Hi All,
I am not on the ABYC committee, but have provided some input and have some visibility into what is going on.
Keep in mind that TE-30 is not the final standard and it will be more detailed. Also, the 48Vdc is nominal. I have suggested a hard limit at 60Vdc to remove any ambiguity, but don't know what the final verbiage will state. Again the 48Vdc is nominal. The people writing it are well aware of the actual voltages present in systems made of "6V" or "12V" lead acid batteries and 16 cell LiFePO4 stacks. My understanding is these will be considered as 48Vdc nominal systems.
I think this is a good practical limit for systems wired to E-11. There is very little electrical shock protection required in E-11, so this makes sense. Boats are damp and batteries are often placed in awkward to reach locations. Accidental contact is easier than a typical automotive application where the componenents are under the hood.
Of course, there is nothing preventing higher voltage systems. There will be a learning curve and some new components may be needed, but I don't think it is going to be as large a hurdle to overcome as I thought when I first read TE-30. What I have seen of the current draft looks reasonable.
In the meantime, I would encourage anyone building higher voltage systems to provide a means to isolate the batteries in 48Vdc (nom) sections. This will help in meeting the standard when it comes out.
Happy Sailing,
Scott McMillan
Electric Yacht
--- In electricboats@yahoogroups.com, "Tom" <boat_works@...> wrote:
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> I agree Eric, I have never had my "48V" bank below 50V. So can I really consider it to be a 48V installation? What if I added another cell to make it a 17 cell bank? Where does a nominal voltage end, if it can be incremented 3.2V at a time?
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> Probably a moot point, and I'll probably never get called on it, but it would be nice if this was better defined in the regs and standards.
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> -Tom
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> --- In electricboats@yahoogroups.com, "Eric" <ewdysar@> wrote:
> >
> > Hi Tom,
> >
> > ABYC's TE-30 is pretty clear about what is high voltage, as you can see HV AC systems are 300VAC+ and HV DC systems are 50VDC+. Every interpretation that I have heard focuses on nominal voltages so our typical 48V systems are covered under ABYC E11. Even without considering charging voltages, a fully charged 48V lead acid battery pack sits at 51.2V, although the voltage will drop below 50V with almost any propulsion load. My Li pack (probably yours too) rests right around 53V and stays above 50V with a 50A load.
> >
> > Fair winds,
> > Eric
> >
> > From ABYC's TE-30
> > "INTENT - This technical information report addresses AC and DC electrical systems used on boats alternating current (AC) systems operating at more than 300 VAC, but less than 1000 VAC, and direct current (DC) systems operating at more than 50 VDC but less than 1000 VDC, including battery banks, motors, and controllers for the purpose of propulsion."
> >
> > --- In electricboats@yahoogroups.com, "Tom" <boat_works@> wrote:
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> > >
> > > A bit of thread drift:
> > >
> > > The last time our USCG rep visited us I asked him specifically about the "above 50V" specifications in the CFRs and the ABYC standards. Specifically, would they apply to a nominal 48VDC system that would charge to well over 50V?
> > >
> > > He said that the over 50V category was only meant to address AC installations. I thought this was strange, why not say so in the regs? It's not like anybody is running 55VAC house loads...
> > >
> > > -Tom
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> >
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