Mppt 100/20 only bulk charges empty 12v battery for a few seconds
I have a smart solar mppt 100/20
Charging a 100ah 12v and 70ah 12v battery
These batteries are empty...
With one at a 8v charge and the other one at 10.6v
When i attach the mppt it goes into bulk for only a few seconds on each... and then the voltage quickly rises and goes to absorption at 14.4v which both batteries reach within about 10 seconds...
Should the mppt not provide most power in bulk mode before going into aborption... hours later , rather than seconds...
Why are the batteries going to 14.4v so quickly, as then im getting only about 25 to 30w in from my 150w solar panel, when it can provide lots more power.. resulting in a very slow almost trickle charge of 2amps into a 70% depleted battery...
Which will take days to recharge
Im puzzled,
Any help please would be appreciated