Battery charger specs..I’m confused…

Hello everyone.

I need help. I bought a universal mobile phone battery charger from Aliexpress. The specs of the charger is as follows:

Input Voltage Range:100-240VAC
Input Frequency:50-60Hz
Clip output : 4.2V ,800mA
USB output : 5.2V , 1300mA

For me, clip output was important, since it seemed as if it would be able to charge a battery faster than a standard 500mA charger. The charger arrived, but it takes just over 5 hours to charge a 2100mAh battery. I also tested it with a 2500mAh battery. The charger took nearly 6 hours to charge it.

If it charges the batteries at the advertised 800mA, it should not take that long to charge the batteries. So, I contacted the seller, and he said “the energy wasted on device hotting,so need cost more time for charging”. The thing is, it is currently winter where I am, and all my tests were done a a room temperate of between 10 and 18 degrees C, and the charger did not get hot at all.

I also tested the USB output of 5.2V, 1300mA with a 1A load, and the charger can only deliver about 0.57A. WAY below the advertised 1.3A. I also tested charging a LG G3 Beat and Samsung I9300 and various power banks. I never saw more than about 0.58A from the charger.

I again contacted the seller, and he keeps on telling me: “do you study “conversion ratio” ,than you will learn”. So yes, I’m just a hobbyist, but I don’t understand what “conversion ratio” I must study. I tested one of my power banks that specifies: DC 5v – 1000mA. With the 1A load, I measured 4.88V at 0.96A.

The specific charger is more expensive that similar looking/branded chargers that offer a clip output of DC 4.2V 400mA +/-50mA. If I simply wanted a charger to charge a battery outside a phone, I would have bought the cheapest one, but I wanted one that can charge faster.

So, what am I missing with the advertised charging capabilities of the charger I bought, and what “conversion ratio” must I go and study?

Unfortunately, the Chinese seller is more correct than wrong. For the price, you got a fair charger.

You can study here http://batteryuniversity.com

Seriously, charging is never 100% of the input I*E, even with fast-charge batteries that can withstand 0.8C … most normal cells in a “nominal” cycle will be 0.4C down to a low of 0.1C

Fast-charge cells either add an ingredient to the electrolyte to absorb gas produced and often implement some type of heat-pressure controls… trust me, you do not want a lithium cell to explode!

As the charger is “universal”, my guess is the design is on the conservative… the manufacturer does not want an explosion either.

Lithium chargers are constant current with the last portion of the charge cycle constant voltage.

If you want a truly fast-charger, buy the batteries with the fast charger… these matched sets will deliver on what they advertise.

Ray

In my experience, most of these chargers use a small number of generic charger chips. Generally the charge current is controlled by changing the value of one resistor. If we knew which chip the charger was based on, then it might be possible to mod the charger to use a higher current. The manufacturers have a nasty habit of removing the marking from the chips however, so we may be out of luck.

This obviously assumes the battery in question can handle being charged at 800mA rather than 500mA if not, be prepared to extinguish the fire.

Also in my experience, most (99%?!) of vendors don’t actually A) know what they are selling, and B) know what they are talking about. This is a bit of a generalisation, your experience may be different… The phrase “do you study “conversion ratio” ,than you will learn”. suggests that this individual is full of it. If the charger wasted 3/8 of the current it used as heat, then it would be pretty inefficient, and also pretty warm.

You can mod one of these boards. to produce up to IA

http://www.ebay.co.uk/itm/1pcs-Mini-USB … xy0zhTLOpm

However… you do so entirely at your own risk, and bear in mind, that you will need to

A) Confirm that the board you receive uses the same chip as the one in the example.
B) Be able to solder an 0603 resistor.
C) Be responsible for any resulting fire when you charge a battery faster than it can cope with.

Resistor SMD 0603 Charging Current
30k 50mA
20k 70mA
10k 130mA
5k 250mA
4k 300mA
3k 400mA
2k 580mA
1.66k 690mA
1.5k 780mA
1.33k 900mA
1.2k 1000mA

The lowest 50mA current would be suitable for one of those tiny quad copter batteries, or an 808 spy cam battery, 1A would be suitable for something heftier, like a high quality 18650 cell, and might be a little excessive for a small phone battery, you would need to know what charge current the battery you are trying to use is rated for.

Thank you for the replies.

Today I opened up the charger:

Top side of PCB:

20160711_112843.jpg (94.87 KiB) Viewed 1205 times

Ken,
It can’t. It could have if a transistor was used to boost the power. But I’ve seen an influx of knock-offs and over-rated items everywhere. been there, done that. Then decide if it’s possible or worth modifying it or just use it or trash it. For myself I go ahead and take the chance in hopes that if it’s not rated that well I can cheaply modify it for my needs.

Michael

Kenjutsu wrote:
<…>
How can this IC then deliver on the advertised 800mAh on the clip, and 1300mAh on the USB?

mrburnette wrote:
…
Edit: lookin’ at the pix again, this is not a bad looking design except the charging specs are incorrect.
Ray

Hmm, there is a free running switching power supply (2 transistors, no feedback from secondary side), none voltage regulator at the secondary side, none transistors around the chip for a current boosting.
It is simply wired exactly as depicted on the schematics in the link above.
Trash it..

I have opened a dispute to get a partial refund.

My message was: Attached a photo to show that at a 1A load, the charger can only deliver about 0.57A. WAY below the advertised 1.3A on USB out

20160708_083959.jpg (45.44 KiB) Viewed 1138 times

Can’t you just make a simple setup to prove your point?
Not charging anything, but just connecting it to some resistor(s) capable of showing the charger not living up to its specs. 1A @5V requires a 5 Ohm resistor. If you don’t have a resistor of that value that can handle 5W power over it, maybe just a lot of resistors in parallel until they can handle the 1A current @ 5V, and have a resistance equivalent to 5 Ohm, connect the charger to it and measure the voltage over your resistor network, and you’ll see how much current it’s capable of giving on such a perfect load .
Not sure how such a cheap charger would handle that, i assume the voltage will just drop and still give just 0.5A or something like that, but if it blows up, it’s not my fault :p.

I would simply emphasize that the specification of the charger you received, was not as good as the advertised spec.

The picture on the back should be sufficient. This is a better pic, from Amazon of what appears to be the same charger.

The fact that the label states it can only deliver 350mA and 800mA should be sufficient.

So far as I am concerned, if Ali quibble, then you show them the pictures, since they actually prove that the charger cannot meet the advertisers spec. either when charging, or when powering a load.

In all the photos I uploaded to the seller, I used a USB 1A/2A load, similar to this one: http://www.aliexpress.com/item/USB-Port … 99710.html

With mine, with the switch in position “0”, the load is about 1A, and with the switch in position “1”, the load is about 2A. I don’t understand why the seller can’t understand what I’m saying

I will wait for his reply, and if he does not agree to a partial refund, I will escalate the dispute. Hopefully the person reviewing the dispute will understand better…

If I just wanted to buy a universal charger, not caring about the capabilities on the clip or the USB port, I would have searched for the cheapest universal charger. The cheapest one I can find, as of today, is product ID: 32492020121. Shipped to my country is about US$ 2.37. I paid more money to get a charger that is advertised as supplying 1300mA at 5.2V on the USB port and 800mA at 4.2V on the clip.

@ahull: that charger is one of my older chargers, but when I connect the 1A load to it, it actually gives 0.90A @ 4.6V, which is not bad for a charger that specifies 800mA @ 5.2V

Just some feedback. The seller kept on insisting that “no refund the buyer didnt understand whats is the power conversion”. So all I did was get more USB chargers and connecting them not only to the 1A/2A load, but also to my old Samsung P1000 tablet. I uploaded the photos showing how other chargers are able to deliver on, or very close to, their advertised capabilities.

Today, AliExpress ruled in my favour. I will get a US$4.00 refund if I don’t respond within 4 calendar days. The seller nearly caught me with a counteroffer of US$2.00. I went back to the AliExpress email, and the “fine print” states: “If you fail to choose or reach an agreement with seller within the response time, option 1 will be executed”. So, I will simply not respond and wait for the 4 days to pass