Solar Charger - need advice

[Earthling]

I have read several times in Hurricane Sandy experiences a comment on how important it was to have a solar charger for cell phones, laptops, and batteries. I have no experience with this. What do you all recommend? Thanks for your help!!

[Noahs ARK]

We just bought an Opteka BP-SC4000 solar cell phone charger from Amazon. Need to play with it when it gets here.

My battery charger works ok, but I wasn't too impressed so I bought a bunch of 10+ year batteries.

[mgriffith]

There are so many solar chargers out there, it is difficult to recommend any one. I have several 15 watt solar panels for emergency use and built a small platform to hold them and allow me to move them around. Five or six of these 15 watts panels will give you 5-6 amps of 12v power in strong sunlight, enough to charge a good size deep cycle battery or car battery in one day. There are lots of these available on eBay. The 15 watt panels are going for about $75 now, and the more power per panel, the more they cost, but it is generally cheaper to buy the larger wattage panels like 100 or 150 watts, than several of the smaller ones if you can afford $400 or more at one time.

For small battery charging, I picked up a couple of these from eBay. They work, nothing fancy. Charge time depends upon the sun strength, etc, but for $10 each, it's not too much to dish out. There are more expensive ones available if you think these are too cheap. :001_tongue:

http://www.ebay.com/itm/New-Solar-Battery-Charger-for-4-pc-AA-AAA-Green-Power-J15-/310434386803?pt=Battery_Chargers&hash=item484754d373

One thing though, of course solar chargers rely upon the Sun, so if it is cloudy or at night, you are out of luck. This is a neat alternative:

http://biolitestove.com/

It seems to work, and you can heat up your hot chocolate at the same time. There are several reviews online but I would think this is only good for a cell phone or similar but I have not tried it. There are some USB powered battery chargers available that you might want to try with this stove. :thumbsup:

I have not tried out any of the more fancy flexible solar panels or camping styled solar panels, but they should work as advertised. I just think they are too expensive for me.

I also keep all the battery powered stuff I buy to use just AA or AAA batteries so I don't need more than one type of charger.

Mark

[waif69]

There are so many solar chargers out there, it is difficult to recommend any one.

This confirms what I have determined myself. There are a lot of options out there, sort of like cars. Almost all of them will provide to you what you need, just some are a bit faster or bigger than others.

[Rand]

This one has great reviews and is on my christmas list.

http://www.rei.com/product/837625/joos-orange-portable-solar-charger

[Noahs ARK]

We just bought an Opteka BP-SC4000 solar cell phone charger from Amazon. Need to play with it when it gets here.

It's here & hubby loves it. It's got all sorts of different plugs & one of them fits my Kindle...YAY!

[Earthling]

This one has great reviews and is on my christmas list.

http://www.rei.com/product/837625/joos-orange-portable-solar-charger

Will it charge an ipad or laptop? It looks great!

[mgriffith]

Will it charge an ipad or laptop? It looks great!

This unit has a built-in 4500mh battery which is charged by the solar panel, and in turn is used to charge smaller batteries. The solar panel probably produces about 2 watts of power given its size and the specs that show it takes 12 hours of direct sunlight to charge the internal battery. And iPhone battery is rated at about 1400mh, so the 4500mh internal battery can charge it with no problems. This is how these devices work, charge an internal battery in 12 hours, then you can charge your cell phone three times before you need to leave it in the sun again for 12 hours.

However, an iPad battery is rated at 6500mh, more than 4 times larger than the iPhone, so the internal battery would soon exhaust itself trying to charge an iPad. The solar panel would then be trying to charge the internal battery as well as provide power to the USB port and it can't do both.

So basically, the answer to your question would be no. :l0 (33):

Mark

[BackBlast]

I have read several times in Hurricane Sandy experiences a comment on how important it was to have a solar charger for cell phones, laptops, and batteries. I have no experience with this. What do you all recommend? Thanks for your help!!

The quickest, easiest, and cheapest solution to charge these devices in a short term emergency is to get a car charger for the devices and store a bit of extra gasoline. You can use a car as a generator with battery buffer in this manner and keep yourself running for the cost of a few cheap adapters and a bit of knowledge of when to use your battery and when to charge it up - having a volt meter for your car battery is a good idea if this is your intended route.


Opteka BP-SC4000Some quick observations on this recommendation...

The internal battery is a LiPoly cell. The entire unit is black, and appears to have no provisions for heat removal. It claims a 2 year warranty, but I bet that warranty excludes the battery itself which I would guess would last less than a year in regular use due to how much time it would spend in the sun at elevated temperatures.

Without use the battery will degrade significantly over time, a maximum of a 3 year life span if kept in a basement. Longer if you store it in the fridge or freezer.

Once the internal battery is dead, it will still probably provide some service. However at greatly reduced performance and only when the sun is near perfect. The internal battery is not user replaceable.

The unit appears to only be capable of 5v output, it will not charge your laptop and will not power good AA/AAA chargers.


There are so many solar chargers out thereYes, and so many bad designs. Here are the general product class types and which ones will serve you the best.

No internal battery portable charger < internal battery portable charger < heat managed internal battery portable charger < external battery portable charging system

I, frankly, wouldn't really mess with anything that has an internal battery. Especially one that is not user replaceable - without this provision it is obviously intended as a "throw away" device.

Life span on the battery used if the system is largely idle:

LiPoly < Lead acid < LiFePO4

Life span on the battery if used a lot and cycled deeply but having proper temperature management:

Lead acid < LiPoly < LiFePO4

Life span on the battery if used a lot and cycled shallowly but having proper temperature management:

LiPoly < Lead acid < LiFePO4


Bad temperature management:

LiPoly < Lead acid < LiFePO4


Generally, the better systems are not cheap. Goal Zero has some respectable stuff for off the shelf systems and have mechanisms for battery replacement on their external packs as well as letting you size the various parts to fit your needs. Most of their stuff is lead acid, they have also sold LiFePO4 too.


http://www.rei.com/product/837625/jo...-solar-charger (http://www.rei.com/product/837625/joos-orange-portable-solar-charger)Heat provision (white, ventilation) +1, internal battery -1, no user battery replacement -1. Appears to have a similar 5v limitation as the first product, will not power laptops or good AA/AAA chargers. LiPoly battery.

If your only interest is small devices with lithium batteries themselves, phones, ipod/ipad variants, a small solar panel with no internal battery can serve with a simple 5v regulator and charging the device directly off solar. The battery buffer is more important to devices that have more specialized charging profiles, including AA/AAA batteries and laptops.

[cHeroKee]

Having spent a number of years in fuel cell research and development I am privy to the cheap small fuel cells.
One can buy small fuel cells now that charge up to 2W. It is a small device.
By adding water, and plugging it into a electrical wall-socket (or a solar panel), you can generate hydrogen and store it in a solid form automatically. Then deliver it via USB.

Yes, everything uses energy to make energy. This device is one I have and won't be without it.

[Rand]

I want it for a cell phone for sure, but I will use it for other items, and it seems it will do an ipad. I will find out if Santa cooperates. As per the great post above it won't do laptops. :-( I assume it is accurate.

[arbilad]

I seem to remember something about Apple patenting a method of using fuel cells in portable electronic devices, such as cell phones. Obviously it hasn't made it to market yet.

[mgriffith]

As an experiment, I took four AAA batteries that were fully discharged (reading .001 volts), and put them in this solar charger (I mentioned it before):

http://www.ebay.com/itm/New-Solar-Battery-Charger-for-4-pc-AA-AAA-Green-Power-J15-/310434386803?pt=Battery_Chargers&hash=item484754d373

After five hours in the bright winter Missouri sun, they were fully charged, reading a voltage of 1.4 volts. These are used in a small FRS/GMRS radio for family communications. So one winter day in the sun charged them fully. Tomorrow I will do the last two so both radios will work.

Of course this means that radio communications is dependent upon two days of good sun, and the radio usage does not drain the batteries in less than that time. Obviously the same applies to any other usage, like LED lights, FM/AM radio, etc.

For this reason, I prefer to use the six 15-watt solar panels and a frame sitting on the ground applying power to a large deep cycle or car battery. That way, I can keep the large battery charged and then charge anything I need from there, day or night.

On the other hand, four of these little chargers and a day of sun will charge up anything I would need "on the road", so I'll get a few more of these. At $10 each, its not too much of an investment.

Mark

[BackBlast]

Having spent a number of years in fuel cell research and development I am privy to the cheap small fuel cells.
One can buy small fuel cells now that charge up to 2W. It is a small device.
By adding water, and plugging it into a electrical wall-socket (or a solar panel), you can generate hydrogen and store it in a solid form automatically. Then deliver it via USB.

Yes, everything uses energy to make energy. This device is one I have and won't be without it.

Do you have a link? Do you know the Wh/kg energy density of the device? Cycle life? I'm curious what has been managed...

[BackBlast]

As an experiment, I took four AAA batteries that were fully discharged (reading .001 volts),

Is over discharged... 0.9v is considered fully discharged, there really isn't much juice in there 0v-0.9v. Your cells won't like being taken to near zero repeatedly, and then slammed with current from a dumb charger :d0 (29):. I expect it won't last very long. A C9000 will gently bring a cell back up to a normal range if it has been discharged below 0.9v before beginning a normal charge cycle.

You also risk a reverse voltage state for cells in a string when they get zeroed out like this, NiMH will often go belly up if this happens. This is typically only an issue with larger strings and pulling larger currents - more of a pack risk.


and put them in this solar charger (I mentioned it before):

http://www.ebay.com/itm/New-Solar-Battery-Charger-for-4-pc-AA-AAA-Green-Power-J15-/310434386803?pt=Battery_Chargers&hash=item484754d373

After five hours in the bright winter Missouri sun, they were fully charged, reading a voltage of 1.4 volts. These are used in a small FRS/GMRS radio for family communications. So one winter day in the sun charged them fully.Direct charging AAA and AA cells from solar is hard on them. Yes, you will get a full charge, but if you leave them in the sun too long you will bake them with a constant overcharge - same as most cheap chargers do to cells. It will reduce their longevity significantly to get baked in such a manner repeatedly.

In the summer this is more pronounced because of already high environmental temperatures.


For this reason, I prefer to use the six 15-watt solar panels and a frame sitting on the ground applying power to a large deep cycle or car battery. That way, I can keep the large battery charged and then charge anything I need from there, day or night.This is a good plan. It requires more equipment, but this is easier and better for your other cells in addition to being convenient. For on the road use, I would simply pack more cells or a 12v car charger rather than a poor solar charger :/

[thomasusa]

...

I agree.
But I have not been able to convert my wife from using her dumb charger/cooker to using my C9000.

[mgriffith]

Backblast....I do not disagree with anything you said. Yes, these batteries were pretty well discharged, and yes, pushing them to a full charge in 5 hours is a lot. Interesting though, they were not even warm....not like the other four AAA batteries I have in a more expensive 110VAC charger that are pretty hot and still charging after 12 hours. I guess having them out in the cold made some difference. Also, I just checked the voltage again, and even after six hours they still show at 1.4 volts. These are actually 300mh NiMH batteries so they should really show 1.2 volts so yes, they are probably overcharged and will not last long with these extremes in their cycle. But they are cheap and it's a worthwhile experiment. Now I know if I can carry a few of these little (and they are little, about the size of a pack of cigarettes) chargers I can top up my batteries in a few hours.

My point was that even a cheapo $10 solar charger can make a difference in an emergency situation. You don't need to spend a lot of money as long as you understand the limitations and that you have to monitor what is going on. In a real emergency, I'm not gonna care about the overall life of the battery as long as I can recharge it and use my radios during a time of real need.

Mark

[cHeroKee]

Do you have a link? Do you know the Wh/kg energy density of the device? Cycle life? I'm curious what has been managed...

170 Wh/kg
Cycle life: > 500 times charging rate

where as a Li-Ion rechargeable battery = 150 Wh/kg

[BackBlast]

Backblast....I do not disagree with anything you said. Yes, these batteries were pretty well discharged, and yes, pushing them to a full charge in 5 hours is a lot.

Actually, an "ideallic" charge time is about 2 hours or .5C. Much lower and smart chargers can't reliably detect the end-of-charge signal so they act more like dumb/trickle chargers - which is worse for the cell than a faster charge rate.


Interesting though, they were not even warm....not like the other four AAA batteries I have in a more expensive 110VAC charger that are pretty hot and still charging after 12 hours. I guess having them out in the cold made some difference. Cold environment will help, but too cold and you'll damage them as well. You shouldn't charge cells when they are below freezing - yet another risk with these. Anyway, 5 hours actually isn't bad on a dumb/trickle charger - the real issues come into play when you leave them on for 20-30 hours and they cook and cook and cook. 2 days of that and they've probably about had it. Probably something you're less likely to do on a solar charger than one that's plugged in, but I can't imagine that a summer charge would be easy on any cells :/


Also, I just checked the voltage again, and even after six hours they still show at 1.4 volts. These are actually 300mh NiMH batteries so they should really show 1.2 volts so yes, they are probably overcharged and will not last long with these extremes in their cycle. But they are cheap and it's a worthwhile experiment. Now I know if I can carry a few of these little (and they are little, about the size of a pack of cigarettes) chargers I can top up my batteries in a few hours.I would consider 1.4-1.5 volts a good end voltage for a charged cell. It will probably settle into the 1.35v range given a week or so depending on the cell quality and age. 1.2v off the charger and it probably didn't reach 100%. In the winter and only for 5 hours, you probably didn't hurt hat cell much other than it was zeroed and then directly charged. My intent is only to show potential long term risks. It does work, and that cell appears to have successfully taken a charge.


My point was that even a cheapo $10 solar charger can make a difference in an emergency situation. You don't need to spend a lot of money as long as you understand the limitations and that you have to monitor what is going on. In a real emergency, I'm not gonna care about the overall life of the battery as long as I can recharge it and use my radios during a time of real need.

MarkSmall emergencies, I agree with everything you're saying here. Extra wear and tear on cells isn't a big deal.

Things look different with a long term grid-down situation where you want your equipment to last if you can manage it.

[BackBlast]

I agree.
But I have not been able to convert my wife from using her dumb charger/cooker to using my C9000.

But they are so cool!! :D