Question about transporting panels and how much heat they can take

LoougleLoougle Registered Users Posts: 10
I have a 15w solar panel w/ a 7amp controller

http://cgi.ebay.com/15W-12VOLT-SOLAR-PANEL-BATTERY-CHARGER-7-AMP-CONTROLLER-/400105207280?pt=LH_DefaultDomain_0&hash=item5d2820f5f0#ht_3416wt_933

bought this

going to be taking it to Coachella Music Festival in April in Indio, CA

temperature get up to 100+ degrees. I was wondering what's the best way to transport the panel, I am having a custom made canvas case made but do I need cushion for it? or what padding should I get.

Also how much heat can it take? I was going to leave it in my car during the day and charge this battery pack I have but if I leave it inside the car will it be too hot?

Comments

  • BB.BB. Super Moderators, Administrators Posts: 29,696 admin
    Re: Question about transporting panels and how much heat they can take

    Temperature will not be ap problem for your panel (damage wise--solar panel output voltage does fall as panels get hot).

    Treat your panel like window glass. Any hard hits, scratches, twisted frames will shatter the glass.

    Otherwise, a 15 watt panel is very small amount of power. Are you sure 60 watt hours or 5 amp hours at 12 volts going to be useful for your needs?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • LoougleLoougle Registered Users Posts: 10
    Re: Question about transporting panels and how much heat they can take
    BB. wrote: »
    Temperature will not be ap problem for your panel (damage wise--solar panel output voltage does fall as panels get hot).

    Treat your panel like window glass. Any hard hits, scratches, twisted frames will shatter the glass.

    Otherwise, a 15 watt panel is very small amount of power. Are you sure 60 watt hours or 5 amp hours at 12 volts going to be useful for your needs?

    -Bill


    Melting wouldn't become an issue would it?

    Yeah basically we will only be at our for a few hours throughout the festival and we only really want it to charge our cell phones, and small uses, the battery pack we are using says it can power a - Camcorder (8w): 24hr

    are cell phone batteries are about 3.7v so roughly 4w would be double that amount, so then using the solar charger it should just keep the battery charged and going for the 4 days we'll be there?

    thoughts?
  • BB.BB. Super Moderators, Administrators Posts: 29,696 admin
    Re: Question about transporting panels and how much heat they can take

    I don't know about your panels--but the typical good quality solar panel is designed for +85C maximum (185F) maximum... Should not be a problem.

    Roughly, thin film panels are about 1/2 as a efficient as crystalline panels--so they are 2x the area as the more expensive panels.

    Also, if these are glass panels, make sure they are well staked to the ground (or mounted to the car) so they don't blow over in a wind storm/somebody tripping on the cord. Typically the panels will quickly fail if the glass/plastic covering is broken/pierced.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Question about transporting panels and how much heat they can take

    wow, they still make these pvs.:confused: it should not be outside exposed to winds or possibly even rain/snow, but the sun won't hurt it. i bought one of these pvs many years ago in the 90s at a hamfest (ham radio fleamarket) for about $40. the seal on them is questionable and that's why i stated about rain/snow possibly being a problem.

    i do hope the supplied controller works without being connected to a 12v battery as some require a battery to be present. if it works ok without the 12v battery it will still take time to charge items connected to it as most chargers are not fast chargers. some are and if the pv can deliver the power your battery could be fully charged by it in a day. if you over-extend the loads to be charged, ie too many watts needed as compared to how many watts delivered, then it will take a longer time than what the chargers normally would need. of course if a charger states it takes 16hrs to charge then don't count on it charging in a day as possibly 3 or more days of full sun are needed to fully charge the battery.
  • LoougleLoougle Registered Users Posts: 10
    Re: Question about transporting panels and how much heat they can take

    Yeah due to the fact there could be winds and the fact that I don't want anyone to easily steal the panel I was going to put it on the upper part of the backseat in my car. so the rear window will hit directly to the solar panel.

    I'm using this, http://www.amazon.com/Wagan-400-Watt-Jumpstarter-Built-Compressor/dp/B000WJEPCI

    51cXSvLTgcL._SL500_AA300_.jpg

    The wall charger for it said the input was 15w w/ an output of 400w, obviously I won't be using all the charge the battery has nor will I be getting the largest charge ever with the solar panel but i'm hoping this will last me the weekend *crosses fingers*
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Question about transporting panels and how much heat they can take

    i now understand better what it is you have and the limit to the weekend at first will be the battery capacity. ideally that should only be half of the battery ah capacity to preserve battery life and i'm leery of their only giving cold cranking amps as that's for starting batteries and not deep cycle use.

    even if the battery would suffice would the pv give enough power to cover the loads you require as the battery needs to be fully recharged after discharging it.

    basically, i have no idea if that will work out for you.
  • LoougleLoougle Registered Users Posts: 10
    Re: Question about transporting panels and how much heat they can take
    niel wrote: »
    i now understand better what it is you have and the limit to the weekend at first will be the battery capacity. ideally that should only be half of the battery ah capacity to preserve battery life and i'm leery of their only giving cold cranking amps as that's for starting batteries and not deep cycle use.

    even if the battery would suffice would the pv give enough power to cover the loads you require as the battery needs to be fully recharged after discharging it.

    basically, i have no idea if that will work out for you.

    if I only use the battery pack during the day while it is getting solar charge, any idea how fast I would be depleting the pack (using let's say... 10v of energy) vs. how fast it would be charing?
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Question about transporting panels and how much heat they can take

    it doesn't quite work that way. power is measured in watts and watts is the result of multiplying the voltage and current. when that is done over time the watts becomes watthours like for example a load of 1amp at 12v for 1 hour is 1a x 12v x 1hr = 12amphours(ah). now you don't have a 10v battery and the voltage is going to be 12v. what will vary is your load current and the time it is drawn. it would be difficult for us to determine with accuracy what you may be able to do with it, but the power delivered to the battery over the course of the day by the pv will be a deciding factor in that. the output of a pv isn't a constant either due to weather and the general season it is along with such other things like if properly aimed and the amount of losses involved in the wires, cc, and other efficiency factors.

    i can take a rough guess and say maybe 0-5ah per day for anywhere from 0-60wh per day. so it may do something well one day and not the next depending on all of those factors and your loads. this isn't much help, but i'm afraid it's about the best we can say from where we sit.
  • LoougleLoougle Registered Users Posts: 10
    Re: Question about transporting panels and how much heat they can take
    niel wrote: »
    it doesn't quite work that way. power is measured in watts and watts is the result of multiplying the voltage and current. when that is done over time the watts becomes watthours like for example a load of 1amp at 12v for 1 hour is 1a x 12v x 1hr = 12amphours(ah). now you don't have a 10v battery and the voltage is going to be 12v. what will vary is your load current and the time it is drawn. it would be difficult for us to determine with accuracy what you may be able to do with it, but the power delivered to the battery over the course of the day by the pv will be a deciding factor in that. the output of a pv isn't a constant either due to weather and the general season it is along with such other things like if properly aimed and the amount of losses involved in the wires, cc, and other efficiency factors.

    i can take a rough guess and say maybe 0-5ah per day for anywhere from 0-60wh per day. so it may do something well one day and not the next depending on all of those factors and your loads. this isn't much help, but i'm afraid it's about the best we can say from where we sit.

    Interesting.... thanks for the help. Yeah if I end up taking my van it has a rack on the top I was thinking of using that rack as a way to prop the panel towards the direction of the sun as it passes through the day...

    gosh I really hope this works, not from a need stand point but it would definitely be comfortable to have some luxury while there.

    In the future, which panels should I be looking at buying, like... what's the cheapest route I can take to have this work fully functioning and have this suite my needs?
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Question about transporting panels and how much heat they can take

    you have to determine what the loads are better. add those all up and add another 30% at least due to the inverter efficiency and another 30% due to other inefficiencies which includes pv inefficiency. you may need even more than that, but i can't say for sure.
  • icarusicarus Solar Expert Posts: 5,345 ✭✭✭✭
    Re: Question about transporting panels and how much heat they can take

    the basic off grid calc that I use is this:

    Take the nameplate rating of the pv, divide that in half to account for all cumulative system loses, then multiply that by 4 and you can come up with a number to work with.

    For example a 45 watt panel might look like this: 45/2=22.5*4=90 watt/hours per day on average. In an RV installation the number is even worse, as the Pv is almost never ideally aimed at the sun, so ti might look more like this 45/3*4=60 wh/day.

    If you are starting with a cheap HF or Nortool PV it is probably worse than that.

    45 watt panel would be hard pressed to keep up with the parasitic and natural discharge of a battery of any size. I would guess it would be hard pressed to put out more than ~ 2 amps under full sun.

    T
  • LoougleLoougle Registered Users Posts: 10
    Re: Question about transporting panels and how much heat they can take

    What is the efficiency of Mono-crystalline panels?

    http://www.amazon.com/dp/B004FX1192/ref=pe_62810_18957840_pe_vfe_t4

    If I connected the 2 panels together would I get enough energy for what I needed?
  • BB.BB. Super Moderators, Administrators Posts: 29,696 admin
    Re: Question about transporting panels and how much heat they can take

    They are a couple percent more efficient than Poly-Crystalline panels. Basically, you can get a little more power from the same physical size panel.

    However 20 Watt Mono/Poly/Amorphous panels will all output pretty much the same amount of power into your battery bank (panel efficiency does not affect panel wattage rating).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • LoougleLoougle Registered Users Posts: 10
    Re: Question about transporting panels and how much heat they can take

    Ok so if I returned my previous solar panel then, I used

    http://www.newegg.com/Product/Product.aspx?Item=N82E16882260046

    and got 2 of them, using the previous formula it would be 100/3 x 4 = 133w/hrs a day

    Would that be enough to charge the battery to make it at least effective?
  • BB.BB. Super Moderators, Administrators Posts: 29,696 admin
    Re: Question about transporting panels and how much heat they can take

    I think your Wagan has a 18 AH 12 volt sealed battery in it... Rule of thumb is 5-13% rate of charge from solar.
    • 18AH * 14V charging * 0.05 * 1/0.77 derating = 16 watts
    • 18AH * 14V charging * 0.13 * 1/0.77 derating = 43 watts
    So, from a battery point of view, the "optimum" panel size would be around 15-45 watts... Your 100 Watts of panels will be very "significant" and will quickly recharge your battery.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • LoougleLoougle Registered Users Posts: 10
    Re: Question about transporting panels and how much heat they can take
    BB. wrote: »
    I think your Wagan has a 18 AH 12 volt sealed battery in it... Rule of thumb is 5-13% rate of charge from solar.
    • 18AH * 14V charging * 0.05 * 1/0.77 derating = 16 watts
    • 18AH * 14V charging * 0.13 * 1/0.77 derating = 43 watts
    So, from a battery point of view, the "optimum" panel size would be around 15-45 watts... Your 100 Watts of panels will be very "significant" and will quickly recharge your battery.

    -Bill

    To connect the two panels together do I just connect the 2 ends of each panel and place them together (obviously same color w/ same color) then get a wire that connects to the battery regulator then from the battery regulator to the battery?

    Big thanks to you guys, i'd be really confused right now about all this if weren't for everyone on this forum.
  • BB.BB. Super Moderators, Administrators Posts: 29,696 admin
    Re: Question about transporting panels and how much heat they can take

    Do you have any specifications for these panels? From one place, I saw Imp=3.3 amps which would be 15.15 Volts Vmp... These panels are designed to recharge a 12 volt battery bank with using a charge controller (if I have the right information).

    I kind of try to steer people away from amorphous panels except that you can get them very cheap.
    1. You are now have the choice of connecting the two panels in parallel and then recharging your Wagan--Which for short term use (like your plans) is probably just fine.
    2. Or, you can connect the two of them in series and get a small MPPT charge controller like the Morningstar SunSaver 15 Amp MPPT Solar Charge Controller for $250.
    3. If you had Vmp~17.5 volt panels, then you could have used a PWM charger like the Sunlight Solar Lighting Charge Controller 20-amp 12 volt for $135 and two the panels in parallel.
    Any of the above solutions is OK for short term usage. #2 can be done with your existing panels. #3 perhaps--if I have the wrong specifications for your solar panels you have on order and they really are Vmp=17.5 volt panels (which is "standard" for "12 volt" off-grid systems).

    It is probably too late now--But I highly recommend that you design the system around your needs first instead of trying to purchase bits and pieces and fit them together. There are a lot of specifications to review and match--And I am probably just going to frustrate the bejesus out of you with my "nit picking" and backtracking. Sorry:blush:

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • LoougleLoougle Registered Users Posts: 10
    Re: Question about transporting panels and how much heat they can take
    BB. wrote: »
    Do you have any specifications for these panels? From one place, I saw Imp=3.3 amps which would be 15.15 Volts Vmp... These panels are designed to recharge a 12 volt battery bank with using a charge controller (if I have the right information).

    I kind of try to steer people away from amorphous panels except that you can get them very cheap.
    1. You are now have the choice of connecting the two panels in parallel and then recharging your Wagan--Which for short term use (like your plans) is probably just fine.
    2. Or, you can connect the two of them in series and get a small MPPT charge controller like the Morningstar SunSaver 15 Amp MPPT Solar Charge Controller for $250.
    3. If you had Vmp~17.5 volt panels, then you could have used a PWM charger like the Sunlight Solar Lighting Charge Controller 20-amp 12 volt for $135 and two the panels in parallel.
    Any of the above solutions is OK for short term usage. #2 can be done with your existing panels. #3 perhaps--if I have the wrong specifications for your solar panels you have on order and they really are Vmp=17.5 volt panels (which is "standard" for "12 volt" off-grid systems).

    It is probably too late now--But I highly recommend that you design the system around your needs first instead of trying to purchase bits and pieces and fit them together. There are a lot of specifications to review and match--And I am probably just going to frustrate the bejesus out of you with my "nit picking" and backtracking. Sorry:blush:

    -Bill

    I can still return the 1 panel I have purchased (granted I'll take the hit on shipping but whatever)

    My main concern is charging the wagan effectively but being as cheap as possible...

    I know those 2 things counter act each other but I'm willing to spend a little more for quality and for this set up to work.
  • BB.BB. Super Moderators, Administrators Posts: 29,696 admin
    Re: Question about transporting panels and how much heat they can take

    The big thing with getting crystalline solar panels is that they are ~1/2 the square footage for the same rating. Also, many of the Sunforce/Harbor Freight panels do not really do a good job of meeting their advertised ratings.

    At this point, the panels should work in parallel and recharge your battery pack fairly quickly on a sunny day (that is a lot of solar power).

    The problem with battery packs is the battery does not last much longer than a year anyway (quality and usage patterns by the owner)--So for me to push $200-$400 more on "high quality" panels and charge controllers gets pretty silly unless you have future plans for the hardware...

    Then I would re-evaluate the whole Wagan thing...

    Solar is expensive, lead acid batteries are heavy for their capacity, and MSW inverters are cheap--so vendors put large MSW inverters on small battery (banks). Running the inverter at 400 watts will drain the internal battery in 20 minutes or so... It does work, but running the battery "dead" will also give you a battery life in weeks or months.

    Obviously, for an Off-Grid cabin or home, we are aiming for 5-15 year battery life. A completely different application/requirement.

    So just slap my hand if I am going off the rails regarding your needs. ;)

    -Bill "bad boy" B.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • LoougleLoougle Registered Users Posts: 10
    Re: Question about transporting panels and how much heat they can take
    BB. wrote: »
    The big thing with getting crystalline solar panels is that they are ~1/2 the square footage for the same rating. Also, many of the Sunforce/Harbor Freight panels do not really do a good job of meeting their advertised ratings.

    At this point, the panels should work in parallel and recharge your battery pack fairly quickly on a sunny day (that is a lot of solar power).

    The problem with battery packs is the battery does not last much longer than a year anyway (quality and usage patterns by the owner)--So for me to push $200-$400 more on "high quality" panels and charge controllers gets pretty silly unless you have future plans for the hardware...

    Then I would re-evaluate the whole Wagan thing...

    Solar is expensive, lead acid batteries are heavy for their capacity, and MSW inverters are cheap--so vendors put large MSW inverters on small battery (banks). Running the inverter at 400 watts will drain the internal battery in 20 minutes or so... It does work, but running the battery "dead" will also give you a battery life in weeks or months.

    Obviously, for an Off-Grid cabin or home, we are aiming for 5-15 year battery life. A completely different application/requirement.

    So just slap my hand if I am going off the rails regarding your needs. ;)

    -Bill "bad boy" B.

    Yeah I mean this would just be used for occasional camping trips and such, maybe used 2-3 times a year.

    I may not be getting those 50w panels from new egg because they charging $100 to ship 1 of them so I guess, what type of solar panel and how much wattage total should I be using to charge my battery.

    I'll have at least 10hrs of (possibly non direct for a few of those hours) sunlight.

    and I mostly used the Wagaan rig because I can store that in my car and use it for other uses than this haha.

    I understand this is all theoretical because who knows what could happen out there, but the weather has been pretty crappy in California so I haven't been able to do much tests.
  • BB.BB. Super Moderators, Administrators Posts: 29,696 admin
    Re: Question about transporting panels and how much heat they can take

    It really gets back to your energy needs...

    In my humble opinion, Solar panels used a few days a year almost never make economic sense...

    Let us look at 100 watts of solar panel in nice weather and good sun (no shade/shadows, 9am-3pm sun exposure at least, 5+ hours of sun per day). We start with the assumption that your system will be ~52% efficient (assuming AC inverter usage) and a three day festival.
    • 100 watts * 5 hours of sun per day * 0.52 eff * 3 days = 780 Watt*Hours of energy
    To store that in a 12 volt lead acid battery, it would require with a maximum of 50% state of discharge for long battery life:
    • 780 WH * 1/12 volts * 1/0.50 max discharge = 130 AH @ 12 volt bank
    Basically, two $70 car sized storage batteries would easily store 3 days worth of power (and 6 days if you take the battery dead as in the case of emergency).

    I would propose that 130 AH of 12 volt batteries are easier to transport than the Wagan+100 watts of solar panels.

    What I do (I am a cheap guy) at home--I use one of those 1-2 Amp trickle chargers and place it on a "lamp timer" set for ~1 hour per day... That gives about 30 hours per month charging which is usually enough to keep the batteries happy without boiling them dry (seems to always be my problem with any maintenance chargers I have used).

    You can also look at the Honda eu1000i/eu2000i gensets. Basically around $750/$920 shipped to your front door (there is a +$20 for California emissions--may be included in above costs).

    The Honda eu1000i will power a 225 watt load on 0.6 gallons of fuel for 8+ hours and weigh ~30 lbs (+3.6 lbs of gasoline or 0.6 gallons).
    • 225 watts * 8 hours = 1,800 WH
    Or about 2.3x the amount of available power than your 100 watts of solar panels.

    A good quality poly crystalline solar panel plus supporting hardware:
    You can mix and match the above (for example Generator + battery + charger + inverter)...

    The Honda's are very quiet... You can easily hold a normal conversation standing next to one--And in a busy city environment, you cannot even hear them running unless you really try and listen for the genset.

    Depending on your needs, you may choose to run battery/inverter in the evening (a few lights, radio, charge the camera, computer, and phones) and run the genset during the day to recharge the battery bank and run some power tools.

    You could also choose to use AGM batteries (less messy, 10% more efficient, and great for surge current support).
    Forgot to add, if using a generator, your battery could be 1/3rd the size (and cost) as you can recharge the next morning and do not need to store enough power for 3 days of usage:
    No right or wrong answer--just different ways of designing a solution.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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