Anarchy05

Try botshop, robofactory or seweb.co.za

I also had this issue a while ago with a king that refused to talk to up5000 batts, turned out the battery firmwares needed upgrading and comms started working

This is a wild gamble, but I have read your post and have a theory, these inverters, well the older ones like mine have a bypass enable and disable setting, it somehow decides that when drawing too much current from the batteries, to protect it it bypasses, my theory is that this is what is causing yours to do this, and this setting is based on your charging current to the batteries, so I think if you were to set this to a high value it might not do this. But then you risk the battery. 
The guys who know the firmware might know how these calculations are done.

Just to let everyone know, my install is up and running, currently only with 3 panels and 4 batteries, just using as a backup at the moment and to run about 55watts of outdoor lights every night. 
Will expand as my budget allows in the near future.

@pilotfish, did I tell you about that time my dog tested the RCD? It was a wet rainy day in August 2013, some people were working at the house and an extension cord was plugged into an outside outlet, and our Jack Russell hadn't quite gotten rid of the habit of treating all new objects in his space as a chew toy. The next moment all hell broke loose as the lights went out and the most sorrowful yelping filled the air...
After that the chewing problem was solved. I imagine the dog must have almost died that day.

Hi Anarchy05,
I have just found this useful forum and am not surprised to find quite a few Witbankers here...
I installed my system last weekend 15/10/17 and it consists of 6 x 300W panels, 4 x 110AH batteries and a 5Kva Mecer inverter.
You are welcome to come have a look although I must point out that i am a total novice and am still learning as I go along.