mick
Well-Known Member
I have a Beta 13.5 with a 40 amp alternator. If I run the engine at idle, how effective would this be at charging my batteries?
Idle charging
- Thread starter mick
- Start date
VicS
Well-Known Member
It may not charge at all. Stick a voltmeter on and see what you get. Increase the revs until you get a reasonable voltage, at least 13.6 preferably around 14.
markdj
Well-Known Member
Running any diesel engine at idle or at increased revs for long periods of time while not under load will only glaze the bores of the engine causing increased oil usage.
Far better to fit a marine (fully isolated) AC charger and use shorepower or a portal generator to charge the batteries.
In answer to your question, it all depends on the regulator. Probably anything over 1200rpm will be enough to give a good charge.
Far better to fit a marine (fully isolated) AC charger and use shorepower or a portal generator to charge the batteries.
In answer to your question, it all depends on the regulator. Probably anything over 1200rpm will be enough to give a good charge.
William_H
Well-Known Member
The amount of charge is best measured by an amp meter. It tells you exactly what is going into the batteries. A volt meter will indicate that the batteries should be charging on the basis of the voltage presented at the terminals. The actual current going in depends on the state of charge of the batteries.
Charging by runn9ing the engine at idle or a bit above is a very inefficient way to charge the batteries. Again an amp meter will show just how usefull the engine run is and it depends on battery charge state. But it is easier to get an initial charge into a very flat battery than to get a battery fully charged.
Generator (alternator) systems are really designed for use on engines that run for a long time for other purposes. Driving the car truck or boat. The charging system has to be inocuous so it won't cook or overcharge the batteries over a long run.
A smart charger regulator can improve this situation by getting the alternator to work as hard as possible to charge the batteries. But even that will probably need more revs than just idle. This depends somewhat on pulley sizes on the alternator. It is alternator speed that matters.
As suggested if you don't run the diesel engine for working purposes as in driving the boat enough to charge the batteries then another charging source would be desirable. Shore power charger is the best cheapest. But some of us don't have shore power available.
Alternatives are wind power solar or self contained 240V generator driving a 240V charger.
Despite all these short comings batteries survived on boats charged only from a generator for many years before we invented solar and wind power and the more efficient alternator. Many of my friends simply run the engine once per week to warm it up and charge the batteries a bit. Perhaps do a run up the river.
So perhaps you worry too much. good luck olewill
Charging by runn9ing the engine at idle or a bit above is a very inefficient way to charge the batteries. Again an amp meter will show just how usefull the engine run is and it depends on battery charge state. But it is easier to get an initial charge into a very flat battery than to get a battery fully charged.
Generator (alternator) systems are really designed for use on engines that run for a long time for other purposes. Driving the car truck or boat. The charging system has to be inocuous so it won't cook or overcharge the batteries over a long run.
A smart charger regulator can improve this situation by getting the alternator to work as hard as possible to charge the batteries. But even that will probably need more revs than just idle. This depends somewhat on pulley sizes on the alternator. It is alternator speed that matters.
As suggested if you don't run the diesel engine for working purposes as in driving the boat enough to charge the batteries then another charging source would be desirable. Shore power charger is the best cheapest. But some of us don't have shore power available.
Alternatives are wind power solar or self contained 240V generator driving a 240V charger.
Despite all these short comings batteries survived on boats charged only from a generator for many years before we invented solar and wind power and the more efficient alternator. Many of my friends simply run the engine once per week to warm it up and charge the batteries a bit. Perhaps do a run up the river.
So perhaps you worry too much. good luck olewill
lw395
Well-Known Member
It depends on the alternator and the ratio of the pulleys. More modern alternators are often pretty good at low rpm. In my yanmar manual there was a graph for the Hitachi alternator which showed it would not have much more than the fridge would draw at low rpm. I fitted a Bosch alternator from a Mondeo, with a pulley from a Viva I think, big improvement.
The point about glazing the bores can be valid, but its nice to charge the batteries and cool the beer while you're leaving harbour! Equally its good to run the engine regularly in the winter if its not winterised. You may find data for your particular alternator on the web. Modern cars need a lot of current at low rpm, yet the engines rev to 6k or more, so alternators have had to move on. Hope that helps.
The point about glazing the bores can be valid, but its nice to charge the batteries and cool the beer while you're leaving harbour! Equally its good to run the engine regularly in the winter if its not winterised. You may find data for your particular alternator on the web. Modern cars need a lot of current at low rpm, yet the engines rev to 6k or more, so alternators have had to move on. Hope that helps.
VicS
Well-Known Member
[ QUOTE ]
Equally its good to run the engine regularly in the winter if its not winterised.
[/ QUOTE ] There is some debate about the bore glazing issue (search the forums for about the last 5 years to find all the arguments) but running the engine for shortish periods during the winter is not a particularly good idea. Unless the engine is brought up to full working temperature and run at that for a while there will be condensation into the oil and in the cooler parts like around the valve gear. The later can lead to rusting then cracking and ultimately breaking of the valve springs The consequences of a broken valve spring are not a pretty site and make a big hole in the wallet to fix!
Equally its good to run the engine regularly in the winter if its not winterised.
[/ QUOTE ] There is some debate about the bore glazing issue (search the forums for about the last 5 years to find all the arguments) but running the engine for shortish periods during the winter is not a particularly good idea. Unless the engine is brought up to full working temperature and run at that for a while there will be condensation into the oil and in the cooler parts like around the valve gear. The later can lead to rusting then cracking and ultimately breaking of the valve springs The consequences of a broken valve spring are not a pretty site and make a big hole in the wallet to fix!
mick
Well-Known Member
As ever, thanks for help.
Searush
Well-Known Member
Gerroff yer mooring & go for a pootle about. Even if it's only up & down the river. I go for at least a 20min run every time I visit the boat, usually it's 30 mins or more. It gets the oil moving, the engine up to working temp, recharges the boat batteries & mine as well! Even if it's only twice round the harbour, I can do some slow stuff & some full throttle too. Eg power turns on full throttle for a few seconds doesn't produce any wash or speed, but doeas turn me quick due to propwash. Similarly, build up a little speed, go astern & then boost to full throttle to stop/ reverse. It all keeps the cables & controls moving & engine exercised.
Tick-over on a mooring just fills your & neighbouring boats with fumes & screws up your engine.
Tick-over on a mooring just fills your & neighbouring boats with fumes & screws up your engine.
lw395
Well-Known Member
Yes, its a good idea to let it warm up properly, it will need to run for 45mins or so to do much for the battery anyway, also you should change the oil late autumn or so to have cleanish oil over the winter. To me it was all part of the compromise of a swinging mooring. Is this time to re-start the synthetic oil debate?
Cheers,
Chris
Cheers,
Chris
ccscott49
Well-Known Member
Best time to change your oil, autumn! Stops all the nasty acids etc. which have built up, whilst the boat was in full use over the summer, from causing corrsion inside your engine. I agree a good bit of exercise for the engine will bring benefits in engine longevity and reliability.
Bore "glazing" is a much talked about, around bars, subject, but rarely actually happens these days, due to improvements in tolerances and mainly oils and additives.
Most of the horror stories you hear are just that, stories, normally from folk who know little or nothing about the causes or even the effects of this phenomena.
But still not a great idea to leave a yacht engine/small genny idling for extended periods.
We leave large engines idling in the oilfield for longish periods, between periods of heavy use and have very little if any problems with "glazing"
Bore "glazing" is a much talked about, around bars, subject, but rarely actually happens these days, due to improvements in tolerances and mainly oils and additives.
Most of the horror stories you hear are just that, stories, normally from folk who know little or nothing about the causes or even the effects of this phenomena.
But still not a great idea to leave a yacht engine/small genny idling for extended periods.
We leave large engines idling in the oilfield for longish periods, between periods of heavy use and have very little if any problems with "glazing"
