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 Post subject: Portable solar trickle charger
PostPosted: Tue Aug 14, 2018 6:53 am 
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Joined: Mon Oct 02, 2017 8:56 am
Posts: 46
I don't know if this exists or not, or could possibly be cobbled together with parts.

Say that you want a solar J1772 trickle charger that doubles as a sun shade. You carry the rolled or folded solar panel in the back, and when you park, pull it out and unfold/unroll it from the roof down over the windshield and the hood. Plug in the J1772 cable in the corner. It should include a cable lock of some sort, and there should be a way to tie it down so it won't blow or slide off.

Does this exist? If so, does anyone know where it's sold?

If it doesn't exist, and you wanted to make one, any ideas on where to get the appropriate parts? Assume for the sake of argument that you don't care how much charge it actually generates as long as it's enough to signal the J1772 and put the car in charging state. Also assume for the sake of argument that you don't care how much it costs, just whether it's possible. And assume that you don't care how much carrying it around would reduce your range (although you do care how difficult it is to roll/unroll or fold/unfold, and it must fit entirely on top of the car, including roof/windshield/hood, and it must fit in the back when rolled/folded).


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 Post subject: Re: Portable solar trickle charger
PostPosted: Tue Aug 14, 2018 7:45 am 
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Joined: Wed Jul 11, 2018 9:38 am
Posts: 12
Assuming best case angled mount full southern summer sun all day in California with a top quality residential roof mount (40 lbs) Panasonic panel you're looking at 2KWh a full day vs 12 minutes on a 40amp LV2. Even before dealing with trying to feed the system enough min amps to even start. You'd probably have to design a system to feed that non standard amount of power through the regenerative braking system like the Jdemo does which requires the RAV to be turned on at the time.

Better off getting a (70 lbs) Yeti portable 3KWh battery system to recharge Rav @12amps 120V using the standard cable. Yeti offers solar panel systems to recharge the battery. Just depends on your purposes. Though that will be a lot of weight and cargo space used.

Flexible solar cells creating reasonable power at a reasonable price are still years away.


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 Post subject: Re: Portable solar trickle charger
PostPosted: Tue Aug 14, 2018 3:32 pm 
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Joined: Wed Nov 14, 2012 9:50 pm
Posts: 4075
Location: San Diego
The 70 pound trickle charger is ridiculous.

Also, if you’re going to charge the car with it on, you’ll need DC power, not AC.

JdeMO™ does not use regenerative braking, nor does it use the motor at all all.

All the trickle solar charging ideas are extremely slow and very expensive.

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 Post subject: Re: Portable solar trickle charger
PostPosted: Tue Aug 14, 2018 3:37 pm 
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slorav4 wrote:
Assuming best case angled mount full southern summer sun all day in California with a top quality residential roof mount (40 lbs) Panasonic panel you're looking at 2KWh a full day vs 12 minutes on a 40amp LV2. Even before dealing with trying to feed the system enough min amps to even start. You'd probably have to design a system to feed that non standard amount of power through the regenerative braking system like the Jdemo does which requires the RAV to be turned on at the time.

Better off getting a (70 lbs) Yeti portable 3KWh battery system to recharge Rav @12amps 120V using the standard cable. Yeti offers solar panel systems to recharge the battery. Just depends on your purposes. Though that will be a lot of weight and cargo space used.

Flexible solar cells creating reasonable power at a reasonable price are still years away.


Thanks for the reply. The vision would be to haul the thing out of the hatch, lay it over the car like a sun shade or car cover, and keep the car cool while maybe adding a mile or two to the range, if it was left on all day. It wouldn't be very effective, but it could be used anywhere. Sounds like there needs to be some advances in panel technology before it'll be possible.


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 Post subject: Re: Portable solar trickle charger
PostPosted: Tue Aug 14, 2018 3:42 pm 
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TonyWilliams wrote:
All the trickle solar charging ideas are extremely slow and very expensive.


The idea here is to shade the car from the heat, and possibly gain a mile of range while doing it. I wasn't picturing doing DC->AC->DC using a "system" and an EVSE, I was picturing a cable with a J1772 plug that came directly off the corner of the "shade".


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 Post subject: Re: Portable solar trickle charger
PostPosted: Tue Aug 14, 2018 3:43 pm 
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Joined: Wed Nov 14, 2012 9:50 pm
Posts: 4075
Location: San Diego
AgingHippie wrote:
TonyWilliams wrote:
All the trickle solar charging ideas are extremely slow and very expensive.


The idea here is to shade the car from the heat, and possibly gain a mile of range while doing it. I wasn't picturing doing DC->AC->DC using a "system" and an EVSE, I was picturing a cable with a J1772 plug that came directly off the corner of the "shade".


I guess we start with, “How much money do you have to spend?”.

Of course, it can be done. There’s not much that cubic dollars can’t fix.

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1780-104 La Costa Meadows Drive
San Marcos, California 92078 USA
tony@QCcharge.com
www.QCcharge.com
Twitter: QCPower
1-844-EV-PARTS
1-844-387-2787
1-760-798-0342 Office
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 Post subject: Re: Portable solar trickle charger
PostPosted: Tue Aug 14, 2018 4:04 pm 
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TonyWilliams wrote:
Of course, it can be done. There’s not much that cubic dollars can’t fix.


Seems like flexible solar panel technology is an obstacle for now. I have a small folding set of panels that can charge a phone using about 2 SF, but they aren't actually flexible, they're just connected by a fabric frame. Also, there's the question of minimum power levels to trigger the car to enter charging mode. I saw an incomprehensible table about this, and I wasn't able to decipher what the minimum power would be to raise and detect the signals - I know the L1 that comes with the car uses 12A, but does it have to be that high to signal properly? When I plug into a Chargepoint, it starts charging at .01, then jumps after a few seconds to the capacity of the unit; could it have continued charging at .01 or would the onboard charger have detected a failure and stopped?

As an aside, I didn't picture this item as specific to any one model of EV, I was thinking more of a general EV accessory that could provide shade and the tiniest trickle charge to any EV with a standard J1772 plug.


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 Post subject: Re: Portable solar trickle charger
PostPosted: Tue Aug 14, 2018 4:14 pm 
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Joined: Wed Nov 14, 2012 9:50 pm
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Location: San Diego
You didn’t mention how much money you had to spend for this.

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QC Charge
1780-104 La Costa Meadows Drive
San Marcos, California 92078 USA
tony@QCcharge.com
www.QCcharge.com
Twitter: QCPower
1-844-EV-PARTS
1-844-387-2787
1-760-798-0342 Office
Hours M-F, 9-5 Pacific Time


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 Post subject: Re: Portable solar trickle charger
PostPosted: Tue Aug 14, 2018 6:27 pm 
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Joined: Mon Apr 01, 2013 11:42 pm
Posts: 308
Location: San Diego, CA, USA
AgingHippie wrote:
TonyWilliams wrote:
Of course, it can be done. There’s not much that cubic dollars can’t fix.


Seems like flexible solar panel technology is an obstacle for now. I have a small folding set of panels that can charge a phone using about 2 SF, but they aren't actually flexible, they're just connected by a fabric frame. Also, there's the question of minimum power levels to trigger the car to enter charging mode. I saw an incomprehensible table about this, and I wasn't able to decipher what the minimum power would be to raise and detect the signals - I know the L1 that comes with the car uses 12A, but does it have to be that high to signal properly? When I plug into a Chargepoint, it starts charging at .01, then jumps after a few seconds to the capacity of the unit; could it have continued charging at .01 or would the onboard charger have detected a failure and stopped?

As an aside, I didn't picture this item as specific to any one model of EV, I was thinking more of a general EV accessory that could provide shade and the tiniest trickle charge to any EV with a standard J1772 plug.

Yeah, you're not getting it. The minimum the J1772 standard can handle is 6a @ 120v. The on-board charger is completely unable to deal with the tiny amounts of power you would be able to generate from a portable solar panel. You'd have to do a custom charger connected to the battery directly to have any prayer of getting your few miles of charging. It's a complete non-starter, which is why no one has done it.


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 Post subject: Re: Portable solar trickle charger
PostPosted: Wed Aug 15, 2018 4:48 pm 
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Joined: Wed Aug 13, 2014 8:30 pm
Posts: 275
Location: San Diego Co
So you would need a minimum of 720 watts AFTER conversion available to the car (so only when sun is high, like 1am to 1pm, or maybe 2 kW of panels so it works most of the day), inverter to convert to 120 VAC, then provide the signal telling the car how much power is available. So at least 3 but probably 6 350 watt panels. I don't think 350 watt panels are flexible yet, and they still cover near 20 square feet each? At least that's how I see it.

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