Different Resistor Values for 2v on D+ and D- ??

[nikg]

Hi,

Great job hacking the AAA powered charger for Apple i-things. I am trying to build my own solar/AA powered charger for Apple products and had a few questions about the data pins on the USB. I would like to maintain the 500mA charge rate, so I need 2v on each line. I saw that the recommended resistors were 75k ohm and 49.9k ohm. I could not easily obtain these in the time I needed them, so I went ahead and ordered some 1% resistors at 150K ohm and 100k ohm to maintain the same ratio and produce 2v. According to what I read, the higher rated resistors will consume less energy but will also produce less output current on those lines. So....

1) Are these resistor values OK to use? The ratio is 3:2 just as the 75k ohm and 49.9k ohm. I am assuming (hopefully) that the i-pods, phones etc. only want to detect 2v and not really draw any current on those data lines, so I should be OK. Can anybody confirm this? Is it dangerous or worse to use these resistors for any reason?

2) Should I just use two of the 150's and two of the 100's in parallel to create 75k and 50k ohms respectively?

3) Instead of making a separate divider for each data pin, can you just do one? For instance each line has (+5v ----- 75K ----- Vout ----- 50K ------ GND) where Vout goes to either D+ or D-. Could I just take that Vout and run two wires off it and connect one each to D+ and D-, or will that screw things up? Has anybody tried it?

I can't really afford to have my i-things ruined and replace them, so I am looking for safety and "not blowing anything up" as my priority here. I don't think that any of the i-devices would be ruined from such small voltage/current feeds, but either way I want to be on the safe side.

Thank you so much for the help.

Nik

[adafruit_support_rick]

I can't really afford to have my i-things ruined and replace them, so I am looking for safety and "not blowing anything up" as my priority here.

We're not Apple, so we can't guarantee that any answers we provide won't damage your devices.

Although lower current on D+ and D- may or may not work for recognition purposes, it seems unlikely that lower current would increase the risk of damage.

I don't know the answer the question #3

[nikg]

Thanks for the reply. I think I am going to try them out...I agree with you and don't think that the greater resistance would do harm.

[criquecote]

good morning

i m reading a lot off sujects about d+ and d- and put resistance etc etc

i try to charge a i phone with 4 AA accu in serie

just with cable ubs
the red with the green toghether for the +
the black for the -

and the last white , nothing with it

and the phone charge more than 50°/°

so i don t understand the probleme with D+ and D-


THANK YOU

[adafruit_support_bill]

so i don t understand the probleme with D+ and D-

Different phones have different charging protocols. Some require certain voltages on D+ and D- to charge. But if yours works without it, then you are lucky!

[criquecote]

i dont think it s only my i phone 4s could be ok

i read a lot off text and i t s always this probleme d+ and D-

PERHAPS with my methode i t would be ok for all the i phone

try it and say me

and no probleme with the resistance only to connect the good colours

thank you