solar power charging query

[Murflynn]

I have 2 identical power systems on my new plastic project boat, alternating in use to power a trolling outboard motor, each comprising:

 

• 2x100W PV panels
• Victron 75/15 smart MPPT controller set to 'batterylife' mode
• ammeter/voltmeter on the battery supply side of the controller
• 2x110Ahr batteries

 

• the boat is on a trailer at home. The batteries have been charging nicely in the recent sunny weather, reaching maintenance stage with the voltage reading about 13.5V.
• the batteries have not been been on load for 3 weeks.
• all the (semi-sealed 'maintenance-free') batteries have been checked for electrolyte levels - no problem there.
• both of the batteries read 13.2V with the solar switched off.
• battery bank 1 always reads 13.5V @ 0amps with the solar switched on.
• battery bank 2 occasionally reads 16.5V @ 1.2amps with the solar switched on. This is a fairly new pair of batteries, only used for powering the trolling motor for about 10 hours, but was once run down to 11.5V.

 

I understand that 16.5V is only reached if the smart controller trying to recondition (de-sulphate??) the batteries.

 

 

is battery bank 2 knackered, or what?

Edited September 4, 2016 by Murflynn