Friday, January 31, 2014

[Electric Boats] RE: House battery

 

I have a Corsair F27 trimaran and removed two 12v lead acid batteries.  I replaced them with 2 x 40ah rated 12.8v packs wired in parallel.  The batteries are GB cells similar to the more common CALB prismatics.  I use an Elithion BMS with small led fuel gauge.  I have a 45 watt panel and use the Genasun solar charge controller. 


I'm building a DIY charge controller & BMS of my own design that will use bluetooth to communicate with my laptop.  Its of my own design and has features the Elithion and Genasun combo don't provide.


I saved about 50 lbs and gained energy reliability and space.  Light weight is very important to small trimarans.


Steve

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Thursday, January 30, 2014

RE: [Electric Boats] Electric propulsion motors

 

I just recently retrofit some propellers getting ready to test our new electric outboard motor prototype from Volt boats https://scontent-a-sjc.xx.fbcdn.net/hphotos-prn2/t1/1545038_873835950604_620856544_n.jpg

https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-frc3/t1/1796494_873835985534_1080755533_n.jpg

We will be testing these on both our 500W and 1000W motors. I will post the results of these tests in the coming weeks.

 

From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com] On Behalf Of Carel Ruysink
Sent: Thursday, January 30, 2014 1:09 AM
To: electricboats@yahoogroups.com
Subject: Re: [Electric Boats] Electric propulsion motors

 

 



I agree with John. MinnKotas props have a very low pitch, good for sneaking around while fishing, but if you want to go from A to B???

Kipawa make "better" props but still have just a bit to litlle pitch.

I want to try this summer to use a converted Torqueedoprop on my MinnKota and do some experiments with model airplaneprops.When I have some results then I wille publish them here.

 

One more remark. MinnKotas are outboards and are designed as such. They are quite dependable but I would not trust the shaftseals to be submerged for weeks/months when permanently attached to the rudder.

If that would work it would be ideal but I have doubts there.

 

succes, Carel.

 

----- Original Message -----

From: oak

Sent: Thursday, January 30, 2014 3:08 AM

Subject: Re: [Electric Boats] Electric propulsion motors

 

 

David,

 

As an experiment, I tried using a MinnKota 24V Traxis 80 (80# Thrust) on my Catalina 22.

The motor would push the boat - up to a max of about 3.2mph into a moderate breeze (around 10-12mph).

 

The two issues I had with that motor were that 1) due to the low pitch of the prop, max speed still didn't get the boat speed I wanted, and 2) at full speed, the control head got hot to the touch within 30 min or so.

 

It sounds like it might do what you need.  But if you bolt it to the hull, you'll have a LOT of drag when you're sailing.  If you run the motor at slow speed, you could at least overcome most of the drag - though your boat would likely be able to sail faster than the motor can power it in a good breeze.

 

Good luck!

John

 

From: "mail@digiwis.com" <mail@digiwis.com>
To: electricboats@yahoogroups.com
Sent: Monday, January 27, 2014 10:01 AM
Subject: [Electric Boats] Electric propulsion motors

 

 

I'm thinking of fitting a Minn Kota 24 volt RT80EM Saltwater Motor (80 Lbs. Thrust) or something similar, bolted on the hull near the rudder of my 23 foot sailboat.... this propulsion is just to get the sailboat in and out of the creek, not more than 300 ft until I can pick up the wind. Speed is not an issue, but we do have maybe a one knot tide worst case. Does anyone have any experience of this kind of propulsion? Are there any alternatives out there for hull mounted electric propulsion units? I don't want anything hanging over the transom.  Thanks... David

 

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Re: [Electric Boats] Electric propulsion motors

 



I agree with John. MinnKotas props have a very low pitch, good for sneaking around while fishing, but if you want to go from A to B???
Kipawa make "better" props but still have just a bit to litlle pitch.
I want to try this summer to use a converted Torqueedoprop on my MinnKota and do some experiments with model airplaneprops.When I have some results then I wille publish them here.
 
One more remark. MinnKotas are outboards and are designed as such. They are quite dependable but I would not trust the shaftseals to be submerged for weeks/months when permanently attached to the rudder.
If that would work it would be ideal but I have doubts there.
 
succes, Carel.
 
----- Original Message -----
From: oak
Sent: Thursday, January 30, 2014 3:08 AM
Subject: Re: [Electric Boats] Electric propulsion motors

 

David,
 
As an experiment, I tried using a MinnKota 24V Traxis 80 (80# Thrust) on my Catalina 22.
The motor would push the boat - up to a max of about 3.2mph into a moderate breeze (around 10-12mph).
 
The two issues I had with that motor were that 1) due to the low pitch of the prop, max speed still didn't get the boat speed I wanted, and 2) at full speed, the control head got hot to the touch within 30 min or so.
 
It sounds like it might do what you need.  But if you bolt it to the hull, you'll have a LOT of drag when you're sailing.  If you run the motor at slow speed, you could at least overcome most of the drag - though your boat would likely be able to sail faster than the motor can power it in a good breeze.
 
Good luck!
John

From: "mail@digiwis.com" <mail@digiwis.com>
To: electricboats@yahoogroups.com
Sent: Monday, January 27, 2014 10:01 AM
Subject: [Electric Boats] Electric propulsion motors

 
I'm thinking of fitting a Minn Kota 24 volt RT80EM Saltwater Motor (80 Lbs. Thrust) or something similar, bolted on the hull near the rudder of my 23 foot sailboat.... this propulsion is just to get the sailboat in and out of the creek, not more than 300 ft until I can pick up the wind. Speed is not an issue, but we do have maybe a one knot tide worst case. Does anyone have any experience of this kind of propulsion? Are there any alternatives out there for hull mounted electric propulsion units? I don't want anything hanging over the transom.  Thanks... David


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Wednesday, January 29, 2014

[Electric Boats] RE: My new Electric boat with solar panels

 

It depends on the sun on what speed I achieve with it. Full sun over the panels is 4-5 MPH (with 2 panels)   but I am balancing the amps coming in from the panel with what amps are being used by the motor. If the batteries are topped of and I full throttle it it will go faster for a while.  I have a third panel now but can't test it till the sun comes back to the Northwest this spring. lol

Then again if I hook the Honda EU2000i I can maintain 10mph. I did a test and found out if needed I could go 10mph and the generator is always at a idle and go a 100 miles on a gallon of gas. I don't plan on doing that unless its a emergency etc. but it will do it. 

Here have a look at the generator test. Click on the short video "Generator Test"

https://sites.google.com/site/serenitysolarcanoe/home/short-videos-from-serinity

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Re: [Electric Boats] Electric propulsion motors

 

David,
 
As an experiment, I tried using a MinnKota 24V Traxis 80 (80# Thrust) on my Catalina 22.
The motor would push the boat - up to a max of about 3.2mph into a moderate breeze (around 10-12mph).
 
The two issues I had with that motor were that 1) due to the low pitch of the prop, max speed still didn't get the boat speed I wanted, and 2) at full speed, the control head got hot to the touch within 30 min or so.
 
It sounds like it might do what you need.  But if you bolt it to the hull, you'll have a LOT of drag when you're sailing.  If you run the motor at slow speed, you could at least overcome most of the drag - though your boat would likely be able to sail faster than the motor can power it in a good breeze.
 
Good luck!
John

From: "mail@digiwis.com" <mail@digiwis.com>
To: electricboats@yahoogroups.com
Sent: Monday, January 27, 2014 10:01 AM
Subject: [Electric Boats] Electric propulsion motors

 
I'm thinking of fitting a Minn Kota 24 volt RT80EM Saltwater Motor (80 Lbs. Thrust) or something similar, bolted on the hull near the rudder of my 23 foot sailboat.... this propulsion is just to get the sailboat in and out of the creek, not more than 300 ft until I can pick up the wind. Speed is not an issue, but we do have maybe a one knot tide worst case. Does anyone have any experience of this kind of propulsion? Are there any alternatives out there for hull mounted electric propulsion units? I don't want anything hanging over the transom.  Thanks... David


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[Electric Boats] RE: My new Electric boat with solar panels

 
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Tuesday, January 28, 2014

Re: [Electric Boats] RE: 48 volt solar panel array

 

The system I am familiar with feeds 4 (24v rated) 36 volt mpp  panels into 48 volt mppt charge controller. It is not this simple on a boat. Any partial shading of a panel brings charging to nothing when using crystaline panels. To guard against this it might be best to use micro inverters on every panel. This can be in the form of buck/boost dc to dc converters or as is practiced in some arrays that put out an ac current.

I would suggest using high voltage panels like the for mentioned 36mpp panels. Remember that losses can be high with dc to dc converters. Choose them based on efficency not on price all converters are not equal. Some have losses as high as 15% or more and that will be a lot in terms of boat real estate.

Kevin

 

These nominal 250W panels actually vary in voltage from about 24-30V  and outputs of 225W to 270W for the same roughly 55"x39" panel size. Since the charge voltage for a 48V FLA bank tops out at about 57V in the final phase of charging I would be sure to pick a panel that is closer to 30V.
 
The Flexmax80 charge controller I am using recommends a minimum 60 Volt input for a 48V battery bank so if your panel has a 24V open circuit voltage you'll actually need to string 3 of them together in series to get the required voltage. While this will work fine, I think it's better to use two 30V panels. Panels in series are more susceptible to greater losses from partial shading and working with an integral of 3 panels in series to make up your array can be more problematic.  
 
These voltage numbers are specific to FLA and are a little different if you're charging AGMs or LiIon but I don't know what those values are.
 
Carter


On Friday, January 24, 2014 9:49 AM, "stmbtwle@yahoo.com" <stmbtwle@yahoo.com> wrote:


I agree with using the "24v" 250w panels mentioned as they are a lot less expensive per watt than 12v panels.  Connecting 2 in series will get you the 48v you're looking for to charge your propulsion batteries.

To run the 12v accessories I'd have a 12v "house" battery and charge it from the 48v system using a 48v-12v charge controller. 




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Re: [Electric Boats] RE: 48 volt solar panel array

 

Yes, READ the specs carefully.
 
Individual panel characteristics are all over the map. Most are more like 30V nominal these days with open circuit voltages  that can go way higher. Find one at the sweet spot right around 30-36V and it will work great. The standard size is about 30"x56" for these panels and this frame size will give you anywhere from 210W to 270W. Generally, the higher the output, the higher the voltage.
 
Also look at the output verses temperature curve. As the panels heat up, they lose capacity and some lose more than others.


On Tuesday, January 28, 2014 8:11 AM, Roger L <rogerlov@ix.netcom.com> wrote:


nicely put, Pat.
What I got from kcr's posting is something so basic I'm reminding myself not to forget it..... might even post it in some form right on my workshop wall.
Kcr points out that it's reasonable to control an electric motor's current draw - and therefore its power output - by simply selecting to feed it a few different discrete battery voltages. No more fancy controller is required. On a multiple battery array, he can vary the motor's drive with nothing more complex than a handful of knife switches.
 
Those knife switches make for the simplest, most inexpensive & dependable control with the smallest possible energy lost to the controller. Of course what is lost that way is continuous variability, but for a heavy boat that stores so much energy in it's own motion, I'd imagine that just turning the motor on/off while switching between speeds becomes a reasonable way to make the small speed changes necessary for docking. 
 
Re: Ohm's Law calcs....I saw kcr's Ohm's Law example as more an illustration of voltage switching than an actual power calculation. For real calculation he wouldn't be using his battery voltage as the input voltage to the motor, it would be the battery voltage minus the small decrease due to voltage drop as well as a much larger input loss due to the back emf generated (Bemf) as the motor turns. Since kcr also uses the motor as a generator, he's aware of all that - particularly the Bemf part since that is where his generated power comes from when the diesel is doing the pushing.
Depending on the efficiency of the prop, Bemf can also be what provides a speed limit on the motor revs when the electric motor is doing the pushing.
   just sitting here with coffee & doing some thinking this mornin'.....
      Roger L.
----- Original Message -----
From: Forums
Sent: Tuesday, January 28, 2014 5:24 AM
Subject: RE: [Electric Boats] RE: 48 volt solar panel array

No.  You are calculating two different things.  Your math is correct for how much current is needed to still get 1000 watts at those voltages.  His was how much current will be drawn if you feed a 48 volt motor lower voltages (24 or 12 volts).
 
Pat
 
 
From: electricboats@yahoogroups.com [mailto:electricboats@yahoogroups.com] On Behalf Of Steve Dolan
Sent: Tuesday, January 28, 2014 7:01 AM
To: electricboats@yahoogroups.com
Subject: RE: [Electric Boats] RE: 48 volt solar panel array
 
 
KCR,
I think you multiplied when you should have divided.
 
1000/48 = 20.8A
1000/24 = 41.6A
1000/12 = 83.3A
 
Steve in Solomons MD
 
Sent: Saturday, January 25, 2014 6:38 PM
Subject: Re: [Electric Boats] RE: 48 volt solar panel array
 
 
The elec motor works pretty simply...   V = I x R that is the rule --> Volts = Current(amps) x Motor Resistance(Ohms).  Since (Watts=Amps*Volts) at 1000w and 48v, current(I) = 20.8 Amps; therefore the motor resistance is 48v / 20.8A = 2.3 Ohms.
The motor, at 48v uses 21 Amps, at 24v it uses 10.5 Amps, and at 12v it uses 5.25 Amps. If your motor is designed to take 48v then it will definitely run cool at 24v or 12v (much less power). The problem comes in when you take 48v and try to reduce the speed through resistors (old golf carts) or use pulse controllers(which cost money, overheat under high loads, and do not like salt water). However switching the battery voltage from 48v to 24v eliminates those problems.
I presently have a small 1000w 48v motor just to move in and out of dock and of course to charge my batteries when the diesel is running. Actual motor cost was $160 but I spent another $200 for couplings, brackets, etc. In the future I may replace the 1Kw motor with a 5Kw or 10 Kw as the price of lithium batteries (or sugar fuel cells) come down.
 




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Re: [Electric Boats] Solar Panel setup

 

The diodes will give you some protection so that you don't lose everything but it is still better to parallel them if you can.  On my arrays I have two panels paralleled, then I series groups of them together. I have seen just a small amount of shade on one panel virtually knock out the output for that particular pair in the array. The shaded panel really drags its partner down.  I mean like 10% shade cause a 70% loss in some circumstances. 

The diodes protect the output of the individual panel so the whole thing isn't killed by a little shade but the current of the two panels will be limited by the shaded one and if the shade happens to cross more than one circuit on the individual  panel, the pair can really take a hit. 

Paralleling is better whenever you can unless there is no shade issue and you want to save on wire size.


On Monday, January 27, 2014 9:07 PM, James Sizemore <james@deny.org> wrote:


The shading issues is not a concern between parallel/series panels setups. Almost all solar panels have at least one bypass diode.  The manual for you MPPT will have a voltage range it works best at.  However you configure your panels to reach that voltage range is your best option. Most vendors have a string calculator. Use it to find the best combination. Your vendors is below:



Most vendors have a sizing calculator on there web site.   

On Jan 27, 2014, at 7:23 PM, Carter Quillen <twowheelinguy@yahoo.com> wrote:

 
Steve,

I don't know anything about your particular charge controller but most of the MPPT controller I've seen will take much higher voltages and step them down for a 12V bank. My Outback will accept 90V and charge a 12V bank if you want to set it up that way.  Paralleling the two panels to feed your controller 24V would definitely be the way to go to avoid the partial shading issue. The advantage to series them and feeding it 48V would be to use a smaller wire but a 240W panel at 24V is only going to give you about 10 amps so the two of them together will only require about 12 guage wire, although 10 would probably be better.

I'd buy a panel that was made in the USA, you'll pay a few cents more per Watt but I don't think you can go wrong that way. Some of the Chinese stuff is fine, a lot of it not so much. The trick is in the solder connections, a lot of things are done by hand in China and all the stuff from the USA is done by robots and they generally provide more consistent quality control.

Carter


On Monday, January 27, 2014 12:33 PM, Steve Dolan <sdolan@scannersllc.com> wrote:


I'm getting ready (therefore just know trying to learn) to install solar panels on my cat for the house bank. They just don't have anything out there for 144V (Propulsion pack) systems as far as controllers go. So I have decided that rather then charge my Propulsion pack I'm going to charge just the House bank made up of 3 12V AGM batts. All charging of the House Bank is through the Propulsion bank down to a 144V to 12V charger. I have a few questions on solar systems.
 
I'm looking at 2 Mono 240W panels with a TriStar MPPT 45 controller.
It seems that I should go parallel with 2 panels in case one panel is partially shaded.
When wiring in parallel will the individual panels both go to a junction box at the panels then I can run a single heavy wire (probably 4/6 gauge) back to the controller?
I like the TriStar because I can get a remote display. Any comments on the controller?
My panels will be mounted on the davits so I can tilt them.  
I'm guessing that the panels should be 24V ea. Is there any advantage to going with the higher voltage rather than going 12V ea.?
Any suggestions on the manufacture of the panels or who to stay away from?
 
The loads on the house bank are about 18A so by eliminating this draw down from the Propulsion bank I'm hoping to extend the travel time on batteries alone and decrease the genset run time.   
 
Thanks guys for any input. I would like to get this right the first time, 8o)
 
Steve in Solomons MD








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