Tuesday, May 31, 2011

Re: [Electric Boats] Newbie

 

Good points Myles, and well summarised in your succinct summary of the situation.


Its true that there have been some fires and there's uncertainty about the cause of these.  So that may mean for Rob the comparison would be between AGM batteries and purpose built marine batteries such as the new ones from Torqeedo which have substantial built in protection mechanisms, which don't come with the cheaper lithium cells.

My own take on the situation of the fires is that they seem to be associated with charging with mains chargers, which for EV's can deliver a substantial current in order to recharge in a short time. My thinking is that the low charge rate of a solar system will be to a degree self protecting because high charge currents are not involved.  But even so at this point my approach should still be considered just an educated guess.

Cheers

Chris

On 31/05/2011, at 11:40 PM, Myles Twete wrote:

 

Great advice Chris…

In light of this being advice to a newbie, I do believe that downside risks deserve mention as regards to the cheaper lithium batteries.   First, the longevity: While these cells are claimed to be good for 1000's of cycles, their guaranteed 'lifespan' is merely in the low order of years---i.e. even at a relatively high usage rate of 4 times per month, you might not see 500 charge/discharge cycles in 10yrs---not sure what the expected lifetime is for the latest of these batteries, but I'd guess 10yrs might be pushing it.  With but 500 cycles within a 10yr span, you might do better with lead acid.  Second, while repeated deep discharges of lead acid batteries reduce the life of the battery, a single deep discharge of a lithium battery can cause it to be a boat anchor (if it were heavy).  Charge cycle life could instantly end at that point for any cell that experiences this.  Third, and perhaps most important to mention is the risk of fire.  There have been numerous EV car fires in recent years ---most all of these involved cars with lithium batteries as I understand.  There has been hot debate with EV-ers as to whether or not these were due to failures in BMS modules, flaws in BMS module design, dense packing of cells and overcharging, defective lithium cells or poor workmanship/mistakes by the operator/converter, etc.  Among the casualties was Neil Young's Lincoln Continental EV called the "LincVolt", which also ended up damaging a substantial part of Neil Young's personal memorabilia collection in the fire.  There's a strong case to be made that the BMS units are a significant contributing factor, if not the cause, of these fires.  As a result, a number of EV'ers have taken the stand that some of the BMS modules and systems out there are not robust enough to ensure that a cell can't get overcharged, overheat and cause a fire.  Or more likely: That these BMS's are not robust enough and that they can internally fail shorted, causing a lithium cell to dump massive amounts of current into them, causing both to overheat and melt anything nearby, if not cause a fire.  That shouldn't happen with a BMS module that truly has a fuse.

 

It's great to have automatic controls that allow safe charging and discharging to ensure longevity of our batteries and the rest of the system.  I totally trust my Lester golf cart charger to charge my lead acid batteries when I walk away.  Given recent stories regarding lithium EV battery pack fires though, I'd want to have significant extra safety items in place to detect when something goes wrong if I had a lithium pack… even an over-temp-triggered relay that shuts a charger down would help----however, that wouldn't help at all to prevent a poorly designed BMS module without a fuse from suddenly shorting and melting your pack even without the charger on.

 

-Myles Twete, Portland, Or.

 

From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com] On Behalf Of chris Baker
Sent: Tuesday, May 31, 2011 3:49 AM
To: electricboats@yahoogroups.com
Subject: Re: [Electric Boats] Newbie

 

 

Hi Rob,

 

I have a totally solar trimaran and you can see the details at http://currentsunshine.com

 

I've used a Torqeedo outboard (and since installing it have become a dealer for them) and lithium batteries with solar as the main energy source.  I also have a wind generator and Honda for emergencies.

 

The charge controller I use is a Xantrex C40 (other vendors have similar devices) which is a load diversion style controller and is suited to multiple charging sources.  And cute thing about it is that by using a water heating element as the diversion load I get hot water whenever the batteries are full and there's leftover power.

 

I'd encourage you to consider lithium batteries, such as those from either Winston (was Thundersky) battery or CALB (was Sky Energy) which are chinese makers of these cells, and which need some time for setup of a battery managements system, or purpose built marine lithium batteries such as from Torqeedo.

 

In my calculations, based on Australian prices, the chinese lithium batteries are about the same cost as good quality AGM batteries, and offer substantial advantages particularly for a load sensitive solar powered yacht.

 

The weight will be about a third of that of a comparable AGM pack.  And on a trimaran this can be important.

 

The losses in charging and discharge are near enough to zero, compared with lead acid cells which have a loss of around 15 to 30%.  This means you need 15 to 30 % less solar panels for the same energy harvest.  So its useful to consider this cost saving when comparing battery prices.

 

Another advantage is that they are tolerant of low state of charge which can easily happen on a solar powered boat during extended rainy and overcast periods.  Lithium cells can be discharged to low levels without harm.  And even then their expected life cycles is way better than lead acid cells discharged to only 50%.

 

I hope this helps, and good luck with your project,

 

Cheers

 

Chris

 

 

On 31/05/2011, at 10:55 AM, roblanford wrote:



 

Hey all. I am just restarting a rebuild project on my 34' Sailing trimaran. Have been looking around at several vendors for a conversion kit and am pretty well sold on the electric yachts 180ibl. Will go with AGM batteries, wind generator, solar, Honda portable, and a folding prop. The boat will be used for full time cruising hence the added power source choices. I also intend to use a 48v/12v converter for all the house loads.

I would like to know if anybody has set up a battery bank charging system and charged from multiple sources at the same time? I envision being under sail taking advantage of the regen ability, and charging from the wind generators and solar panels.

I was also thinking about an electric outboard for the inflatable but I have not researched that much yet.

Thanks for any input and advice.

Rob

 



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[Electric Boats] affordable useful trolling motor

 

MANGO is a Bristol 19 and length is 19'6", beam 6'6", draft 2'9", wt 2724 pds. This is a displacement hull maintaining good coasting momentum once you get her going in the desired direction. There is an inboard engine well and I would like to put an affordable electric outboard in the well. Torqeedo and other 'traditional' electric outboards seem too expensive, too powerful and too luxurious for my needs. All I want to do is get off the mooring in a narrow creek, motor to the bay 10 minutes away and then hoist sail and be gone. I think I could use a husky trolling motor with electric cable to a lead acid motorcycle battery in the cabin six feet forward. Weekdays I would put a solar panel on the small cabin top to recharge the motorcycle battery, or take the battery ashore for charging. The trolling motor would be easy to remove and store in the small cabin.

I hereby respectfully solicit your thoughts and recommendations.

Thank you,
Steve

http://www.bristolowners.org/19/bristol19.html

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RE: [Electric Boats] Newbie

 

Great advice Chris…

In light of this being advice to a newbie, I do believe that downside risks deserve mention as regards to the cheaper lithium batteries.   First, the longevity: While these cells are claimed to be good for 1000’s of cycles, their guaranteed ‘lifespan’ is merely in the low order of years---i.e. even at a relatively high usage rate of 4 times per month, you might not see 500 charge/discharge cycles in 10yrs---not sure what the expected lifetime is for the latest of these batteries, but I’d guess 10yrs might be pushing it.  With but 500 cycles within a 10yr span, you might do better with lead acid.  Second, while repeated deep discharges of lead acid batteries reduce the life of the battery, a single deep discharge of a lithium battery can cause it to be a boat anchor (if it were heavy).  Charge cycle life could instantly end at that point for any cell that experiences this.  Third, and perhaps most important to mention is the risk of fire.  There have been numerous EV car fires in recent years ---most all of these involved cars with lithium batteries as I understand.  There has been hot debate with EV-ers as to whether or not these were due to failures in BMS modules, flaws in BMS module design, dense packing of cells and overcharging, defective lithium cells or poor workmanship/mistakes by the operator/converter, etc.  Among the casualties was Neil Young’s Lincoln Continental EV called the “LincVolt”, which also ended up damaging a substantial part of Neil Young’s personal memorabilia collection in the fire.  There’s a strong case to be made that the BMS units are a significant contributing factor, if not the cause, of these fires.  As a result, a number of EV’ers have taken the stand that some of the BMS modules and systems out there are not robust enough to ensure that a cell can’t get overcharged, overheat and cause a fire.  Or more likely: That these BMS’s are not robust enough and that they can internally fail shorted, causing a lithium cell to dump massive amounts of current into them, causing both to overheat and melt anything nearby, if not cause a fire.  That shouldn’t happen with a BMS module that truly has a fuse.

 

It’s great to have automatic controls that allow safe charging and discharging to ensure longevity of our batteries and the rest of the system.  I totally trust my Lester golf cart charger to charge my lead acid batteries when I walk away.  Given recent stories regarding lithium EV battery pack fires though, I’d want to have significant extra safety items in place to detect when something goes wrong if I had a lithium pack… even an over-temp-triggered relay that shuts a charger down would help----however, that wouldn’t help at all to prevent a poorly designed BMS module without a fuse from suddenly shorting and melting your pack even without the charger on.

 

-Myles Twete, Portland, Or.

 

From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com] On Behalf Of chris Baker
Sent: Tuesday, May 31, 2011 3:49 AM
To: electricboats@yahoogroups.com
Subject: Re: [Electric Boats] Newbie

 

 

Hi Rob,

 

I have a totally solar trimaran and you can see the details at http://currentsunshine.com

 

I've used a Torqeedo outboard (and since installing it have become a dealer for them) and lithium batteries with solar as the main energy source.  I also have a wind generator and Honda for emergencies.

 

The charge controller I use is a Xantrex C40 (other vendors have similar devices) which is a load diversion style controller and is suited to multiple charging sources.  And cute thing about it is that by using a water heating element as the diversion load I get hot water whenever the batteries are full and there's leftover power.

 

I'd encourage you to consider lithium batteries, such as those from either Winston (was Thundersky) battery or CALB (was Sky Energy) which are chinese makers of these cells, and which need some time for setup of a battery managements system, or purpose built marine lithium batteries such as from Torqeedo.

 

In my calculations, based on Australian prices, the chinese lithium batteries are about the same cost as good quality AGM batteries, and offer substantial advantages particularly for a load sensitive solar powered yacht.

 

The weight will be about a third of that of a comparable AGM pack.  And on a trimaran this can be important.

 

The losses in charging and discharge are near enough to zero, compared with lead acid cells which have a loss of around 15 to 30%.  This means you need 15 to 30 % less solar panels for the same energy harvest.  So its useful to consider this cost saving when comparing battery prices.

 

Another advantage is that they are tolerant of low state of charge which can easily happen on a solar powered boat during extended rainy and overcast periods.  Lithium cells can be discharged to low levels without harm.  And even then their expected life cycles is way better than lead acid cells discharged to only 50%.

 

I hope this helps, and good luck with your project,

 

Cheers

 

Chris

 

 

On 31/05/2011, at 10:55 AM, roblanford wrote:



 

Hey all. I am just restarting a rebuild project on my 34' Sailing trimaran. Have been looking around at several vendors for a conversion kit and am pretty well sold on the electric yachts 180ibl. Will go with AGM batteries, wind generator, solar, Honda portable, and a folding prop. The boat will be used for full time cruising hence the added power source choices. I also intend to use a 48v/12v converter for all the house loads.

I would like to know if anybody has set up a battery bank charging system and charged from multiple sources at the same time? I envision being under sail taking advantage of the regen ability, and charging from the wind generators and solar panels.

I was also thinking about an electric outboard for the inflatable but I have not researched that much yet.

Thanks for any input and advice.

Rob

 

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Re: [Electric Boats] Newbie

 

Hi Rob,


I have a totally solar trimaran and you can see the details at http://currentsunshine.com

I've used a Torqeedo outboard (and since installing it have become a dealer for them) and lithium batteries with solar as the main energy source.  I also have a wind generator and Honda for emergencies.

The charge controller I use is a Xantrex C40 (other vendors have similar devices) which is a load diversion style controller and is suited to multiple charging sources.  And cute thing about it is that by using a water heating element as the diversion load I get hot water whenever the batteries are full and there's leftover power.

I'd encourage you to consider lithium batteries, such as those from either Winston (was Thundersky) battery or CALB (was Sky Energy) which are chinese makers of these cells, and which need some time for setup of a battery managements system, or purpose built marine lithium batteries such as from Torqeedo.

In my calculations, based on Australian prices, the chinese lithium batteries are about the same cost as good quality AGM batteries, and offer substantial advantages particularly for a load sensitive solar powered yacht.

The weight will be about a third of that of a comparable AGM pack.  And on a trimaran this can be important.

The losses in charging and discharge are near enough to zero, compared with lead acid cells which have a loss of around 15 to 30%.  This means you need 15 to 30 % less solar panels for the same energy harvest.  So its useful to consider this cost saving when comparing battery prices.

Another advantage is that they are tolerant of low state of charge which can easily happen on a solar powered boat during extended rainy and overcast periods.  Lithium cells can be discharged to low levels without harm.  And even then their expected life cycles is way better than lead acid cells discharged to only 50%.

I hope this helps, and good luck with your project,

Cheers

Chris


On 31/05/2011, at 10:55 AM, roblanford wrote:

 

Hey all. I am just restarting a rebuild project on my 34' Sailing trimaran. Have been looking around at several vendors for a conversion kit and am pretty well sold on the electric yachts 180ibl. Will go with AGM batteries, wind generator, solar, Honda portable, and a folding prop. The boat will be used for full time cruising hence the added power source choices. I also intend to use a 48v/12v converter for all the house loads.

I would like to know if anybody has set up a battery bank charging system and charged from multiple sources at the same time? I envision being under sail taking advantage of the regen ability, and charging from the wind generators and solar panels.

I was also thinking about an electric outboard for the inflatable but I have not researched that much yet.

Thanks for any input and advice.

Rob


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Monday, May 30, 2011

[Electric Boats] Newbie

 

Hey all. I am just restarting a rebuild project on my 34' Sailing trimaran. Have been looking around at several vendors for a conversion kit and am pretty well sold on the electric yachts 180ibl. Will go with AGM batteries, wind generator, solar, Honda portable, and a folding prop. The boat will be used for full time cruising hence the added power source choices. I also intend to use a 48v/12v converter for all the house loads.

I would like to know if anybody has set up a battery bank charging system and charged from multiple sources at the same time? I envision being under sail taking advantage of the regen ability, and charging from the wind generators and solar panels.

I was also thinking about an electric outboard for the inflatable but I have not researched that much yet.

Thanks for any input and advice.

Rob

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Re: [Electric Boats] MAYDAY! She just quits when hot??

 

On 31/05/11 08:56, Beau wrote:
> Hi,
>
> I have an older Duffy 21 Electric Boat with a 36 Volt System. This morning after an hour long full speed run she just quit. Would not go forward but would go in reverse, made for an interesting trip home.

Sounds like the thermal protection kicked in for the controller. It
probably only needed 30 minutes or so to cool down.

It's probably also worth not running 'full speed' all the time. Back
off the throttle a touch from maximum. Going just a touch slower can
significantly reduce the power consumption. (And waste heat production -
that heat is power not used for propulsion).

I've seen a rental electric boat where it's owner has put a screw into
the throttle control to stop hires from running the motor at full power
all the time. He took the limiter off when demoing the boat to me and it
was clear that while the power consumption went up significantly at
'Wide Open Throttle', we didn't get much extra speed over the limited
position he'd chosen.

> About 6 hours later I went out to see if the prop was fouled but when I tried the throttle everything was working fine in both forward and reverse.

It had cooled down and reset. It probably didn't need 6 hours :-)

> Anyone had this problem?????
> Any ideas where to start????? As you can imagine my wife is not thrilled to take the boat out. Mayday, Mayday, Mayday!

Find where the motor controller box lives. If the enclosure is force
ventilated, the fan may have failed and/or the grills blocked with crud.

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[Electric Boats] MAYDAY! She just quits when hot??

 

Hi,

I have an older Duffy 21 Electric Boat with a 36 Volt System. This morning after an hour long full speed run she just quit. Would not go forward but would go in reverse, made for an interesting trip home. About 6 hours later I went out to see if the prop was fouled but when I tried the throttle everything was working fine in both forward and reverse. Anyone had this problem?????
Any ideas where to start????? As you can imagine my wife is not thrilled to take the boat out. Mayday, Mayday, Mayday!

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Re: [Electric Boats] Re Charging controllers. amps - supplemental to 'amps explained'

 

Hi John,

Voltage changes on the supply line only because the potential to feed the batteries is very low.  Many PV panels have an open voltage of 20 or more volts. This voltage will not change in sunlight or other light sources that are compatible with the cells being used. Wattage will change with how you face the panel to the source.  It should be noted that reflection off the surface is the reason for most of the energy loss from the sun. Surface area and panel tech determine how much you can get from the sun.

The type of window may effect the output of the panels more than you are thinking. One reason is transmittance of light waves. Some glass will let more of a wave length spectrum through the glass or plastic than one composed of other material. It is good to know what part of the spectrum a panel works best in to determine if your windows will effect the output to much to make the plan worth while.

You can build your own panel using cells from ebay. If you do this you can use plexi-glass as the protecting surface of the panel making location less of an issue. Although it is said anyone with a soldering iron can do this job, I would suggest you avoid the idea if you are not competent with soldering low temp connections.

If I were making a aux sailboat from scratch I would invest in rigging that sent all the sheets aft to the cockpit and plan never to need to go on deck. The deck would be mostly solar cells.  This in it self is problematic as a panel needs to be in the sun without a shaded cell or two, as output is severely effected when a cell is shaded.

Some poly panels are produced using silkscreen techniques. I am wondering if one could use a roller furling and silkscreen the sail to help charge the bank.  Such an Idea would be short lived as far as life expectancy, but the idea would be a neat one just the same.

Kevin Pemberton

On 05/29/2011 08:05 PM, John Green wrote:

 

Hi, Kevin, thanks for the interesting mine of info on this.
Seems that it is not as easy as I thought.

Am I correct that you are saying that you have a wind generator that
produces
100 volts, and you feed this direct to the battery with no controller,
and the
'shorting' effect of the battery cushions it at roughly 12 volts?
Hmmm, if that's the case, might be better not leaving that running
unattended!

I have, in the few days since my last post, checked out my little
'battery top-
up' solar panel a bit more. It is about a single watt, as far as I can
remember.
You would think it would be written on it, but nothing, not even in
Mandarin.
Seems from my experiments that the volts do not go much lower when it is
faced even 45 degrees away from
direct sun.
I am not sure if panels get the power from the sun increasing the amps,
or just
the volts, but if it is solely the volts, I was getting 20 when facing
the sun,
and still as high as 17 or 18 when it was no longer direct. And I was
still
getting well over 14 volts even with no sun, just light, medium bright
day, but cloudy.
If this is the case, I could fit solar panels on the insides of the
cockpit
footwell when away from the boat. There is also a little room under
where the
hatch slides to when open. Again, my understanding is that provided I
get over
about 13.7 volts, I am good to go, just feed it into a charge
controller, and
bingo. I realise that a controller probably converts the extra volts
into more amps, so the higher the output the better.

I have to admit to have given up on the idea of a small trickle charging
windmill. Maybe something to experiment with later. I suspect solar
might be
better suited. Your experiences seem to back that up.
I am going to soon be wiring up for the bilge pump, and once the boat is
in the
water, will get a pair of batteries, one I can put on the car as a
second
battery to charge when doing the 30 mile or so drive to the boat, then
swap them
out each visit or as required. Or I might find that I have no need to.

My first electric drive experiment will hopefully be using a 24 volt 500
watt motor, on a
15 foot dinghy as a test bed. I will know more about that later this
week, I am
trying to gather parts locally to avoid massive shipping charges.
I probably will not pull out the Atomic 4 gas engine from the sailboat
this
season, but neither will I bother getting it running.
So, from what you are saying, windmills on boats are problematic.

I just might be able to get enough power from solar panels, bearing in
mind that
I will have only two batteries, not a big bank of them.
My understanding is that I can just add panels wired in parallel, and if
so, I can
build up a piece by piece system. And I can mix in wind power later as
well, I
assume, provided I have diodes so the power goes only one way. I know
that adding small panels is expensive, but it also gives greater
redundancy if a panel gets broken, and they can be hidden more,
especially on a small boat, where larger panels would look overpowering.
(no pun intended, but it was a good one!)

Another place for solar when away from the boat would be directly in the
windows, kind of against the
glass.
That would give me about 5 watts from a single square panel in front of
the
hatch, and another 4 watts total from the main windows, and I could
probably fit
another couple of 1 watt ones beside the mast. About 10 watts, but at
low
efficiency. Maybe another 5 watter vertically over the hatch door while
away.
Low efficiency, but quiet. And that is with only discreet mounting
places used.
Overall, I think after looking at what you have experienced, I ought to
be
getting a few solar panels first, then look into wind as a secondary
thing.
Even using 24 volts, I can charge 12 v singly, and have a changeover
system like
RV use, in their case charging the starting battery first, house battery
second.
Interesting that your experiences match my own reservations, with having
stuff whizzing around!
Of course, at the low levels of solar I am speaking of, maybe a mini
windmill or two makes a bit more sense.
My battery drain might not even be measurable most of the time. Just a
few minutes use for approaching and leaving a mooring. But, human nature
being what it is, the appliances get added later, or, laziness
encroaches, and the sails don't go up as often as they should.
It will be interesting to see what comparative results you get with a
'designed' prop.
Thanks again,
John



--  AspireOne Netbook running Ubuntu 11.04 Safe, Secure, Easy to use, Free Open Source Linux OS. Leaving Virus worries to the Windows Users!

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Recent Activity:
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Re: [Electric Boats] Re Charging controllers. amps - supplemental to 'amps explained'

 

On
> Seems from my experiments that the volts do not go much lower when it is
> faced even 45 degrees away from
> direct sun.
> I am not sure if panels get the power from the sun increasing the amps,
> or just
> the volts, but if it is solely the volts, I was getting 20 when facing
> the sun,
> and still as high as 17 or 18 when it was no longer direct. And I was
> still
> getting well over 14 volts even with no sun, just light, medium bright
> day, but cloudy.

PV cells are current devices, not voltage devices. Reading just the
open circuit voltage will not tell you very much, most panels will
manage to produce near their rated voltage in quite poor light, but the
actual power produced would be low.

Stick a resistor (of a suitable rating, it will get very hot, very
fast) across the output and repeat your measurements. You should now see
significant differences in output as you move off being aimed at the sun.

The intelligent controllers in 'grid tie' inverters do something
called 'Maximum Power Point Tracking' where the controller tries find
the optimal current draw that obtains the maximum power for the
conditions and keeps that 'Maximum Power Point' as the conditions
change. (If you pull too much current, the voltage will sag and you
could end up worse off, the MPPT finds that 'sweet spot').
I think you can get MPPT equipped solar battery chargers. They will be
the more expensive sort :-). I think the simple solar charge controllers
are just a simple shunt voltage regulator to stop you from cooking the
battery in bright light. They make no effort to find the sweet operating
point of the attached panel for maximum efficiency.

So don't believe the results obtained from just sticking your volt
meter across the output terminals of a solar panel...

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Recent Activity:
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Sunday, May 29, 2011

[Electric Boats] Re Charging controllers. amps - supplemental to 'amps explained'

 

Hi, Kevin, thanks for the interesting mine of info on this.
Seems that it is not as easy as I thought.

Am I correct that you are saying that you have a wind generator that
produces
100 volts, and you feed this direct to the battery with no controller,
and the
'shorting' effect of the battery cushions it at roughly 12 volts?
Hmmm, if that's the case, might be better not leaving that running
unattended!

I have, in the few days since my last post, checked out my little
'battery top-
up' solar panel a bit more. It is about a single watt, as far as I can
remember.
You would think it would be written on it, but nothing, not even in
Mandarin.
Seems from my experiments that the volts do not go much lower when it is
faced even 45 degrees away from
direct sun.
I am not sure if panels get the power from the sun increasing the amps,
or just
the volts, but if it is solely the volts, I was getting 20 when facing
the sun,
and still as high as 17 or 18 when it was no longer direct. And I was
still
getting well over 14 volts even with no sun, just light, medium bright
day, but cloudy.
If this is the case, I could fit solar panels on the insides of the
cockpit
footwell when away from the boat. There is also a little room under
where the
hatch slides to when open. Again, my understanding is that provided I
get over
about 13.7 volts, I am good to go, just feed it into a charge
controller, and
bingo. I realise that a controller probably converts the extra volts
into more amps, so the higher the output the better.

I have to admit to have given up on the idea of a small trickle charging
windmill. Maybe something to experiment with later. I suspect solar
might be
better suited. Your experiences seem to back that up.
I am going to soon be wiring up for the bilge pump, and once the boat is
in the
water, will get a pair of batteries, one I can put on the car as a
second
battery to charge when doing the 30 mile or so drive to the boat, then
swap them
out each visit or as required. Or I might find that I have no need to.

My first electric drive experiment will hopefully be using a 24 volt 500
watt motor, on a
15 foot dinghy as a test bed. I will know more about that later this
week, I am
trying to gather parts locally to avoid massive shipping charges.
I probably will not pull out the Atomic 4 gas engine from the sailboat
this
season, but neither will I bother getting it running.
So, from what you are saying, windmills on boats are problematic.

I just might be able to get enough power from solar panels, bearing in
mind that
I will have only two batteries, not a big bank of them.
My understanding is that I can just add panels wired in parallel, and if
so, I can
build up a piece by piece system. And I can mix in wind power later as
well, I
assume, provided I have diodes so the power goes only one way. I know
that adding small panels is expensive, but it also gives greater
redundancy if a panel gets broken, and they can be hidden more,
especially on a small boat, where larger panels would look overpowering.
(no pun intended, but it was a good one!)

Another place for solar when away from the boat would be directly in the
windows, kind of against the
glass.
That would give me about 5 watts from a single square panel in front of
the
hatch, and another 4 watts total from the main windows, and I could
probably fit
another couple of 1 watt ones beside the mast. About 10 watts, but at
low
efficiency. Maybe another 5 watter vertically over the hatch door while
away.
Low efficiency, but quiet. And that is with only discreet mounting
places used.
Overall, I think after looking at what you have experienced, I ought to
be
getting a few solar panels first, then look into wind as a secondary
thing.
Even using 24 volts, I can charge 12 v singly, and have a changeover
system like
RV use, in their case charging the starting battery first, house battery
second.
Interesting that your experiences match my own reservations, with having
stuff whizzing around!
Of course, at the low levels of solar I am speaking of, maybe a mini
windmill or two makes a bit more sense.
My battery drain might not even be measurable most of the time. Just a
few minutes use for approaching and leaving a mooring. But, human nature
being what it is, the appliances get added later, or, laziness
encroaches, and the sails don't go up as often as they should.
It will be interesting to see what comparative results you get with a
'designed' prop.
Thanks again,
John

2a. Re: Re Charging controllers. amps - supplemental to 'amps explained'
Posted by: "Kevin Pemberton" pembertonkevin@gmail.com the_right_lane
Date: Fri May 27, 2011 2:21 pm ((PDT))

Hello John,

I have been playing around with the wind for a while. The wind-generator
I now play with trying to get things just right will produce over 100v
open circuit. Charge control can be accomplished by shorting the leads
coming from the generator, and is the most common way of limiting charge
current. 100 volts from a limitless supply could be a big problem when
shorted out, but because (like all natural supplies) the power behind
the circuit is so low. The battery bank will shunt the voltage down to
charging voltage without as much as a spark. Well ok a little one, but
the wires (12gauge) don't show signs of heat.

The generator I have built from parts (not a motor of any sort) is rated
close to 3hp (2000w). my last attempt proved poorly. It was an auto
alternator re-wired to produce 48v by using smaller gauge wire with more
turns. Installed were PMs on the rotor, but alas the generator would not
stop the blades in a blow so proved dangerous.

The blades purchased from the survival unlimited site are of such low
pitch that a stiff breeze is required to start turning. These are the
same blades I am now using on the latest attempt but I have changed the
pitch of the blade. With out the change the blades would howl loud
enough to wake people a mile away when unattended and the wind came up.
I am happy to report that using my oversized over-voltage (100+v open)
the windmill while charging is whisper quiet and operates at almost
stall while pumping 13v into my battery.

Today's test (gusts as High as 40mph) would not make the windmill over
spin even when running open. The 29 series battery used for the test was
topped from a starting voltage of 12.00v by 2PM. This is not bad
considering the blades were designed for higher speed usage and were
running at an almost stalled condition. To top this off changing the
pitch altered the effective foil from hub to tip.

What I didn't like about previous generator set-ups:

Unless you are on a mooring (not at anchor) when the wind picks up
enough for a wind-generator to produce useful current Anchor watch is
necessary. Add to the problem wind-age that affects the way the boat
lays, as well as strain on the anchor rode.

I once had to go to sea in a blow because I became exposed to the wind.
The wind generator kicked in as we were getting ready to head out.
Communication because of the noise became almost impossible.

Any anchorage windy enough for a wind generator is most uncomfortable,
making the anchorage undesirable or the wind generator, take your pick.

One more bit. notice the conditions for my test today. 20mph will get
most wind generators rotating. some will stay turning at speeds as low
as 7mph. Most will not produce as much as a 45w solar panel at that low
a wind speed. At 20mph the output is not that great. 40mph is as close
to gail force as I want to get on the water ever again. I have been
there, done that, and it made for a very long uncomfortable night as I
made unbelievable way on my passage.

McMaster Carr used to sell panel mounts for stanchions. now that is not
what they were made for but they worked great. I had two panels that I
could drop vertically when I wanted them out of the way. Boats house
electric may be the best use of solar panels to date. By my own
experience I don't thing wind generators are. By the way. My next
project wind generator is the manufacture of a classic style prop
designed for wind generators and a much lower RPM than other blades on
the market today, we will see how that goes. I am going to use an Oscope
to measure the RPM my generator puts out charging current and make the
blade based on that.

Kevin Pemberton


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