T-Pain Is On A Boat: Re: [Electric Boats] Electric Risør 27

Hi!

I just discovered the boost converter-solution myself, but thanks for the hints! ;-)

I have not found suitable solar boost charger so far, but I am wondering if this one can do the job (12V-80V,600W): http://www.ebay.com/itm/New-DC-DC-600W-10-60V-to-12-80V-Boost-Converter-Step-up-Module-Power-Supply-/271271664247?pt=LH_DefaultDomain_0&hash=item3f290d1a77

I see two solutions:

Either to connected the boost converter between the solar controllers (for example 24V) and the battery (in parallell over the battery to achieve up to 160V). But I dont know if this set up can charge batteries, I would expect some need for voltage regulation since the Nicd cells rise from 6V to 8.15V during charging.

The other solution is to make a 24V battery from the Nicds - and connect the boost converter between the battery and the motor to increase the voltage to 120V. Then there will be needed around 40 of these boost converters (connected in series/parallell) to handle the peak power demand of approx 20kW.

I dont know if this will work, and I dont know if the efficiency of the boost converter vil drop dramatically when converting such large voltage step-ups. I better send the manufacturer a question... or I can buy a couple of them and test for my self. But how can a constant current source like a solar panel be imitated?

Lots of ?

I have started to repeat electric curcuit theory, but things take time with three small kids around ;-)

Bendik

2014-06-25 3:12 GMT+02:00 withaar@wylch.fastmail.fm [electricboats] <electricboats@yahoogroups.com>:

You need a "boost converter".

E.g.: http://www.electroschematics.com/9718/solar-boost-converter-mppt-charge-controller/

A search on "solar panel boost converter" should get you some results.

Willem

On 14-06-20 11:51 PM, Bendik Vignes bendik.vignes@yahoo.com [electricboats] wrote:

Are there any solar controller/charger for converting the low voltage signal from solar panels (several "12V"-panels i parallell) to a high voltage battery (120V).
Transformation from 12 to 120 volts should i theory not be a big deal, but I cant find solar controller/chargers for this purpose. Do any of you know?

Bendik

2014-06-19 10:39 GMT+02:00 Bendik Vignes <bendik.vignes@yahoo.com>:

Here is a picture.of my boat. Not a beautiful one, but really nice for the family and it did not cost me a fortune:-)

On the front cabin roof there is space for five 0,5m2 panels. On the back cabin roof it space for one panel. And possibly one panel one each side of the boat (under the window)

Should all be connected in parallell I think...

2014-06-17 17:25 GMT+02:00 James Sizemore yamez4u@gmail.com [electricboats] <electricboats@yahoogroups.com>:

I'll be very interested in your Think drive train project.

There are a couple of SolbianFlex clones out there that use the same cells but at a much more "reasonable" price:

http://www.sacredsolar.com/index.aspx?menuid=12&type=introduct&lanmuid=26&language=en

http://www.grapesolar.com/component/virtuemart/residential/photoflex-100w-detail.html?Itemid=0

They may both be the same panel just re-branded by Grape. I have installed the Sacred ones on my boat and they do put out there rated power.

I do "walk" on them but only barefoot and very gingerly. At three hundred dollars a panel, they are much cheaper then Solbian, but still expensive enough that I would not like to replace any!

Two things to note. First they did not use stainless steal for the through holes and second dealing with the top mounted connectors ascetically is challenging to say the least. Here are pictures of my install with the finger ducts I used to hide the top mount connectors:

http://www.deny.org/Escape_the_American_Dream/Work_Blog/Entries/2014/5/26_Solar_worked_great..html

On Jun 17, 2014, at 8:14 AM, Bendik Vignes bendik.vignes@yahoo.com [electricboats] <electricboats@yahoogroups.com> wrote:

Hi!

I live in Arendal, Norway, and I am new to this group. I dont have experience with these yahoo groups so sorry if I act a bit clumsy.

I am working on a electric propulsion boat project:

It is a 27 feet "yacht" (Risør 27) from the early seventies. Displacement hull. 3500kg

Now it has a 1964 Mercedes OM636 diesel engine. Still works OK.

I bought the boat last summer and rather quickly I started to think about conversion to electric/hybrid.

Since this is a very low budget project am looking for cheap and smart solutions...

As a "donor" a bought a 2001 Think electric car (payed about 1000 dollars). It had a charging issue, but I belive I have fixed that.

It has a 17kW Siemens 3-phase motor, Siemens simotion inverter, 19*6V, 100Ah Nicd battery (from SAFT), Actia charger, Actia BMS, a DC-DC converter and other stuff i might need... The battery, motor, controller, DC-DC are water cooled. There are quite a few people here in Norway with rather deep experience and knowledge about this car (it was made in Norway), so I believe I can get the specific technical tips about this car when I need them..

I measured the boat's "drag" by pulling it with another boat and measuring the force F with a spring weight, and the speed v with a smart phone. At 5knots, the force was 60kg*9,81N/kg, and at approx 4,5 knots the force was 40kg*9,81N/kg. Since the power P is given by P=F*v, the power at 4,5knots is about 900W. If I assume 55% propeller efficiency (is this OK?), and 80% electric to mechanical effeciency, the electric power needed is about 2kW (no wind and waves). I do expect up to ten times this power in special situations, i.e. sharp maneuvers in strong wind.

I believe it is better to leave the diesel engine: in worst case if the electric propulsion is a total failure, the boat is still usefull!

My plan is to mount a cogwheel between the diesel engine's gear box and the propeller shaft (there is not much friction when the gearbox is in neutral), and mount the electric motor just behind the diesel engine. The propeller is made for 900rpm. Gear ratio 1:3 should go fine (the motor has a max torque of 180Nm -means a current of 280A- at 1000rpm, which is about 18,8kW of power).

The motorcontroller are prepared for generative breaking, so when going by diesel power the electric motor can work as a generator and charge the batteries.

I also plan to use the batteries, BMS, charger and so on. The batteries will give me approx 5 hours driving before I need to start the diesel engine. Since Nicds should not be stored fully charged, I will need some kind of remote control to start charging some hours before a trip.

BUT, I would really like solar panels to increase the range (and possibly to replace the diesel "generator"). I guess I would need at least 500W of solar power. Here I have several difficulties:

-available space for panels (suitable for walk-on etc)

-solar charging of a relatively high voltage Nicd battery

-cost of solar panels

Since walk-on, flexible, high efficiency panels (like SolbianFlex) are really expensive, I was about to give up this solar power idea. But last night I thought that the panels dont really need to be "walk-on" - types. I could cover ordinary flexible/thin panels with a plexi glass (an a couple of cm of air gap). Now I can sit on, walk on them, drop hard things on them... But I will need cooling. This could be solved with aluminum plates and circulating water - not to difficult. Probably, there will be some more reflections due to plexiglass? Or what do you people think?

There is space for several 100*50cm panels. Maybe 7 panels.

I do believe the monocrystalline is the best option. What about these: http://www.ebay.com/itm/261501848394 ???

How is monocrystalline compered to amorphous/CIGS when the sun angel is small, and under somewhat cloudy weather? Will the voltage drop too much? I have read that the a-Si/CIGS panels works OK in shaded / partly shaded conditions. Any experinces??

Is it worth waiting a year or two for even cheaper, more robust, more effective panels??

Charging is a complicated issue I think. I cant find solar Nicd charges on the market. It might be possible to use a ordinary solar inverter and connect this to the cra*s buildt in charger. But I dont know if the charger would like such small currents that a solar array can deliver (the charger draws 10A when connected to the 230V net), and I dont know if the controllers can be reprogrammed such that the "car can drive when the charger is attached": of course I want solar power also when driving. And the charger's effeciency is probably around 75%. Togheter with the inverter*s effecincy the total charging efficiency is about 60%...

Any comments?? Better solutions??

Please tell me about similar projects that I can get som good inspiration;-)

Best regards

Bendik. Norway