I have a pair of Lifeline AGM batteries that I want to equalize/condition, as they’ve been sitting unused for a while. Lifeline recommends doing this periodically, as follows:
“First go through the normal charge cycle to bring the battery to full charge. The conditioning charge should then be applied by charging for 8 hours. At 77°F (25°C), the conditioning voltage should be set at 2.58 VPC (15.5 volts for a 12 volt battery).”
(There follows a temperature compensation chart. At my ambient temperature, 15.6 V is what they recommend.)
The gist of my problem is this: I have been unable to get my 75/15 to put out anywhere near 15.6 V in equalization mode, or to equalize for more than an hour at a time, regardless of what settings I choose in the VictronConnect app. I’ve read and reread the 75/15 manual, but it doesn’t cover manual equalization, or any of the “Expert Mode” settings available in the Victron app.
Here’s my hardware setup:
* Two 100 W solar panels, tilted and aimed at the sun, under clear Arizona skies. They’re connected in series and are putting out more than 40 V. From past experience I know I can get at least 180 watts from them under these conditions.
* Victron 75/15 solar controller (firmware v1.42), with settings controlled by the VictronConnect app (v5.11) running on an iPhone (iOS 13.1.3).
* Two Lifeline GPL-6CT batteries connected in series, for 300 amp-hours at 12 V.
Again, my goal is 15.6 V for 8 hours, as the battery manufacturer recommends. So I go into the VictronConnect app’s battery settings. I choose “Expert Mode.” I set the equalization voltage to 15.6 V. I set the equalization stop mode to “fixed”, and the equalization duration to 8 hours. I tap the button to start manual equalization. That’s where things go wrong.
First I get a warning that equalization will be limited to 1 hour. And indeed it is: regardless of settings, I have to manually restart the process every hour. What happened to my 8-hour fixed time setting?
Worse, the controller never puts out more than 15.2 volts, despite the fact that I set it to provide 15.6 V in equalization mode. It has plenty of power available from the panels, but is only drawing 19 watts. 15.2 V is obviously not enough to do the job, per Lifeline’s recommendations.
What am I missing here? Why can’t I get the 75/15 to do what its settings say it will do? Any help will be much appreciated.
