tdansmith

Thanks for your comments, and correction on kW vs kWh - I blame writing the post on a phone You are of course correct that I am looking for a 15kWh battery and was originally looking to spec a 3.6kW inverter. In terms of balancing a 3 phase demand - yes, in theory this would be ideal, but I’ll let them worry about that on the supply side. The main question I’m looking to answer is whether it is possible for an inverter and battery on a single phase to offset usage on all 3 phases - beyond the Powerwall 3, which apparently does this. If the answer is no, I may well stick to using just a single phase, including the future ASHP and EV charger, but it does seem a wasted opportunity.

Hi, I am in the process of pricing up a PV install with battery storage. Due to space constraints, I suspect I will end up with 10-12 panels, and was therefore thinking a 3.6kw hybrid inverter would suffice and also get me below the G98 threshold. I would compliment this with battery storage - initially 15kW which would cover our current needs, but with potential for expansion if I install a heat pump. The battery would store energy from PV, but would also allow us to charge at cheaper night rates and discharge during the day when rates are higher. My situation is slightly complicated by the fact that we have a 3 phase supply. Currently we use only a single phase for our whole house, but in time we may reserve a second phase for the heat pump, and potentially an EV charger on another. I understand the principal of net metering, and we have an Octopus smart meter that would accommodate this, so in theory we can place a single phase PV inverter (and battery storage) on any of the phases and this would be able to offset use on any of the three phases. However, I do not fully understand if single phase inverters / battery controllers are smart enough to monitor usage on all three phases and hence discharge an appropriate amount to offset the combined usage. As an example, if the inverter and battery are on phase 1, but I am using 5kW on phase 2, will the battery be aware of the usage on this different phase and discharge 5kW on phase 1 to offset this? I understand that the Tesla powerwall 3 may be able to perform this task, but is this true of any other systems? The Powerwall is quite an expensive solution (£/kWh), and I was initially looking to get something like a Fox or Givenergy as these are cheaper and seem to be very good. If I am limited to Tesla it might be cost effective to instead get a 3 phase inverter from Fox/Givenergy - which would surely be able to monitor use across all phases. Hopefully this all makes sense, and apologies for my ignorance! This is all quite new to me, but I am keen to understand more.