Hi,
We have just bought our first narrowboat and have a few questions IRT the electrical system. We bought the boat with the intention of only using it for about a month per year for the next 5 years until we fully retire and then live aboard permanently as CC. Current setup is as follows (installed new in 2008, so all about 10-12 years old)
Isuzu 42 with two alternators (80 AMP)
Sterling Alternator to Battery charger
Sterling Battery charger (plugs into wall socket when on shore power)
Sterling Battery to Battery charger
Sterling 3000W Inverter (seems to use a bit of power from the batteries)
Sterling Battery Management system
Fridge – 12v
Washing machine, dryer (only used on shore power by previous owner) and freezer - AC
6 x domestic battery bank (5 years old)
1 x starter battery
2 x bow thruster batteries
On the first day we collected the boat we had the alternator alarm sound after start up and after calling in an electrician, it was discovered the Alternator to Battery charger was faulty and as we had to move the boat that day he ‘bypassed’ the unit meaning that the domestic bank was only being charged by 1 x alternator. On our first night after cruising for about 6 hrs, the battery management system had the batteries in the 13s and as ‘fully charged’, but after about 2 hours use (TV, lights, pumps NO washing machine, dryer- high draw items) the inverter alarm sounded and we noted that the batteries were in the low 11s. We turned the inverter off and after cruising the next day for about 8hrs the same thing happened again that night. After ringing the previous owner and surveyor it appears the domestic batteries are on the way out.
So from here the questions I have are:
Given our current situation, what would be the best set up if we wish to use the dryer (about 1.5kw) and freezer whilst CC without regular access to shore power?
Obviously, the dryer draws a lot of current, so would we simply use it through the inverter with the engine running? Would the 2 x 80 AMP alternators cope? If we decide to run the dryer in this way, do we make sure the domestic battery bank is fully charged prior? In order to get the domestic battery bank up to charge quickly, do we replace the old model Sterling Alt-Batt charger with an updated model? Is there a better make that people can recommend? The mariner where the boat currently sits recommends Adverc over Sterling, thoughts? Also are we better off replacing the current 6 x domestic batteries with another set of lead acids?
Or are we betting getting off getting a small petrol generator to run our high load items whilst we’re off shore power? If so, does the generator plug into the boats shore power connection (so we then turn the electric supply from Inverter to Shore Power) or do we plug in the Sterling Battery Charger to the generator to charge the batteries and use the dryer through the inverter? It would seem that plugging the generator to the shore power connection would make more sense but I’m not sure about any potential sine wave/earthing issues. Any recommendations? Something above 2kw?
Finally, as we have the boat on hardstand for 11 months each year, we are thinking of installing a small solar panel to keep the batteries topped up. However, we thought we may as well get a decent system to help charge the batteries whilst we’re cruising. For aesthetics, we would only be interested in the flexible units and can install a number across the roof. Any recommendations?
At this stage we have not yet conducted a detailed power audit, but (apart from the dryer) normally at night we just watch TV, have a few LED lights on, fridge on DC, freezer on AC and maybe charge the phone or laptop, as well the normal water pumps for showering etc. We understand the previous owner used to turn the freezer off last thing at night and all food products still be fine in the morning.
Apologies for the long post but look forward to any advice and recommendations. When we do eventually CC, we would like to relatively self-sufficient power wise and not rely on access to shore power especially in winter to power all our electrical items (not all at the same time...)
Many thanks!
