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IssacZachary
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Solar to CHAdeMO solar trailer?

Fri Jan 20, 2017 8:43 pm

Doing some calculations here it seems like it would be not only possible, but actually feasible to tow around as much as a 6kW solar trailer or even more with a CHAdeMO plug. The trailer would have to fold up of course, and then be unfolded to plug in and charge. It would also have to be a huge trailer when unfolded, or possible several solar panels set onto the ground. I calculate an estimated 480 square feet of PV panels. An 8' x 20' trailer that has three stacks of solar panels could be put together. The stacks could easily slide out from each othe making a 24" x 20" panel. Or it could be folded even more. For an example 24 of 4' x 5' panels stacked on top of each other. If made thin enough, like 1/2 inch, 48 of 2' 6" x 4' panels could even fit inside the car!

Solar can be done for as little as $1 per watt or even less nowadays. I was noticing PV kits for as little as $250 per kilowatt with everything except glass and frames. If there were a cheap but sturdy solution to glass and frames, with a 1,000lb trailer only costing $250, and the CHAdeMO plug being around $1,300 this is starting to look feasible. The book to CHAdeMO protocol costs some $160. The solar cells can be arranged in a 400V DC configuration. Of course a lot of small panels would require a lot of high voltage DC connectors. But 600V DC connectors aren't that expensive actually.

Besides a cheap and lightweight glass and frame system that's foldable and able to be angled towards the Sun, what I'd also be lacking is a way to control the current and the CHAdeMO communications. Of course most of the time the solar panels will likely put out much less current than called for by the Leaf, so it may be as easy as a simple contactor that shuts off when charging voltage gets high after 80% instead of ramping down the current at that point. Then the panels can be folded up and stored away and the Leaf would have another 60 or 80 miles to go again anywhere there's sunlight. A backup generator could also be taken along on the trailer.
2013 SL 50,000 miles.
12 bars until 44,300 miles on June 2, 2017. :D
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The Nissan Leaf is the fourth best long distance car for highway driving. >>Best Long Distance Cars<<

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TonyWilliams
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Re: Solar to CHAdeMO solar trailer?

Sat Jan 21, 2017 6:52 pm

If the solar output or limited to something below 395 V you'd probably be OK at super low amps.

Are you going camping, or out to the desert (some place that has no electricity?)

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IssacZachary
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Re: Solar to CHAdeMO solar trailer?

Sat Jan 21, 2017 7:53 pm

TonyWilliams wrote:Are you going camping, or out to the desert (some place that has no electricity?)

Yes yes and yes.

I love to camp, there are lots of barren wastelands around, and many roads where even gasoline stations are few and far apart. And we generally get lots of sunshine year round.

I do realize that there are several disadvantages to what I'm proposing. But if the Solar Taxi can do it, why can't I?
2013 SL 50,000 miles.
12 bars until 44,300 miles on June 2, 2017. :D
11 bars current. :)
The Nissan Leaf is the fourth best long distance car for highway driving. >>Best Long Distance Cars<<

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JeremyW
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Re: Solar to CHAdeMO solar trailer?

Sat Jan 21, 2017 8:06 pm

CHAdeMO doesn't support a "dynamic" charge from a charger at least in the 0.9 spec. The protocol dictates that the charger tell the vehicle how much maximum current it supports, but that value is not suppose to change during the charge session. You will probably need some small amount of storage to make it work, or charge very slowly using less than the MPPT of the panels you have to provide some reserve.
Former 2012 SL leasee 6/23/12 - 9/23/15
Now driving Honda Fit EV, License plate: CHADEMO
2000 Honda Insight for long trips

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IssacZachary
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Re: Solar to CHAdeMO solar trailer?

Sat Jan 21, 2017 8:11 pm

JeremyW wrote:CHAdeMO doesn't support a "dynamic" charge from a charger at least in the 0.9 spec. The protocol dictates that the charger tell the vehicle how much maximum current it supports, but that value is not suppose to change during the charge session. You will probably need some small amount of storage to make it work, or charge very slowly using less than the MPPT of the panels you have to provide some reserve.


I was afraid of that. Any idea of what would happen if the current varied during the charge? I guess the car would detect it and just shut everything down. Correct?
2013 SL 50,000 miles.
12 bars until 44,300 miles on June 2, 2017. :D
11 bars current. :)
The Nissan Leaf is the fourth best long distance car for highway driving. >>Best Long Distance Cars<<

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TonyWilliams
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Re: Solar to CHAdeMO solar trailer?

Sat Jan 21, 2017 8:51 pm

IssacZachary wrote:
JeremyW wrote:CHAdeMO doesn't support a "dynamic" charge from a charger at least in the 0.9 spec. The protocol dictates that the charger tell the vehicle how much maximum current it supports, but that value is not suppose to change during the charge session. You will probably need some small amount of storage to make it work, or charge very slowly using less than the MPPT of the panels you have to provide some reserve.


I was afraid of that. Any idea of what would happen if the current varied during the charge? I guess the car would detect it and just shut everything down. Correct?


Yes, if the vehicle saw that the actual current differed by the CANbus reported value, the car would shut it down. The assumption is the charger is not controllable.

The CANbus data stream is in 100ms intervals.

You could write a program that varied the maximum charger current, because that's the only way it will make sense to the car, up to the max amps reported to the car from the charger.

So, the initial exchange would be the car saying it wants to receive up to 125amps, then the charger would respond with a 1 amp max message.

When the contactors close, you need to be able to ramp up at rate not to exceed 20 amps per second. The LEAF may or may not be ok with 20 amps instantaneously, that's why I picked 1 amp. That will take experimenting.

You could control the DC output with shutters on the panels, but I f you can't get the CANbus message and the current flowing within 100ms, it might not work. I am speaking from experience here by the way ;-)

Perhaps you could have an alternate load (like a battery) with similar impedance that would get the current flowing, then switch over at exactly the right moment

Then open your shutter VERY slowly to add extra amps, and make your CAN message follow the actual amps as the maximum allowed by the charger. The slower, the better, until you hit max power of 20 amps. By the way, the 2011-2012 LEAF might not be able to do this, but newer ones should.

Honestly, I think you'll find that you need a way to manage the DC output to make this work, but who knows? You might also be ok with ON / OFF at whatever amps are available with a 1 up to 20 amps initial ramp CANbus message, then immediately adjust the max amps from 20 to whatever is actually flowing, and adjust every 100ms.

Why not do this the EASY, far cheaper and simple way? Solar with a battery and off-grid inverter, then plug in with a normal J1772.

You will have to actively regulate the J1772 pilot signal to match the actual output of the solar, and the relatively small battery will give you some buffer.

The only real design work is the load regulator. We can help you with that. The rest is commercially available parts.

Do you want to plug in, or be a science experiment?

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IssacZachary
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Re: Solar to CHAdeMO solar trailer?

Sat Jan 21, 2017 9:52 pm

TonyWilliams wrote:Why not do this the EASY, far cheaper and simple way? Solar with a battery and off-grid inverter, then plug in with a normal J1772.

You will have to actively regulate the J1772 pilot signal to match the actual output of the solar, and the relatively small battery will give you some buffer.

The only real design work is the load regulator. We can help you with that. The rest is commercially available parts.

Do you want to plug in, or be a science experiment?


Well if a little solar to CHAdeMO is all too complicated and expensive and the solar to inverter to EVSE is cheaper and easier to do then by all means let's do that!

I was under the impression that solar to CHAdeMO would have been cheaper since there would be no inverter needed. Which brings up an important question I've always had. Wouldn't I need a more expensive pure sine wave inverter? I've always been under the impression that modified inverters could damage the Leaf. Also if I had a backup generator, wouldn't out have to be of an inverter type?

Of course if I had a PV array and a backup generator I'd only need one inverter, a 12V or 24V or 48V battery and an engine with a high output 12V or 24V or 48V alternator for the backup generator.

Also, Thanks a bunch for the info and help!
2013 SL 50,000 miles.
12 bars until 44,300 miles on June 2, 2017. :D
11 bars current. :)
The Nissan Leaf is the fourth best long distance car for highway driving. >>Best Long Distance Cars<<

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TonyWilliams
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Re: Solar to CHAdeMO solar trailer?

Sun Jan 22, 2017 1:02 pm

IssacZachary wrote: Well if a little solar to CHAdeMO is all too complicated and expensive and the solar to inverter to EVSE is cheaper and easier to do then by all means let's do that!

I was under the impression that solar to CHAdeMO would have been cheaper since there would be no inverter needed. Which brings up an important question I've always had. Wouldn't I need a more expensive pure sine wave inverter? I've always been under the impression that modified inverters could damage the Leaf. Also if I had a backup generator, wouldn't out have to be of an inverter type?

Of course if I had a PV array and a backup generator I'd only need one inverter, a 12V or 24V or 48V battery and an engine with a high output 12V or 24V or 48V alternator for the backup generator


The AC powered method is proven off-the-shelf technology; no surprises. The unregulated DC straight into a battery through a digital protocol is a huge experiment that could cost a lot of headache and a lot of money and may never be able to work the way you envision it.

Since it appears you'd rather charge more than experiment, let's stick with the easy way.

1) You need an EVSE with an REAL-time adjustable pilot signal. You will have to build this.

2) You need the solar panels

3) You need a trailer to haul it all on

4) You need a trailer hitch for your LEAF

5) You need some batteries, which can be lead acid deep cycle. Do not use automotive batteries

6) You need an (off-grid) inverter. I'm going to specify the Outback GFX1548 that is SUPER flexible. You can stack them in parallel, series, 120vac, 240vac, 208vac, etc. Each one is 1500 watts with 48vdc input. You can augment with a generator or other AC power source.

You need to size this inverter based on the anticipated power available, which we will start at 12 amps / 120vac with just ONE of the above inverters. You don't even need the solar yet to see this work.

Buy four 12 volt storage batteries and connect in series, buy the Outback GFX1548 inverter, and plug in the original LEAF charge cable to the LEAF.

It should charge the LEAF. Add as much solar as necessary to maintain the batteries to continue at a 1.44 kW charge rate. This entire thing is modular and expandable, so you can build from there. Add an additional inverter, more batteries, and more solar, and charge at 2.9kW. As big and expensive as you need.

But start at 1.44kW.

Special note for summer desert operations: the inverter’s maximum wattage will derate in temperatures above 77 °F (25 °C)

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IssacZachary
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Re: Solar to CHAdeMO solar trailer?

Mon Jan 23, 2017 10:09 am

¡Thanks!

I really like the modular add-on idea! It would be a little by little!
2013 SL 50,000 miles.
12 bars until 44,300 miles on June 2, 2017. :D
11 bars current. :)
The Nissan Leaf is the fourth best long distance car for highway driving. >>Best Long Distance Cars<<

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