Is is harmful to a 27 hp engine to be run in neutral at 1800 rpm for an hour for the purpose of charging the batteries? -Thanks
Is running diesel engine to charge batteries harmful?
- Thread starter Ken Kindrick
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Yes...diesels are designed to be run at 70-85% of max. rpm under a LOAD. Running at low speed with no load is the worst thing for them. Main issue is glazing of cylinder walls and not running at correct operating temperature. Just not good for them...thats what battery chargers, solar panel banks, or wind generators are for.
Well, to be sure Honeyman is correct about running for extended periods of time, however running your engine for an hour at half throttle will definitely not cause your engine any harm. It might be beneficial however to use a battery charger if at all possible.
If I am underway and need to charge the batteries I will put the engine in gear to keep a load on the engine. But if you are at anchor or on a mooring ball and need to charge your engine an hour here or there, what other choice do you have. I will turn off the refridgerator when I go to bed and put a LED in the anchor light. Generally, sailor are pretty easy on their diesel
It's still the number one way to charge the batteries for boats underway. People do it every day every where. Hence the interest in high end alternators and regulators (as in faster better charging). Some of those diesels have quite a few hours on them and still seem to turn the prop and alternator OK.
Like everyone else I too have no choice when out over a few days on the hook to charge the batteries. With a big alternator properly installed it will use about 3 horse power out of the engine. That puts a load on the engine but in reality not enough. I run mine in neutral at 2500 RPM to get the max charge out of my Balmar alternator.
I believe Cruising magazine this months issue, just had an article on running a diesel engine at low speed. Like everyone has said it is not good for them. However, always run the engine at higher RPM 80-90% afterwards to clean out the engine afterwards will help. The big thing is don't make a habit of running the engine at less than 80% and one should be alright. I have seen sailors put on a over-pitch prop thinking that running the engine at low RPMs and better fuel mileage is better. In reality it only hurts the engine.
I believe Cruising magazine this months issue, just had an article on running a diesel engine at low speed. Like everyone has said it is not good for them. However, always run the engine at higher RPM 80-90% afterwards to clean out the engine afterwards will help. The big thing is don't make a habit of running the engine at less than 80% and one should be alright. I have seen sailors put on a over-pitch prop thinking that running the engine at low RPMs and better fuel mileage is better. In reality it only hurts the engine.
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