18 replies to this topic

[cynicz]

Ok I dont know much about how much power the usb charging port on the razr maxxs can handle. Therefore i am asking for input/advice on this idea.
If my research is correct. a single usb phone charger can transfer 5V of current to the phone per USB connection. I have seen the micro usb cable for like 20$ that has a cable connection the 2 usb ports to each other (pic below for an idea)



I was wondering, since I have plenty of extra wire, heatshrink tubing, and solder, would the following work

Take a single tip of a phone charge, soldering it to 2 pieces of 12guage wiring (positive and ground). Then on the opposite end soldering 2 Female connectors.
Then having 2 seperate pieces, each piece containing a male connector on 1 end followed by 2 usb hubs. (pic below)



Therefore you can use 1 or 2 connector which will allow access to 2 or 4 USB hubs.
Then using the following in a car (use 1 or 2 depending if you want to use 2 or 4 USB hubs.


Theoretically this should provide 4x the current and charge the phone at 4X the normal charge speed.

Would this work well or would it overload the phone.
The reason behind this idea is i work 2 full time jobs given a 1 hour break in between the 2 which i need to charge my phone for the next shift.

[cynicz]

I thought so as well haha. Just wondering if this design would work as I assume. If it would I plan on butchering a couploe phone chargers and making a nice charger and will return with pictures.

[priddyma]

Best I would say is.... find an old phone that uses micro usb to charge and attempt it with it and see how long it takes to charge or if it fries the phone.

[cynicz]

I dont have any old phones or access to any. I was hoping a more experienced user could chime in. I will probably only do a 2usb rig as ive seen these sold before but was more curious to if the 4 usb would work well

[cynicz]

I will make a stop by radio shack for some male/female connectors tomorrow. would still like for someone with more knowledge on the phones max capabilities to chime in.

[lovemyram4x4]

It will only work up to the point of the limit of the charging circuit unless it's a factory cable(bypasses charge circuit). If you did bypass the charge circuit IIRC the Max current for a 3300mah LiPo is about 3amps. Also LiPo packs are potentially dangers when it comes to charging/discharging with risk of fire/explosion so wouldn't recommend charging faster than the charging circuit does.

The first dual plug cable would be helpful when charging off standard USB ports that are only have 500mah output so you can full charge rate though.

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[cynicz]

So based on what you just said basically is saying that the 4 usb version would be too much. The only real ideal method would be a dual usb hub model of my idea. since a char charger has a approx value of about 2000mah even just using 1 of the 2 usb hubs would provide the same transfer as 2 since i plan on splicing in 12 guage wire vs the original like 18/20 guage wire

also the only real benefit of having 2 usb hubs would be for connecting to a computer since those USB only have a 500mah output value correct?

[lovemyram4x4]

Yeah, it doesn't do any good to supply more current than the phones charging circuit & current power usage(if phone is on) will use. Most cables & car chargers can already supply the Max the phone would use. Most PC USB ports & some wall chargers are less but most of that are will be 500mah so using 1 dual plug would give you 1amp.

I actually have a cable that ironically came with a 2amp car charger that won't pass enough current to charge my phone while in the car(BT, GPS, data, screen on, etc) due to the phone using all the current it can pass(not sure how much it actually can). It does charge under lighter loads so I just use it has my PC cable where the USB port is normally the limiting factor.

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[Alex.Abraham]

Look online first you might find a cheap cable that has 2 USB connectors in back and micro USB connector in front

I bought a USB hard drive which uses a Mini USB connector and that came with the type of cable you are describing BC laptop USB ports don't generate so much power

[HouseMD]

I see his idea. Firewire would have similar capabilities, just with data, am I correct? Since you plug two firewire ports into an ext HD and the other 2 into your computer, it's still one data connection.

So, I'm not technically literate in the battery world, but i know their are certain limits the batter can charge to without exploding. and, I wouldn't risk exploding my maxx battery, kinda need it

[srzero]

Well as for using two usb ports in the car to charge one phone, wouldnt the power from the cig lighter port be divided amongst the two ports? Making them 6v each? So wouldnt you get just as much power from a single port as you would by using two?

CarbonRazr, it's sharper than yours

[MasterGadgets]

also the only real benefit of having 2 usb hubs would be for connecting to a computer since those USB only have a 500mah output value correct?

Am I understanding correctly: you plan to connect a USB plug to a USB port on a computer as well as the phone while charging?
Feeding 5VDC back into a PC USB port does not seem like a good idea to me.

[lovemyram4x4]

Well as for using two usb ports in the car to charge one phone, wouldnt the power from the cig lighter port be divided amongst the two ports? Making them 6v each? So wouldnt you get just as much power from a single port as you would by using two?

CarbonRazr, it's sharper than yours

Each USB port should out put 5VDC, no matter how many it has. Normally if the charger is rated a lets say 2amps & has 2 ports you'll only get 1amp at each port(this seems to be what those mini charge from the OP tend to be), if you used only one of these port, both or a single port 2amp charger your charge times should he about the same, as in this example the phone charging circuit is the limiting factor.

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[lovemyram4x4]

Am I understanding correctly: you plan to connect a USB plug to a USB port on a computer as well as the phone while charging?
Feeding 5VDC back into a PC USB port does not seem like a good idea to me.

He wants to plug into multiple PC USB or other USB power ports to increase the current to the phone for faster charging. What he's wanting to do does work & they sell USB cables that come with 2 PC USB connectors just for this normally used for portable USB HD cases as mentioned above. This however will only help charge times if the USB power ports put out less current than the phones charging circuit will use. If the ports output the same/more than the phone's charging circuit will use the doing this won't make a difference.

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[Nitewolf]

[snives]

Yeah... Not a good idea, don't do this. Making a double wouldn't be bad, but 4x would be a complete waste. As has been said throughout this it will not charge any faster than the charging circuit allows, and bypassing the charging circuit is a very bad idea. I haven't looked at the tech sheets, but comparing my charging rates on various charges I've seen that the circuit seems to limit us to 750-1000mA. If you build your own computers, there is no need for something like this as mobo manufacturers are offering over standard amp (standard is 500mA) USB ports now. Often times the voltage to devices can be limited by power saving features, especially on laptops. In that case, using multiple connections also might have no benefit. I'd check into turning off some power saving features and testing that before making up a cable.

To confirm the earlier points... When electric current is divided on multiple channels, there is theoretically only a split in amp load and a potential change in vars. Being that we are dealing with batteries, vars don't matter to us and can be ignored. Voltage (theoretically) remains constant. In practical application there will be a voltage drop technically, but not significant enough that matters to us in this case.

[dpratt23]

Just a quick suggestion. Do not do this on a phone that has a non removable battery, unless of course you intend to take the phone apart, voiding warranty, to replace a ruined battery.

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