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Solar panel -> Lithium Ion Battery - WITHOUT controller - is it ok?

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  • #16
    Originally posted by Sunking View Post
    OK help me out with some info that puzzles me. What is being referred too when they specify 1S, 2S, 3S... battery packs? Is that the number of parallel strings in the pack for AH? Or number of series cells for voltage?
    Each "s" stands for a cell. So a 3S battery is 3 cells @ 3.7 volts per cell or 11.1volts total. A 2S would be a 7.4 volt 2 cell battery. Since the total battery voltage is the additive of each cell they would have to be in series.

    The bigger the cell is, the more ah the battery is rated. I have batteries from 1300mah to 3300mah. The more battery mah the longer I can fly.
    Last edited by SunEagle; 05-31-2013, 01:24 PM. Reason: add ah info

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    • #17
      Originally posted by Sunking View Post
      OK help me out with some info that puzzles me. What is being referred too when they specify 1S, 2S, 3S... battery packs? Is that the number of parallel strings in the pack for AH? Or number of series cells for voltage?

      I suspect Series voltage because of this spec.
      That website is where I have purchased the majority of my batteries. They are much cheaper than other companies and they now have a US warehouse which gets them to me much faster.

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      • #18
        Originally posted by SunEagle View Post
        The bigger the cell is, the more ah the battery is rated. I have batteries from 1300mah to 3300mah. The more battery mah the longer I can fly.
        But the heavier the battery, the less likely you are to get off the ground.
        SunnyBoy 3000 US, 18 BP Solar 175B panels.

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        • #19
          Originally posted by SunEagle View Post
          Each "s" stands for a cell. So a 3S battery is 3 cells @ 3.7 volts per cell or 11.1volts total.
          Yeah I figured it out right after I pinged you. Should have read some more. Check your PM box.
          MSEE, PE

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          • #20
            Originally posted by inetdog View Post
            But the heavier the battery, the less likely you are to get off the ground.
            Actually you get much more thrust from the bigger battery that weight is easily offset. Now if I used one of them Deep Cycle FLA batteries, I would be flying a tank.

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            • #21
              Originally posted by SunEagle View Post
              Actually you get much more thrust from the bigger battery that weight is easily offset. Now if I used one of them Deep Cycle FLA batteries, I would be flying a tank.
              Good point! But there is also, for a given drive system, a limit to how much you can extend the flight time just by adding more battery.
              SunnyBoy 3000 US, 18 BP Solar 175B panels.

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              • #22
                Originally posted by inetdog View Post
                Good point! But there is also, for a given drive system, a limit to how much you can extend the flight time just by adding more battery.
                Also each new load to the plane changes your center of gravity which requires some additional weight at the opposite end to maintain balance. Too much nose or tail weight makes for a very stressful pilot.

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                • #23
                  If you have this solar panel :
                  Operating Voltage: 15.4
                  Wattage: 28
                  Current: 1.8 amps

                  And have a Li-Po charger from somewhere like www.hobbyking.com.

                  And charge your batter at 1A or less, you *might* be able to charge this from 11am to 1pm with a really good sun day. But without the panel putting out full power, the input amps to a charger will drop and you will get a too-low condition in an RC charger.

                  If you have two of these panels in parallel, the output voltage of 15V and 3+ A may be better.

                  All of this is "experimental" and of course, a bad way to go for anything that is to be used a lot.

                  You can use an 18V Solar panel of say 100W (intended for off-grid battery systems) and clip that to an RC charger and perhaps get successful Li-Poly battery charging with a DC-input RC charger. It's all experimental, of course - enjoy trying things out. But do not charge your Lithium packs directly from a Solar module without using a balancing Lithium charger. Not good at all. Lithium RC chargers stop charging when the voltage of the target cells reach 4.2V. This is the smart-balance charging that these are intended for.
                  PowerOne 3.6 x 2, 32 SolarWorld 255W mono

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                  • #24
                    To answer the original question, I did some experimenting last year with some Lithium Ion batteries I took out of an old laptop. I made a small solar mobile phone charger. To make a long story short, it worked for a short time, about a month. But then the batteries stopped holding a charge. I think what happened was, even on my very small scale the lack of a CC overcharged and fried them. They didn't blow up, but they were toast.

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                    • #25
                      Originally posted by green View Post
                      To answer the original question, I did some experimenting last year with some Lithium Ion batteries I took out of an old laptop. I made a small solar mobile phone charger. To make a long story short, it worked for a short time, about a month. But then the batteries stopped holding a charge. I think what happened was, even on my very small scale the lack of a CC overcharged and fried them. They didn't blow up, but they were toast.
                      I hope you didn't perform your experiment inside. These batteries will cook off and light up very quickly.

                      I use a special "bag" to charge my LiPo batteries. It will contain a violent release of gas and flame if the battery decides to let go. Some people use a sealed metal box but that has it's own issues if it is air tight. The expanding gasses will make the box balloon or come apart quickly.

                      Whatever you do always use a balancing charger for a LiPo or you will have an early 4th of July party.

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                      • #26
                        Originally posted by bonaire View Post
                        If you have this solar panel :
                        Operating Voltage: 15.4
                        Wattage: 28
                        Current: 1.8 amps

                        And have a Li-Po charger from somewhere like www.hobbyking.com.

                        And charge your batter at 1A or less, you *might* be able to charge this from 11am to 1pm with a really good sun day. But without the panel putting out full power, the input amps to a charger will drop and you will get a too-low condition in an RC charger.

                        If you have two of these panels in parallel, the output voltage of 15V and 3+ A may be better.

                        All of this is "experimental" and of course, a bad way to go for anything that is to be used a lot.

                        You can use an 18V Solar panel of say 100W (intended for off-grid battery systems) and clip that to an RC charger and perhaps get successful Li-Poly battery charging with a DC-input RC charger. It's all experimental, of course - enjoy trying things out. But do not charge your Lithium packs directly from a Solar module without using a balancing Lithium charger. Not good at all. Lithium RC chargers stop charging when the voltage of the target cells reach 4.2V. This is the smart-balance charging that these are intended for.
                        Hello Bonaire !!!

                        That's, that`s what I need!
                        Finally, i understand all about my question.
                        Thank you very much !!!!!!!!!!!!!!

                        Now, i think buy one more battery pack, but NOT Li-Ion, because it is can explode.

                        I think for me, for everyday using better LiFePO4 battery pack - no explode, better Cycle Life:

                        http://www.batteryspace.com/lifepo4cellspacks.aspx

                        About solar charge controller i think about controller from GENASUN, like this:
                        http://genasun.com/products-store/mp...ium-batteries/

                        or this PWM Solar Charge Controller:
                        http://www.batteryspace.com/Charge-C...LA-or-LFP.aspx
                        This controller have programmable timer function to turn on load upto a max of 14 hrs after sunset, but it`s not important for me.

                        I think MPPT GV-5 it`s my choice.

                        And maybe, i buy one more same solar panel 28W 15.4V.

                        Total:

                        Solar panel 28W/56W 15.4V 1.8/3.6A

                        MPPT from GENASUN (i think this is a really good quality for everyday and long time)
                        or PWM solar charge controller.

                        LiFePO4 battery pack 12.8V 20-40Ah (256-512Wh)

                        DC-DC/DC-AC converters i already have ))

                        Finally i think it`s all!

                        Thanks absolutely all for you help, wisdom and frendly

                        Have a nice day!

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                        • #27
                          Originally posted by SunEagle View Post
                          I hope you didn't perform your experiment inside. These batteries will cook off and light up very quickly.
                          No, that thing never came inside, it was just an experiment. And I'll add it was one I didn't trust and would never repeat. I'm actually very safety conscience. I don't know what possessed me to try that.

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