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PDANET w/ iPhone plugged in still seems to drain the battery

spaceballl

spaceballl

macrumors 68030
Original poster
Nov 2, 2003
2,938
362
San Francisco, CA
Has anyone else noticed this?

This seems to be pretty consistent behavior that i've observed a few different times. Last week I was in a 4 hour meeting, and I was browsing via pdanet the whole time... At the end of the meeting, i was expecting my iPhone to have full battery life. Instead, it had like 50%. So yeah... just seeing if anyone else has observed this.

Thanks!
 
yes. charging even with the actual wall adapter cannot keep up with tethering + 3g speeds apparently.
 
Has to be some sort of software error. Most 3G phones can tether just fine when connected to power and not lose their charge. Anyhow, I guess the good news is that other people are having the same issue (just so i know my phone isn't a dud). Bummer that this is happening.

I'm eagerly waiting an official tethering solution so I don't need to jailbreak anymore.
 
This is pretty common. My 3G can hold its charge if I am doing light web surfing and email. Media really pulls the battery down. This behavior is not limited to the iphone. I had the same issue with my BB 8830.
 
Its probably a software issue as my findings are, if you tether using openssh with insomnia along with proxifier, the battery charge holds up full with 3g speeds.

I believe the only difference here is the wifi router which must be a little more demanding.
 
Ah i see - thanks for all the insight. So i'm guessing that when (if?) Apple comes out with an official tethering solution, it will go through the USB cable, that way there's no wifi drain and nobody will ever get to see how bad a streaming 3G connection kills the battery since it will be getting charged via usb hahaa.
 
PDAnet/firmware interaction = interrupted charging

Howzit?

I guess I'm glad to hear that others are having this problem too. I've actually found that there seems to be some sort of bug that causes intermittent loss charging ability when PDAnet is in use. If you keep your screen on and unlocked while using PDAnet, you'll notice your battery indicator on the task bar (not the numeric readout within PDAnet) will change from the "charging" lightning bolt icon to the "charged" plug icon. It does this dispite being far from fully charged. When this happens, PDAnet just keeps draining the battery (easily tracked with the PDAnet numeric battery display). Sometimes I can initate charging again by unplug/replugging in the phone, but this is short lived and doesn't always work. Incidentally, if you look at the lock screen battery icon, it correctly displays battery charge.

I have no idea what causes this and I think this is new since the 2.2 firmware update. My battery drain is actually worse than under 2.1, dispite all of the upgrades to PDAnet's efficiency. If anyone can shed some light on this, PLEASE post whatever information you have...and maybe share it with PDAnet developers!

FYI - the same issue is occuring with Netshare...comething to do with 3G and wireless being active at the same time...the pessimist in me wonders if it wasn't purposely introduced by apple in an effort to get everyone onboard with the pending "official" tethering options from apple/att.
 
how come when I have it plugged in the USB while using PDANet, my connection speed slows down??
 
DMoney0023 said:
how come when I have it plugged in the USB while using PDANet, my connection speed slows down??
Click to expand...

that's a really good question. I hadn't noticed that, but if there's some sort of resource conflict between cellular network, wifi, and charging operations, then this actually makes perfect sense to me. Can't say I have a clue regarding mechanism though. Let me know if you find anything out. I love PDAnet but can't stand the charging issues. I've also found that if I don't force quit PDAnet after use and fully disable wifi on my phone, the interrupted charging will persist, sometimes even after reboot.
 
cvdubb said:
If you keep your screen on and unlocked while using PDAnet, you'll notice your battery indicator on the task bar (not the numeric readout within PDAnet) will change from the "charging" lightning bolt icon to the "charged" plug icon. It does this dispite being far from fully charged.
Click to expand...

I notice this same behavior with intermittent charging and the battery icon changing and I don't have PDAnet or Netshare installed. I just restored and re-JB my phone and going to monitor it. I didn't install anything else yet like OpenSSH or anything. Could be other programs that are making this happen too.
 
mtehonica said:
I notice this same behavior with intermittent charging and the battery icon changing and I don't have PDAnet or Netshare installed. I just restored and re-JB my phone and going to monitor it. I didn't install anything else yet like OpenSSH or anything. Could be other programs that are making this happen too.
Click to expand...

It definitely makes sense that there might be other aps out there with this problem as well. Do you have any apps that seem like they might involve both the wireless and cellular connections? Any other hacks to fool the system into thinking you're on a wireless connection (so you can place VOIP calls, access iTunes store, etc.?). I wouldn't be surprised if one of those would trigger it too.

In my case I've done a clean restore of my phone, installed only PDAnet, and verified that the problem still exists. I'd love to get rid of some other app and have PDAnet work correctly, but it appears there's no way around it.
 
Response from Junefabrics (PDAnet Developers)

Just thought I'd drop in this response from the Junefabrics guys:

"This seems to be a known issue, not caused by PdaNet in particular but have something to do with a firmware bug that got triggered when using PdaNet. We still don't have the exact detail but it could be caused by usage of both of the Wifi and the 3G data. We are not sure if it is from the OS firmware or just the jailbreak firmware or if there is anything we could do at the software end to avoid triggering this issue. Hopefully we would be able to get more information and a solution on this in near future."

So...if anyone out there has any more detailed info about the potential cause of this, please chime in so we can get this fixed!

Thanks
 
cvdubb said:
Just thought I'd drop in this response from the Junefabrics guys:

"This seems to be a known issue, not caused by PdaNet in particular but have something to do with a firmware bug that got triggered when using PdaNet. We still don't have the exact detail but it could be caused by usage of both of the Wifi and the 3G data. We are not sure if it is from the OS firmware or just the jailbreak firmware or if there is anything we could do at the software end to avoid triggering this issue. Hopefully we would be able to get more information and a solution on this in near future."

So...if anyone out there has any more detailed info about the potential cause of this, please chime in so we can get this fixed!

Thanks
Click to expand...

This is a Good Finding. For some reason Its hard to believe its a bug. Its probably intended by Apple as they are notorious in OS Alterations to work towards their favor. eg: the new macbooks couldn't pawn.

One consideration is that this gets fixed with the next firmware as its said to believe that the official tethering plan is on its way.
 
Same issue here

Same exact issue for me too. The PDAnet dev team must be aware already. Would love a solution!
 
Same issues here... on a 30 hour drive at the moment, so I should be able to try a few things...

I'm using PDANet 1.4 and fw 2.2; have the phone plugged in to the stock 1A USB charger... Had the screen on the whole time and it got down to 19%....

With PDANet as the forefront application though, you can lock the screen and still stay connected. Doing this seems to work for now (Charge back up to 25% and climbing...), but I can't really tell yet; I'm on EDGE now, and not 3G.

FWIW, this is *not* a PDA Net issue; Back when 2.0 was out, the 3G couldn't hold a charge plugged in while using GPS + 3G with google maps and the screen on. I guess it just draws more than the 1A then the little brick can supply...
 
Nope, still doesn't hold a charge even with the screen off.. Just did a 37MB d/l over 3G.. phone was at 50% when I started... When it was done was at 38%.
 
Hmm.. this seems to be working so far... start with a full charge.

Then you can tether with 3G with it plugged in and it holds its charge. (At least so far, still testing)

Makes sense too.. Adapter uses all its power to power device and doesn't need to bother with charging...
 
FWIW, This also means that this *is* a software and/or firmware bug that apple needs to fix...

Here's an example of how the phone seems to be behaving now:

Say the phone needs a minimum of 250mA to charge. It can use up to a full amp, and charge faster, but it will continue to (trickle) charge even with 250mA...

When the phone is plugged in and being used, it will use the amount of power that it needs to operate the phone, and if this amount is less than 750mA (in my example), than the leftover power is used to charge the phone.

This is where the expected behavior and the actual behavior differ:

The phone, ideally, should never use more than an amp of power. This may or may not be the case (if it does use more than an amp under heavy load, then we're SOL, as that's all the stock adapter can supply... my current observations don't support this though, as its currently maintaining a full charge using 3G).

If the phone uses MORE than 750mA of power, then the phone wont be able to charge, just maintain its current charge and use the adapter to run the phone. This seems to be what its trying to do (and certainly what it *should* do), as the phone switches over to its "plugged in" icon.

That's not happening though; the phone is for some reason not able to maintain its current charge when its not full, which indicates that the phone is trying to charge and failing due to not having enough power, but also thinking it doesn't have enough power to run off the adapter (even though it does), presumably due to trying to allocate some power to charge with... If this is actually the case, its a bug, and apple needs to fix it.

Also, what's definitely a bug is even after the phone is no longer using excessive power (IE, no longer on 3G), it wont start charging again... It remains "plugged in." To start charging again you need to unplug and replug the cable.

If the phone is actually using more than an amp... we need a bigger power supply ;) (Though, the current one is already double USB spec, which maxes out at 500mA @ 5V).
 
appleguru1 said:
If the phone is actually using more than an amp... we need a bigger power supply ;) (Though, the current one is already double USB spec, which maxes out at 500mA @ 5V).
Click to expand...

Where did you get your analysis from. This seems to make sense. there was a time I could not get my PDA to charge while connected to the bluetooth GPS, however finally managed to get that to work with a stronger power supply for the CAR.

I wonder if this will be fixed when Apple/ATT come out with an official tethering plan.
 
The strain on the AC cord may be too much maybe while trying to pull 3G data and send it to your computer so I think (assuming that is) it uses your battery to compensate for what it needs. In the end, when your battery dies I think that's when you see the real performance slow down.

However, like you said I hope AT&T does release the official tethering software. I just don't think they should charge $30 extra, more like $20 and they'll have me tethering.
 
navigates said:
Where did you get your analysis from. This seems to make sense. there was a time I could not get my PDA to charge while connected to the bluetooth GPS, however finally managed to get that to work with a stronger power supply for the CAR.

I wonder if this will be fixed when Apple/ATT come out with an official tethering plan.
Click to expand...

My analysis is based on anecdotal observations of the way the phone behaves. And it really doesn't have much to do with tethering, other than that tethering is a 3G intensive network applcation. Like I said before, you can notice the same effects on a stock phone using google maps and GPS with 3G data.

The stock AC power supply included with the iPhone (3G) outputs a maximum of 1 amp @ 5V DC. This can be read on the backside of the plug. (5V is the voltage provided by USB). The USB specifications say that any given USB device can only use 500mA of bus power, so the power supply is supplying power over USB that is "out of spec"... This doesn't matter much though, as the charger isn't ever part of a traditional USB chain. When you connect your iPhone to your computer it draws at maximum 500mA (and thus will take longer to charge then when plugged into the USB adapter).

This isn't a mains AC supply issue; 120V AC is waaay more than sufficient to handle the iPhones load (a typical circuit in your house is 20 amps @ 120V AC)... its on the DC end that we need more power, and even if we were to supply it the iPhone likely wouldn't use it in its current configuration (which is designed to limit current draw to an amp).

In any case, I haven't hooked up an ammeter and taken any real measurements, but the scenario I described certainly fits the phone's behavior. If I get ambitious at some point I might pull the phone apart and check the draw from the battery, but its not high on my list of things to do at the moment ;)
 
So far confirmed... downloaded the same ~37MB file as before (averaged ~150K/s this time, about the same)... Phone didn't budge from 100%.

So, it seems like the workaround for now is to start with a full charge and leave it plugged in, and it'll stay full.
 
jav6454 said:
The strain on the AC cord may be too much maybe while trying to pull 3G data and send it to your computer so I think (assuming that is) it uses your battery to compensate for what it needs. In the end, when your battery dies I think that's when you see the real performance slow down.

However, like you said I hope AT&T does release the official tethering software. I just don't think they should charge $30 extra, more like $20 and they'll have me tethering.
Click to expand...

The cable is never used for data transmission. Even if it was, it wouldn't affect power supply.
 
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