I have been a fan of the Varistream controllers from the beginning and haven't had much bother with them at all. I have always recommended them as they have been a real asset to our business.
But I'm now not sure about the latest unit fitted to my son in laws van. His van has been idle for the last 2 weeks and the leisure battery is slowly discharging. His 85amph battery fully charged will lose about 25% of its charge a week.
Where earlier models completely switch off, the new varistream uses a minimal current in the switch off mode, I expect to monitor the state of charge of the battery. When you reconnect the terminal on the leisure battery there is a 'clunk' , like a solenoid engaging that comes from the pump. There is also a spark.
Williamson pumps have confirmed that the behaviour of this new Varistream is correct.
Today I have cured this battery 'drain' by fitting an isolator (on/off) switch between his leisure battery and the Varistream. It will still register the state of the battery once the isolator switch is turned on, so personally, I can't see the need for it to be live all the time, unless it means an extra switch circuit and more complex electronics. At the moment I have enough on my proverbial plate without messing on with charging a leisure battery every few days. One day I foresee getting caught with 'my pants down' having a flat leisure battery with a full day's work planned for it.
As I still have another new Varistream in the spares cupboard, I will need to get another isolator switch so they can be fitted together.
Long term, I will reconsider my options when the time comes and will have a much closer look at Springs new analogue controller, which I think ticks all the boxes except for the option of checking the battery's charge state. That will have to be done with a separate digital voltmeter.
Spruce