Opteka BP-SC4000 Ultra Thin Solar Powered High Capacity (4000mAh) Backup Battery and Charger for Cell Phones, iPhone, iPod, and Most USB Powered Devices

by Opteka

Product Details

• Shipping Weight: 1 pounds (View shipping rates and policies)
• ASIN: B005ZSVZRY
• Item model number: BPSC4000OPT
• Average Customer Review: 3.3 out of 5 stars  See all reviews (428 customer reviews)
• Amazon Best Sellers Rank: #325 in Cell Phones & Accessories (See Top 100 in Cell Phones & Accessories)
  • #1 in Cell Phones & Accessories > Accessories > Chargers > Solar Chargers

Product Description

The Opteka BP-SC4000 Ultra Thin Solar Powered Mobile Device Charger allows you to charge your mobile devices when a wall outlet or USB power source are not available. The BP-SC4000 contains a 4000mAh lithium-polymer power bank which charges up via solar energy or computer USB port, and features 10 mobile-device connecting tips, extension cable and USB port making the BP-SC4000 compatible with most Nokia, Samsung, LG, Palm, Blackberry, Apple iPhone, iPod, iPad, Motorola, Sony, Bluetooth, GPS, various digital cameras, PSP, various eBooks, tablets, Nintendo DS, Kindle, and other devices.

Specifications
Battery Type: Lithium-polymer
Battery Capacity: 4000 mAh
Voltage: Output DC 5V 1000mA, Max Solar charge: 250mA
Operating Temperature: 0°C-45°C
Dimensions: 4.5" x 3.3" x 0.5" (114 x 84 x 14mm)
Weight: 6.5 oz (185g)

Most Helpful Customer Reviews

1,313 of 1,335 people found the following review helpful

3.0 out of 5 stars Worst documentation ever February 13, 2012

By Scott F Fitzgerald

Amazon Verified Purchase

This solar charger comes with a one page "manual" that tells you absolutely nothing about how to use the product. The charger has 4 blue LEDs in the bottom right corner, and at first they seemed to flash at random.

On the plus side the charger, when exposed to direct sun light, (not indirect winter light) charges quickly and provides more than enough power to charge my Android phone every night.

On the negative side, if you don't figure out how to use the charger (and you won't from their instructions) you can't charge your device. Here's the owners manual they should have included:

1) When placed in direct sun light, the four LEDs at the bottom right of the device will flash from left to right. The rate at which they are flashing indicates the rate at which the internal battery is being charged. The faster they flash, the more power you are getting from the sun. Put the solar cells in direct sun light for maximum charge.

2) When the device is fully charged (although it does not have to be fully charged to attempt to charge your device) all the LEDs will go out.

3) While the battery is charging (and the LEDs are flashing) you can press the silver button quickly to see an indication of the internal power level of the battery. (1 LED = 1/4 charge, 2 = 1/2 charge, 3 = 3/4 charge, and *none) = fully charged)

4) To charge your device, plug it into the included USB adapter. If the solar LEDs were still flashing, charging of your device will begin immediately. If the LEDs were not flashing, hold the silver button down for 3 seconds to begin charging your device. When charging is complete the LED will go out....

5) You can pre-charge the battery in the Opteka BP-SC4000 by connecting a standard mini (not micro) USB cell phone charger into the connector on the side of the solar charger (the one marked "input"). (If you are going on a trip you might want to precharge the internal battery so you can charge your device before the sun comes up.)

Opteka may not use the instructions here unless they send me 5 free chargers. Read more ›

327 of 341 people found the following review helpful

5.0 out of 5 stars Very Useful, Well-made Accessory February 18, 2012

By S. Jennings

Amazon Verified Purchase

I ordered both the Opteka BP-SC4000 and the XTG Technology Solar Charger, just to compare the two. I was looking for a compact, lightweight, solar-rechargeable backup power supply for my iPod Touch, satelite GPS unit, and cell phone. Bottom line: Except for the User Guide, which is practically worthless, I found the Opteka unit to be superior in almost every way to the XTG model; here's why:

1. The specs for the Lithium-polymer battery on the Opteka BP-SC4000 claim 4000mAh capacity -almost three times the capacity of the battery on the XTG.

2. The maximum solar charge rate for the Opteka is spec'd at 250mA - more than twice the 120mA rate specified for the XTG. This should translate into significantly faster recharging of the Opteka's onboard battery for the same amount of draw-down. (Example: If your cell phone, during recharging, draws 1000ma, it will take about 4 hours of direct sun to replace the charge in the Opteka vs approx 8.5 hours for the XTG.)

3. The Opteka BP-SC4000 comes with a complete assortment of adapters to accomodate just about any small, USB-rated, battery-powered device. The XTG came with only a USB-to-mini-USB cord.

4. The workmanship on the XTG seems a bit shoddy, with noticeable gaps at the edges of the plastic sealant that coats the solar panel. The Opteka, by comparison, appears sturdy and well made.

5. The Opteka weighs about 7oz compared to 5oz for the smaller XTG (significant, perhaps, only to ounce-parsing backpackers like me). But those two extra ounces appear to translate into significantly better performance that is well worth the weight.

6. It took a little over an hour for the fully-charged Opteka to completely charge my iPod Touch.... Once the iPod was fully charged, the Opteka showed about half of its capacity remaining - enough to charge another device. (I was unable to test the XTG's battery capacity in this way since I didn't have the proper adapter, but I suspect, given it's smaller specified capacity, that the XTG would barely have enough juice to fully charge even one device.)

7. The Opteka has a conspicuous and intuitive LED display on the front that tells when it's charging, when it's discharging (i.e. charging an external device), and, at any given moment, how much charge remains in the onboard battery. (When charging an external device, you do have to remember to hold down the button for 3 seconds to begin the process. Also, to check the state of the battery when the unit is idle, press the same button briefly.) The XTG has a display that performs basically the same function, but is on the back of the unit and therefore not in view when the unit is "sunning".

8. At $25.07 through Amazon, the Opteka BP-SC4000 is almost $3 cheaper than the XTG - a clear tie-breaker. Read more ›

188 of 196 people found the following review helpful

4.0 out of 5 stars Performs exactly as advertised. Some confusion caused by its (non-linear) battery status indicator July 27, 2012

By NLee the Engineer HALL OF FAMETOP 10 REVIEWER

When I first received this product (Opteka BP-SC4000 Ultra Thin Solar Powered High Capacity Backup Battery and Charger), I was surprised by its small size and light weight. That makes me suspicious about its claim of '4000mAh' battery capacity. However, after thoroughly testing the unit, I'm convinced that the capacity rating is accurate.

Here's how I conducted my test:
First, I make sure that the internal battery is fully charged from external USB adapter. Next, using the provided USB cable and plugs, I connected a 50W 5-ohm load resistor to the USB output. The load current I measured is 0.98A, and the output voltage is regulated at 4.85V. This gives an output power of 4.75W. I then timed how long it took for the converter to shut off. The last status indicator bar went out shortly after 158 minutes.

How does this runtime relate to the battery capacity?
The 5V output has to be boost-converted from the internal 3.7V battery. Assuming a typical conversion efficiency of 85%, the internal battery has to supply at least 1.51A (3.7V*1.51A*0.85 = 4.75W). A 4000mAh battery should then last for 4000mAh/1510mA = 2.65 hours, or 159 minutes.

So my test above proved that the battery capacity rating of '4000mAh' is right-on. However, in the process of this test, I also discovered a confusing behavior about the battery status bars...

There are four status bars for the battery indicator, with 4 bars being full and zero being empty. Naturally, people will assume that each status bar represent 25% of the capacity left. This is NOT the case. The status indicator is actually a non-linear representation of the battery capacity.... Here is what I figured after repeating my experiment (all percentage numbers are approximate):

4 bars = 87 - 100% full
3 bars = 73 - 86% left
2 bars = 58 - 72% left
1 bar = 1 - 57% left
0 bar = empty

For example, when the status indicator drops from 2 bars to 1 bar, people will assume that there's less than 25% of energy left. But in fact the battery is still more than half full. So people will under-estimate the capacity of this battery pack during discharge.

On the other hand, after I recharge the internal battery from empty at 1A for 1.5 hour, the status shows 3 bars, even though the battery cannot be more than 40% charged. So in this case people will over-estimate the fullness of the battery, only to be disappointed later since it does not provide 75% runtime as expected.

As a solar charger, the Opteka BP-SC4000 suffers from the same problem as other similar products: it takes days to recharge using solar power. The maximum charging current is only 250mA under optimal condition, so to recharge a 4000mAh battery it will take 16 hours of peak sunlight. In real life this means at least 3 sunny days.

Previously I evaluated another far more expensive product, the Soladec Hybrid All-in-One Portable Solar Power Charger (SD4000LP). Both claim the same 4000mAh battery capacity. But this Opteka unit offers several advantages:
- It can supply at least 1A of output current continuously, while the Soladec maxed out at just 800mA.
- It has an on/off switch to conserve power while not in use. The Soladec drains 3mA from its battery all the time.
- It comes with an USB cable plus 10 adapters for charging various devices. The Soladec only comes with an USB-to-microUSB cable.
- It's cost is just 1/3 that of the Soladec

Bottom Line:
The Opteka BP-SC4000 performs exactly as advertised, which (sadly) is a rarity nowadays. The only drawback is its non-linear battery status indicator, which can cause confusion for the user. Overall, this is still a great product, especially considering its low price.

[Update on Dec 3, 2012]
During my summer vacation trip, the SC4000 proved to be a life-saver. On many occasions, I have used it to rescue other battery-powered appliances such as camera, cell phone, GPS and media player. For that I'm satisfied with this product.

[Update on Dec 7, 2012]
I just noticed there is another similar product sold here at Amazon:
EZOPower Universal USB Solar External Rechargeable Backup Battery - 3000mAh
It looks identical to the SC4000 except for battery capacity. So I suspect some customers may have received this lower capacity unit instead of the SC4000. Use caution when you shop. Read more ›