I got a 2 amp car charger for my nook color and want to know if its safe to use for the Evo. I know the Evo typically charges at either 1 amp (out of wall) or 0.5 amp (out of computer), but not sure if this was risky.
actually i think its likely the cause the evo will throttle the amp down to 1, right?
Can we use a 2 amp USB car charger on the EVO?
When the EVO is on and pluged into the car charger charging at 1 amp (1000 mHa), and the EVO is taking up ~680 mHa being on with say Navigation, the actual juice going INTO the EVO is 1000 minus 680 or 320 mHa max charging.
So a 2 amp car charger would be great when you need to BOTH charge the EVO at it's max 1000 mHa rating AND use it for energy hungry applications (like navigation).
Or can the EVO not be able to do this?
Can we use a 2 amp USB car charger on the EVO?
When the EVO is on and pluged into the car charger charging at 1 amp (1000 mHa), and the EVO is taking up ~680 mHa being on with say Navigation, the actual juice going INTO the EVO is 1000 minus 680 or 320 mHa max charging.
So a 2 amp car charger would be great when you need to BOTH charge the EVO at it's max 1000 mHa rating AND use it for energy hungry applications (like navigation).
Or can the EVO not be able to do this?
The EVO stops charing when it's full. This is part of its design. I don't think any heat will build up.
The ROCKETFISH charger I have says 2A on it. Everything works fine.
The EVO stops charing when it's full. This is part of its design. I don't think any heat will build up.
The ROCKETFISH charger I have says 2A on it. Everything works fine.
Are you able to verify the following with the Current Amp Widget:
With an almost drained battery: Charge the EVO with your ROCKETFISH charger AND run Google Navigation with 4G, Bluetooth, WiFi all set ON and see what the charger is charging the EVO at?
My EVO consumes around ~680 mAh with all of those features turned on including Navigation.
Your ROCKETFISH charger should be able to charge close to the 900-1000 mHa (while consuming ~680 mHa) with it's 2 AMP rating.
Are you 100% sure that the EVO will draw more than 1 amp? I could forsee a situation where the HTC engineers have put a limit to the current draw of the EVO. Even if I can supply 2 amps, the EVO may never draw more than 1 amp. Or 1.25 amps...or whatever random number they decided to cap it at. IMHO, the main reason for the 2 amp charger is so that when you use the extra USB port on it, you can get 1 amp to two different devices...rather than 2 amps to a single device. A quick question about your settings...do you simply have BT on, or do you actually stream music via A2DP to BT?
I was unable to let my battery drop all the way down, but I did a test at about 50% on my way in to work today. I had 4G on, GPS on with Google Nav directions to the office, streaming Pandora, and sending the audio via BT A2DP to a BT FM Transmitter and I left the screen on. I forgot to leave WiFi on, sorry about that. The results are below. I deleted all redundant information from the log. If there were 10 entries for 408mA at 51%, I used the first entry, and deleted the other 9. Some of the really low dips are likely when Pandora started downloading the next song, but I can't confirm this.
2011/01/14 07:59:42,-618mA,50%
2011/01/14 07:59:52,0mA,50% (plugged it in right here)
2011/01/14 08:00:02,632mA,50%
2011/01/14 08:00:28,580mA,50%
2011/01/14 08:00:58,384mA,50%
2011/01/14 08:01:29,590mA,51%
2011/01/14 08:02:02,594mA,51%
2011/01/14 08:02:32,408mA,51%
2011/01/14 08:02:58,398mA,51%
2011/01/14 08:03:28,542mA,52%
2011/01/14 08:03:58,392mA,52%
2011/01/14 08:04:29,290mA,52%
2011/01/14 08:04:59,596mA,53%
2011/01/14 08:05:30,536mA,53%
2011/01/14 08:06:00,418mA,53%
2011/01/14 08:06:31,412mA,53%
2011/01/14 08:07:01,368mA,53%
2011/01/14 08:07:32,370mA,54%
2011/01/14 08:08:02,432mA,54%
2011/01/14 08:08:32,566mA,54%
2011/01/14 08:08:58,442mA,54%
2011/01/14 08:09:29,302mA,55%
2011/01/14 08:10:02,374mA,55%
2011/01/14 08:10:32,358mA,55%
2011/01/14 08:10:58,432mA,55%
2011/01/14 08:11:28,582mA,56%
2011/01/14 08:11:59,426mA,56%
2011/01/14 08:12:29,376mA,56%
2011/01/14 08:13:00,366mA,56%
2011/01/14 08:13:30,404mA,56%
2011/01/14 08:14:00,384mA,57%
2011/01/14 08:14:31,480mA,57%
2011/01/14 08:15:01,326mA,57%
2011/01/14 08:15:32,562mA,57%
Evo limits power drawn. Charger delivers more than needed. No transformer in between. Any extra power will be converted to heat. Good news is charger probably doesn't have regulator putting out only 2 amps and instead has one that puts out up to 2 amps.
Are you 100% sure that the EVO will draw more than 1 amp? I could forsee a situation where the HTC engineers have put a limit to the current draw of the EVO. Even if I can supply 2 amps, the EVO may never draw more than 1 amp. Or 1.25 amps...
Thanks Palmetto, that is very helpful.
So here is the critical question. When we see an entry like:
- 632mA,50%
Does that mean 632mA going to charging the Battery (I think so)? If yes, then the EVO is indeed taking in more than 1Amp. I say this because the EVO with all of the things turned-on you have above will draw more than 700mA.
So if the EVO is consuming say 700mA and the log shows a possitve 632mA, then total energy going into the EVO is 1,332mA of which 632 went to the battery.
Any electrical folks here that knows the answer?
I must admint, I'm no electrician...
Why would there be extra power? The EVO will take what it wants, and leave the rest. Why is it that the charger must send the extra power somewhere (heat)?
Imagine plugging a 3 amp device into a standard 15 amp NEMA home outlet. What happens to the extra 12 amps? Is a tremendous amount of heat generated?
I'm not an electrician, but I build and tinker with electrical components as a hobby. As a general rule, amps are usually not a problem as they're really controlled electrical flow. The control comes from the device's current regulators (transformer or software requesting amount of power). Those requests are made from the Voltage of the powering device - your iPad charger - which also makes that same request by dipping into the outlet for power. The iPad charger has a transformer to smooth out and dissipate the extra voltage that comes from the wall (volts are spikes rather than continuous flows of power).
As long as the iPad charger Voltage does not greatly exceed the voltage of the Evo, you should be fine. The amps really aren't a factor.
The reason US-intended electronics fry on international outlets is the volts. The power spikes are too high for the transformer/software regulators to handle.
It's not an iPad charger. It's for all micro-USB devices. It is a 5V device, and internally fused at 2 amps. Since the amps aren't a factor, I don't see where the excess heat is going to come from. What did you mean before about the excess heat?
I can run another log while not charging to see the total draw while running all those services.
Any excess voltage has to be dissipated somewhere, either in the charger (resistors), the cable (inherent resistance), or the device (capacitance). All excess is turned into heat and must sink. Think of this as running your finger across a piece of wood. As long as the friction you're creating doesn't exceed the ability of the medium to dissipate the energy created, all is comfortable. Do it too fast and you're gonna need a bandaid.
It's always best practice to unplug any device as soon as you see a "full charge" indicator.
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