VSR Relay (Cyrix) + Solar Questions

Hey y’all, I recently installed a Cyrix VSR (voltage sensing relay) on top of pre-existing solar setup on my van. Had some questions about the operation of the VSR.

My setup is this:

  • 1 lead acid starter battery
  • 2x 12V lead acid house batteries in parallel
  • 1 Renogy Voyager charge controller
  • 2x 200W renogy panels
  • Renogy battery monitor
  • (new) Victron Energy Cyrix

My goals were:

  1. Solar panels charge the starter battery when the van is parked and not in use (often for weeks at a time)
  2. House batteries can jump start the starter battery in a pinch
  3. Alternator can charge the house batteries (not really critical, the solar panels charge the house batteries quite well!)

After installing the Cyrix, it seems like the Cyrix is quite slow to disconnect. For example, the van’s been in partial shade all day today, so not too much charge, and sunset was at 5:30pm. As of 7:30pm, the cyrix still had the batteries connected, and the battery monitor was reading a voltage of 13V and a draw of 3w. I assume most the draw is from the cyrix itself (220ma draw when connected, 4ma draw when disconnected), with an additional ~50ma parasitic draw from the van.

As a test, I put the van ignition to on (but did not start the engine). Headlights & accessories came on, voltage was reading 11.xV, but the cyrix stayed connected for well over 3 minutes before i discontinued the test.

So a few questions:

  1. How come my battery voltage is still at 13V several hours after the panels stopped generating power? Shouldn’t it come to rest at 12.7V after the panels stop putting out power?
  2. Has anyone noticed that the Cyrix is slow to disconnect?