dynastart

[Ardenfour]

hi there
I have a ducati air cooled diesel fitted with a dynostart device. I can't find any info on the charging rate and the boat is fited with two batteries. is the dynamo likely to provide enough current to keep them topped up?

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[William_H]

What you really need is an ampmeter. I fear you may have been intimidated by the ratings of alternators at 60 amps plus. About the only time that you can actually approach 60 amps from a typical installation is with a very large current drain from accessories ie lights frig. heater microwave etc. If you are primarily concerned with battery topping up then I feel sure your dynastart will be up to the job. i would expect that it would happily supply 20 amps if necessarily before voltage out starts to fall. Current into batteries is a function of the charge state of the batteries the capacity of the batteries and the voltage of the regulator. That doesn't mean you could charge at 20 amps unless in to a large flat battery then only for a short time before current falls. Don't worry just enjoy. The down side to the dynastart is that all current passes through the brushes which should be checked regularly for length and condition of the commutator. Did you know that most small turbo prop and small jet aircraft use a form of dynastart (bigger than yours) that can chargwe at 300 amps at 24 volts. regards will

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[MarkJohnson]

Hi,

I had a dynostart in my Halcyon 27, and it was rated at about 12 amps. And then when the engine was going full pelt. At tickover, it barely produced any power at all.

I guess there were a lot of boats with dynostarts, but their power consumption was pretty minimal compared to boats today.

Could you fit an alternator to the engine? Electrically they are easy to fit, but drive belts etc are tricky, but can be done.

Good luck



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[greatspirit]

Is an updated version of the dynastart used on the Toyota Prius?

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[Ardenfour]

thanks for that info. Ammeters are fitted on the boat, but I haven't had a chance to check out the electrics yet - have just bought it. My concern is, my maiden voyage in her will involve a passage through the Forth and Clyde canal system, where the engine will be subjected to lots of stops and starts (40+ locks) and the mast will be down to negotiate bridges. Could always use the towpath and a long rope I suppose!
The engine has a second pulley wheel above the dynastart drive wheel, but I believe this is for a starting cord, seagull outboard fashion. Would it be possible in any case to fit an alternator and retain the dynastart for starting the engine only?
cheers

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[DavidTocher]

I have a Vire 6 with a dynastart. Either the regulator or the dynamo part of the dynastart failed so I fitted an alternator that I had in the garage. I mounted it on the other side of the engine and drove both with a longer V belt. It all works fine though it would have been better to have interchanged the starter and alternator positions to keep the belt tension between the driver and driven pulleys both for starting and charging.

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[gstutch]

Hi

Had Halcyon 27 with Dynastart - used for starting only, with Bosch 55Ah alternator for charging. worked fine

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