T-Pain Is On A Boat: Re: [Electric Boats] Solar Catamaran Project

Sunday, September 6, 2015

Re: [Electric Boats] Solar Catamaran Project

With nominal 30V panels he's only going to have two panels in series and then all the series sets in parallel so the gain in avoiding partial shading with micro inverters is not going to be that great. I don't see the justification in adding the complexity and cost of a micro inverter system. Especially since his traction system is DC to begin with.

And you would miss out on the advantage gained by the MPPT technology which can be quite significant.

I just don't see how micro inversion would provide much advantage in this application and it would certainly add signicant cost and inversion losses going back and forth from DC to AC to DC. Not to mention all those micro inverters are going to be subjected to a marine environment, ie.the possibility for salt water frequently splashing on the panels and all those attached micro inverters (or converters). Just sound like a lot more component to potentially fail to me.

Micro inverters are great but I don't see it as a significant advantage or worth the extra expense for this type of system.

Capt. Carter

www.shipofimagination.com

On Sunday, September 6, 2015 8:54 PM, "Jason Taylor jt.yahoo@jtaylor.ca [electricboats]" <electricboats@yahoogroups.com> wrote:

One theoretical advantage of the individual panel micro inverters is partial shading of a series array of panels. If each panel has its own micro inverter, a shaded panel won't bring down the whole string. On a sailboat with a mast and rigging, it's pretty darn easy to get partial shading across a panel and if it's in series with a bunch of others then the whole string could suffer. I would see the micro inverters as a way of banking as much power from each panel as you can. And as the microelectronics get more efficient (and cheaper), I don't doubt that this is how things will trend. Also, the inverter doesn't have to mean that it converts to 120VAC. It could also just mean that it uses a double inverter to convert DC voltages. Syncing the waveforms of a bunch of discrete inverters onto an AC buss would be a coordination nightmare and may wind up being more expensive than just using micro DC/DC converters at each panel that output a common desired voltage on the DC buss.

/Jason

On Sep 6, 2015, at 20:03, Carter Quillen twowheelinguy@yahoo.com [electricboats] <electricboats@yahoogroups.com> wrote:

If he's going to charge batteries why would he want a micro inverter? Then he would be going from DC to AC and then back to DC again. Unless he's feeding it into a fancy BMS that needs 120V AC to operate I don't see the point and even then is seems like way to much conversion.

I think your best bet would be something like an Outback Flexmax 60 or 80. They can be programmed to essenital be a Battery Management System and you get the advantage of MPPT with minimum conversion. And it would be lot cheaper than micro inverters feeding into a 120V AC fe d BMS and then feeding your motor from that.

You can series your panels in sets of two or three to get your voltage where you need it and then gang them together in parallel. Outback is the vendor of choice for a lot of solar boats but there are certainly several good MPPT charge controller to choose from and I would strongly recommend going with an MPPT controller. Way better than PWM as they really optimize your array to get the most power possible to your motor when you running directly off the sun.

Capt. Carter
www.shipofimagination.com

On Sunday, September 6, 2015 2:11 AM, "Hannu Venermo gcode.fi@gmail.com [electricboats]" <electricboats@yahoogroups.com> wrote:

Very interesting project.
Nice set of gear, updates are very much appreciated.

On 02/09/2015 03:36, albert682@yahoo.com [electricboats] wrote:
> Hi Group :)
>
> Just an update on the 8 Metre Solar Catamaran Project.

--
-hanermo (cnc designs)

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Posted by: Hannu Venermo <gcode.fi@gmail.com>
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