# I Series hooked up 4 batteries of 1.22V made a power bank not charging my phone

Joined Nov 21, 2018
166
and hooked up usb +/-, measured total V = 4.96V, just not charging, why?
Thanks

#### Sensacell

Joined Jun 19, 2012
2,519
There is more to it than just 5 V.

Some phones "shake hands" with the charger- for various reasons.

#### MisterBill2

Joined Jan 23, 2018
4,579
In addition to the fact that the phone may indeed be programmed to only work with the OEM charger, it also takes a higher voltage to force current into the battery being charged. That is true of ALL rechargable battery types. So you will need to know what the charging voltage is for that specific battery type.

#### crutschow

Joined Mar 14, 2008
23,806
What batteries are you using?
What is their AH capacity?

#### MisterBill2

Joined Jan 23, 2018
4,579
Keep in mind that a 4.88 volt battery pack is not even theoreticaly able to supply the 5 + volts needed to charge a phone. Besides that, a USB charging arrangement does indeed need to communicate with the phone before any power transfer can happen. The entire USB concept is based on a whole lot of communication going on.

#### ebeowulf17

Joined Aug 12, 2014
2,965
Keep in mind that a 4.88 volt battery pack is not even theoreticaly able to supply the 5 + volts needed to charge a phone. Besides that, a USB charging arrangement does indeed need to communicate with the phone before any power transfer can happen. The entire USB concept is based on a whole lot of communication going on.
USB spec tolerances allow voltages as low as 4.45V. I've personally measured several devices between 4.85 and 4.9 that successfully charged anything I plugged in.

As for communication, I know many power hungry devices rely on communication to determine whether they can draw higher currents or not, and they'll default to a lower current draw if they don't get a response.

I haven't seen anything myself that wouldn't charge on dumb devices with no communication. I'm not saying such devices don't exist, but I think they're unusual.

#### MisterBill2

Joined Jan 23, 2018
4,579
USB spec tolerances allow voltages as low as 4.45V. I've personally measured several devices between 4.85 and 4.9 that successfully charged anything I plugged in.

As for communication, I know many power hungry devices rely on communication to determine whether they can draw higher currents or not, and they'll default to a lower current draw if they don't get a response.

I haven't seen anything myself that wouldn't charge on dumb devices with no communication. I'm not saying such devices don't exist, but I think they're unusual.
The Mac products in our family seem to be very picky and demand a Mac charger.

#### ebeowulf17

Joined Aug 12, 2014
2,965
The Mac products in our family seem to be very picky and demand a Mac charger.
One of the reasons I hate those products. Our iPhones will allow any charger, but only work with Apple certified cables. So ridiculous. Oh, well.

#### MisterBill2

Joined Jan 23, 2018
4,579
One of the reasons I hate those products. Our iPhones will allow any charger, but only work with Apple certified cables. So ridiculous. Oh, well.
The whole realm of demanding proprietary accessories is rather evil, at best. I know that there are arguments offered that convince our legislators, but that is because the lobbyist with the most money wins. I have HP laptop computers that will not accept other than an HP power supply, which costs $120, as opposed to$25 for a good brand one from Amazon. The other brands are cheaper.

#### BobTPH

Joined Jun 5, 2013
2,137
Lots of misinformation in this thread. What you need is two voltage dividers setting the voltages on the D+ and D- pins. I am too lazy to look up what they need to be (for various charging rates). If you have a charger that works, you could measure these voltages and duplicate them.

Bob

Joined Nov 21, 2018
166
Thanks for all reply.
clarify some thing as:
1. the battery source I used are Ni-Cd from a cordless drill 9.6 V now (was 4.88V) + 7805, output 4.93 V;
2. The I phone charger measured output 5.11V stable, and the one Android charger output 3.5-4.4 vary (don't know why?), which is the best charger for me;
3. The i phone can be charged by : both chargers and laptop; the Android can be charged by both chargers, laptop, and battery bank （bought on EBAY）;
4. only the battery bank can be charged by my battery source.

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#### ebeowulf17

Joined Aug 12, 2014
2,965
Lots of misinformation in this thread. What you need is two voltage dividers setting the voltages on the D+ and D- pins. I am too lazy to look up what they need to be (for various charging rates). If you have a charger that works, you could measure these voltages and duplicate them.

Bob
That depends on what device you're trying to charge. This stack exchange discussion seems to have a lot of good information on the subject:

#### Dodgydave

Joined Jun 22, 2012
8,594
Thanks for all reply.
clarify some thing as:
1. the battery source I used are Ni-Cd from a cordless drill 9.6 V now (was 4.88V) + 7805, output 4.93 V;
2. The I phone charger measured output 5.11V stable, and the one Android charger output 3.5-4.4 vary (don't know why?), which is the best charger for me;
3. The i phone can be charged by : both chargers and laptop; the Android can be charged by both chargers, laptop, and battery bank （bought on EBAY）;
4. only the battery bank can be charged by my battery source.
To make an Android phone charge, connect the Data +/- wires together ( green / white), this will put the phone in Charge mode,and feed it with 5V...