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Off-grid Solar Charging?

Discussion in 'Model S: Battery & Charging' started by javawolfpack, Aug 3, 2016.

  1. javawolfpack

    javawolfpack Member

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    So I enjoy backpacking & getting into the wilderness. I was curious if anyone has any thoughts on if solar systems like this Indiegogo project: https://www.indiegogo.com/projects/the-kodiak-off-grid-home-solar-system-in-a-box#/

    I'm curious if it might be capable of charging the Tesla at a trailhead while I'm out enjoying the wilderness. Might need to build some kind of lockbox to keep the solar system from being stolen but otherwise... Thoughts? I had the idea if I got a Model X that maybe a system could be hooked up to the accessory/towing hitch to lock/hold the solar panels while parked.
     
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  2. PtG62901

    PtG62901 Member

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    I have few answers, but this is an interesting idea, so I have questions. I don't see how it wouldn't be stolen, but a Harbor Freight solar setup that drives a standard 110 plug should work under perfect conditions? They have systems marketing toward RV's, that should fit in a MX. I have read other threads about people using generators, and how the car decides how much current is available and doesn't really adjust after that, but I'm not sure how that works. I wonder if you put the system out, a cloud goes over and you get no current, and the car doesn't charge anymore? Or a cloud goes over, and it stays at the lower level? If you figure it out, please let us know.
     
  3. cronosx

    cronosx Member

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    In the better case it needs 1 day to charge 1kw.. since you have at least 60kw, i would say this is fine if is all sunny and you need to charge the tesla in 60-80 days.. ?
     
  4. javawolfpack

    javawolfpack Member

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    @cronosx I'm not saying this is the solution... agree it's a bit low powered, but the charge for the battery can be reduced with more panels. I'm definitely going to keep thinking on this, but agree issues such as what happens as the solar power varies due to cloud cover/etc... How to insure it isn't stolen easily... And how to generate a reasonable amount of power (at least a wall outlet amount while there is sunlight).
     
  5. Electric700

    Electric700 Member

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    You can add solar panels to the system, but you'd need almost 30 of them to charge at 4 miles / hour at 120 V and 12 A (1440 W / 50 W per panel = 29 panels). I'm not sure that many panels would be supported, so lowering the car's current might be necessary. Also there's the question of whether the Mobile Connector might detect a line issue and prevent charging, so some testing would be needed.

    Very interesting though! I think it's a great idea.
     
  6. Rocky_H

    Rocky_H Member

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    Yeah, I doubt this has a real ground, so the mobile charge cable almost certainly won't like it.
     
  7. javawolfpack

    javawolfpack Member

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    That's easy... literally run a line into the ground :) But yeah honestly think might be something that has to be designed from the ground up.
     
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  8. ShockOnT

    ShockOnT Quickish

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    I was considering this same question! Imagining being stuck in the Australian desert with nothing but my wits and a solar panel :)
    1 x 250W panel would give about 1.25kwh per day, so about 6km (4miles) if driven slowly. Better than nothing!
    Plus you could fit perhaps 10 panels in the back with the seats down, getting about 60km/day range (Martian-style)...
     
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  9. javawolfpack

    javawolfpack Member

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    I'm definitely going to keep thinking on it... might need to devise a novel solution vs finding something pre-built. But agree some locations are so remote that even a wall outlet isn't an available charging option.
     
  10. cronosx

    cronosx Member

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    I would say that if you find yourself in this situation you have done something wrong.. something really really wrong.

    If you really must, must, do it, do it with a normal generator. yes, of course using the solar is good etc etc, but this is being stubborn.
    In case of an emergency you need something really really reliable. the sun isn't.

    This kit is good for a caravan, being out camping etc when you need little power, but not for charging an electric car that need tons of power
     
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  11. ShockOnT

    ShockOnT Quickish

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    Was just a thought experiment :)
    Perhaps post-apocalyptic Tesla usage? Also, silent vehicles useful for sneaking past zombies.
     
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  12. javawolfpack

    javawolfpack Member

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    If you are going to be away from the vehicle for possible upwards of a week while in the back country the intermittent solar charging may be more than adequate. Also a generator only runs while you have fuel... what if you ran out of fuel or as @ShockOnT joked are in a state of society where generator fuel may not be available. Solar has the downside of needing the sun to be out to generate power; however, as long as the sun is still there you have "fuel" for the solar generator... and if the sun isn't there I think we have serious other problems.
     
  13. AB4EJ

    AB4EJ Member

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    Whether a few solar panels is useful for charging a Tesla while parked kind of depends on how much charge you have left when you park the car, length of the stay, and how much charge you need to get to the next charging point after the camping outing. Even the best panels are not all that efficient... all the charge you can realistically apply may be only enough to replace your vampire load.

    If it were up to me, I would try to arrive at my trailhead with enough charge to be able to get to next charge point after the camping outing even with vampire losses... then play with a solar panel or two and see how your charge differs from your calculated charge without it. I wouldn't depend on the panels (at least, until after I had tried it a few times first)...
     
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  14. LoL Rick

    LoL Rick Like Buttah

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    TL;DR: not likely anytime soon

    I have a 10kW home solar system with 2 SMA Sunny Boy 6000 Inverters. The cool thing about these inverters is that they each have an outlet for emergency use when the grid is down. Although they advertise a 1500W capacity, the reality is that the power is far from stable and the Tesla UMC doesn't handle that very well. I did some experiments with off-grid mode and car charging, and found that even the lowest amperage setting on the car eventually experienced enough faults that it would stop charging. I think it would recover for about 5 or 6 instances of the inverter cutting power because it could not keep up, but then the charge port would turn red and I had to unplug/replug to get it to charge again. This was with a rooftop 5kW setup in Florida, so I find it highly unlikely that you'll get anything useful out of a portable rig. You could walk to civilization faster than charging by portable solar.

    SUNNY BOY 3000TL-US / 3800TL-US / 4000TL-US / 5000TL-US / 6000TL-US / 7000TL-US / 7700TL-US
     
  15. cronosx

    cronosx Member

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    I would say it's easied to sneak out some tank of gas than stay in the broad daylight for days :D

    If you want to play it theorical.. fine, but again, try let's say in 10 years, maybe the panel efficency has gained something
    but for now, it's totally useless

    The best shot, if you really want to do it ( albeit inefficent ) is to store the solar power in battery, then use the battery to charge the car at regular interval for short period.
    Just say you have a 5kw battery thas is being charged from the solar panel, then, you charge the car from this battery for.. let's say 1h? then you shut it down for 5h, then again, 1h, then of course it's night, and you try again the day after.
    this could be planned i suppose.. but it's really prone to problem

    I also suppose that, if we just put it in the theorical planet, you don't really need to togle the cable and put it in again, this is a software choice ( the need to disengage ), so you can remotely reset it ( maybe you need root access or similar )
     

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