question about DIY Solar Garden Light Battery Charge 4 Solar Cell

[Guest]

Im trying to get some answers from people of youtube and other forums. So I figure I ask here

As you can see its just Solar Garden Lights not very powerful but just wondering if you knew that this setup would not make battery go nuclear. like i mean explode upon charging.
I was told before on youtube that the charge regulator. Or the IC chip acts like charge controller?

One other person told me- That the power to low so there is no need to worry that there is no controller in the solar garden setup.

Okay Give me your best
merr Christmass

[Mike90250]

Lithium batteries are so knife edge balance, a sneeze can light them off.
NEVER use a Lithium battery without a charge controller. There will be fire, after 20 or 80 cycles, If you have to ask, you cannot know what the design for safe operation is, and should not attempt it, I'm not trying to sell you anything, I don't want you to burn your house and your neighbors house down.

[Guest]

Its so hard to find a charge controller for tiny devices like this on ebay for AA-AAA batteries.
I havnt been using these devices yet to charge batteries in fear that it will explode. But I have a bunch of dead batteries now and plan on charging them I will stick around of course and watch them charge with bucket of water at my side.

I did a charger that has 8 of these solar cells connected. I will try these ones out to..

I kinda wanna stick to the garden solar lights charger.
but I think i will make couple of these

http://www.instructables.com/id/DIY-SOLAR-LI-ION-LIPO-BATTERY-CHARGER/

[J.P.M.]

I'd do my homework and brush up on extinguishing lithium battery fires - water may not a good idea. A class D fire extinguisher may be a better choice. While I was at it, if I attempted to charge the batteries at all, I'd do it in an environment where the surroundings would not support combustion, like in a sand pit, or a fireplace.

[PNPmacnab]

I don't care if you burn up. Search ebay for TP4056 modules. I buy ten at a time shipped for $3.50. These can take about 8V input max and likely survive a small solar panels voltage and current. They will shut off when 4.2V is reached preventing overcharge. Designed for larger 18650 cells, charge current will be limited probably by panel. They will at least prevent overcharging which takes a toll on battery life.

[Guest]

I'd do my homework and brush up on extinguishing lithium battery fires - water may not a good idea. A class D fire extinguisher may be a better choice. While I was at it, if I attempted to charge the batteries at all, I'd do it in an environment where the surroundings would not support combustion, like in a sand pit, or a fireplace.

Ya I figured I had to use fire extinguisher I was concerned about lithium also. Thanks for the input! I will get this fireextingusher type D class

I am trying to also learn electronics. So I purchasing Electronic starter kits on ebay.

Im so pre-occupied with DIY hobby things these days like micro wind turbines.

I try to be safe as possible working with material always eye protection hasnt dawned on me to get fire extunigsher tho that is good.

Also I dont own a house yet. so I live in apartment but hopefully in couple months i get house.


But I going to charge some battery today see if it get full or not without charge controller.
I was told that the IC Chip in Solar garden lamp is good for cutting off much power to battery and that it is fine with 4 garden solar lamp.
So will see...

[Guest]

So I Charged Up my AAA battery today The solar panel got atleast 5+Hrs of light today. When it got dark the LED would turn on. But battery got charged up.

I recorded it at 1.22volt and 0.06amp charging. I like these solar cells they are so sensitive to light producing plenty of volt easily. Im not sure if 6-8amps could do damage to battery? becuase so small of power? let me know. I was told that since power is so weak that you need not worry. True false?

[Sunking]

So I Charged Up my AAA battery today The solar panel got atleast 5+Hrs of light today. When it got dark the LED would turn on. But battery got charged up.

I recorded it at 1.22volt and 0.06amp charging. I like these solar cells they are so sensitive to light producing plenty of volt easily. Im not sure if 6-8amps could do damage to battery? becuase so small of power? let me know. I was told that since power is so weak that you need not worry. True false?

Neither True or False as it is not a valid question.

Those are NiMh batteries. THERE IS NO SUCH THING as a AAA Lithium Ion battery. Now there are so called AAA Lithium batteries, but those are Primary cells. (Not rechargeable)

Any decent Solar Lighting use NiMh cells and require no controller of any kind other than a photo detector to turn the light on/off and maybe a 1-cent diode to prevent the battery from discharging into the solar panel at night. . How do I know?

Well to start I am an engineer, and most importantly NiMh cells are 1.2 volts. Lithium for all intent and purposes are 4 volts and do not play well with moisture, water, heat and cold. Not to mention extremely expensive, short lived and require expensive controllers. That is why they use safe simple and effective NiMh cells. There is no advantage to using Lithium, and you might be able to find some, but smart money uses NiMh. Solar Landscape Lights typically use a 1/10 to 1 watt 2 volt panel and NiMh cells. To charge a single cell lithium battery requires at least a 5 volt panel and an expensive controller device.

Another tip and clue. NiMh cells need NO CONTROLLER of any kind. Just a current source like a Solar Panel. Cheap and effective that people can afford and safe to use.

[Guest]

Neither True or False as it is not a valid question.

Those are NiMh batteries. THERE IS NO SUCH THING as a AAA Lithium Ion battery. Now there are so called AAA Lithium batteries, but those are Primary cells. (Not rechargeable)

Any decent Solar Lighting use NiMh cells and require no controller of any kind other than a photo detector to turn the light on/off and maybe a 1-cent diode to prevent the battery from discharging into the solar panel at night. . How do I know?

Well to start I am an engineer, and most importantly NiMh cells are 1.2 volts. Lithium for all intent and purposes are 4 volts and do not play well with moisture, water, heat and cold. Not to mention extremely expensive, short lived and require expensive controllers. That is why they use safe simple and effective NiMh cells. There is no advantage to using Lithium, and you might be able to find some, but smart money uses NiMh. Solar Landscape Lights typically use a 1/10 to 1 watt 2 volt panel and NiMh cells. To charge a single cell lithium battery requires at least a 5 volt panel and an expensive controller device.

Another tip and clue. NiMh cells need NO CONTROLLER of any kind. Just a current source like a Solar Panel. Cheap and effective that people can afford and safe to use.

Sorry I dont know why I say Lithium. Is cus I been working with some Lithium battery which are expensive and big.
Stupid me I mean NiMh my bad.

-so are you saying I dont need a controller for these batteries even if I do Use lets say. 1.2volt @0.25amp? and higher?? Do I have to worry about overcharging the batteries. Yes and No would be good enuff answer

So you are engineer do you have website?

[Sunking]

Yes and no.

Sorry for the conflicting answer. NiMh and NiCd are either the most difficult or easiest to charge. If you charge faster than >= C/10 (fast), then require special Delta V and or Delta T chargers using a current source. C/10 means 10% or more than the battery capacity rating. Example if you have a 2500 mah cell .25 amps or higher. Slower than that then does not require any special controller at all. just a current source than can provide the required current up to 1.6 volts until eternity.

With solar you can pretty much throw all the battery charging rules away because all the rules are written for commercial power which has no power or time limits. Solar is extremely limited in both Power and time of use. Example a 10 wat panel does not generate 10 watts at any time of day. At best generates 7 to 9 watts a few minutes around solar noon. This is why solar daily output is calculated by Sun Hours and do not think because th esun is shining for 14 hours a day means 14 Sun Hours, more like 4 to 5 Sun Hours. At very best a 10 wat panel can generate up to 40 or 50 watt hours per day. Add in efficiency of 50% efficiency of a NiMh cell down to 20 to 30 watt hours.

However you need not concern yourself with Watts as you could care less what the wattage is using a panel to charge NiMh batteries. All you care about is what the panels Imp panel current rating is and keeping it between C/20 and C/5 of the battery. Using the 2500 mah example again .125 to .5 amps. As long as the Panel Voc voltage is greater than 1.5 volts for every cell in series is all you want to know. At .5 amps could be as low as 0.75 watt panel for a 2-cell panel up to 35 watts for a 70-cell panel. The battery will only use up to a maximum of 0.6 watts. How much money and power can you afford to throw away? Issue is the 2-cell 1 watt panel wil be about as expensive as a 20 watt standard 32-cell 12 volt battery panel. All you care about is Imp.

However there is a Trick. How to size the battery to the LED. With a Landscape light you want to size the battery to discharge roughly 80 to 90% each night. To do that you need to know what the LED current is x the maximum number of hours the LED is On for each night. Eaxmple lets say LED uses .15 amps and it needs to burn 14 hours every night to discharge no more than 90%. You would need a NiMh cell = .15 amps x 14 hours / .9 = 2.3 amp hours or 2300 mah. Go shop for a 2500 mah cell.

Now for panel current depends on how few Sun Hours you get in the shortest day months. Say 4 Sun Hours. I and you could careless what wattage it is as long as the Imp roughly equal at least 2300 mah / 4 h = 0.575 amps. With only 2-cell panel 1.5 volt panel would be roughly 1 watt, up to say 10 watts for a standard 36 cell 12 volt battery panel. Ironically the 10 watt panel is likely less expensive.

The forum prevents me from telling you my web address. Even if allowed would be of no use to you unless you want to build a large scale power plant for cities or large scale solar battery systems for commercial use. I retired and gave it all to my Son and Partners. I just do consultant work now days to give me something to do when not playing golf in paradise. At age 60 I have no need for work or money anymore.

[Guest]

I understand Voltage Needs to be higher than the rated battery of 1.2v Rechargeable. So., my next question is How much Volts is Too much volts for 1pcs. AAA-800mAH NiMH

Say voltage drops below 1.2v does the battery stop charging? Whats the max Vmp for A battery of 1.2v

From your example.
you said

"C/10 (fast), then require special Delta V and or Delta T chargers using a current source"
"panels Imp panel current rating is and keeping it between C/20 and C/5 of the battery. Using the 2500 mah example again .125 to .5 amps"

Do I need Delta V or Delta T if I use C/5 .50 amps? you said that .25 amps or higher you dont need controller but then you also stated that you need require Delta V or Delta T charger?

Slightly confused by this.

[Sunking]

Say voltage drops below 1.2v does the battery stop charging?

It stopped charging at 1.4 volts

Whats the max Vmp for A battery of 1.2v

Batteries do not have Vmp, that is strictly a Solar Panel term. Batteries have nominal voltage which has little to do with charging voltage. Battery charge voltage is a product of the charge current. open circuit voltage the internal resistance of the battery, and the battery SOC. Example a 12 volt 100 AH battery with an open circuit voltage of 12 volts. (copletely discharged) will only go up to 0.1 volts for each 10 amps of charge current despite you setting the charge voltage to 14.4 volts. The battery is charge several hours later after it finally reaches 14.4 volts and charge current stops.

A battery rated voltage is nominal, and for NiMh is 1.2 volts. However if you read th evoltage open circuit wikll range from .8 volts dead to 1.4 volts fully charged.

From your example.
you said

"C/10 (fast), then require special Delta V and or Delta T chargers using a current source"
"panels Imp panel current rating is and keeping it between C/20 and C/5 of the battery. Using the 2500 mah example again .125 to .5 amps"

Do I need Delta V or Delta T if I use C/5 .50 amps? you said that .25 amps or higher you dont need controller but then you also stated that you need require Delta V or Delta T charger?

Slightly confused by this.

That is because you missed when I said the rules are written for chargers using commercial AC power. For AC power charger on Nickel batteries there is Fast and Slow. For fast charger you apply a Constant Current of C/5 up to 1C until 1 or 2 things happen or both. When the voltage or temp starts to shoot up over a specified amount of time. Terminate the charge or the battery will vent. If it feels warm, STOP. Technically Slow is C/10 or less. You apply a Constant Current of C/10 or less until you die. Have your survivors turn it off after the funeral and throw it away. Either way the designers us 1.5 volts supply for each cell in series. I have a Charger that will charge from 1 cell up to 27 cells in series. I use a hybrid method algorithm that charges fast at C/2 until Delta Voltage Bump is reached, then it backs off to c/20 until I either die, or turn it of and use the battery. It keeps the battery fully charged until I use it.

With Solar none of that is remotely possible and all the rules and design changes. Well it is possible to do harm if you say use a C1 charge current with too high a voltage will explode the battery Day 1

Try reading this White Paper as it describes all approved charging algorithms using a commercial AC charger. Keep in mind that is written for commercial AC chargers. With Solar you have a decent size window and have to make a design decision of not enough to more than enough. With Solar you deign for extreme worse case. In winter you size the panel to just make slightly undercharged, In Summer it has to be over charged, but not so much it damages the battery causing it to vent. Look for a panel voltage with no less than than 1.5 volts per cell and no more than 2 volts per cell. Good luck trying to find such panels and if you do will pay a premium. Do what most DIY use, salvaged Landscape lights from Chi-Coms.

Last tip determine you winter sun hours. Say 4 hours. Select as low of a voltage panel as you can with a Imp of C/4. Got shade half a day or live in Seattle and you are SOL or completely oversize the battery and panel to match. Once you drop below 3 Sun Hours in winter, Solar is pointless and battery systems become too expensive and extremely dangerous.

Good luck and hope that helps.

SK

[PNjunction]

We are over-complicating things.

If you want to get the low down on how to properly charge dinky nimh or lithium, be sure to also visit the Candlepowerforums. (aka "CPF"). Or Budgetlightforums (aka "BLF").

http://www.candlepowerforums.com/vb/...eries-Included

Basically, this cuts down on the repetition you may find here, as good as we are.

From a practical standpoint, the use of nimh batteries in solar garden lights has been superceded by the the use of lithium batteries. HOWEVER

That does NOT mean using the common 3.7v "18650" (although that is merely a size, not a chemistry designation) such as those found in your laptop. Or seen on instructable articles that foolishly include "Ultrafire" batteries and promote unsafe projects made out of used / counterfeit trash.

These days, solar garden lights are made with a different lithium chemistry, which is far safer. LiFeP04, which is a nominal 3.2v cell.

If you want, you can basically pull apart a $5 solar garden light powered by LiFeP04, and get panels, cells, and charging boards all in one swoop. Start with a NEW one found at your local home hardware store.

As always, *any* battery needs to be handled safely, regardless of chemistry.

[Guest]

PNjunction what is wrong with Ultrafire batteries? They make a LED last a long time better than AA-AAA?
The Ultra Fire Battery I have is 18650 3.7v and 9800mAh

So lets see if I get this straight..


So A 800mAh battery .80 amps? is okay for charging? at C/10?
Is that how you calculate how much amps you need to charge?

What is Chi-Coms? I get my solar lights for $1.25 piece. I got lucky on Ebay and there was a seller selling 300 of these tiny cells all deconstructed just solar cells for pretty cheap.
Im sure I have well over 700 of these tiny solar cells.

Say I wanted to charge 20pcs AA- I had Solar panel that produces 1.5v and 0.80. Would These 20batteries charge? What would happen?
Im probably going to ask alot of stupid questions.

Is possible to make Solar panel or battery in closed circuit?

All this information is new im learning it all or try to. some words you use is unknown to me. such as c/10.

this is good information and little overwhelming

[Sunking]

So lets see if I get this straight..


So A 800mAh battery .80 amps? is okay for charging? at C/10?
Is that how you calculate how much amps you need to charge?

Completly arsebackwards. C/10 = 800 mah / 10h = 80 ma or .08 amps. You only mised missed by a factor 1000. Hit them with 80 amps and they explode in your face.




What is Chi-Coms? I get my solar lights for $1.25 piece. I got lucky on Ebay and there was a seller selling 300 of these tiny cells all deconstructed just solar cells for pretty cheap.
Im sure I have well over 700 of these tiny solar cells[/QUOTE]

Chi-Coms = Chinese Communist. Counterfeit copies or junk. That is why they are cheap and over priced for what you get.