Firstly thanks for all the replies/info.
batteries. Maintained by link2000/Freedom458 when away.
Volts/amps from link and checked by multimeter.
I decided to charge o/night then disconnect batteries and check volts and clean all terminals. Batt No 2 showed 7.7 volts ( so truly u/s). Batt No 1 showed 12.9 v.
I cleaned up the terminals ( not dirty/corroded) and decide to repeat my test on the one "good" battery. Starting with 12.85v
Discharged at 16 amp for 20 mins batt volts 11.95. Discharged a further 30 mins at 30 amp batt volts 10.55 (10.64 by multimeter at post).
removed load and battery recovered to 12.55v in 1-3 mins ( about 85/90 % capacity I think.
Ahrs removed measured as 19Ah
Placed on charger
Started as 14.2v at 33 amps. After 6 mins dropped to 13.2 at 8 amps and is slowly declining. Is this normal?
Why the big volt drop when under load.....I suspect the battery has seen better days ?
Sidetracked onto Generator
battery which is an AGM
only from the Gen alternator
at 15.7 volts ! I assume this is the voltage regulator
which i can easily order.