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Posted: Mon Jun 02, 2014 8:23pm

Post Subject: Conflict of interest

We are advised by CRT not to charge in gear whilst moored for fear of eroding the canal bed. However I have always understood that to prevent bore glazing the engine should preferably be under load when running to charge. Therefore when moored and requiring to charge one's batteries there appears to be a conflict of interest. Can anyone offer advice.

Tony-B
Tony-B

Posted: Tue Jun 03, 2014 8:27am

Post Subject: Conflict of interest

First of all it is not advice, its in the CaRT bylaws so presumably you could get fined for doing it - or a withdrawal of your license. Somewhere at home I have an old Waterways World article that says a full length narrowboat only takes 2 to 3 hp off the engine at canal speed. This is supported by the difference between the quoted fuel consumption and the much lower quantity is normally achieved. It is often said that an automotive alternator is only about 30% efficient. A 70 amp alternator charging at 13.5 volts = 945 watts. To generate that at 30% efficiency requires an input of about 2835 watts and a 746 watts per hp that equals nearly 4 HP. Multiply that up for twin alternator and high output installations. If canal cruising does not glaze bores then the earlier stages of charging will not. Do not carry out all the charging at idle. If you have an ammeter increase the engine revs until the ammeter rises no further. Then as the charge falls reduce the engine revs to maintain maximum charge. Also stick with the SAE and API specification oil recommended by the manufacturer, especially during running in new engines. (e.g. 15w40 in API CC). Do not use fully synthetic engine oil. Where responsible and possible give the engine a good hard run. I try to visit a river every year. The above is related to the possibility that the additive pack in high spec oils may be implicated in bore glazing (among other things you an not affect. Otherwise minimize the need to charge from the engine by installing as much solar as you can afford. You will probably have to run the engine frequently in the winter but not as much in the summer. Tony Brooks

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Posted: Sun Jun 08, 2014 5:22pm

Post Subject: Conflict of interest

Tony, Am I correct in assuming from your numbers that as long as I don't charge in tick over i.e. apply cruising revs, it doesn't make any real difference if the engine is under load with respect to bore glazing. I do use non-synthetic oil from Morris Oils.

Tony-B
Tony-B

Posted: Mon Jun 09, 2014 7:49am

Post Subject: Conflict of interest

My numbers were intended to show you that for much of the charging time the engine is under load from the alternator(s). Towards the end of charging when the charge is maybe 10 to 20 amps that load will be low whatever speed you are running the engine at. At that time most setups will be providing the charge at idle revs. There are a number of things that affect the propensity of a particular engine design to bore glazing so there is no way I can give you the assurance that you ask but one can say the more often and the longer you run the engine under light load the more likely it is to glaze the bore. I would run at about 1000 rpm when charging to try to ensure efficient combustion, but that is all I can say or advise. Tony Brooks

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Posted: Mon Jun 09, 2014 12:03pm

Post Subject: Conflict of interest

Tony, Thanks, I generally try to avoid charging unless underway, however when stationary I run at around 1000rpm, I understand you can't give assurances, but your guidance is always appreciated.

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