Hi, I’ve had solar since Jan 19 and already upgraded adding a 2nd array.
Initially, it was all about cost savings so that in retirement my pension will go on enjoyable things not utility bills. I also decided to consolidate energy use by changing to heat my hot water by electric not my oil boiler. I’ve also swapped to an electric car. Adding solar meant I needed to increase my Electricity use to justify adding solar. Increading my usage meant I needed to generate more energy. It’s a strategy not just a decision.
Going forwards I will want to replace my central heating and add a battery too.
From my experience, batteries are difficult to cost justify so the benefits are more about flexibility and convenience not cost savings. Longer term income should be possible from a battery as it’s cheaper for the grid to use virtual power stations than build new physical ones.
The problem as I see it is that the interface currently tends to lock battery customers into one virtual power plant solution. Ideally the interface needs to be compatible allowing customers to move between providers otherwise fair value might not be returned to customers.
Battery wise, my list if desires are an efficiency level which enables near zero grid use. This needs a fast responding system which can cater for a fluctuating grid.
I also need the ability to control a margin on the grid set point this allowing other smart devices to define priority subject to the margin of export set.
Data collection and an accurate and responsive real time interface is a must on mobile devices primarily, PCs 2nd. Data export and a great graphical interface. I’ve tested Victron, Puredrive and Lux inverter interfaces and all are lacking and don’t choose the best graphs. I’m an ex IT capacity and performance specialist so data presentation is important to me. Some systems are colourful but lack the numbers, others use bar charts when area charts would be better. Flexibility to alter the graph is important too. Graphs and data seem to be a weakness to batteries at present but they’re the only view if the battery a customer sees so very important imo.
I’m currently testing a battery for an installer and run a YouTube channel covering EVs , Solar and Home Batteries.
Another key requirement is a modular design allowing easy increases in capacity. Buying too big a battery wastes money as it’ll not cist justify buying too small makes you wish you’d bought more. Buying smaller then upgrading makes sense.
Capacity wise I’m looking for minimum 5kw but preferably 10kwh. Power wise , I’d like to be able to schedule a time boost of my immersion heater so need about 3.3 to 3.6kw minimum continuous power. To charge my EV faster a higher power output would be nice.
Timed charging with a soc limit is needed to take advantage of cheaper overnight Electric. Some form of interface to a varying tariff by hour of needed similar to Octopus Agile.
Control over SOC is important to protect the battery from degradation and the battery should be insulated enough to not go cold in a garage environment in order to prevent lower charging and discharge rates.
Power cut protection isn’t important to me as we rarely have a power cut for more than a few minutes.
I’m still torn between AC coupled and DC coupled as DC to DC charging avoids additional losses. Round trip efficiency is important as is the speed at which load increases are fully covered.
Hope my thoughts help and I’d love to be involved IF your battery solution is a good one.