How to Ensure Proper charging with converter-chargers

A recurring issue our customers experience is one where their Trimetric TM-2030 monitor does not reset to 100% when their rig is connected to shore power at a campground.  We hope that the workaround we offer below will solve this issue.

The Trimetric monitor uses two criteria to detect a fully charged battery state.  These criteria are set in parameters P1 and P2.  Parameter P1 is the voltage condition.  The battery voltage must reach (or exceed) this value and stay there until the second criterion is met – the charging current criterion.  Stored in P2 as a percent of battery bank capacity (in Amp-hrs, stored in P3), this condition must be met simultaneously with the first condition.  The monitor uses time-averaged values of voltage and current for making these decisions.  To see the average values, press & hold RESET while on Volts or Amps display.  

When used with our SC-2030 Solar Charger, the Trimetric is in control of the charging process.  It drives the SC-2030 until the two criteria are met so that the state of charger indicator may be reset to 100%.  When connected to shore power, the battery charging process is not controlled by the Trimetric monitor; it is simply a monitor.

Most converter/chargers, especially older units,   do not take the charging voltage high enough to meet the P1 criterion the Trimetric uses or maintain the voltage at or above P1 value until the current drops below the value implied by P2.  Instead, the converter/chargers either briefly boost the voltage to 14.3 V and immediately go to float or keep the voltage at high 13’s for the entire charging process.  This leaves the Trimetric monitor waiting for the two events that do not occur, unable to reset to 100%.

A simple workaround is to install an inexpensive industrial power supply designed for LED lighting and funnel its current thru the SC-2030 to charge the batteries in conjunction with the built-in converter/charger.  These power supplies deliver 10-30 Amps (depending on the model) at 15 or 16V DC.  The SC-2030 delivers this current to the batteries as per the profile stored in the TM-2030 and ensures that the battery bank is charged until the two criteria are met.

The illustration below shows how an industrial power supply may be wired to a SC-2030.  Please note that the illustration is not a detailed ‘How-to’.  Your specific situation may call for a different approach.  Please contact us if you questions/comments on this or any other related topics.

Link to 15 VDC, 10 Amp Industrial Power Supply –