Dear Alex,
The batteries will not charge when the load on the converter keeps the voltage at 13.2v, unless the batteries are extremely low. The motor will use the entire output of the chargers until you turn off the motor. Once the load is removed, the converters will switch to charging mode. I suggest that you should consider running the generator long before you're faced with a dead battery string to avoid power sharing. Plan ahead. Lead acid batteries will also last considerably longer if kept above 50% Depth-Of-Discharge (DOD). At 50% DOD, the converters will not charge the batteries until the motor load is removed.
Good questions, thank you for the steady keel...
Be Well,
Arby
From: kotyara73 <krollokot@gmail.com>
To: electricboats@yahoogroups.com
Sent: Friday, November 16, 2012 11:35 AM
Subject: [Electric Boats] Re: Planning Cal 2-27 conversion, advice needed
Arby, I agree completely with the "overbuild" sentiment. That's why this whole area of chargers and gennies is so confusing.
It's not running in WOT that concerns me. I'm worried about being able to use the motor at all with the genny when the beatteries are depleted. In this case, wouldn't they draw as much power as they can get? (actually, is there a limit to the amps they can draw?)
So, if a WFCO can provide 35amps, that current will be split between the battery and the motor, so in effect it doesn't matter how low you set the throttle, it'll still draw 35amps.
Another question is how much of that power will go to the motor when both it and the batteries are drawing. I'm guessing the motor will have first dibs, since it's probably lower resistance?
I supposed it would be ideal if a 35amp converter could be specifically set to be limited to, say, 25amps. That would allow Honda to operate at its rated continuous 1.6Kw and leave a margin on the converters. Is there a way to do that?
John, I agree with you rant to a degree. It is a sailboat, after all, and FWIW, I do intend on using the sails whenever I can. As to why I'm looking at dumping $5K into it, two reasons:
1. I'm a newbie sailor and want a safety margin in case my sailing skill fail.
2. It's a fun project that will allow me to learn a lot.
I realize it's possible to sail a boat even without an engine, but then it's also possible to cross the Atlantic in a Zodiac. So the question is where do you draw the line between the two extremes? I'm guessing I'll be comfortable enough with a genny-backed EP system. What's your comfort zone?
Cheers,
Alex.
--- In electricboats@yahoogroups.com, "Mark n Angela" <mstafford@...> wrote:
>
> John, Great rant. You nail the cultural bias of Western Societies: dominating power vs accommodating environment. This myopic proclivity has advanced the whole world with fantastic alacrity, but now threatens our survival as a species. Will we be able to put down the crack pipe and live in complex relationship with our environment? Or will we use a bigger throttle, bigger gun, bigger wallet, to assert our self-centered ego? Stay tuned!
> Mark Stafford
>
> --- In electricboats@yahoogroups.com, John Francis <surv69@> wrote:
> >
> > WOW!
> >
> > We are talking about sailboats . . . aren't we?
> >
> > Personally, I don't know why anyone would even consider $5000+ to put an
> > electric motor in a sailboat and still have to concern themselves with
> > whether or not it might not be enough engine for the boat.
> >
> > I have a 70-pound thrust motor on my 28' Newport . . . adequate propulsion
> > for a boat that generally doesn't need an engine. Years ago(about 15), I
> > adequately operated my MacGregor 25 with a 37-pound thrust motor.
> >
> > I have made many, many thousand mile trips on a 250cc Yamaha. My 400cc
> > Yamaha was always more than enough engine to make trips. BUT still
> > virually E-V-E-R-Y-O-N-E claims that 1100cc is the absolute minimum engine
> > needed and a lot of posters on the internet say something around 1500cc.
> > Even if a discussion includes a utilizing a 650cc motorcycle, it seems
> > everyone jumps in to virtually berate the very idea of using 650cc for
> > trips.
> >
> > Why is everyone so doggone power crazy . . . especially in an endeavor
> > that's not about "*POWER*", such as sailing.
> >
> > Seriously . . . this leads me to wonder if this is a real discussion about
> > green energy, which generally requires some degree of compromise(on the
> > side of conservation), on the part of participants, or is this really just
> > another conversation of one-upmanship and full-speed ahead in what's new
> > for the moment?
> >
> > If everyone so desperately needs the speed and power they've always enjoyed
> > in the past(and over utilized), then why not just keep the old boiler-plate
> > engines in place, keep the speed as high as possible and leave the smell
> > behind . . . in your oily wake.
> >
> >
> > argh
> >
> > On Fri, Nov 16, 2012 at 7:48 AM, Arby Bernt <arbybernt@> wrote:
> >
> > >
> > >
> > > Yes.
> > > Running at wot (wide open throttle) will require a generator and power
> > > converters rated appropriately. WFCO makes 35amp units that have a foldback
> > > voltage feature. You pull more than the rated capacity, and their output
> > > voltage will decrease proportional the the load, until the converter shuts
> > > down.
> > > If you're running a Honda "2kw" genny, it can maintain a continuous
> > > output of 1.8kw (reference from memory) continuously. This means you can
> > > run your system at PARTIAL throttle only, basically drawing 1.8kw max. Buy
> > > a set of 95a WFCO converters, and a much larger genny, or two paralleled
> > > smaller ones, and you'll be able to run more power.
> > > Be careful, however. Running any system at 100% capacity is a fool's
> > > errand. Build headroom into your design, and plan on over-spec'ing your
> > > components. I use Kelly controllers turned down to 60%, for example, to
> > > build a more stable product. Yes, you can pull 35a out of a unit rated as
> > > such, but why push the limits. You don't shift your car at redline, so why
> > > treat your boat motor system any differently?
> > > Sailboats can motor at low speed very efficiently. if you plan on extended
> > > motoring, get a generator at least 20% larger than required by the power
> > > converters. Size the converters at least 20% over your motor load.
> > >
> > > Be Well,
> > > Arby
> > >
> > > On Nov 15, 2012, at 11:05 PM, "kotyara73" <krollokot@> wrote:
> > >
> > >
> > >
> > > Wouldn't 35amps x 4 overload the Honda? if the batteries are drawing all
> > > they can, that wouldn't leave much room for the motor. Or am I
> > > misunderstanding all this?
> > >
> > > --- In electricboats@yahoogroups.com, Arby Bernt <arbybernt@> wrote:
> > > >
> > > > Go with the WFCO units. Each unit tends a single battery, 35a continuous
> > > output with three stage charging. Dozens installed, not a single failure
> > > (except one installed in reverse polarity, don't go there...)
> > > >
> > > > Be Well,
> > > > Arby
> > > >
> > > > On Nov 15, 2012, at 8:28 PM, "kotyara73" <krollokot@> wrote:
> > > >
> > > > > One thing that I never really gave much thought to is the battery
> > > charger. But now, having read the recent discussions on the topic, I
> > > started doing some more research on it and now I more confused than ever.
> > > So, I'd like some help choosing the right unit. Battery bank will likely be
> > > 4x100-150Ah AGMs feeding ME907/Sevcon kit. Here're the requirements (or at
> > > least draft requirements :)
> > > > >
> > > > > 1. Has to be able to work with the Honda genny. I gather that means
> > > drawing between 13.5 and 14 amps from it, which should result in ~25amp on
> > > DC side.
> > > > >
> > > > > 2. Has to be able to supply that power to the motor when the batteries
> > > are low. Otherwise, what's the point of a backup genny?
> > > > >
> > > > > 3. 4-bank 12v charger so as not to worry about battery imbalance? Not
> > > too sure about this one, but it seems reasonable.
> > > > >
> > > > > 4. Has to be robust enough to be left plugged in for a couple of weeks
> > > and keep the batteries happy. There won't be any other load at this time.
> > > > >
> > > > > 5. Solid state rather than transformer, for efficiency.
> > > > >
> > > > > 6. Not too expensive. I'm figuring $500 tops, but obviously the lower
> > > the better.
> > > > >
> > > > > Here're the options that I've gleaned from discussions in this group:
> > > > >
> > > > > 1. Elcon. Sounds like the right unit (except for being serial), but
> > > it's $750...
> > > > >
> > > > > 2. QuickCharge. Transformer, doesn't sound very robust.
> > > > >
> > > > > 3. DualPro. Issues with motor load while charging.
> > > > >
> > > > > 4. Zhivan. Not sure what to think of this one.
> > > > >
> > > > > 5. ProMariner. Saw it mentioned once. Sounds good, but I can't figure
> > > out their specs. When they say it's 4-bank 60Amps 12/24/36/48, what exactly
> > > do the amps refer to? They don't list their input amp draw either.
> > > > >
> > > > > 6. 4xWFCO converters. Arby's special :) Seems like a good solution,
> > > but single unit would be nicer. They also sell main boards, would it be
> > > difficult to put four of them in a single enclosure?
> > > > >
> > > > > So, as I said, I'm confused. What say you? What would be the best
> > > option?
> > > > >
> > > > >
> > > >
> > >
> > >
> > >
> > >
> >
>
It's not running in WOT that concerns me. I'm worried about being able to use the motor at all with the genny when the beatteries are depleted. In this case, wouldn't they draw as much power as they can get? (actually, is there a limit to the amps they can draw?)
So, if a WFCO can provide 35amps, that current will be split between the battery and the motor, so in effect it doesn't matter how low you set the throttle, it'll still draw 35amps.
Another question is how much of that power will go to the motor when both it and the batteries are drawing. I'm guessing the motor will have first dibs, since it's probably lower resistance?
I supposed it would be ideal if a 35amp converter could be specifically set to be limited to, say, 25amps. That would allow Honda to operate at its rated continuous 1.6Kw and leave a margin on the converters. Is there a way to do that?
John, I agree with you rant to a degree. It is a sailboat, after all, and FWIW, I do intend on using the sails whenever I can. As to why I'm looking at dumping $5K into it, two reasons:
1. I'm a newbie sailor and want a safety margin in case my sailing skill fail.
2. It's a fun project that will allow me to learn a lot.
I realize it's possible to sail a boat even without an engine, but then it's also possible to cross the Atlantic in a Zodiac. So the question is where do you draw the line between the two extremes? I'm guessing I'll be comfortable enough with a genny-backed EP system. What's your comfort zone?
Cheers,
Alex.
--- In electricboats@yahoogroups.com, "Mark n Angela" <mstafford@...> wrote:
>
> John, Great rant. You nail the cultural bias of Western Societies: dominating power vs accommodating environment. This myopic proclivity has advanced the whole world with fantastic alacrity, but now threatens our survival as a species. Will we be able to put down the crack pipe and live in complex relationship with our environment? Or will we use a bigger throttle, bigger gun, bigger wallet, to assert our self-centered ego? Stay tuned!
> Mark Stafford
>
> --- In electricboats@yahoogroups.com, John Francis <surv69@> wrote:
> >
> > WOW!
> >
> > We are talking about sailboats . . . aren't we?
> >
> > Personally, I don't know why anyone would even consider $5000+ to put an
> > electric motor in a sailboat and still have to concern themselves with
> > whether or not it might not be enough engine for the boat.
> >
> > I have a 70-pound thrust motor on my 28' Newport . . . adequate propulsion
> > for a boat that generally doesn't need an engine. Years ago(about 15), I
> > adequately operated my MacGregor 25 with a 37-pound thrust motor.
> >
> > I have made many, many thousand mile trips on a 250cc Yamaha. My 400cc
> > Yamaha was always more than enough engine to make trips. BUT still
> > virually E-V-E-R-Y-O-N-E claims that 1100cc is the absolute minimum engine
> > needed and a lot of posters on the internet say something around 1500cc.
> > Even if a discussion includes a utilizing a 650cc motorcycle, it seems
> > everyone jumps in to virtually berate the very idea of using 650cc for
> > trips.
> >
> > Why is everyone so doggone power crazy . . . especially in an endeavor
> > that's not about "*POWER*", such as sailing.
> >
> > Seriously . . . this leads me to wonder if this is a real discussion about
> > green energy, which generally requires some degree of compromise(on the
> > side of conservation), on the part of participants, or is this really just
> > another conversation of one-upmanship and full-speed ahead in what's new
> > for the moment?
> >
> > If everyone so desperately needs the speed and power they've always enjoyed
> > in the past(and over utilized), then why not just keep the old boiler-plate
> > engines in place, keep the speed as high as possible and leave the smell
> > behind . . . in your oily wake.
> >
> >
> > argh
> >
> > On Fri, Nov 16, 2012 at 7:48 AM, Arby Bernt <arbybernt@> wrote:
> >
> > >
> > >
> > > Yes.
> > > Running at wot (wide open throttle) will require a generator and power
> > > converters rated appropriately. WFCO makes 35amp units that have a foldback
> > > voltage feature. You pull more than the rated capacity, and their output
> > > voltage will decrease proportional the the load, until the converter shuts
> > > down.
> > > If you're running a Honda "2kw" genny, it can maintain a continuous
> > > output of 1.8kw (reference from memory) continuously. This means you can
> > > run your system at PARTIAL throttle only, basically drawing 1.8kw max. Buy
> > > a set of 95a WFCO converters, and a much larger genny, or two paralleled
> > > smaller ones, and you'll be able to run more power.
> > > Be careful, however. Running any system at 100% capacity is a fool's
> > > errand. Build headroom into your design, and plan on over-spec'ing your
> > > components. I use Kelly controllers turned down to 60%, for example, to
> > > build a more stable product. Yes, you can pull 35a out of a unit rated as
> > > such, but why push the limits. You don't shift your car at redline, so why
> > > treat your boat motor system any differently?
> > > Sailboats can motor at low speed very efficiently. if you plan on extended
> > > motoring, get a generator at least 20% larger than required by the power
> > > converters. Size the converters at least 20% over your motor load.
> > >
> > > Be Well,
> > > Arby
> > >
> > > On Nov 15, 2012, at 11:05 PM, "kotyara73" <krollokot@> wrote:
> > >
> > >
> > >
> > > Wouldn't 35amps x 4 overload the Honda? if the batteries are drawing all
> > > they can, that wouldn't leave much room for the motor. Or am I
> > > misunderstanding all this?
> > >
> > > --- In electricboats@yahoogroups.com, Arby Bernt <arbybernt@> wrote:
> > > >
> > > > Go with the WFCO units. Each unit tends a single battery, 35a continuous
> > > output with three stage charging. Dozens installed, not a single failure
> > > (except one installed in reverse polarity, don't go there...)
> > > >
> > > > Be Well,
> > > > Arby
> > > >
> > > > On Nov 15, 2012, at 8:28 PM, "kotyara73" <krollokot@> wrote:
> > > >
> > > > > One thing that I never really gave much thought to is the battery
> > > charger. But now, having read the recent discussions on the topic, I
> > > started doing some more research on it and now I more confused than ever.
> > > So, I'd like some help choosing the right unit. Battery bank will likely be
> > > 4x100-150Ah AGMs feeding ME907/Sevcon kit. Here're the requirements (or at
> > > least draft requirements :)
> > > > >
> > > > > 1. Has to be able to work with the Honda genny. I gather that means
> > > drawing between 13.5 and 14 amps from it, which should result in ~25amp on
> > > DC side.
> > > > >
> > > > > 2. Has to be able to supply that power to the motor when the batteries
> > > are low. Otherwise, what's the point of a backup genny?
> > > > >
> > > > > 3. 4-bank 12v charger so as not to worry about battery imbalance? Not
> > > too sure about this one, but it seems reasonable.
> > > > >
> > > > > 4. Has to be robust enough to be left plugged in for a couple of weeks
> > > and keep the batteries happy. There won't be any other load at this time.
> > > > >
> > > > > 5. Solid state rather than transformer, for efficiency.
> > > > >
> > > > > 6. Not too expensive. I'm figuring $500 tops, but obviously the lower
> > > the better.
> > > > >
> > > > > Here're the options that I've gleaned from discussions in this group:
> > > > >
> > > > > 1. Elcon. Sounds like the right unit (except for being serial), but
> > > it's $750...
> > > > >
> > > > > 2. QuickCharge. Transformer, doesn't sound very robust.
> > > > >
> > > > > 3. DualPro. Issues with motor load while charging.
> > > > >
> > > > > 4. Zhivan. Not sure what to think of this one.
> > > > >
> > > > > 5. ProMariner. Saw it mentioned once. Sounds good, but I can't figure
> > > out their specs. When they say it's 4-bank 60Amps 12/24/36/48, what exactly
> > > do the amps refer to? They don't list their input amp draw either.
> > > > >
> > > > > 6. 4xWFCO converters. Arby's special :) Seems like a good solution,
> > > but single unit would be nicer. They also sell main boards, would it be
> > > difficult to put four of them in a single enclosure?
> > > > >
> > > > > So, as I said, I'm confused. What say you? What would be the best
> > > option?
> > > > >
> > > > >
> > > >
> > >
> > >
> > >
> > >
> >
>
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