Interesting what you say about battery output being limited. When I look at the specs for the PureDrive battery the only ones that mention output are:
Discharge cutoff voltage: 45v
Continuous discharge current: 100A
Max discharge current: 350A (3 sec)
From this, how do you work out its maximum output?
If it is AC connected then it is whatever the AC inverter in the battery is rated at, so for the PureDrive Energy AC 10kWh system it is 5000VA. However they do quite a few models so its not a great idea for me to guess which one you are referring to, do you have model number?