Author	[Modern View]
Stan in Oly, WA 12-23-2012 18:55:04 174.31.203.167 Report to Moderator	My wife bought some speakers for her MP3 player. They contain lithium ion batteries and are recharged by connecting to a charged USB port. The speakers that this pair replaced did not have batteries. They would run off the MP3 player by itself, including when my wife would have the MP3 player plugged into a house current outlet in its recharging mode. The instructions with the new speakers say they can be used while being recharged, but don't say whether they can be used while the MP3 player is being recharged. I'm strongly inclined to say that they can, but not quite so strongly inclined as to suggest that she try it and find out. My wife is not the kind of person to return a product claiming it doesn't work if she's the one who made it not work---you know, honest. Does anyone have specific knowledge of this issue? As I said, I've already got a best guess myself, so I'm hoping for something more specific than that. Thanks, Stan [Reply]   [No Email]
sotxbill 12-26-2012 14:09:53 69.152.248.105 Report to Moderator	Re: Using speakers with a device which is recharging in reply to Stan in Oly, WA, 12-23-2012 18:55:04   some usb ports support the "high power" spec and most do not. On laptops, only a one of the usb ports will do high power and the others dont. so.. trying to power both could ask for more power than the usb port can put out. especially if its a "low power" or standard usb port.   [Reply]  [No Email]
ss55 12-24-2012 10:46:37 173.31.19.80 Report to Moderator	Re: Using speakers with a device which is recharging in reply to Stan in Oly, WA, 12-23-2012 18:55:04   It should work with everything powered and recharging from the MP3 player, but it could tax the MP3 players power supply. Try it and see how it works. If you want all the components to recharge faster or if you are concerned about overloading the power supply in your MP3 player, you could use an inexpensive externally powered USB hub to recharge/power just you add-on components. The MP3 player would still run and recharge from it's own power supply, but the speakers would run and recharge on the hub's power. I've had to do that with an older computer that had a small power supply and a power hungry TV video card. Externally powered hubs only cost $10 to $20.   [Reply]  [No Email]
Stan in Oly, WA 12-24-2012 11:13:47 174.31.203.167 Report to Moderator	Re: Using speakers with a device which is recharging in reply to ss55, 12-24-2012 10:46:37   Thanks. I'm getting lots of good information about this situation, but so far nobody has addressed the specific question I'm asking. (Well, maybe MarkB has and it was too technical for me to recognize that he had answered it---I'm working on that.) The question is, could it hurt the speakers to play them when the MP3 player is plugged in in its recharging mode, taking into consideration that the speakers don't recharge through the MP3 player? They recharge by being plugged into a powered USB outlet, which the MP3 player does not have. Stan   [Reply]  [No Email]
MarkB_MI 12-24-2012 19:04:52 75.198.106.214 Report to Moderator	Re: Using speakers with a device which is recharging in reply to Stan in Oly, WA, 12-24-2012 11:13:47   Stan, Assuming there's no issue with sourcing enough current to charge and operate both devices, then I think the only concern would be a voltage difference between the ground references of the two devices. These days, engineers know to watch out for these sorts of problems and design interfaces that isolate ground references between devices. I don't think there's anything to worry about.   [Reply]  [No Email]
MarkB_MI 12-24-2012 02:45:23 75.198.33.197 Report to Moderator	Re: Using speakers with a device which is recharging in reply to Stan in Oly, WA, 12-23-2012 18:55:04   The only issue is whether the power supply for the MP3 player can provide enough juice to power the player, charge the player's battery and have enough left over to provide juice to the USB port. USB 2.0 normally can source up to 100 milliamps, although there is a "battery charging" spec that can source 1.5 amps. My guess is your speakers draw the full 100 milliamps when charging, Take a look at the specs on the charger for the MP3 player: if it's only rated at, say, 120 milliamps, it's probably not going to be able to charge both the speakers and player simultaneously and still be able to operate both devices. It's not going to hurt anything, it will just never finish charging. Safest thing to do is to bring both devices to a full charge before hooking them up. Then the charger for the MP3 player should have no problem keeping them both charged.   [Reply]  [No Email]
Stan in Oly, WA 12-24-2012 09:22:54 174.31.203.167 Report to Moderator	Re: Using speakers with a device which is recharging in reply to MarkB_MI, 12-24-2012 02:45:23   Thanks, Mark, Since I know so little about this, I don't know if this matters, but it might. One of the speakers attaches to the MP3 player via a single prong earphone type plug. The speakers attach to each other using a different type of plug. They charge through a USB plug, which is not connected during normal play---although possibly it could be. The speakers work when the MP3 player is not connected to anything else. Previously, using speakers which did not have batteries, my wife would frequently use the speakers while the MP3 was plugged into a 120 volt outlet, as for recharging. In this configuration, the speakers did not drain the MP3 player's battery so quickly---maybe not at all. I hope that's clear. I have a feeling that if I didn't have everything where I could see it, it wouldn't be clear to me. My wife's concern is that nothing in the literature accompanying the speakers mentions whether it is safe to use the speakers while the MP3 player is plugged in for recharging. We wouldn't expect them to recharge in this case---only to not discharge the MP3 player's battery. Does any of that change anything? Thanks, Stan   [Reply]  [No Email]
Inno 12-23-2012 21:28:17 70.49.136.91 Report to Moderator	Re: Using speakers with a device which is recharging in reply to Stan in Oly, WA, 12-23-2012 18:55:04   If the MP3 player can be used while recharging and the speakers can be used while recharging then yes, she should be just fine to do that.   [Reply]  [No Email]