Electric power, RE-E-Power

Ross · Jan 31, 2009

it requires about 3/4 ton of lead-acid batteries to equal the energy in one gallon of gasoline.

Ross · Jan 31, 2009

Serenity said:
Ross,
Now I,m really confused. I will admit that despite the fact that my education was fulfilled in certain disciplines there is a complete void when it comes to understanding electricity. According to the Re E Power people and documented by users, the most I would need would be four #27 deep cycles. With the absence of my two gas tanks and my 90 Lb OB I'm sure I can find room for four additional batteries. Am I wrong? thanks...

Fair winds,
>>ron<<

One hp equals 63.3 amp hours per hour at 12 volts. One HP equals 550 foot pounds per second. 55 pounds thrust at 3.6 kts equals one HP. Can your group 27 batteries deliver that much power that quickly?

sailaway78 · Jan 31, 2009

Without the facts and figures

Without any facts and figures, which Ross covered pretty good, with todays technology, if you plan on much more than motoring in and out of the slip, you will have to have one very large battery bank. Enough battery power to give you the equal to a 9hp outboard, for more than a few minutes, would also give you a boat that sails like a total slug.

Bill Roosa · Jan 31, 2009

There is no practical replacement for dead dionasours

Literally millions of folks have been trying to make electric vehicles since Faraday's day.
The fact that we don't have one viable example of a battery powered vehicle is proof that it is not possible with the current technology to store enough energy in chemical batteries to be handy in driving vehicles.
You have to have some sort of genset driving the electric motor. There are some applications where this provides an advantage RE: trains where the 100% torque of an electric motor at 0 RPS is the only way to get a train going. You simply can't get a diesel engine to produce that torque at low RPM.
On a boat you have a prop and water so why even bother. This is why you don't have any gears other than forward and reverse! The efficiencies of diesel engine driving a generator driving an electric motor are fairly low compared to just using the engine and a direct drive transmission.

ecsimonson · Jan 31, 2009

http://www.teslamotors.com/
viable, maybe not but i want one

Bill Roosa said:
The fact that we don't have one viable example of a battery powered vehicle is proof that it is not possible with the current technology to store enough energy in chemical batteries to be handy in driving vehicles.

themacway · Jan 31, 2009

i really, really like the intelligence on this site. warms my heart. ross is right in his simple equations, bill roosa is spot on with his 'dead dinosaur' statement in principle. i'm an environmental geoscientist by education and a petroleum geologist by profession, so i took a chance and waited a day to see who'd say what here. everybody's right. amazing. can't believe it. gonna throw a party. woo ha! righty oh!
there is no cost-effective, reasonable substitute for the hydrocarbon molecule for energy output for motoring uses at this time and on into the future for a fur piece. ain't none. won't be anytime soon. quitcher worryin'. buy better sails, trim your rig better, buy a more efficient, quieter outboard/inboard. buy oil stocks (please! somebody! quick!). quit worryin' 'bout electric. hybrids aren't here either - yet. closest thing i've seen to date in the 'really great electric idea' arena for boats is the torqueedo. size it up for a bigger boat's propulsion needs and go get a (large) second mortgage to pay for it. gonna cost a ton. ain't worth it. watch the super bowl. buy popcorn. make some nachos. do up some yee ha gumbo. drink a brewski or two. take a few gaviscon or rolaids. put your feet up. have a good time.
btw ron - why are you even looking at the electric propulsion thing? you must really want the perfect boat. most of us would just about kill for your rhodes 22 just as she sits! i know i sure would, it'd be like nirvana for me. i also want a telstar 28, but that ain't happenin' just yet either... now those two boats are things worthy of a worryin' mind.
jack b

in midland, tx usa

Bill Roosa · Feb 1, 2009

There are electric solutions...

Just not ones that require electricity to be stored in chemical batteries.

Mr. Tesla, inventor of alternating current, had a pretty nifty way of distributing power wo wires that would work for cars, trucks, airplanes, and boats. Even planes and boats out in the middle of the ocean would be covered.

Alas, you can't put a meter on this system and charge for use so there is not much incentive for anybody to try and make money doing it.

All you need is an areal up the mast connected to a distro box and then a ground (neutral since it is AC) connected to the keel ground. The areal to ground circuit then behaves just like you normal AC circuits with switches motors etc.
You can build this kind of thing for next to nothing and, you could see how pirating the power would become a problem.

Perhaps the democrats could fix this for us with their infrastructure stimulus plan

Bill Roosa · Feb 1, 2009

Viable vs affordable

I'll admit that you can build an electric vehicle that works, but you have to admit there are not going to be many of them sold given the cost and range limitations.

By viable I was meaning I could actually install one and not have it destroy my finances and I have to give up sailing to continue to eat.

ITMaster · Feb 1, 2009

What is sad is how we have failed to develop the harnessing of hydrogen power and other alternatives. Let's see, it was back in 1973 when we had our first rape of our economy from OPEC if my memory serves me.

Since then, in response to that embargo, I guess we have had technology improvements that have shown us how we can use hydrogen power and emit water vapor as a by-product, wind power to harness the highest consistent winds on the planet in the great plains that could provide us with 20% of our national electric requirements, the location of natural gas reservoirs which only is used to provide 1% of our transportation fuel requirements, and alas, NP diode technology to convert light photons to electric wattage.

Yet we continue to allow our addiction to oil and don't implore our government to do anything about them not forcing our automotive manufacturing community and big oil companies to develop alternative energy sources to stop the rape of our economy.

Haven't we as a society had enough yet? When will we learn? I guess that at least we are the one community that makes use of a natural resource to provide ourselves with a responsible resource use pass time.

Sorry for the drift, the concept of electric vs. petro just kicked my mind into a peeve of mine.

Colin · Feb 1, 2009

Battery Calculations

Actually, the calculations for the battery requirements aren't that bad:

If you use 4 Trojan T-105 batteries (these are 6-volt golf cart batteries) you'd set them up as two strings of two batteries, giving a battery pack with 12 volts and half the current flows comes from each string. So, to use Ross's example where steady motoring at 3.6 knots requires a steady 63-amp current from the battery pack, each of the two strings will need to be supplying 32 amps. This would be a total of 250lbs of batteries.

Now, if you look at the specs for the T-105's you'll see that they have a 5-hour rate capacity of 185 amp-hours. That means that you can pull 37 amps out of them for 5 hours if you completely drain the battery from fully charged. Of course, you should never do that: You shouldn't take even a deep discharge battery below 50%, so that gives us a limit of about 2.5 hours. In other words, you should be able to use a pack of 4, T-105 batteries to provide a steady 1-hp of drive for 2.5 hours before you need to recharge.

This is quite a bit more than just getting in and out of your slip, but isn't going to get you down the ICW, or drive you into waves, against currents, etc unless you have a generator connected to provide the power when needed. If you're a larger cruising boat that was going to have a generator anyway, this hybrid approach might be a nice way to go. If you're a small sailboat and in/out of the marina is all you use your engine for, the batteries-only system might make sense. The mid-size vessels are where the economies of marine electric drives are still rather dubious.

Ross · Feb 1, 2009

Don't use my example of 55 pounds thrust at 3.6 kts. as anything useful. I don't think a 22 foot boat can be pushed to 3.6 kts with 55 pounds of thrust.

Bill Roosa · Feb 1, 2009

It is the invisible hand of Adam Smith

that is causing all the problems.

Nobody is going to buy a CNG vehicle if there is no CNG filling station on the way home from work. Same same for H2, ..... lots of stuff. So why doesn't an enterprising young man who wants more in live fill this gap?
Well you can't make any money doing these types of things. Alternative fuels are more expensive and so the majority of folks will opt for the cheapest ones.
Nobody is going to pay 2x the price for fuel unless they have to.

There are ways to make these things happen but you would need a very large group of people cooperating to their own disadvantage.

dvideohd · Feb 1, 2009

You set up an interesting challenge and test...

So this spring...

a lot of folks might test this idea of how fast their boat will go - versus power used...

A Minn Kota 40, 55, or 80 motor.....

"some way" to measure power used... (what meter to use??)....

you GPS...

and just post the speeds/powers used on windless days...

***********

I wonder if Minn Kota has this information - I did not see from their web site...

A Catalina 22, Macgregor 26, a Cat, and a J boat.... would be good test boats.....

*********

I would guess that MOST of the time - you won't need a lot of KwH.... for example, coming into the dock - or headed out...

so there are two numbers... low speed performance - and maximum impulse performance - that you might need...

**********

perhaps this idea could be refined??

--jerry

RE-E-POWER · Feb 16, 2009

From the horses mouth

Hi Ron,

I don't usually do this but I was encouraged to do so by several customers. Sometimes the math is not what it appears. In reality things sometimes work differently.
For instance, we have a customer who (last October) set off from Chicago, down the Illinois river in a 22' pocket cruiser weighing in at 4500 lbs. That's 4500 BEFORE batteries.
She motored about 95% of the time. Her average speed was 4 knots and she motored about 10 hours per day. Yes, ten hours without plugging in or running the generator. One day she went 12 hours, but that was a total drain on the pack. She has eight, 6 volt T-105 batteries which weigh in at 65 lbs each. So a total weight of 520 lbs. Now, keep in mind that she didn't expect to get that much range out of the batteries. By the same equation, four, 12 volt group 27 batteries would probably get you a little less than half the running time that she experienced. So 4-5 hours would certainly be realistic. Our motors are actually performing much better than we had originally expected and this has been the experience across the board with our new systems. I'm not going to argue the issue and if folks want to quote all the figures they know that's fine. I only know what is happening in the real world by reports from our customers. You can get on our owners forum and read many of the posts there as well.
Hope this information helps!

Kevin Plank
Owner RE-E-POWER.com

Serenity said:
Has anyone any experience or any information on using the re-e-power.com unit for propulsion? They have a very interesting and persuasive web site. Any info will be greatly appreciated. From what i can tell their 200+ unit should give me about the same HP as my Nissan 9.8. My major concern is length of available power between charging. There are times when I have not gone out because of weather and spent the day travelling the ICW to my gunkhole destination. Thanks...

Fair winds,

>>ron<<
S/V Serenity

Ross · Feb 16, 2009

RE-E-POWER said:
Hi Ron,

I don't usually do this but I was encouraged to do so by several customers. Sometimes the math is not what it appears. In reality things sometimes work differently.
For instance, we have a customer who (last October) set off from Chicago, down the Illinois river in a 22' pocket cruiser weighing in at 4500 lbs. That's 4500 BEFORE batteries.
She motored about 95% of the time. Her average speed was 4 knots and she motored about 10 hours per day. Yes, ten hours without plugging in or running the generator. One day she went 12 hours, but that was a total drain on the pack. She has eight, 6 volt T-105 batteries which weigh in at 65 lbs each. So a total weight of 520 lbs. Now, keep in mind that she didn't expect to get that much range out of the batteries. By the same equation, four, 12 volt group 27 batteries would probably get you a little less than half the running time that she experienced. So 4-5 hours would certainly be realistic. Our motors are actually performing much better than we had originally expected and this has been the experience across the board with our new systems. I'm not going to argue the issue and if folks want to quote all the figures they know that's fine. I only know what is happening in the real world by reports from our customers. You can get on our owners forum and read many of the posts there as well.
Hope this information helps!

Kevin Plank
Owner RE-E-POWER.com

Kevin, I fail to see a benefit. My Volvo diesel and 40 liter fuel tank do not weigh as much as the battery pack in the 22 foot boat. You don't mention the weight of the motor, drive shaft, controller and electrical cables. This I carry in a 30 foot, 9500 pound sloop and I can motor at 4 knots in flat water for more than 40 hours before refueling in 20 minutes.

Ross · Feb 16, 2009

Serenity said:
Ross,
Now I,m really confused. I will admit that despite the fact that my education was fulfilled in certain disciplines there is a complete void when it comes to understanding electricity. According to the Re E Power people and documented by users, the most I would need would be four #27 deep cycles. With the absence of my two gas tanks and my 90 Lb OB I'm sure I can find room for four additional batteries. Am I wrong? thanks...

Fair winds,
>>ron<<

Ron, How long can you run your 90 pound OB at 4 knots on 1 gallon of gas? I have two group 31 batteries for my house bank and somehow I don't think they could bring me home with a minikota hung off the stern.

Benny · Feb 16, 2009

I'm confused, if they are using a generator to recharge the batteries where are the benefits? Our diesel engine powers the boat and recharges the batteries all at once.

Ross · Feb 16, 2009

Benny said:
I'm confused, if they are using a generator to recharge the batteries where are the benefits? Our diesel engine powers the boat and recharges the batteries all at once.

The benefit accrues to Kevin Plank who is in business selling the system.

Electric power, RE-E-Power

Florida sail

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Ross

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Florida sail

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Ross

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sailaway78

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Bill Roosa

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ecsimonson

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themacway

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Bill Roosa

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Bill Roosa

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ITMaster

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Colin

Ross

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Bill Roosa

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dvideohd

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RE-E-POWER

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Ross

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Ross

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Benny

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Ross

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