I'm sure the Sterling unit is well-made and efficient, but I really wonder whether it's worth over £200. Just recently, I bought a new charger for use in the garage at home. It's fully automatic (switching to a float voltage when the batteries are charged), it's switchable for regular or maintenance-free batteries, it's made in Germany. It cost about £30 from Halfords. OK, it won't charge gel batteries, it only has about 10amp output, and the output probably has a bit of AC ripple in it. But I wonder whether it might make a very cost-effective boat charger.
Car type chargers are transformer based and require a minimun supply voltage to work correctly If you are at the end of a pontoon or heading of to the sunny part of the world where voltages are not so reliable you, may find that you do not fully charge the batteries. If this reduced state of charge is maintained you will loose efficiency and capacity in your batteries. They are also inefficient especially if your marina charges by the unit for electricity.
Sterling chargers are switched mode. This technique does away with inefficient transformers and allows the charger to charge correctly at a much wider supply voltage range. 90%+ efficient as oppossed to about 60%. Plus various other features that are not quite so important.
Dave? thanks for the plug (thread 1) most appreciated. and no he doesn't work for us!!
I bought a 2 year old boated fitted with a Sterling charger which failed about 6 months after I bought the boat. I had no receipts but when I rang Sterling they said send it back and then sent me a new one by return.