Most PW owners in the USA aren't allowed to charge from the mains supply due to the way the tax credit they get for installing solar power. Stormwatch is the agreed exception to this requirement. In the UK there's no similar restriction on charging from the mains and those with backup gateways can charge the battery at any time by increasing the backuo reserve. Those, like me, without the backup gateway can't do this but given that everything will stop if the mains goes off then having a full battery is irrelevant. Fortunately I live in a town where the supply is relatively reliable (I appreciate some of the benefits of the urban life after being brought up on a farm in rural Somerset).