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Adding 200W 18V Panels to my Th!nk EV ~ needs a boost!

 
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Ok, so as it stands now, I find myself regularly charging my new-to-me 2011 Th!nk EV with a gas powered generator: Booooo!!

This situation has arisen because we live off-grid up in the mountains, and our batterey-inverter situation just isn't cutting it for charging with 110-120VAC. (I am considering a buck/boost converter to help with this situation too)  Our Honda eu2000i will charge it just fine but...  Gasoline!  *Planetary belch!

So I just bought (forgive me this bit to global-manufac) two 100W, 18V panels, thin flexible ones that together weigh less than 10 lbs.  This little Th!nk has a roof rack on it, and I am planning to devise some system for being able to clip these panels onto the roof rack with an easy adjustment for side to side movement (for aiming at the sun). It will give the flexi panels a bow, so they will be arodynamic-ish, if I want to drive around with them, but I could also pop them off and use the roof rack for gathering supplies.

I don't care that it's going to take a ridiculously long time to charge the car (24kwh/200w=120hrs of full sun, or 15 days). I only need to charge it up an extra 10-20% to make it over the hump and get back to town (I have only been charging with the Genny for a few hours here and there.) So with my real charging need being about 15% of the total capacity, I will need about 3,600 Watts from these little panels, so I figure ...  5 days in Winter if I'm lucky? Something like 1-2mi/day in Winter maybe? Booya! I'm gonna make it...

My big question is this....  how am I going to custom diy (on the skinny) the boost converter these panels will need to direct DC-DC charge this batterey.  (F a charge controller more complex than a manual on/off switch and a voltage read-out)

I can't even figure out what the nominal charging voltage is for the drive battery on a 2011 Th!nk ~ not much information out there since they were discontinued so quickly...?  But I figure I will get the voltage once I pull the seats out and get in there.  So with my two panels in series I will need to go from 36V to... ? (Guessing something in the 250-400V range?)

Only needs to be 200W beefy...  maybe 400 watts, because I might plug it into some more panels when it's parked at home. I just don't know enough about electronics to really understand this buck/boost converter schematic I downloaded. I don't understand what components I would need to change/adjust to modify the parameters I am trying to effect. So help me self-learn! Where can I get some basic electronics learning materials which might include for-dummy in depth explanations of this type of circuitry?

I have heard of brilliant people like Duncan on the diy EV conversion forums making their own motor controllers, and I am so inspired by this! I am not there yet, but I also don't feel terribly far away in my e.skills.  Maybe DIYing a 400W Voltage Boost converter would be in the scope of salvaging components from TVs / microwaves?  Perhaps it would be an approachable entry-level project compared to motor/speed/regen controllers, and sound synthesizers?

So help me help myself!  Any advice or ways to get started?  I have these panels on hand ... The only thing stopping me, from retiring this petrol-genny, is a little know-how and hopefully a very little $.
Filename: Buck_Boost-Voltage-Converter-Schematic-Circuit-Diagram.pdf
File size: 257 Kbytes
 
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Location: pietermaritzburg, South Africa
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forest garden chicken bee
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id say if you are not skilled in electrical/electronics that you shouldent be messing with a 400v battery pack if say the easiest/cheapest way for you would be to feed the power from the pannels via an mppt charge controler into a small battery then charge the car off of a 240v inverter running off of that
 
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Location: Abkhazia · Cfa (humid subtropical) - temperate · clay soil
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cat forest garden trees solar wood heat woodworking
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A quick search suggests that your car uses a "48V eltek flatpack". Connecting the solar panels via a DC-DC charge controller sounds much better to me.
 
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How much did you pay for those 100W panels?  What I've discovered is you get far, far better deals with newer grid-tie panels.  Earlier this year I was buying panels in 1000W groups for about 220$.  These purchases were from local Craigslist sellers.  I ended up buying panels for both myself and the neighbors using solar.  The key to getting good deals in solar is to buy local, with local pickup, so you skip shipping charges.  The shipping on some panels is higher than the panels themselves.

As Brian says though, if you don't know much about electricity, you're better off sticking with off-the-shelf parts.  Magnum, Outback, and Schneider all make standard 120/240VAC split-phase inverters designed to be whole-house wired.  That means the inverter is connected directly to the house panel rather than having plugs you plug into.

It's all doable, with the right design.  Just don't run off half-cocked and start buying random stuff just because it looks good.  Design first, purchase second.
 
pollinator
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Location: Nomadic
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If I recall correctly the Think has a 72 volt battery. That’s within the capability of commonly available and cheap buck boost DC-DC converters.
 
I found some pretty shells, some sea glass and this lovely tiny ad:
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