Frequently Asked Question

CLASSIC - LITHIUM Quick Start Simplified
Last Updated 3 years ago

The other CLASSIC & Lithium battery papers were left for archival purposes.  Below find a simplified "Quick Start" guide to setting up the Classic (tm) Charge Controller to work with Lithium batteries.

First consideration, the Classic Line was developed before Lithium Chemistry was available to the Solar Power crowd.  It was never nativity designed to charge Lithium batteries and most likely will not be updated via Firmware anytime in the near future. This does not mean it can't be used to charge lithium, they just don't have some of the nice features required of lithium such as reduced charging on a cold battery, BMS direct control, etc.

REMOVE THE BTS (Battery Temperature Sensor)

There are 4 voltages that need to be set and 2 CHARGE TIMES need to be changed from the default setting. The RULE:  REBULK lessthan FLOAT lessthen ABSORB

  • This says REBULK voltage is always less than FLOAT voltage and FLOAT is always less than ABSORB voltage.
  • EQ or EQUALIZE is a Lead battery function and is not used for lithiums.
  • ABSORB = Lithium Charge Voltage from battery manufacturer
  • FLOAT = .4 to 2V less depending on if battery bank is 12, 24, or 48V
  • REBULK = again, as above.

For example, if the charge voltage for a 12 volt lithium is 14.5V, then:

  1. ABSORB = 14.5  (24V Lithium 29)
  2. FLOAT = 14.0   (24V Lithium 28)
  3. REBULK = 13.5  (24V Lithium 27)

As you can see, they are .5V apart.  This may work for a 12V system or may need adjusting to .4 V spread or .6V spread.  A 24V or 48V battery may need 1 to 2 volt spread.  Try it.

CHARGE TIME set ABSORB = 00:05 (5 minutes) and EQ = 00:00 (zero time)

Please Wait!

Please wait... it will take a second!