[RE-wrenches] Outback Grid Problems

[R Ray Walters]

We currently have a Grid Tie system with a pair of Outback inverters that are regularly dropping out of sell mode, and letting the arrays spend all day charging the battery bank.
It seems to do this several times a week, and the customer is losing substantial production, and gassing the batteries too much.
It will reset itself the next day, or the customer resets it by turning off the inverters manually.
The system is 24 v, with an old array of 1800 watts running through 2 FM60s, and a new array of 2800 watts running through another pair of FM60s.
The battery bank is HUP about 4100 Ah @ 24 v (3 strings of 1375 Ah each) Big battery, I know, but the customer is an electrical engineer, who wanted maximum storage capacity.

Outback tech support has not resolved the issue, and this has turned into several service calls, and customer frustration.
We've tried running the controllers through the HUB, and also independently, and that doesn't make a difference.
I have numerous Outback GT installs dating back to 2003, and have never had a problem like this.
Any help or advice would as always be greatly appreciated.

Thank you in advance fellow Wrenches,

R. Walters
ray at solarray.com
Solar Engineer