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loading batteries



I have a malfunction during loading of batteries. As I am not sure what is the cause I like to ask users if they have similar experience.

I have a grid-tied system intended as back-up system including excess solar feed in into grid. Some particulars:
Solar panels 2,4 kwP
Smartsolar MPPT 150-100
Multigrid II 48/3000/35/32 230V
ColorControl GX
4x12V-136Ah lead acid batteries (third party). 
ESS is applicable with mode "keep batteries charged" and "feed-in exces solarcharger power". Also absorption voltage and float voltage according manufacturer's specs. 

During the night we had a grid-failure. After return of the grid system started reloading batteries. First in bulk stage and after reaching absorptionvoltage system switched into absorption mode. About 30 minutes in absorption mode voltage slowly dropped and current was kept steady. Normally absorption should have stopped but this did not happen apparently. As it was during the night (and we were asleep) we did not notice this until the next morning. The result has been that batteries have been charged with approx. 1500W for 9 hours continiously in absorption mode while my batterysystem has only 6,5 kW capacity.   

I wonder what might have caused the system not to stop absorption (t.i. switch into float)? Any advice will be highly appreciated.


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Sorry for late reply. I did not receive notification of replies.

I am certain the above has to do with faulty batteries, but my supplier does not agree (due to warranty? Batteries are less than two years old). What I would like to know is how the absorption time is maintained. Apparently the absorption kept on going long after the set absorption time. I wonder why the system did not stop itself after reaching the maximum absorption time.  I am just curious how the absorption stage is maintained by the Multigrid II 48/3000/35/32 230V. I suspect not only time is calculated but something like voltage is verified as well? I realise for this answer I need somebody who is familiar with the Multigrid software. 

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