# inflight charging of the batteries through solar panels

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i am working on a project of a solar powered flying wing.
i am using a motor having an operating current of 40A and run by a battery whose capacity is 5000mAh and voltage is 18.5V. the battery gets discharged in 15 minutes.

i want the batteries to be charged from the solar panels in such a way that the solar panels charge the battery before it gets discharged resulting in continous running of the motors.

what current and voltage should the solar panels give to charge the batteries??

what components are required to build up an inflight charging system??

All help would be appreciated.

Shuja.

• Solar Expert Posts: 101 ✭✭
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Re: inflight charging of the batteries through solar panels

Is this really something you are "working on", or are you trying to get someone else to do your homework for you, which is certainly what this sounds like, at first read-through.
:roll:
Generally people who actually work on such projects are able to do basic math, which will answer most of the questions you ask. It won't answer the questions of what happens in real application, since that is rather more complicated. You won't learn anything if you don't do the homework... yourself.

It is interesting that you're claiming to run a 40 amp load for 15 minutes (10 amp-hours) from a 5000mAh (5 amp-hours) battery - does the motor draw less than 40 amps in actual use, is there some sort of switching conversion to a lower voltage...?

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Re: inflight charging of the batteries through solar panels

actually i am doing aerospace engg. and my focus in the engg. is designing of the air vehicles. we are introduced with very basic electronics just to solve simple problems. our major focus is on the mechanical side.
i calculated the power required for my plane and looked for the appropriate motor. the battery was recommended by the hobby lobby support people.
and there is no such conversions involved.
i just want to get a start about the systems designed to charge batteries through solar panels.
• Solar Expert Posts: 101 ✭✭
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Re: inflight charging of the batteries through solar panels

Well, the basic requirement is that your solar panels need to provide at least enough voltage and current to run your motor - and they need to provide a bit more if you want to charge a battery, though a battery that only allows for 15 minutes without sun might prove to be more bother than it's worth.

NASA had or has a big project along these lines, with a goal of being able to loft a platform that could remain in flight for very long durations - flying above cloud level, and with adequate battery and glide capacity to stay aloft overnight, though I don't recall that they had ever achieved the latter, and I don't know if the project is still active; web page was last updated in March.

http://www.nasa.gov/centers/dryden/news/FactSheets/FS-054-DFRC.html

Efficiency and weight of the cells becomes a big issue in trying to fly them. Non-ideal orientation to the sun reduces performance more.
• Solar Expert Posts: 10,300 ✭✭✭✭
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Re: inflight charging of the batteries through solar panels

if memory serves me i believe they achieved a worldwide flight without batteries and stayed exposed to daylight. i can't say for sure if that was a worldwide flight, but staying exposed to daylight was the requirement. i can't swear they had no batteries either, but if they did it was minimal.
to power a motor with 40a requires a great deal of pvs. this adds much weight and they used special lightweight amorphous pvs to achieve that. i don't remember the motor requirements for their plane, but you can see by ecnerwal's pic that it has a huge wingspan to help accomodate the many solar cells it needs as well as for better gliding, just in case. i might add that this would not be my preferred way to travel as safety would be a grave concern being it requires the sun's presence to work.
• Solar Expert Posts: 9,583 ✭✭✭✭✭
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Re: inflight charging of the batteries through solar panels
niel wrote: »
i might add that this would not be my preferred way to travel as safety would be a grave concern being it requires the sun's presence to work.

Whe the sun goes out, we will all be in trouble.
Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

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• Solar Expert Posts: 10,300 ✭✭✭✭
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Re: inflight charging of the batteries through solar panels

i guess we are in trouble every evening then. have you done very many solar flights at night mike?:D:p