperature and the items inside the fridge.    In spite of that you could infer that the fridge would run for about 13 hours before the batteries were discharged to 50%. (80 amp hours / 6 amps = ~13)

How do you best use this system while camping? First, you start with fully topped off batteries, so if the fridge is on or the system is electrically loaded while at home, the Noco charger should be plugged in.     Having the charger plugged in also helps with overall battery life, even if unloaded.

How can you keep your batteries topped off on the road and off grid?

1) Plugged into the tow vehicle by 1 of 2 options:

 a) The aux pin in the 7 pin box (ensuring this connection is fused with a 30 amp fuse inline, proper sized wire is used – 10ga or larger, and that the vehicle/7 pin ground is properly attached between the tow vehicle and the trailer batteries.)
 b) more suitably, a proper DC/DC charger for RV battery systems.

2) Solar panels can be attached via a suitable charge management system.

When shore power is again available, the Noco charger can be used to replenish the batteries.   

Here are some links to other Knowledge Base articles on the trailer electrical systems:

Electrical Systems - Expedition and Pando (

On the "7 Pin" Trailer Wiring System (