### Can I make a solar power source with a car battery, 5 watt 12v solar cell, and 12 volt to 110 vac 400 watt inverter? Answered

The title sort of says it all but what I am wondering is  if the solar cell can keep up to the inverter...

Question by Super_Nerd 7 years ago  |  last reply 4 years ago

### solar cell amperes

Lets say I have a solar panel that gives off 5 volts at 30mA. if I were to put a ten ohm resistor in series with it would There be basically no effect because a 10ohm resistor woulkd limit it to half an amp, which is way more. Or does the solar panel act like ~ 167 ohm resistor, and adding a ten ohm resistor will limit it to 28mA?

Topic by guyfrom7up 11 years ago  |  last reply 11 years ago

### Math help needed for converting volts/watts in solar

Here's what I know: Watts (P) = Amps (I) x Volts (E). What I don't know is if I have a solar panel that is rated at 12v, 0.125 mW I can do the above equation to get that my amps are 0.01. Does that sound right? My real Q, is what is the best power battery to store this energy? Should I only use 8 "D" cells? Could I use a 12 v motorcycle battery? If I use Ni-Cd batteries, is the fact that the batteries are rated at 2500 ma make any difference? Is there a website where I can get a good feel for what batteries are good for what type of activity, solar cells, etc? thanx, sam

Topic by wanzie 8 years ago  |  last reply 8 years ago

### Solar Light box

Hi, I would like to make a lightbox and charge it from a Solar cell . I saw a 5v ledstrip online , but I am wondering wich battery and wich Solar cell I have to buy? I mean how much voltage en watt does this ledstrip need? Wich diode do I need?  Another question: I want the Solar cell to charge during the day and I need it's power during the night , do I have to do something special with it ? I mean in the most cases you will have the energie richt away, that is not my plan .... I rather not use an on and of switch , I want to use it automaticaly.    I  just started with the diy adventure? Forgive me :)  greetings deborah

Topic by DeborahM8 3 years ago  |  last reply 3 years ago

### 12 Volt 5 Watt Solar Panels- \$19.99

UL Solar has 12 volt 5 watt solar panels for \$19.99. I bought a couple of these about 2 years ago. The price has not been this low since then.     http://www.ul-solar.com/5_Watt_12_Volt_multicrystalline_solar_panel_p/stp005p.htm Luxstar is not affiliated with UL Solar.

Topic by luxstar 6 years ago  |  last reply 6 years ago

### solar cell 100 watt operating voltage 21.4 , operating current 4.7, will it damage a 12 volt batteries?

Question by parhamw 3 years ago  |  last reply 3 years ago

### Solar power questions? Answered

I have this same solar panel 5 watt 12 volt panel  http://store.bruntonoutdoor.com/portable-power/panels-and-chargers/solarflat-trade-5-12v-orange/ And a 400 watt power inverter. What type of lightweight battery should i get? (12 volt, something amp battery)

Question by alpe_97 7 years ago  |  last reply 4 years ago

### LEDs Driveway Solar Setup

Help with LEDs (2 Part Question- Answer what you can) I got a reel of 5 Meters SMD 3528 Epistar LEDs Power Source: 12 Volts DC Wattage: 60 Watts Power Consumption (W/m):18 Watts / Meter LED Chip Model: SMD 5630 LEDs Number/M: 60 pcs / Meter How many Amps needed in a charge controller? Solar Cells Average Power (Watts): 2.6 Wp Average Current (Amps): 5.2 Imax Average Voltage (Volts): 0.5 Vmax Do I need to wire the solar cells 3 in series to reach 15.6 volts (Calculated loss so not 12v) and then parallel to reach 60 watts for the LEDs? (I plan to have around 70 watts just for incase and rely on the charge controller to lower voltage to 12V.) ------------------------------------------------------------------------------------------------------------------------ (I am using a standard car battery. An old one that has lost a lot of juice, but I tested the LEDs on it and it still works.) Is this okay? Am I doing things right? Thank you all for your help!!! :o)

Topic by Learning Exp 4 years ago

### Solar Cell/Panel Wiring?

Here I have 2 questions inside a question. 1. How to connect 2 or more solar cells/panels; series, parallel or some other, third way so....for example if I have 3 solar cells that give 5 Volts each, I connect them in some way and in the end have 15 Volt coming out... My question is hot to connect the solar panels to the the output described??? 2. Now that I have, for example 15 Volts coming out from these 3 small panels, I need to store that electric energy somewhere...So would a diode just to ,point, the electricity and a ultra capacitor to store it ,or does it have to be a circuit that involves rechargeable batteries and a special recharger circuit.

Question by comodore 10 years ago  |  last reply 7 years ago

### When to use solar cells w/ 5 to 8 amps vs. cells with 3.5 amps?

What are the ups and downs of using solar cells with higher amps like 5 or 8amps does it all break down to use of space? Do you have any examples for me?

Question by golfdeals 9 years ago

### how many watts for two freezers will i need to make solar panel?

Im trying to power two 4 amp 115 v 60 hz freezers for an icecream truck by using a solar panel but am having trouble figuring out how many solar cells i am going to need or watts i will need so i can figure out how many cells. i dont know if the voltage is right on the cells when they produce the right watts. any one know how i can figure this out?

Question by vampseve 9 years ago  |  last reply 4 years ago

### I'd like to replace 2 c batteries with solar cells, to run a toy? Where can I buy the solar cells?

How much solar power do I need (do I need to measure both watts and Amps)? Where can I purchase the solar cells, inexpensively? This is for sunlight use, only. If I want to store the energy for nighttime use, also, what will I need?

Question by 10 years ago  |  last reply 10 years ago

### How to wire this solar cell?

Hey there! I'm a beginner in solarbots and I just acquired a couple of paper thin solar cells that are paper thin and about 5 by 5 cm. The backside seems to be plain paper or something. I already broke one! I can't figure out how to wire or solder it, that is where the plus and minus poles are. Can someone give me a hint? Thanks! Sebar

Topic by sebarr 7 years ago  |  last reply 7 years ago

### Which wiring option is better, left or right? Answered

I am constructing the 60 watt panels listed on the site, I want to know what is the best method for joining the top set of cells with the bottom. See drawing if I upload right. Thank you.

Question by pokey02 9 years ago  |  last reply 9 years ago

### Solar charge circuit question

Hi, I have a 12 volt / 0.5 watt solar cell and I am hoping to charge a 9 volt / 200 mAh rechargeable battery with it. I think I have a suitable diagram for the circuit here... http://www.flickr.com/photos/oskay/2963306721/ I was wondering if using a 12 volt cell was ok for charging the 9 volt battery? Would I need to add resistance to the solar cell to bring it down to 9 volts? If so where would I add the resister to that diagram? If it's relevant, the load will be a fan. Thanks.

Topic by horsebones 7 years ago  |  last reply 7 years ago

### Small PV Solar Cell Charger Questions

I volunteer as a ski patroller at a ski resort in northern Vermont.  Like many other ski resorts, we monitor Family Radio Service (FRS) Channel 9-11 for skiers who might get lost or hurt within our resort's boundary or sometimes outside the resort boundaries.  Due to the FCC restriction that FRS channels are limited to only a half watt (0.5w) they have very limited range.  So in order to monitor channel 9-11 effectively, we keep FRS radios plugged in all over the mountain in all of our ski patrol huts where there are always patrollers on standby in case of injuries or lost skiers.  One of our huts does not have any electrical power, so we are constantly cycling freshly charged radios to and from that hut, almost every day.  It would be a lot less of a nuisance if we could charge that radio with solar power.   On the wall outlet plug for charging station for the radios we use, the label says the power output from the ac/dc adapter says it outputs 9VAC 200mA.  I assume this means 9 volts alternating current at 200 milliAmps.  Could I simply find a PV solar cell that outputs 9 volts a/c and connect it to the wire that runs into the radio charger?  Most of the PV cells I found online have a watt rating, but I'm not sure if that matters or not.  Where is a good place to find a specific PV cell for this purpose, for reasonable price? If anyone person in the Northeast is able to offer significant help for this, I could probably take care of one free lift ticket for your time and help.  I'm also posting an image of the wall outlet plug label and charging station. Thanks, David

Topic by dtepper 7 years ago  |  last reply 7 years ago

### Why can I recharge lead acid batteries with solar but not lithium ion?

I just got a 5 watt solar panel and started experimenting with it today.  I want to use it to charge a single 10 watt hour/2.5 amp hour 18650 lithium ion cell.  The solar panels have an open voltage of 22 volts.  I connected the solar panel to an anyvolt3 (boost/buck power regulator), set the anyvolt3 to put out 4.2 volts, then connected  the anyvolt to the lithium cell with a blocking diode.  I accounted for the voltage drop of the blocking diode and the panels charged the lithium cell at .1 watts.  Pathetic. Then I tried charging a 20 amp hour Werker sealed lead acid 12 volt battery.  I set the anyvolt to 14.4 volts.  The panels charged the lead acid battery at 4.5 watts.  Thats pretty good.  Now why can I charge the lead acid but not the lithium.  The lithium is what I really want to charge because i want to use the solar panel to charge lithium cells when I go on long bike tours.  I don't want to take any heavy lead acid batteries on my bike trip. Thanks

Question by Noblenutria 5 years ago  |  last reply 5 years ago

### Do anyone out there have know-how to made solar cell from scratch?

Please advice how to made "3 x 6 solar cell, 1.8 ~ 2 watts, 0.5 volts". Question 1 : Home Made. Note          : I know they are out there make to stock awaiting for buyer. Question 2 : Where to looks for Step-by-Step Guideline. Thank you in advanced.

Question by GearUp 6 years ago  |  last reply 6 years ago

### How to wire small solar cells to increase voltage?

I need 10 solar cells that each produce .57v and .4 amp to be wired together to produce 5 v and 4 or 5 amp. (Series? Parallel? I just can't understand them very well!)A simple drawing would be the best :)Thank you all soooooooooooooooo muchSolved! Thank you for the help! here is a diagram of my solar charger (from what i learned here)

Question by nepheron 9 years ago  |  last reply 9 years ago

I need to charge my iphone on the go, i have solar cells in an array to total up 4.5 volts, i have a diode ( black, gray stripe on one end) connected to a female USB plug, the little iphone adapter puts out 5 volts, please help me if you can! thank you for your time!

Question by led235 9 years ago  |  last reply 9 years ago

### my solar setup wont work with my joule thief, it just bypasses it. why?

I got a few solar cells wired up in a series to produce around 4 volts, so to get more power from it i connect it to a joule thief i made but the power goes through it and isnt boosted at all. the joule thief works. at 1.5volts it makes around 5 volts. so i cut the power on the cells to 1 volt thinking im overloading the circuit but it is still bypassed.  i even connected a couple of capacitors to the solar cell to trick the joule thief into thinking the solar cells are a battery but still no luck. my question is why doesnt the joule thief boost solar cell power but will boost a dead AA battery?

Question by florlayamp 7 years ago  |  last reply 7 years ago

### Designing a Solar powered sign. Need help determining how many watt solar panel? Answered

I am trying to run a sign off of solar power. The sign has 40 LED modules. Each module has 3 individual leds. The specs for each module are 12v, consumes .7 watts, and 50 mA. Multiplying watts and amps by the number of modules you get 28 watts and 2 amps. I'm looking at solar panels from walmart and they come in 10,15,20,30 ,60 watt panels. If the sign is ran 12 hours a night(6pm-6am), That means 28 watts x 12 hours = 336 watts used per night. If the solar panel gets 8 hours of sunlight to charge(8am-4pm), that means 336 watts/ 8 hours means I need a 42 watt solar panel? Also, how big of a battery do I need? 2 amps x 12 hours = 24 AmpHour battery? EDIT: I'm going to use a 12V timer relay so I can run the LEDs from 6-11 pm and 5-7 am. This decreases the on time to 7 hours and 196 watts. With 8 hours of sunlight, that means 25 watt charge. Also 2 amps x 7 hours = 14 AmpHour battery.

Question by tallemertes 3 years ago  |  last reply 3 years ago

### charging lithium ion battery with solar instead of lead acid battery?

Iam using a 6v, 4.5ah lead acid battery to power my 6 leds each of 0.20 watts for around 10 hours . also i am recharging the battery with a 5 watt solar panel . now i want to switch to 3.7v, 5.2ah lithium ion battery. will it work ?

Question by rockyYyY 3 years ago  |  last reply 3 years ago

### Solar Powered Drip Irrigation

Hi. I am in the process of designing and building a balcony garden with drip irrigation for multiple 3' x 1' planter boxes. The idea is to automatically water with a reservoir pump attached to drip line. There is no water or electrical outlet, so it has to be off grid. This being my first solar project, advice and assurance would be much appreciated. The pump would be turned on for about 1 hour every other day or so, this being hot Miami.  Diapragm Pump (12 Volts, 3 Amp draw): should generate enough PSI for the drip line http://www.ebay.com/itm/100PSI-DC12V-4L-Min-Solid-Electric-Diaphragm-Water-Pump-Self-Priming-for-RV-Boat-/281366070408? UPG UB1250 Sealed Lead Acid Battery (12 Volts, 5 Amps): http://www.amazon.com/UB1250-Sealed-Lead-Acid-Batteries/dp/B001DL9IBC/ref=zg_bs_389574011_9 ALEKO® Solar Panel (5 Watt, 17.5 Volt VMP): http://www.amazon.com/ALEKO%C2%AE-5W-5-Watt-Monocrystalline-Solar/dp/B0046HE62G/ref=sr_1_7?s=lawn-garden&ie;=UTF8&qid;=1450573836&sr;=1-7&keywords;=5+watts Docooler Solar Charge Controller (20 Amps, 12 Volts): http://www.amazon.com/Docooler-Controller-Battery-Regulator-Protection/dp/B00L37KZI6/ref=sr_1_3?ie=UTF8&qid;=1450580867&sr;=8-3&keywords;=charge+controller Main concerns: Will the battery and other electronics be able to function through the 100+ degree days of Miami? Does the system have a good power supply? Is the equipment good quality to last 3+ years? Thanks for all the input and insight!

Topic by bzand 3 years ago

### Can I power a motor off a solar 12v cell?

Hi, I have a 12v, 0.5 watt solar cell and wanted to use it to power a motor without the use of rechargeable batteries. Basically, when the sun is shining, the motor is spinning. I have a few small motors lying around and tried to hook them straight up but none of them would turn (even though some of these will run off a 1.2v AAA battery). I'm guessing maybe there aren't enough amps to power the motor so I was wondering if there was any way to bring down the voltage and increase the amps so that it might work? Thanks.

Topic by horsebones 7 years ago  |  last reply 7 years ago

### solar panels questions

In the quest to turn my garage 'green' I started with a purchase of a Sunforce 60 watt solar panel charging kit. I already own a 12v 15amp charge controller that I bought from Green Energies. The Green Energies controller is bigger than the kit supplied so I'm currently using this one. My questions; The Green Energies charge controller is supposed to have a blocking diode in it. When I put my volt meter on the leads going back to the panels (panels dis-connected, controller still hooked to battery) I'm getting approximately 10 volts. Should there be any reading at all? I went out this rainy morning to see if there was any power coming from my panels. To my surprise I read 8-10 volts (depending on cloud cover). This leads to my next question. It is worth adding a boost converter? I suspect the amperage would only be that of the incoming voltage, not what it is boosted up to.. Close? If my guess is correct, my 5amp (system at full power, rated at 24vdc), would only be about 1.6- 2 amps @ 8- 10 vdc. I also suspect the controller is stealing some amperage. 0.5 amps??? That should leave me with at least 1 amp coming in and giving me a 10 amp day. Not bad for a rainy day. Right, wrong or hopefully close? I'm not seeing my battery come up to full charge. I'm using a marine deep cell acid battery from my boat. Every 5 years I replace it to insure the boat will start as needed. Paddling that craft back to shore is not an option. One reason could be the fact of the battery being 5 years old and it will never get back to full. Second I believe would be the draw going back to the panels at night. Will the panels draw power?

Topic by olddawg 10 years ago  |  last reply 10 years ago

### Solar Powered Dehumidifier Help

Hey guys. My dad, my brother and I have been pondering the idea of a solar-powered de-humidifier. So, it would charge using the sun's rays, and then use its power in the dehumidifier. This is something that could be used in parts of Africa with 100% humidity, and not alot of water. It is the perfect tool for anyone to use to obtain fresh water, by harnessing the sun's rays. We have a dehumidifier, and we really want to make it Solar Powered. We just need help in the way to power it.Would we charge a rechargable battery using the Solar Rays, or would we run it on solar power alone. The solar panel that I have been looking at is the Sunforce 50022 5 Watt Solar Battery Trickle Charger. Do you think that that Solar Panel is good enough? It is 5 Watts, so how would we connect it to our dehumidifier? This was the solar panel in the most recent PopSci used in the How 2.0 section. It is used to charge personal electronics. Thanks in advance.

Topic by Brennn10 11 years ago  |  last reply 2 years ago

### Top 5 new Instructables for this week

Check out the new Instructables that have gotten the most pageviews in the last week. All of these Instructables have been published on May 1 or later.Last week we saw a lot of metal and circuits, but this time around it's all about food and solar and make-up. Oh, and three of these Instructables were made by Instructables staff, two by scoochmaroo and one from me. Glad to see that so many other people are as excited about tearing apart Gummi Bears as I am. 5-minute Ice CreamWARNING: The Following Instructable Is Extremely Addictive. Not for the Faint of Heart.You are now always only 5 minutes away from Ice Cream. Are you prepared? also works... posted by scoochmaroo on May 5, 2009 Gummi Bear SurgeryGummi Bears live short lives, but that doesn't mean that they don't have health problems and will occasionally need some care. There are times when these delicate bears will e... posted by fungus amungus on May 4, 2009 How to make a solar iPod/iPhone charger -aka MightyMintyBoostI wanted a charger for my iPodTouch and the MintyBoost was definitely my first choice. I wanted to take it a bit further and make it not only rechargeable but also solar power... posted by Honus on May 2, 2009 My home made solar cell step by stepHere is a low power low efficiency photovoltaic cell that you can make you own in the kitchen with materials from the hardware store.This cell is made from cuprous oxide ins... posted by alessiof76 on May 3, 2009 DIY Mineral MakeupMineral makeup is more than just a new beauty trend - it offers health benefits for skin as well. And now you can make it at home!It's made of all natural, finely ground min... posted by scoochmaroo on May 4, 2009

Topic by fungus amungus 9 years ago  |  last reply 9 years ago

### First solar project. How do i connect a small solar panel to a batter to then supply power for a outlet?

So this is my first time taking a dip into small electrical work. I would like to take a small solar panel and use it to charge a small battery that could supply 5 watts of power for about 4-5 hrs through a standard outlet plug. what would i need to do so and any other guidance would be appreciated.

Question by aoihane 9 years ago  |  last reply 9 years ago

### How do i connect bypass diodes to my series/parallel PV panel?

I have 20 solar cells of 0.45V at 100mA i have connected the first string in series so this will give 1.8V at 100mA with 5 strings horizontally this total of my PV is 1.8V at 500mA my question is how do i connect bypass diode to this it is a 4x5 panel at 180*130 a diagram will be great thanks

Question by jagrai 5 years ago  |  last reply 5 years ago

### What type of solar cell/battery for a garden lamp?

I was looking at an instructable (https://www.instructables.com/id/Solar-Powered-Light-Graffiti-Projector/) involving a garden light hooked up to a red led instead of a white one. It shoots a picture out at night onto a wall or something like that.I'm wondering if the garden lights are too dim or don't charge fully. We used to have some lights of those type, but they would make a dim light for about 5 hours, then emit a very very weak light. I'm thinking about just buying a trickle charger from here, then getting a bright green or blue led, batteries, and waterproofing it. The problem is, I have nil knowledge about solar chargers/what voltage to use.Can anyone help?

Topic by Carmelite 10 years ago  |  last reply 10 years ago

### Solar charger solution for a rural village

As a nonprofit we are looking to adopt a solar technology to provide power for a rural community in Africa for: 1. charging cells phones It should be able to charge at least 5 cell phones at a time 2. charging small electronic cameras batteries It should be able to provide enough power for charging the batteries. 3. Durable and water proof We are looking for a solution that will last longer and provide service to the community If you know a solution we can buy, implement ourselves , or can provide us with solid suggestions for choosing a solar charging system, please let me know. thanks

Topic by dcasmr 9 years ago  |  last reply 9 years ago

### HOW MANY SOLAR PANEL OF WHAT WATTAGE WILL I REQUIRE for my LOAD ?

I want to basically go green (partially for my house)I figured out the following (Kindly correct me if I am wrong):I calculated the KWhs in following way:(Watts x nos x hours)/1000 = KWhs / day (Correct me if I am wrong)LOAD CALCULATION:Room 1 - - 5W LED x 4 nos x 4 hours per day = 0.08 KWh / day- 3W LED x 1 nos x 1 hours per day = 0.003 KWh / dayRoom 2 -- 5W LED x 2 nos x 4 hours per day = 0.04 KWh / day- 15W FAN x 1 nos x 8 hours per day = 0.12 KWh / dayRoom 3 -- 5W LED x 2 nos x 4 hours per day = 0.04 KWh / dayRoom 4 - - 3W LED x 2 nos x 3 hours per day = 0.02 KWh / dayTotal Consumption per day = 0.30 KWhs / DayNow, I calculated the number of solar panel required in following wayOn an average of 5 - 7 hours of full sunlight / day. On an average in this situation a solar panel will product approximately 0.007 KWhs.Therefor I assume I will require 43 Watts of solar panel, by calculating :0.30 (Required KWhs ) / 0.007 (KWhs / watt of solar panel) = 42.85 Watts (Approx 43 Watts)AREA REQUIRED TO PLACE THE PANEL:I got to know on an avearage 1 SqFt is required for 10Watts of panel.Threrefore I shall require 4.5 SqFt area to mount it.Kindly update me if my calculations are correct.ThanksDevNet

Question by dufferdev 9 years ago

### Solar panel uses??

Hey guys I'm needing the expert opinions of everyone here in the tech section. See I just mounted this 0.5 watt solar panel outside on a L bracket today (not just a couple tiny ones I pulled out of solar lanterns (does anyone want to see what it looks like mounted outside? I didn't think to take pictures until I got inside). Anyways, I've mounted it, ran the wire along the ground and in through my window (drilled a small hole below the window). Connectivity checks out good and I get about 20-21v and the full sun hasn't even hit it yet. The only thing is here though, this solar panel is meant as a trickle charging panel for car batteries and whatnot, and as such I only seem to be getting about 10-15ma (seriously wtf). I just resoldered this charging board from a solar lantern I had laying around, however I have a couple questions. I'm not entirely sure if this little board will handle the current/voltage (however it should as it's fairly low current from the solar panel) I've rigged up the board mostly like it was inside the solar lantern except longer/stronger wires. I have a switch on the positive line of the batt+ to the board. I soldered some thicker wires to the SOL connections on the board. Now I've seen a few of these and some are rather simplistic control boards and some actually have a bit of circuitry to them. This one appears to have resistors to current limit the LED (would be good so I don't blow it), however after following the traces on the board the led get's it's positive from that black transistor thing with 5 legs on it (what is that a power regulator?) The idea behind all of this here is that I can maybe charge up my cell with it or usb devices for example, but to have that come from a battery pack of AA's (to work as a buffer sorta-speak like a capacitor bank). I am a little miffled as how to make this work right the way I want it to. I would assume that once I get the battery pack situated I can disconnect the LED and use that connection for a charging cable, but then it would only provide power when theres no sunlight out (when you turn it on it turns the led on if there is no current coming from the solar panel). How can I do this guys I'm sorry to ask such stupid questions as I know to some of you's it's probably fairly mediocre but I'm a bit dumb.

Topic by Punkguyta 9 years ago  |  last reply 9 years ago

### How do I make a solar charger that would have multiple usb ports on it for charging multiple devices at the same time?

I'm going camping with some friends and would like to make a cell phone / device charging station that could accomodate as many as 5 cell phones at one time.  Any ideas on how to do it?

Question by TheGreyWolfe 8 years ago  |  last reply 8 years ago

### Peltier thermoelectric heat pump, can it be used as Solar Generator?.

Can a 40 mm square Peltier thermoelectric heat pump be used as a solar generator It operates on 13 Vdc @ 5 Amps. Operating at 13 Vdc, we measured the hot side at 190 Deg. F and the cold side at 55 Deg F. I have a 6 foot reflector dish and can add Reok led tracker. How many watts will it generate if it does?. Thanks for your help

Question by talei1 9 years ago  |  last reply 3 years ago

### Solar panel maxes at 1A, but expected 3.6A?

I ordered a DIY kit from amazon. They are super flimsy and easy to break, but I was careful. Each cell was supposed to be 1.8W and .5V, ergo 3.6A by the math. But all put together now (in series) I get 5-5.6 Volts and about 1A max (with meter leads directly on each panel terminal). Voltage seems right, but current seems low. I'd expect somewhere in the area of 10%-15% over/under the estimated max, but this seems very wrong. I am guessing one panel in it is bad or cracked and I can't see it, and is limiting the whole deal. Does that sound right? Can I test the panels using the volt meter on the in/out leads on each cell, or do the other cells interfere after they're connected?

Question by Phoenix17 4 years ago  |  last reply 4 years ago

### How many Volts can a 1.2V Nickel-Cadmium battery take?

Hi! I (still) need some help with building a solar charger... I want to charge a Nickel-Cadmium battery (1.2V) with solar cells from a garden light. Unfortunately these cells give me 5V in full sun... Will the battery take the 5 Volts without damage? The amperage is fine, so no questions about that...

Question by Fypsigon 5 years ago  |  last reply 5 years ago

### Solar Panel Battery Charger

I'm doing a solar panel cell phone battery charger project for school using a 9V, 3.3W solar panel that I bought from here: http://www.ebay.com/itm/3-3-WATT-9-VOLT-SOLAR-PANEL-3-3W-9V-Monocrystalline-Solar-Panel-/130612072684?pt=LH_DefaultDomain_0&hash;=item1e691610ec (I can get around 8V under a light bulb and 10.5V under sunlight.) The circuit is shown in the picture with four, 1/4W resistors because the output is going to a USB cable. The regulator I tried at first was a 7805 from radioshack I noticed I was getting exactly 5V on the output, but only getting 1.5mA of current on the output of the regulator. I've tried the MURATA 78SR, Fairchild LM317T, N.S. LM1804IS, and a few others specifying 5V and 1-1.5A of current but I still only get 1.5mA of current on the output (I need at least 500mA). The phones I'm testing will charge, including a ipod classic, but I'm afraid that the 1.5mA of current is far too small and will damage the battery. I have yet to try using 3W or 5W resistors but I still don't think it would help, I'm also considering using a boost converter to get the current up (also the voltage) and then feed that output into the 7805. Am I doing something wrong? Can I get around 1A of output current from the 7805 by doing something else?

Topic by dan1133 7 years ago  |  last reply 7 years ago

### Self-Solar Powered LED Flashlight? Answered

I know it would not be 100% efficient, or even close for that matter. But I was wondering how much battery life could be "recycled" by directly projecting the light from the flashlight onto the solar panel(s)? Say at a 45 degree angle beneath the light. Obviously this wouldn't be a high output LED, and another question at that.. Would a Red LED be more efficient or would the PV cell not do so well with Red LED? Thought this would be a neat idea even if it would only recycle 5-10% battery life. I would love for someone to implement this idea into a project and see how efficient it is.

Question by xSoFx 8 years ago  |  last reply 6 years ago

### Timer for solar LED dusk/dawn light

I needed a solar recharged, LED light that came on at night. I purchased a small LED light (rather bright with 6 LEDs) that has a solar cell, photo eye and 3 AA size rechargeable batteries. Made to clip on the patio umbrella, it is ssmall and light. The solar cell and photo eye are on one piece. The LEDs, batteries and circuts are on another piece. the two pieces are joined by a wire and are hinged together, allowing the unit to clip on the edge of the umbrella. I plan on removing the hinge and extending the wire to allow a two foot separation. I need to add a timer to this. Something that will turn off the light about 4 to 5 hours after it comes on. I assume it will be something that starts when the LEDs are powered up. Though I guess it may be something that is also triggered by an additional photoeye. Or maybe someone has a better idea? thanks

Topic by jnlvngstn 11 years ago  |  last reply 11 years ago

### SOLAR POWERED BOAT FOR TECHFEST...URGENT HELP NEEDED...?

hey we'r makin a solar powered boat for a techfest...it needs to run on solar power provided by 3 500 W halogen lamps..motor is 6V..we'r usin 6 solar panels of 6.5 V and 900mA..ther's a tunnel for a distance of 400mm(4cm) which means we hv to use capacitors for charging when energy is there nd to discharge when solar cell is not workin...also wer're connecting a diode in series with the solar cell ...we'r usin 5 capacitors of 4500uf each..the problem is that the dischargin time of the capacitor is only 2 sec..i dn think tht will b sufficient for runnin in the tunnel...do we need to add mor capacitors or change the circuit...also suggest if we need to add mor than one motor to increase the speed .plz suggest nd giv us sum tips nd answers..plz event is only 2 days away..plz reply fast....

Question by adipdaniell 9 years ago  |  last reply 9 years ago

### Current limiting for around 10 amps at 12 volts for electrolysis cell? Answered

I am running an electrolysis cell off a modified ATX computer power supply. If I run the cell of 12 volts it will draw around 20 amps which is more than the power supply can handle and causes it to shut down after a few seconds. If I run the cell off the 5 volt port it only runs at around 2 amps, well below what I was hoping to get the cell to run at. Does anyone have suggestions to limit the power to around 100 watts (8-10 amps at 12 volts)?

Question by danlab 9 years ago  |  last reply 9 years ago

### How do solar charge controllers work?

I want to get a 5 watt 12 volt solar battery charger but I want to clear up my understanding of how they work before I get one.   FIrst:  The panel comes with a charge controller.  It says it cuts in at 13 volts.  What does that mean?  It starts charging once the battery drops to 13 volts?  That can't be it because 12 volt batteries range in voltage from 11.9 to 12.6 volts (charged/discharged).   Second:  "12 volt panels" output more than 12 volts right?: because batteries need 14.8 volts to charge.   I think they call it a 12 volt volt panel because it charges 12 volt batteries and not because it outputs 12 volts.  It must really output 22 volts and the charge controller steps it down to 14.8 volts. Thanks for the help Jacob

Question by Noblenutria 8 years ago  |  last reply 3 years ago

### What things I should consider while doing a risk assessment of a project that involves a solar simulator? Answered

Hello I am involved in a project related to PV panels laminated with structured glass. I have to do a risk assessment i.e the things that can delay my project. The things that are involved in it are 5 Solar panel samples (will be laminated outside the country) Sun Simulator (often busy) Need to measure some I-V curves I have got identified some risks but I need to get in depth. Any help in this regard will be really helpful Thanks

Question by raishikoh 6 years ago  |  last reply 6 years ago

### Very Small Scale Power Generation in Developing World

Topic by ragun8 5 years ago  |  last reply 5 years ago

### I have a problem in this code for Arduino UNO , Can you help me?

Question by Fares Mareai 1 year ago  |  last reply 1 year ago

### Circuit Design Help

Trying to build a simple circuit to power a small pump while the sun is out. Here are the specifics: Solar Panel (60 cell mono panel) Open circuit voltage 36.4V DC, Short circuit current 7.96A. Pump 12 V DC, 9A max Using E=IR ,  R=E/I, (36.4-12)/7.96 =  3 ohms Power = V(sq)/R = 24.4/3 =198 watts  I purchased a resistor that meets these requirements and hooked everything in series. (Solar panel lead to resistor, resistor to pump, and pump to other solar panel lead. The pump does not turn on when the panel is in the sunlight. I measure the voltage coming out of the panel and it is within specification. I also tested the pump by hooking it up to a car battery and it works fine. Any ideas what I am doing wrong? thanks!

Topic by OMGIMDUMB 3 years ago  |  last reply 3 years ago

### How can I improve the solar water pump in my bird bath?

I have a small electric water pump in my bird bath, powered by a small solar panel about 4.5" square. According to the literature that came with the pump, it runs on 7V/1.05W of power. The panel battery is 7V/1.2W. In practice, this means that the pump runs continuously when the panel is in direct sunlight (about 5 hours a day) and sporadically when it's in the shade. I would like the pump to run continuously more often. I'm guessing that means I need a storage battery with higher capacity and/or a larger panel. Harbor Freight sells this item, which is 24VDC/1.5W. http://www.harborfreight.com/15-watt-solar-battery-charger-68692.html  What kind of battery would I need, and do I need a regulator as part of the system as well?

Question by yoyology 3 years ago  |  last reply 3 years ago

### solar panel cooler party fun guidance on circuitry..

I am making a "party cooler" i want to add a fm radio and aux port and a usb charge station for atleast 3 devices one multi color time changing led and a removable flashlight white led for the inside (nothting fancy), i have 4 6x6 solar cells rated at .5v 3.5w 6.89a i also want to have the battery bank be able to be plugged in to the wall. i am having problems determining the type of battery to use in the bank (rechargable) i also want it to work for atleast 5 hours(not including device charging), (avg kegger/bonfire/beach fun). if anyone knows what i can add to this thing that would be helpfull. i was thinking of AA batts or possibly a few cell phone batts but if their is a better way. the speakers are 3w each running 5v i havent ben able to determine the fm reciever as of now. or a 3.0 usb charger do the volts and amps have to be specificly 4.7v 5a? or does the +- 25% still apply. if any one has any references to help with simple pcb or freeform wiring are most portable speakers/radios rated 5v? (was in a car accident, lost alot of brain buzz.. be nice (used to build beam bots :P) i would like to try to pick up the basics if anyone has any good refrences. circuit/ electric theory. 38 can cooler bigger rubber wheels will be putting the batt bank on the side under the handle.

Topic by CD_tatro 6 years ago  |  last reply 6 years ago