Customer Reviews: Motorola P4000 Universal Portable Power Pack - Retail Packaging - Black (Discontinued by Manufacturer)
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on November 20, 2012
Color: Black|Vine Customer Review of Free Product( What's this? )
This is a really nice power pack, the best one that I have ever used. As with most Motorola products, build quality is excellent. The device is extremely slim so it can fit in your skinny jeans next to your phone, but it still packs a huge 4000mAh of battery power. Modern high powered smartphones usually have 1500 to 2000mAh batteries, so this power pack should recharge those twice. The 8W power output is high enough to charge tablets, unlike most lesser devices.

The size is especially surprising. This thing is only 0.3 inch thick. 4000mAh power packs from other brands that I have seen are twice the size and won't easily fit in to your pants pocket like this one. The built-in micro-USB cable is a big feature; you never loose the cable and it does not add any bulk. With most power packs, you have to carry an extra and bulky cable with you, which is likely not going to fit in your pants pocket along with your phone and the charger. I also own a 10000mAh Anker power pack (for multi-day trips) and that is a much larger unit; 3 or 4 times the size of this Motorola when you include the cable.

Some nice features of this device are automatic on/off so the battery won't run down when nothing is attached (as many cheap power packs will). The power test button is recessed into the side of the device so you can't accidentally activate it. A micro-USB cable is conveniently built in to the charger so you can never lose it. If you're charging an oddball device that doesn't use micro-USB, there is also a full-sized USB port so you can plug in your own cable.

Yes, the price is more than what a generic 4000mAh power pack would cost, but I think the you get what you pay for with the quality level and super-thin size. If your smartphone or tablet burns a lot of power (like most 4G devices do these days) and you're going to be away from a wall socket all day and your device doesn't accept spare batteries (an unfortunate trend), then this is a great device to carry with you. You can even charge 2 devices at the same time, which is great way to meet people at the airport :)
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Color: Black|Vine Customer Review of Free Product( What's this? )
USB battery packs keep your power-crazed smartphone satisfied while on the go.

Many brands to choose from. Prices are bouncy and coming down.

This Motorola P4000 (4000 mAh) is about perfect if the price drops below $25. Until then, best to check out the Joway Jp51 6000mah or other excellent power banks below $25.

I'll update this review if the price gets friendly. (I've set a price alert at camelcamelcamel. Google it and set your own email alerts for any amazon product.)

The imbedded Micro-USB cable is a big plus. Save space. No tangle, mess, or leaving behind. I use it with my iPhone, thanks to a Lenmar Micro-USB-to-Apple-30-pin Converter Tip.


* Thin and light (4.25 oz, 0.40" thick)
* Imbedded cable eliminates multiple hassles
- Fit and finish: Good. Looks and feels like quality.
- Power-in: Standard Micro-USB connector - 42" cable included


- 4000 mAh capacity is good for about 1-1/2 iPhone charges (see Note 1)
- The imbedded cable is heavy duty. Requires some effort to press into its notch.
- 1.5-amp output: Charges some tablets faster than competing models
- Textured surfaces are neither glossy nor rubberized


* Poor value when priced over $30
- Listing copy is misleading in places (see Note 2)

- - - Notes - - -

Note 1: Motorola claims two 90% charges of a "1450 mAh average smartphone battery." That's 1.8 full charges, but my test gave only 1.53 full charges of my iPhone 4S battery (1432 mAh). It charged from 13.8% --> 100% + 29.3% --> 96.0%.

Note 2: "Charges the average smartphone battery up to 2 times and powerful enough to charge your tablet" actually means (according to the footnote on the box) it will provide two 91% charges of a typical (1432 mAh) iPhone battery. Most current Android phones have larger batteries. It will charge a Samsung Galaxy S3 (2100 mAh battery) less than 1-1/4 times. It will boost an iPad 3 battery about 25% of one full charge.

~~~ Comments & questions welcome ~~~
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VINE VOICEon December 20, 2012
Color: Black|Vine Customer Review of Free Product( What's this? )
This is a decent charger and good for travel. I liked how thin it is and thought it would work great for bike rides to keep my iPhone charged and it does. However, it's almost a little too wide to fit nicely in the underseat pack I have on my bike. With the iPhone USB charger plugged in, the device becomes even wider as there is only one USB outlet and it's on the long side. Would have been nice to have it on the thinner end or an optional second one there.

With the USB cable from my iPhone 5 plugged into the side I have to set the battery in the underseat pack at an angle. I wasn't too keen on this thinking that it would bend my iphone charging cable and damage it so I tried to remove the cable and alas, it is permanently stuck into the thing! I've tried just about everything short of taking the unit apart or using pliers to grip it out. So now I have a permanent lightning charger in this and can't use the USB port for any of my other USB devices - unless, of course, they charge with the lightning adapter or use microUSB. ** SEE MY UPDATE BELOW**

As far as charging goes, this works well. After charging the phone completely to 100% the battery pack will shut down as it's apparently no longer charging so goes into auto-shut-down mode to conserve its power. So if you've left your device plugged into it, it will also stop charging and begin to rundown its battery if you have it turned on.

I also have the New Trent iTorch IMP52D 5200mAh External Battery Charger and frankly I would recommend it over the Motorola P4000. Both work fine for the intended purpose, but the New Trent seems to last longer on a single charge (it has 5200mAh while the Motorola is 4000mAh) and the charging outlets are on the end, it's narrower than the Motorola and, best of all, my cable does not get stuck so I can use it for several different devices that connect to power via USB.

So I'd give this a higher star rating if my cable wasn't now permanently attached to it and if it had a USB port/outlet on the smaller end.

**UPDATE 12/23/2012**

I have raised this to a 3 star review because, thanks to a comment from "Gadget Grant" I was able to remove the cable! I have added photos so you can refer to those if your USB cable gets stuck. I also tried other cables in this device and so far the only ones that get stuck are the Apple Lightning cables (used to charge my iPhone 5 and my boyfriend's new iPad mini. so apparently this issue is not Motorola's, but Apples. Although, I must say that so far this is the only usb outlet I"ve had trouble with the cable getting stuck, and I've had it plugged into other USB hubs, my Macbook Pro, my Mac Pro, a USB wall charger (non-apple), and the NewTrent battery mentioned above - all with no problem getting it back out of the device.

So, if your cable gets stuck, see the photos on how to remove it using a thin piece of plastic. I used a Solo cup which worked like a champ - tried an old credit card but that was too thick.
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on July 27, 2014
Update August 2014:

I've had this a month now and still looking good. I had stashed it in the glove compartment for 4-1/2 weeks and took it out yesterday to recharge my HTC One (M8) which was at 10%. It appears that the charger was still fully charged after more than a month, and it took 90 minutes to get the phone back up to 100%; not up to QC-1 standards, but still a fairly quick charge. The charger turned off automatically a minute or so after full charge was reached on the phone. Two of the four power LEDs were still lit at the end, so about a 50% drain to charge the phone. Pretty good performance so far. I'll leave it in the car another month and see how it does on half-charge.

Original Review

Bought this a a backup charger for a pair of HTC One M8 cell phones. So far so good.

The device came almost fully charged out of the box. I immediately hooked it up to one of our phones to see how fast it would charge. The HTC One M8 comes with a Quick Charge 1.0 charger and is QC 2.0 capable. The Motorola charger supports neither standard so I suspected that charging would be slower than using the HTC charger. It is. Nonetheless, it did a pretty good job.

My phone went from 59% to full charge in about an hour. Initially, the rate was faster, increasing by about 1% per minute (59% to 69% in ten minutes). But as the phone approached the 90 percentile it slowed a bit, taking 18 minutes to go from 91% to 100%. This could be a feature of the phone itself to prevent overcharging.

Still, if you're stuck with a dead phone you'll get some good talk time quickly with this item. Plus you can use your phone while charging it.

The power connector on this charger is a micro-USB, but it also has a full-size USB port on the side next to the on/off switch, so you can charge any USB capable device with this. Manual says you can charge two devices at once but I haven't done that yet. A wall charger comes with the kit, with a micro-USB plug to mate with the jack on the side of the Slim Pack charger.

To charge your device, peel the red cable and connector from around the charger, plug it in, then hit the on/off button. Four white LEDs on the face of the charger indicate approximate charger battery strength. The end of the cable connected to the Slim Pack seems robust, but I would hesitate to put too much strain on it.

I recharged this guy overnight so no idea how long it took to get back to 100% charge. However, the manual states that this device has a limiter that will not allow overcharging.

While charging the phone the pack did get a little warm to the touch, but not hot enough to be an issue. Same thing during wall charging of the pack. As a bonus, if you forget to turn it off it will automatically turn off after 30 seconds of inactivity.

This item was $80 at the Verizon store and goes for $50 or more on other sites. For $23+ at Amazon it's a steal.

Overall a nice little device.
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on December 27, 2014
The thing didn't even last a week. It started out working fine but when I tried to re-charge the power pack the second time it would not recharge itself.

**UPDATE** SO I guess I wasn't giving the power pack enough time to recharge. I left it charging one day while I went to the gym and to run some errands and when I came back 4-5 hours later the battery pack had not charged at all. It was at 50% when I started to re-charge so it was not dead and should not take long to charge. To be honest I am still confused as to whether or not this thing works as it is supposed to or not. I was able to re-charge it finally using a different USB cord into a USB outlet that I have. At first I thought the USB cable that came with the battery pack was faulty and was not allowing the battery pack to charge but I used it to charge my phone and it worked so as of right now I am at a loss. I will update this later if I figure out what is going on.
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on December 10, 2014
I had a motorola Droid M and it would never charge on the car charger.....really frustrating when phone won't charge on the go. I just replaced it with a motorola Mini (don't like huge phones), love the phone but had the same problem. Bought the power pack slim and needed it for the first time last evening, my phone went from a 7% charge to 54% within about 30 min. all while in my purse! Fantastic. Love small, slim design, I charged up the unit 2 weeks ago and it's been just sitting in my purse awaiting a need! So small, took up virtually no room in my purse. So excited to have something that works. Now I can truly love my phone, that was the only thing concerning me when I purchased it. Also, it cost twice as much on Verizon so I saved lots by going through Amazon!!
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on August 15, 2013
There is nothing easier than having this device charged and in your pocket for a busy day of using your phone! Even while using it, you can plug in your phone and continue with your conversation/Work . It keeps me from worrying that I will lose power or have to find a socket near my seat for a business meeting to have access to my notes and emails!
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on December 2, 2013
It is rated at 4,000 and should charge my Moto X twice. I was at 15% battery and after a couple of hours, it was up to 85% and the power pack barely had one out of four lights showing the charge remaining. Good think I got the 4000 or it wouldn't even come close to fully charging my phone.

That said, it is really compact and I really like the cable that snaps in and the ability to recharge it and two USB devices at the same time.
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on June 27, 2016
On the packaging, it states that this battery pack can provide 2 full charges. Not true. My phone was down to 40%. I plugged it into the pack (it had a full charge) and my phone made it to 85% and the pack died out. This is the second time that it happened.
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on April 26, 2016
I love how slim this power pack is and how I don't need to worry about bringing my charger cable along since there's one already attached to it. Plus, I really like how it comes with a USB port. So if I wanted to use this to charge my iPad, I could as long as I brought the cable with me. And it works wonderfully. When both my parents were still using a Galaxy S3, it was practically able to charge almost both of them from zero to 100% charge. I'm not that fortunate. I have a OnePlus One so I'll get one full charge from this thing and then a little extra juice but not two full charges. My only gripe with this product is it runs kinda hot. At one point, I had this charging my phone in my pocket and I could definitely notice heat. It wasn't hot to the point that I couldn't hold it but it was uncomfortable enough for me not to want to keep this in my pocket for too long.
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