Tracer 1210rn voltage modification for lithium phosphate.

[joeblack5]

In my converted city bus we have a 24 Volt system.. there are 4 identical groups of solar panels each with there own tracer / epever / 1210rn. 10 Amp mppt control with a mt5 remote readout.

I like the redundancy of several charge controllers and indeed we had one unit damaged several years ago.

Needed to upgrade my lead acid batteries to lithium. We are cooking on induction and also the fridge and freezer and several pumps and fans are running of the batteries.

Installed 24 Volt lishen 272Ah batteries.
I only want to charge to 3.45 to 3.5 Volt per cell. At 3.5 that comes down to 28 Volt.
The charge controller has three lead acid batteries choices. Flooded (3), sealed(1) and gel (2) the number refers to the setting at the controller.
According the manual setting 2 ( gel) charges to 28.4 Volt and does use no equalisation.
So still to high.

With some testing I found the resistor on the board that provides the voltage feedback....R13 at 143 kOhm

When I bypass this resistor with a 1.5 mOhm reducing the overall value to 133 k Ohm.

As a result the battery full indicates starts blinking at.
26.2 Volt and 25.5 Volt #2. Gel
26.6. 26.1. #1. Sealed
26.9. 26.5. #3. Flooded.
Attached a pic. of the modification.

This is still not the correct value but in case people feel like experimenting and have a bunch of old tracer around then it shows that it is possible to make it work.

Oh before I forget.. there is a setting for temperature correction with lead acid batteries.. with the mt5 that can be set to 0 mVolt/ C

Good luck,
Johan

 

[Symbioquine]

Sorry for reviving an old post... I just wanted to say nice job and offer a few comments for other folks who run into this thread;

* This modification is likely applicable to many older or low-end MPPT controllers that don't already provide the right settings in software.
* The key things are;
- Correct boost/float voltages
- Disabling the equalization charging phase
- Disabling temperature compensation
- Low temperature disconnect (optional based on climate or if handled elsewhere in the system)
* Newer EPSOLAR (a.k.a. Epever) controllers - even those with very similar model numbers like "Tracer1210AN" - allow all those things to be done in software (i.e. without a hardware modification/hack)
* I was curious about this older controller model and found a PDF of the manual - attached for posterity