Help with portable solar generator

JeepJeep Registered Users Posts: 17
I want to make a small solar generator for camping/fishing, I plan on using a 10 watt panel, gel motorcycle battery, 100 watt inverter, 3 amp charge controller. I plan on running a radio on my boat, laptop, iPod, phone chargers camping and other small stuff. Will the solar panel charge the motorcycle battery up in one day, I only plan on running it down no more then 30% max? The motor cycle battery is a medium size, I also have a 5 amp hour battery.
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Comments

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Help with portable solar generator

    Welcome to the forum.

    Not knowing how large the battery is it's difficult to say whether it will recharge in one day or not. But I can tell you a 10 Watt panel won't recharge much; it is capable of less than 1 Amp of current (about 0.5) which makes it suitable for nothing more than about 10 Amp hours of battery at most. That's not much power at all (about 60 Watt hours).

    Your small items can add up to a surprising amount of power consumption. The 100 Watt inverter will eat up some too. I think you need to get a better handle on how much power you want to use, and how much trouble you'd be in if you didn't have it.

    It might be better for you to determine the largest panel you can carry along, base the battery size on that, and hope for the best in power consumption.
  • JeepJeep Registered Users Posts: 17
    Re: Help with portable solar generator

    I plan on putting it in a wooden box and making it look neat. I also don't want to down a lot, every thing added up not that I'm looking at is $70 that includes solar panel, charge controller, digital volt gauge, and 100 watt inverter (not a crappy junky car one). I already have that motorcycle battery and the 5 amp hour battery, box, wire, switches, other materials. Just let me know if you have done this and how it worked or if you think it will work, the only solar panels I have played with are the garden light panels (I made a solar powered clock lol)
  • JeepJeep Registered Users Posts: 17
    Re: Help with portable solar generator
    Jeep wrote: »
    I want to make a small solar generator for camping/fishing, I plan on using a 10 watt panel, gel motorcycle battery, 100 watt inverter, 3 amp charge controller. I plan on running a radio on my boat, laptop, iPod, phone chargers camping and other small stuff. Will the solar panel charge the motorcycle battery up in one day, I only plan on running it down no more then 30% max? The motor cycle battery is a medium size, I also have a 5 amp hour battery.
    the most I will probably ever run is a small boom box radio, other wise it will probably only charge small hand held stuff camping.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Help with portable solar generator

    Well, yes a 10 Watt panel will recharge a 5 Amp hour battery under normal circumstances. The 1/2 Amp output is just about exactly 10% peak charge current, which is standard.

    I just think you may find that 30% of that capacity (1.5 Amp hours) won't be enough to do what you want to accomplish (about 18 Watt hours).
  • JeepJeep Registered Users Posts: 17
    Re: Help with portable solar generator
    Welcome to the forum.

    Not knowing how large the battery is it's difficult to say whether it will recharge in one day or not. But I can tell you a 10 Watt panel won't recharge much; it is capable of less than 1 Amp of current (about 0.5) which makes it suitable for nothing more than about 10 Amp hours of battery at most. That's not much power at all (about 60 Watt hours).

    Your small items can add up to a surprising amount of power consumption. The 100 Watt inverter will eat up some too. I think you need to get a better handle on how much power you want to use, and how much trouble you'd be in if you didn't have it.

    It might be better for you to determine the largest panel you can carry along, base the battery size on that, and hope for the best in power consumption.
    ok well if you guys think this will work looks like I'm going to be using the 5 amp hour battery
  • JeepJeep Registered Users Posts: 17
    Re: Help with portable solar generator
    Well, yes a 10 Watt panel will recharge a 5 Amp hour battery under normal circumstances. The 1/2 Amp output is just about exactly 10% peak charge current, which is standard.

    I just think you may find that 30% of that capacity (1.5 Amp hours) won't be enough to do what you want to accomplish (about 18 Watt hours).

    Well every thing 15 watt and up is too big for me to make easily portable. So I should just scrap my idea and spend my money on something else? What makes 15 and so unusable for me is there rectangle (unless you pay twice as much) I'm looking for square
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Help with portable solar generator
    Jeep wrote: »
    Well every thing 15 watt and up is too big for me to make easily portable. So I should just scrap my idea and spend my money on something else? What makes 15 and so unusable for me is there rectangle (unless you pay twice as much) I'm looking for square

    I can understand the problems of space limitation, but that also inflicts power limitation. So if there's no way around the panel size you're stuck with the power the small panel can supply. If this isn't enough for what you want to do, you run out of power. How much of a problem will that be? That is something you have to think about too.

    Small monocrystaline panels are practically non-existent too. Do you have a maximum dimension to work from?
  • JeepJeep Registered Users Posts: 17
    Re: Help with portable solar generator
    I can understand the problems of space limitation, but that also inflicts power limitation. So if there's no way around the panel size you're stuck with the power the small panel can supply. If this isn't enough for what you want to do, you run out of power. How much of a problem will that be? That is something you have to think about too.

    Small monocrystaline panels are practically non-existent too. Do you have a maximum dimension to work from?

    Well it's only going to be used for stuff I want like cameras, radios, iPod charging, phone charging. It's not a emergency if I run out of juice. I'm just wondering if this is even worth messing with, like if it will be so under powered its worthless?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Help with portable solar generator
    Jeep wrote: »
    Well it's only going to be used for stuff I want like cameras, radios, iPod charging, phone charging. It's not a emergency if I run out of juice. I'm just wondering if this is even worth messing with, like if it will be so under powered its worthless?

    Normally we'd recommend measuring loads with a Kill-A-Watt but that would be extreme in this case. But you could calculate the approximate Watt hours from what you want to keep running and see how it fits with your battery plan.

    And since you could use some of the power during daylight, maybe you could use two 10 Watt panels and have one fold over the other for transport then open them up for charging? Is the panel you're considering something like this one: http://www.solar-electric.com/so10wamusopa.html
  • JeepJeep Registered Users Posts: 17
    Re: Help with portable solar generator
    Normally we'd recommend measuring loads with a Kill-A-Watt but that would be extreme in this case. But you could calculate the approximate Watt hours from what you want to keep running and see how it fits with your battery plan.

    And since you could use some of the power during daylight, maybe you could use two 10 Watt panels and have one fold over the other for transport then open them up for charging? Is the panel you're considering something like this one: http://www.solar-electric.com/so10wamusopa.html
    well a iPod charger is like 14 watts and it takes 2 hours to charge it from 0% to 100% but I never run it down all the way, I have no clue how much power a small boom box draws, I might run a lamp with a compact fluorescent light bulb. Like I said its not en emergency if it goes dead, I got the battery for free do if I kill it oh well. I just am totally new to solar so I'm asking you people that know what ur talking about :D
  • PhotowhitPhotowhit Solar Expert Posts: 5,653 ✭✭✭✭✭
    Re: Help with portable solar generator

    Well at one point you asked "if you've done this?"

    So, for a bicycle trip, I used a 2-6v batteries (3.5-4 amps maybe), a bit bigger than the size of a pack of cigarettes. I had a 10 watt panel, aluminum backed that was given for me to use, it was a 12 volt nominal panel. I charged the batteries in series and used them in parallel, I simple had them wired into a connector, I think an 8 pin though I didn't need them all, with 2 female connectors one on the solar panel and one on the load/connectors for 6v applications, originally a mini am/fm/ham radio (stolen early in the trip), a light, later a tiny fan and a TV and a different radio. I allowed it to charge unregulated. It lasted the 8 months or so of the trip and the batteries were about dead.

    I think now with all the devices that have built in chargers, it would be easy to charge from a 6 volt source with a 5v voltage regulator. I know I have an MP3 player, tiny sandisk and a great set of powered speakers, originally designed for cell phone music player (LG MSP-100 great if you can find one). Both would last most of a day with out a recharge, but both have internal charging circuits that use usb mini 'B' charger, so you could attach a voltage regulator to your solar panel and allow them to charge during the day. I have done this with a 6v, 4-5 watt panel and a Nokia N800 (mini linux computer) which is very pick on power supply and it worked fine.

    If you don't want to hunt for a 6V panel and do a tiny bit of sodering, there are all-in-one solar cell and battery USB out units, I'd look at reviews though at amazon and be sure you find one that charges well, as most can be plugged in to charge.

    Well my 2 cents, no change required...
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • JeepJeep Registered Users Posts: 17
    Re: Help with portable solar generator
    Photowhit wrote: »
    Well at one point you asked "if you've done this?"

    So, for a bicycle trip, I used a 2-6v batteries (3.5-4 amps maybe), a bit bigger than the size of a pack of cigarettes. I had a 10 watt panel, aluminum backed that was given for me to use, it was a 12 volt nominal panel. I charged the batteries in series and used them in parallel, I simple had them wired into a connector, I think an 8 pin though I didn't need them all, with 2 female connectors one on the solar panel and one on the load/connectors for 6v applications, originally a mini am/fm/ham radio (stolen early in the trip), a light, later a tiny fan and a TV and a different radio. I allowed it to charge unregulated. It lasted the 8 months or so of the trip and the batteries were about dead.

    I think now with all the devices that have built in chargers, it would be easy to charge from a 6 volt source with a 5v voltage regulator. I know I have an MP3 player, tiny sandisk and a great set of powered speakers, originally designed for cell phone music player (LG MSP-100 great if you can find one). Both would last most of a day with out a recharge, but both have internal charging circuits that use usb mini 'B' charger, so you could attach a voltage regulator to your solar panel and allow them to charge during the day. I have done this with a 6v, 4-5 watt panel and a Nokia N800 (mini linux computer) which is very pick on power supply and it worked fine.

    If you don't want to hunt for a 6V panel and do a tiny bit of sodering, there are all-in-one solar cell and battery USB out units, I'd look at reviews though at amazon and be sure you find one that charges well, as most can be plugged in to charge.

    Well my 2 cents, no change required...
    well I was really looking to go 12 volt with my 5 amp hour battery, I'm very new to solar power and I think I'm starting to realize that solar panels are very week. The 10 watt pannel is the perfect size for me (size not power output) I have no clue if it will be enough to charge the battery during the day, I don't really plan on running any thing more then 14 watts of 110 at night, and maybe like a max of 80 watts in good sun? I have no clue if this will work so I'm just trying to research it. What I'm looking for is a yes it will work or no put your $70 towered a small gas genorator. Thanks
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: Help with portable solar generator

    A "10 watt" panel will output about 77% for ~6 hours a day (~9am to 3pm) during the summer (during the winter, you would get about "2 hours of noon time equivalent sun per day"--plus a little bit more outside that time frame.
    • 10 watts * 0.77 * 6 hours = 46.2 Watt*Hours on a good summer sunny day with panel tilted to sun

    If you use an AC inverter and battery to store/produce 120 VAC power, the end to end efficiency is closer to 52%:
    • 10 watts * 0.52 * 6 hours = 31.2 Watt*Hours per day

    A 14 watt 120 VAC load would run for (roughly):
    • 31.2 WH per day * 1/14 Watt AC load = 2.2 hours per day

    Remember that a solar panel only collects power from the sun when it is pointing at the sun (shading, even partial shading, will usually kill the solar panel output)... If you are hiking/biking--It is much more difficult to "track the sun" when on the move--and you will usually collect much less solar energy. Usually, the panel+charger need to be set facing the sun (picnic table, on open ground, etc.) to capture anywhere near "rated" power/energy.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: Help with portable solar generator

    Depending on your power needs, a small gasoline genset may be a better choice (I have no information about the Harbor Freight genset--But lasting 200-500 hours of use is a strong possibility):

    Harbor freight $130 38 lb 800 watt 1.1 gallons @ 400 watts for 5 hours on 1.1 gallons of gas (2 cycle engine)

    Or, if this is a long term investment, I would go with a Honda eu1000i (or Yamaha/similar) inverter generator instead--they will usually be much quieter and last a lot longer (~2,000+ hours with regular maintenance):

    900 watt, ~$700 30lb 900 watts for 8.3 hours at 200 watts on 0.6 gallons of gas (4 cycle engine)


    If you need "lots of power" on demand for short periods of time (few days/weeks a year)--A generator is very difficult to beat.

    If you need small amounts of power for 9+ months a year (or very small amounts of power in an emergency/hiking for a cell phone charger), then solar may be your better bet.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • JeepJeep Registered Users Posts: 17
    Re: Help with portable solar generator
    BB. wrote: »
    A "10 watt" panel will output about 77% for ~6 hours a day (~9am to 3pm) during the summer (during the winter, you would get about "2 hours of noon time equivalent sun per day"--plus a little bit more outside that time frame.
    • 10 watts * 0.77 * 6 hours = 46.2 Watt*Hours on a good summer sunny day with panel tilted to sun

    If you use an AC inverter and battery to store/produce 120 VAC power, the end to end efficiency is closer to 52%:
    • 10 watts * 0.52 * 6 hours = 31.2 Watt*Hours per day

    A 14 watt 120 VAC load would run for (roughly):
    • 31.2 WH per day * 1/14 Watt AC load = 2.2 hours per day

    Remember that a solar panel only collects power from the sun when it is pointing at the sun (shading, even partial shading, will usually kill the solar panel output)... If you are hiking/biking--It is much more difficult to "track the sun" when on the move--and you will usually collect much less solar energy. Usually, the panel+charger need to be set facing the sun (picnic table, on open ground, etc.) to capture anywhere near "rated" power/energy.

    -Bill
    ok so if I get a USB 12v charger, and put a 12 volt socket in that should be much better on the battery. But I'm still going to get the inverter (if it looks like this setup will work) to use with a boom box, my brothers eletric scooter (1 amp of 120 witch would be the biggest load I ever put on this thing). I'm just looking for a yes it will work or a no not enough power go buy a cheap 1000w genorator
  • JeepJeep Registered Users Posts: 17
    Re: Help with portable solar generator
    BB. wrote: »
    Depending on your power needs, a small gasoline genset may be a better choice (I have no information about the Harbor Freight genset--But lasting 200-500 hours of use is a strong possibility):

    Harbor freight $130 38 lb 800 watt 1.1 gallons @ 400 watts for 5 hours on 1.1 gallons of gas (2 cycle engine)

    Or, if this is a long term investment, I would go with a Honda eu1000i (or Yamaha/similar) inverter generator instead--they will usually be much quieter and last a lot longer (~2,000+ hours with regular maintenance):

    900 watt, ~$700 30lb 900 watts for 8.3 hours at 200 watts on 0.6 gallons of gas (4 cycle engine)


    If you need "lots of power" on demand for short periods of time (few days/weeks a year)--A generator is very difficult to beat.

    If you need small amounts of power for 9+ months a year (or very small amounts of power in an emergency/hiking for a cell phone charger), then solar may be your better bet.

    -Bill
    We get more than 6 hours of sun here. It's not going to run much. A genorator uses gas, two strokes are load, stink and other stuff. I just want to know if it will work, would you spend $70 on this not including the battery and other stuff I have? Like I said the only solar stuff I have messed with is garden lights. Now I can wire stuff up like I wired my tractor when I built it and other stuff
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: Help with portable solar generator

    Actually, most places do not get 6+ hours of noon time equivalent sun per day with a "fixed" array--even during the summer in the far north... For example, using PV Watts for Eau Claire Wisconsin (farther north, not near lake effects), a fixed array tilted to latitude would see:
    Month    Solar Radiation (kWh/m 2/day)
    1      3.29     
    2      4.63     
    3      5.24     
    4      4.84     
    5      5.42     
    6      5.61     
    7      5.66     
    8      5.31     
    9      4.68     
    10      3.82     
    11      2.46     
    12      2.33     
    Year      4.44      
    

    And if you moved the panel every hour to "track the sun", the best you could do (with a 2 axis tracker) would be:
    Month    Solar Radiation (kWh/m 2/day)
    1      4.03     
    2      5.64     
    3      6.40     
    4      6.30     
    5      7.94     
    6      8.40     
    7      8.33     
    8      7.36     
    9      6.00     
    10      4.59     
    11      2.83     
    12      2.80     
    Year      5.89      
    

    So, if you can tend the solar panel and re-aim it every hour or so, you can get significantly more power...

    We are not trying to avoid your questions--But we are just guessing as to your loads. Besides getting a Kill-a-Watt type meter to measure your AC loads. You can also get a DC WattHour/AmpHour meter or even a relatively inexpensive DC Current Clamp Meter to estimate your DC loads.

    We have several ways to design a system... Either we design it to your needs (know your loads)--Preferred. Or, you give us a solar panel or battery and we design the system around it.

    In your case, lets start with a 10 watt panel and assume 7 hours of sun (you will be there to move the panel). We normally recommend a 5% to 13% rate of charge for a lead acid battery (flooded cell, AGM--you probably would get an AGM for your use). Using 10% rate of charge (recharge battery fairly quickly), a 10 watt array would support:
    • 10 watt * 0.77 derating * 1/0.10 rate of charge * 1/14.5 volts charging = 5.3 AH @ 12 volt battery

    And, if you assume 7+ hours per day of sun during summer (with manual tracking), you could expect a system to supply:
    • 10 watt panel * 0.77 panel+controller derating * 0.90 AGM battery eff * 1/12.5 volt * 7 hours of sun per day = 3.9 AH @ 12 volts per day
    • 10 watts * 0.52 AC system Efficiency * 7 hours of sun per day = 36.4 Watt*Hours of AC power per day

    Nominally, a 5.3 AH @ 12 volt lead acid battery would supply at a C/8 discharge rate (discharge the battery flat in less than 8 hours):
    • 5.3 AmpHour * C/8 Rate = 0.66 amp load @ 12 volts
    • 5.3 AmpHour * C/8 Rate * 12 volts * 0.85 inverter efficiency = 6.8 Watt 120 VAC load

    The above would be a good estimate for recharging a smart phone, running a portable radio, etc...

    AGM batteries do have an advantage in that they can output quite high rates of discharge for a short amount of time... I.e., you can probably pull C/1 from a small AGM (i.e., a 5.3 AH battery can output 5.3 amps for a bit less than 1 hour)... But, you have to be careful, from my limited experience, these small AGM batteries will not last very long if discharged at such high rates.

    My usually recommendation is C/2.5 rate of discharge--Useful for running a small water pump (high starting surge current) for a few tens of seconds or minutes:
    • 5.3 AmpHour * C/2.5 Rate = 2.1 amp surge load @ 12 volts
    • 5.3 AmpHour * C/2.5 Rate * 12 volts * 0.85 inverter efficiency = 22 Watt 120 VAC surge load

    So, if you are "on the go" and using the system every day--The above are my suggestions. You can run as low as a 5% rate of charge on the battery and support a 2x larger battery (and 2x larger Amps/Watts/AH/WH) from the storage battery (say you hike for a couple days, then setup camp for a few days)--But having a larger battery is heavier and really does require more solar power if you want to support more loads...

    Your other option is to look at some sort of Li-Ion type battery pack that is setup for solar power... Li-Ion batteries are much lighter than Lead Acid--But are much more expensive and require more care in charging/use. But that still does not address the power limitations of a 10 watt solar panel...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • JeepJeep Registered Users Posts: 17
    Re: Help with portable solar generator
    BB. wrote: »
    Actually, most places do not get 6+ hours of noon time equivalent sun per day with a "fixed" array--even during the summer in the far north... For example, using PV Watts for Eau Claire Wisconsin (farther north, not near lake effects), a fixed array tilted to latitude would see:
    Month    Solar Radiation (kWh/m 2/day)
    1      3.29     
    2      4.63     
    3      5.24     
    4      4.84     
    5      5.42     
    6      5.61     
    7      5.66     
    8      5.31     
    9      4.68     
    10      3.82     
    11      2.46     
    12      2.33     
    Year      4.44      
    

    And if you moved the panel every hour to "track the sun", the best you could do (with a 2 axis tracker) would be:
    Month    Solar Radiation (kWh/m 2/day)
    1      4.03     
    2      5.64     
    3      6.40     
    4      6.30     
    5      7.94     
    6      8.40     
    7      8.33     
    8      7.36     
    9      6.00     
    10      4.59     
    11      2.83     
    12      2.80     
    Year      5.89      
    

    So, if you can tend the solar panel and re-aim it every hour or so, you can get significantly more power...

    We are not trying to avoid your questions--But we are just guessing as to your loads. Besides getting a Kill-a-Watt type meter to measure your AC loads. You can also get a DC WattHour/AmpHour meter or even a relatively inexpensive DC Current Clamp Meter to estimate your DC loads.

    We have several ways to design a system... Either we design it to your needs (know your loads)--Preferred. Or, you give us a solar panel or battery and we design the system around it.

    In your case, lets start with a 10 watt panel and assume 7 hours of sun (you will be there to move the panel). We normally recommend a 5% to 13% rate of charge for a lead acid battery (flooded cell, AGM--you probably would get an AGM for your use). Using 10% rate of charge (recharge battery fairly quickly), a 10 watt array would support:
    • 10 watt * 0.77 derating * 1/0.10 rate of charge * 1/14.5 volts charging = 5.3 AH @ 12 volt battery

    And, if you assume 7+ hours per day of sun during summer (with manual tracking), you could expect a system to supply:
    • 10 watt panel * 0.77 panel+controller derating * 0.90 AGM battery eff * 1/12.5 volt * 7 hours of sun per day = 3.9 AH @ 12 volts per day
    • 10 watts * 0.52 AC system Efficiency * 7 hours of sun per day = 36.4 Watt*Hours of AC power per day

    Nominally, a 5.3 AH @ 12 volt lead acid battery would supply at a C/8 discharge rate (discharge the battery flat in less than 8 hours):
    • 5.3 AmpHour * C/8 Rate = 0.66 amp load @ 12 volts
    • 5.3 AmpHour * C/8 Rate * 12 volts * 0.85 inverter efficiency = 6.8 Watt 120 VAC load

    The above would be a good estimate for recharging a smart phone, running a portable radio, etc...

    AGM batteries do have an advantage in that they can output quite high rates of discharge for a short amount of time... I.e., you can probably pull C/1 from a small AGM (i.e., a 5.3 AH battery can output 5.3 amps for a bit less than 1 hour)... But, you have to be careful, from my limited experience, these small AGM batteries will not last very long if discharged at such high rates.

    My usually recommendation is C/2.5 rate of discharge--Useful for running a small water pump (high starting surge current) for a few tens of seconds or minutes:
    • 5.3 AmpHour * C/2.5 Rate = 2.1 amp surge load @ 12 volts
    • 5.3 AmpHour * C/2.5 Rate * 12 volts * 0.85 inverter efficiency = 22 Watt 120 VAC surge load

    So, if you are "on the go" and using the system every day--The above are my suggestions. You can run as low as a 5% rate of charge on the battery and support a 2x larger battery (and 2x larger Amps/Watts/AH/WH) from the storage battery (say you hike for a couple days, then setup camp for a few days)--But having a larger battery is heavier and really does require more solar power if you want to support more loads...

    Your other option is to look at some sort of Li-Ion type battery pack that is setup for solar power... Li-Ion batteries are much lighter than Lead Acid--But are much more expensive and require more care in charging/use. But that still does not address the power limitations of a 10 watt solar panel...

    -Bill
    My battery is a 5 amp hour AGM. This should work to charge phones and iPods and cameras and stuff right? It no like I'm going to NEED it to run a desk top and I'm asking if this will work. I'm just asking would you buy the components to build this? Also we go camping for like 3 days at a time if that matters
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: Help with portable solar generator

    Lets look at recharging 4x Eneloop Sanyo 2,000 mAH batteries that have been fully discharged.

    A 10 watt panel, 7 hours of sun, and typical losses will take
    4x 2.000 AH * 1.65 volts charging * 1/0.77 panel+controller eff * 1/0.6 NMHi eff * 1/7 hours of sun = 4 days to recharge

    So, a 10 watt panel will take upwards of ~4 days to fully recharge 4x AA Eneloop batteries (could be as little as 2 days if partially discharged and my "typical" efficiency numbers are off a bit).

    Will it work? Yes, it will recharge the batteries. Will 2-4 days per 4x AA batteries on a three day trip be worth it? Probably not.

    I got one of these 7 watt "Goal Zero" kits just to charge my smart phone in an emergency or camping. And I think it will do OK. There have been some complaints here that the folding panels have not be electrically reliable (:cry:). That is ~$130 for 7 watts... Not cheap, but it is portable.

    For "short trips"... I would suggest Lithium "Primary" cells. They are very light and store "AA" worth of power per battery. Very good surge current and low temperature performance. Be careful with Lithium cells... They can come in different voltages (3.6 volt instead of 1.5 volt for example).

    For charging USB compatible devices, I have an Eneloop battery pack/charger. Worked well with my smart phone. Would recharge 1-2x before the battery pack needed recharging.

    Or you can get USB to cell phone chargers that can use AA batteries too (use any AA battery you like, primary or rechargeable).

    For flashlights and such... The modern LED lights with variable output are great... I really love my light that uses two CR123 Lithium primary cells (same light can use 2x AA cells with a different body). Will run literally for 1 month on low (bright enough to walk/read) or 1-2 hours on high (virtually like a small car spot light). A pair of batteries will last a year in ordinary use.

    Yes, I know this is a solar forum... But we are also a practical (and cheap) bunch here. We want to see that your needs are met and none of us here are trying to sell you products that will not. Solar has its place--But so do other solutions.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • JeepJeep Registered Users Posts: 17
    Re: Help with portable solar generator
    BB. wrote: »
    Lets look at recharging 4x Eneloop Sanyo 2,000 mAH batteries that have been fully discharged.

    A 10 watt panel, 7 hours of sun, and typical losses will take
    4x 2.000 AH * 1.65 volts charging * 1/0.77 panel+controller eff * 1/0.6 NMHi eff * 1/7 hours of sun = 4 days to recharge

    So, a 10 watt panel will take upwards of ~4 days to fully recharge 4x AA Eneloop batteries (could be as little as 2 days if partially discharged and my "typical" efficiency numbers are off a bit).

    Will it work? Yes, it will recharge the batteries. Will 2-4 days per 4x AA batteries on a three day trip be worth it? Probably not.

    I got one of these 7 watt "Goal Zero" kits just to charge my smart phone in an emergency or camping. And I think it will do OK. There have been some complaints here that the folding panels have not be electrically reliable (:cry:). That is ~$130 for 7 watts... Not cheap, but it is portable.

    For "short trips"... I would suggest Lithium "Primary" cells. They are very light and store "AA" worth of power per battery. Very good surge current and low temperature performance. Be careful with Lithium cells... They can come in different voltages (3.6 volt instead of 1.5 volt for example).

    For charging USB compatible devices, I have an Eneloop battery pack/charger. Worked well with my smart phone. Would recharge 1-2x before the battery pack needed recharging.

    Or you can get USB to cell phone chargers that can use AA batteries too (use any AA battery you like, primary or rechargeable).

    For flashlights and such... The modern LED lights with variable output are great... I really love my light that uses two CR123 Lithium primary cells (same light can use 2x AA cells with a different body). Will run literally for 1 month on low (bright enough to walk/read) or 1-2 hours on high (virtually like a small car spot light). A pair of batteries will last a year in ordinary use.

    Yes, I know this is a solar forum... But we are also a practical (and cheap) bunch here. We want to see that your needs are met and none of us here are trying to sell you products that will not. Solar has its place--But so do other solutions.

    -Bill
    So basically the 10w solar and 5 amp hour battery will be worthless for me? I just want a strict "yes" or "no"
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: Help with portable solar generator

    For a short hiking trip, I believe that a 10 watt panel + 5 AH lead acid battery is not worth the weight/size to carry.

    For a base camp that is used for weeks to a summer season in length, then it is probably worth it.

    Will a 10 watt solar panel charge a 5 AH lead acid battery nicely. Yes, it will work fine.

    Will a 5 Amp*Hour battery that weighs ~ 3lbs be better than 16x AA 3.0 AH Lithium cells that weigh ~1/2 lb but cost ~$40 or so... Or $60 worth of Sanyo Eneloop AA batteries (~24) at 1.0 lbs...

    An alternative would be to not use an 5 AH battery but instead use AA Eneloop batteries. Charge those directly for use in flashlights/radios/etc. that use AA batteries, and get a simple AA to USB charger to recharge deices (like Ipad/Iphone/etc.) that do not have the ability to replace batteries on the fly. Charging AA batteries directly saves the hauling of a 5 AH AGM battery around. And saves some losses with charging an AGM first, then charging AA NiMH Batteries.

    If most of your charging is for fixed battery devices (again, Apple and other "appliances"), an AGM battery may be the better choice. AGM batteries are 90+% efficient when charging. NiMH/NiCad are ~60% or so efficient. Of course, you could look for small Li-Ion type batter packs too--They are much lighter and still very efficient when charging.

    It all depends on your needs...

    From my point of view, I would go with AA batteries and an AA powered USB charger for active hiking/traveling. If light weight and capacity are issues, then I would go with Lithium (primary or secondary) or even Costco AA alkaline cells. If weight is less of an issue and I wanted to avoid "waste", I would use eneloops--The are pretty good batteries for NiMH and can go for months to a year between needing recharging--Normal NiMH batteries need to be recharged every 1-4 weeks (especially as they age). And AGM batteries need recharging every 1-3 months or so (when sitting on a shelf).

    For long trips with time spent at fixed locations (to setup a solar panel), then you can add a 10 watt solar array to your kit with some sort of recharging station/batteries.

    One reason for having a solar panel+battery for portable charging--You don't have to leave your electronics setting out in the sun/weather/unattended during the middle of the day to recharge... You setup the panel and battery to recharge during the day--And at night you plug in your rechargeable appliances for recharging (will be quicker recharging and you have use of the devices during the day).

    Sorry--There is no yes/no answer here. It is very much a personal choice. A properly configured system will "work". Question is which solution/s is/are "practical" for your needs.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • JeepJeep Registered Users Posts: 17
    Re: Help with portable solar generator
    BB. wrote: »
    For a short hiking trip, I believe that a 10 watt panel + 5 AH lead acid battery is not worth the weight/size to carry.

    For a base camp that is used for weeks to a summer season in length, then it is probably worth it.

    Will a 10 watt solar panel charge a 5 AH lead acid battery nicely. Yes, it will work fine.

    Will a 5 Amp*Hour battery that weighs ~ 3lbs be better than 16x AA 3.0 AH Lithium cells that weigh ~1/2 lb but cost ~$40 or so... Or $60 worth of Sanyo Eneloop AA batteries (~24) at 1.0 lbs...

    An alternative would be to not use an 5 AH battery but instead use AA Eneloop batteries. Charge those directly for use in flashlights/radios/etc. that use AA batteries, and get a simple AA to USB charger to recharge deices (like Ipad/Iphone/etc.) that do not have the ability to replace batteries on the fly. Charging AA batteries directly saves the hauling of a 5 AH AGM battery around. And saves some losses with charging an AGM first, then charging AA NiMH Batteries.

    If most of your charging is for fixed battery devices (again, Apple and other "appliances"), an AGM battery may be the better choice. AGM batteries are 90+% efficient when charging. NiMH/NiCad are ~60% or so efficient. Of course, you could look for small Li-Ion type batter packs too--They are much lighter and still very efficient when charging.

    It all depends on your needs...

    From my point of view, I would go with AA batteries and an AA powered USB charger for active hiking/traveling. If light weight and capacity are issues, then I would go with Lithium (primary or secondary) or even Costco AA alkaline cells. If weight is less of an issue and I wanted to avoid "waste", I would use eneloops--The are pretty good batteries for NiMH and can go for months to a year between needing recharging--Normal NiMH batteries need to be recharged every 1-4 weeks (especially as they age). And AGM batteries need recharging every 1-3 months or so (when sitting on a shelf).

    For long trips with time spent at fixed locations (to setup a solar panel), then you can add a 10 watt solar array to your kit with some sort of recharging station/batteries.

    One reason for having a solar panel+battery for portable charging--You don't have to leave your electronics setting out in the sun/weather/unattended during the middle of the day to recharge... You setup the panel and battery to recharge during the day--And at night you plug in your rechargeable appliances for recharging (will be quicker recharging and you have use of the devices during the day).

    Sorry--There is no yes/no answer here. It is very much a personal choice. A properly configured system will "work". Question is which solution/s is/are "practical" for your needs.

    -Bill
    We don't go hiking camping, the size matters because it needs to fit in the car with every thing else!! I think it will work for what I want, I don't need a lot of power, just enough to keep games a phones charged up, maybe for now I will for get the inverter and just get the pannel, volt meter, and charge controller. Then I will charge stuff with a USB car charger and a 12 volt female socket.
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: Help with portable solar generator

    If you are car camping... You might just want to get a 10-20 watt or so panel and mount it to the car and, if you wish, get a nice quality deep cycle / AGM battery for the car. On my vehicles, I find that virtually all of them will take the next size larger (at least) battery. This gives me more power for running stuff when the vehicle is not running.

    20% of an 80 AH battery is 16 AH... Not too hard on a standard car size battery (especially if it has been replaced with deep cycle type).

    Ham Radio types have made some interesting DC power distribution systems and even those that have automatic cutoffs (to avoid killing the battery).

    Riggrunner with DC battery voltage alarm

    There is a mfg. that makes a "compatible" unit to the above that is programmed to turn off at 13.5 volts, 12.7 volts or 12.0 volts (running and charging, charging, or prevent over discharging of battery)--I cannot find it right now.

    I would either setup to use the car battery, or install a second battery (with isolation) in the car to recharge/run your electronics... Just one less thing to pack and it is always there even for short trips.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • JeepJeep Registered Users Posts: 17
    Re: Help with portable solar generator
    BB. wrote: »
    If you are car camping... You might just want to get a 10-20 watt or so panel and mount it to the car and, if you wish, get a nice quality deep cycle / AGM battery for the car. On my vehicles, I find that virtually all of them will take the next size larger (at least) battery. This gives me more power for running stuff when the vehicle is not running.

    20% of an 80 AH battery is 16 AH... Not too hard on a standard car size battery (especially if it has been replaced with deep cycle type).

    Ham Radio types have made some interesting DC power distribution systems and even those that have automatic cutoffs (to avoid killing the battery).

    Riggrunner with DC battery voltage alarm

    There is a mfg. that makes a "compatible" unit to the above that is programmed to turn off at 13.5 volts, 12.7 volts or 12.0 volts (running and charging, charging, or prevent over discharging of battery)--I cannot find it right now.

    I would either setup to use the car battery, or install a second battery (with isolation) in the car to recharge/run your electronics... Just one less thing to pack and it is always there even for short trips.

    -Bill
    Well like I said I will take it out on my boat too. I ditched the inverter and got the total down to $40 (that includes charge controller, panel, volt meter. Like I said I have a 12v USB charger, 5 amp hour battery, box, switches, wire, excetra
  • gww1gww1 Solar Expert Posts: 963 ✭✭
    Re: Help with portable solar generator

    BB=bill
    Was it you that posted in a different thread the little generator that you put sticks in and burn't to charge a phone and such?

    http://gearjunkie.com/wood-burning-stove-with-electricity-generator

    gww
  • JeepJeep Registered Users Posts: 17
    Re: Help with portable solar generator
    gww1 wrote: »
    BB=bill
    Was it you that posted in a different thread the little generator that you put sticks in and burn't to charge a phone and such?
    gww
    ???? What are you talking about?
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: Help with portable solar generator

    GWW1 Is typing about a "little" outdoor stove that burns leaves small sticks with a thermal pile -- A mixed metal junction that generates around 5 watts at 1 amp of "USB" rated power just from the heat of the fire. Not "cheap"--But a different option.

    Just an alternative for small "out of the box thinking" for portable power.

    I fixed the link to remove the "Comments" tag that dropped you farther down into the comment section for the product:

    http://gearjunkie.com/wood-burning-stove-with-electricity-generator

    In the end, if the system will meet your needs (solar panel + AGM battery)--Then yes, it will work up to its limits (probably no useful AC inverter, but DC lighter plugs for cell phones and small rechargeable computers/games/etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • JeepJeep Registered Users Posts: 17
    Re: Help with portable solar generator
    BB. wrote: »
    GWW1 Is typing about a "little" outdoor stove that burns leaves small sticks with a thermal pile -- A mixed metal junction that generates around 5 watts at 1 amp of "USB" rated power just from the heat of the fire. Not "cheap"--But a different option.

    Just an alternative for small "out of the box thinking" for portable power.

    I fixed the link to remove the "Comments" tag that dropped you farther down into the comment section for the product:

    http://gearjunkie.com/wood-burning-stove-with-electricity-generator

    In the end, if the system will meet your needs (solar panel + AGM battery)--Then yes, it will work up to its limits (probably no useful AC inverter, but DC lighter plugs for cell phones and small rechargeable computers/games/etc.).

    -Bill
    Thank you!! Glad I found this forum and you helped me!! Glad I'm not buying an inverter. I think it will work great for USB charging!!! Then maybe some day I will make a bigger better one once panels come down some more
  • gww1gww1 Solar Expert Posts: 963 ✭✭
    Re: Help with portable solar generator

    bill
    I fixed the link to remove the "Comments" tag that dropped you farther down into the comment section for the product:

    Thanks, I'm not to good at moving things yet. They say they have a cup thurmal generator that goes to 40 watts. I know its not solar but who knows what will work for someone.

    Thanks
    gww
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: Help with portable solar generator

    The problem with TEGs (thermal electric genrators) is that they are not terribly efficient... If you go through the specs for the little stove:

    http://www.biolitestove.com/campstove/camp-overview/tech-specs/#sub
    Fire Power Output Peak: 3.4 kW (LO), 5.5 kW (HI)
    USB Power Output Max continuous: 2W @5V, Peak: 4W @5V

    4 watt output / 5.5 kW input (wood) = 0.0007 = 0.07% efficient

    Of course, if you want to cook for an hour or two anyway, then the 4 watt output is "free".

    In "real" TEGs, they are also not very efficient, but there are no mechanical parts either, so they can get installed on mountain top research stations and such where only a small relatively amount of continuous power is needed. They are around 5% efficient.

    http://tegpower.com/products.html

    "Jeep"--I am truly sorry if I was frustrating you there. It is difficult for us to understand your needs/usage from behind a keyboard. I don't want to waste your money any more than I would want to waste mine.

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