Thanks ET.

Checked it again this morning. Immediately after start, first think in the morning, the scanguage said 12.1v, checked that with a multimeter on the battery, same reading.

Gave it a rev for maybe 1.5 secs, it came up to 13v and sat on 13.9 as I drove.

I will charge up the batteries and see what happens.

I was also wondering if I'm asking too much of the alternator??? I have 3 batteries. Normal crank (105Ah), a 2nd (105Ah) which is charged via a Redarc SBI12 and a 3rd (210Ah lifepo4) which is charged via a 40A DC-DC charger.

I was wondering, if the alternator is being asked to do alot of work, would it get hot/very warm??? After a 45 min drive, it was just warm. I don't know if that indicates that it's not being asked to do alot or not???