The Amazing Portable Solar System - The RPS Power Cube

I like the portability, but I am not impressed with the batteries. Why aren't you using Nickle Iron?

Yes, AC coupling allows one to add panels up to the capacity of the Inverter's input. AC coupling is accomplished by using a micro inverter on the PV panels to convert the output to AC which eliminates all those lousey DC line loss issues.
The charging capacity of the array is not limited by the out put of the Inverter. The only reason to use an inverter with more output capacity would be if your peak load demanded it. What do you need to run all at the same time?= peak load

Concerning your question regarding batteries. The bank is a 48 volt with one string of eight L-16 lead acid batteries w/ 370 AH (@ the 20 hr. rate). It amounts to 17,760 watts (17.7 Kwh) of storage at full charge. The maximum draw is determined by the maximum output of the inverter. How long you may continuously draw power is based completely upon the load demand.

It is the same with any alternative energy battery system. The basic rules are not to draw the State of Charge (soc) below 50%. To discharge them below 50% will dramatically reduce the batteries service life.

Solar system success is ALL about battery maintenance and load management.
When one achieves that balance between the load and the recharge rate it is a sweet and sustainable thing!

Now to the grid tie and emergency uses of the Power Cube.
The unit is code legal to connect to the utility grid through the domestic system using a "service entry transfer switch." The switch serves to isolate the Inverter from the untility grid so that it is not sending power down line to fry some poor unsuspecting utility repair person.
The transfer switch makes it impossible for there to be two AC sources -- which will cause a lot of sparks!
When properly connected, the inverter steps in to fill any gaps by the grid supply and the solar array is able to back feed the grid from the array when the batteries are full. When properly installed by an electrician there are NO legality or insurance issues.

In an emergency or power outage when the unit is not "wired in" one may connect the Inverter out put via a "dryer" receptacle and feed the house. It could also connect to the main service panel via a 60 amp breaker. The Xantrex inverter, indeed grid tie inverters are required to have an internal transfer switch which shuts the inverter down the instant grid power is sensed.
The Xantrex Inverter is exquisitely programmable to function in very specific ways with with the grid. It is pre-programmed according to the use to which it will be put and the needs of the individual.

I have had some experience with the low head high volume style of hydro generators. Their output is not generally as high as a Pelton style micro hydro. I have not looked in a while. But what I remember is that the output was in the 4-600 watt per hour range. It does not sound like much but if you live conservatively it can be done. The Great Thing about hydro is that is does not stop when the sun goes down or wind stops blowing! So that 600 watt per hour output is 14.4K per day of charging.
And the low head systems open up a entirely new range of viable locations.

Have a sunny day where every you are!

Looks a promising bit of kit.

I assume you have linked a solar array rated at <2kW to a 6kW inverter so you can extend the array to 6kW, but if I understand your advertisement correctly you can build the set up to nearly 10kW. So presumably you'd add a second inverter or replace the 6kW with a 10kW one?

What's the Watt-hour capacity and maximum continuous current draw of the standard battery pack for the standard 1.88kW solar panels?

I'm interested to see you suggest connecting it to the house ring-main via a socket. We can fit home solar-panel equipment to homes in the UK but they have to be fitted correctly via appropriate control-gear to the mains (230V twin & earth), not merely plugged into a wall socket. That's partly to accommodate the mains supply / solar-panel matching and feed-in tariff arrangements (including phase and load balancing), but mainly for safety. In fact the way you suggest may even be illegal over here. It would certainly be extremely dangerous and negate your home insurance!

On micro-hydro power, recently I visited a restored water-mill in SW England, that has installed its own alternator powered by a low-head through-flow turbine fed from the mill leat. It generates a useful amount of power, certainly enough for its lighting and other modest power installations. I don't know the actual kW rating.