It was at the end of August when Tom came aboard, and he found that the inverter was also not working, but alarming, showing it was not receiving sufficient 12V supply. This was strange, as during the process of checking the batteries earlier, I had also tested the inverter, and it worked perfectly. Our small domestic batteries were sufficient for out needs, and would last one overnight stay, without any further charging, so I expected the new batteries to be slightly better. We also have C-Tek multi-stage chargers, of the correct size for our batteries, which are connected directly via fuses, and were showing the batteries fully charged. Nantwich Marina, (formerly known as Nantwich Canal Centre), who completed the job of installing the Webasto and the new batteries were contacted, and they kindly arranged an "after-sales visit" to the boat by a technician, in order to diagnose the cause of the problem. This is what he found:
The NCC technician measured excessive voltage from the alternator, but the PDAR has an excessive voltage safety cut-out, with an alarm mode, which is all lights flashing together. As this shows correct operation, I believe we can discount that for the time being.
*The Sterling PDAR, Sterling Power Products, converts the engine's standard alternator into a 4 stage smart battery charger, and gives not only a quick recharge under controlled conditions with built in safety features, but also allows the batteries to accept a far greater level of charge than with just a standard alternator. The downside is, that the battery fluid levels have to be monitored more regularly, as faster charging always equals greater fluid loss.