Julian Tether <[EMAIL PROTECTED]> wrote: >If you consider that a 5hp engine will run a 5kw genset then a 40hp boat >engine is hardly being loaded even with a 5kw travel power attached >running flat out which unless you are running a big aircon or heaters it >wont be, even with a washing machine, 85% of the washing machines cycle >is without the heaters so will be about 3-400watts. >Most use of 230v on a boat (except for charging the boats batteries if >that is done from 230v) is well under 1500w total except for very short >periods, so inverters and a dedicated 24v charging generator makes far >more sense than a travel power both electrically and environmentally.
If I ever convert another barge (the severity of my affliction may be judged from the fact that I am actually contemplating doing this), I am almost convinced that I should use electric drive, with a single engine being used only as a generator. I guess this is much along the Travelpower line. However, there seem to be two key questions. 1. POWER How powerful does the generator engine have to be? When navigating slack water at normal inland speeds, the energy consumption will be quite small, and it should be possible to supply it from the battery alone (with the engine off) for some considerable time, with luck plugging in at night to recharge.. The battery should also be able to provide enough to handle quite heavy loads (e.g. sudden full-power reversing) for at least short periods. It would also be possible to travel with the engine running, so that the generator can keep the battery charged. This would allow somewhat higher speed through the water. Again, since the engine will be smaller than in a conventional gearbox-connected set-up, short-term peak loads can be handled from the battery. The only tricky situation might be long runs at high speed/load, such as when crossing the Channel, or going up a significant river such as the Rhone, during which the generator might not be able to keep up. The engine in my barge is a 60 kW Ford D 4 cylinder (4 litre). Its top permitted speed is 2,600/min, but it has never done over 2,000, so I would hope to get away with something much smaller. But how much? 2. POWER STORAGE At present, it appears the only technology usually appllied is the lead-acid cell. Inefficient, hazardous, expensive, short-lived, heavy, bulky, etc. Is there any better alternative in view? The only currently-feasible one I have come up with is used nicads, which have a long life (15-20 years?), can be charged quickly and left partly-discharged without damage, etc., but are often sold off at quite good prices after (e.g.) five years of use in standby installations. However, many of them are not designed for repeated charge/discharge applications. And how much power (i.e. what battery capacity) is going to be needed? I assume a single main battery will also provide power for domestic appliances (through an inverter), with only a small separate one needed for the generator engine starter. Overall, there seem to many advantages of this set-up, including quietness, reduced fuel consumption, more efficient engine size, etc. And not necessarily (much) extra cost. Comments? Adrian . Adrian Stott 07956-299966
