Has anybody tried powering a Wii from their battery direct?

[oregonguy]

I'm pretty sure the Wii is a 12v device, though the 12v transformer it uses is surely regulated...has anybody had the courage to just plug it in direct to their 12V system without an inverter and the Wii's own regulated power supply? Does it work?

[dreadcptflint]

Do you mean using something like this: http://www.ifuncity.com/wii-12v-car-charger-adapter-power-supply-nintendo-n12.html

[oregonguy]

Hmmm...no, not kinda like that.....exactly like that. Probably shoulda checked the web first....

[wannabefree]

Devices like Wii need several voltages to operate. 1.8, 3.3, and 5V are typical of digital electronics. The "wall wart" provided with the Wii is just a convenient way to provide an intermediate voltage that is low enough to avoid the safety regulations that go with devices that plug directly into the wall. Inside the Wii it will convert that 12V to whatever it needs to operate. That's where the regulation really takes place, though you are probably right in expecting the wall wart to be regulated to some degree.

Now, if it were my Wii I would be tempted to hook it up directly to my trailer's 12V, assuming the Wii is expecting 12V. HOWEVER, my trailer is wired so that when the battery is charging (which can be at about 14.5V and pulsing rather madly) my internal 12V is derived from a separate, regulated power supply. I would also only have myself to blame if the smoke escaped from my Wii. If you do that, you would have me to blame -- so by all means get an auto adapter for that Wii!!!

[wlooper89]

Hello wannabefree,

I know you are an electrical professional and am curious as to the need for the pulsing charger. Could the one with smooth DC power the trailer and charge the battery at the same time? I guess it depends on the amps output of the smooth DC power supply.

If anyone wants to get more into the nuts and bolts of makiing smooth 12V DC from 120V AC I think the article in the link below is a pretty good description in mostly layman's terms. It has been a long time since my ham radio days, but in my very general understanding I believe one would need to add two components to a 12V AC transformer output to get normal 12V DC. First would be a bridge rectifier to get the AC current flowing in one direction instead of back and forth. This would result in pulsating 12V DC. Then a capacitor would smooth out the pulses and make the current steady. The end result is a basic converter. The article goes into a little more detail but still only about one page in length.

http://en.wikipedia.org/wiki/Diode_brid ... _smoothing

Bill

[wannabefree]

Wlooper -
It's just that most modern chargers work that way. There are several ways to control the charging of a battery, the simplest being to insert a series resistor between a simple rectifier/filter (as you cited in the wiki link) and the battery. This has been done for many, many years. While it is simple, it is neither cheap nor the best way to charge a battery. Transformers contain lots of iron and copper. Copper has gotten quite expensive and iron is heavy, so this approach has fallen out of favor for battery chargers.

Modern chargers monitor the voltage of the battery and the charging current, and limit them by pulsing the charge voltage applied to the battery. Some even monitor the temperature of the battery and adjust the charge rate accordingly. This closed-loop charging has the advantage of lengthening battery life while also permitting faster charging.

I made some assumptions about the charger. On the other hand, old-style transformer/rectifier/filter charges regularly skimped on the filtering (many not filtering at all), relying on the battery to filter the power. This works, but isn't necessarily friendly to modern electronics. Both a poorly filtered power supply or a pusling charger can have negative effects on electronics. Not necessarily harmful but it can noticibly affect performance.

After saying all that there are some specifics that can prove it all wrong. Cars charge their batteries directly off the alternator with no filtering. All the electronics in cars work just fine, but they're designed to work in that environment. Wiis aren't, necessarily. So it all comes back to do you want to risk toasting your Wii or spend $20 on a car cord? The Wii is probably very robust and can survive a car environment just fine, but I wouldn't recommend anyone try it because it's not my Wii.

[wlooper89]

wannabefree,

Thank you very much. That does shed some light considering my limited electrical experience. I am still not 100% clear on the term "filtering" but believe that means the bridge rectifier as opposed to simply using the 12V AC output of a transformer.

In my oversimplified idea, I think of a bridge rectifier as getting the AC current to flow in one direction rather than back and forth, but still having the AC pulses. The addition of a capacitor can smooth the pulses by building up an electrical charge internally and releasing it between pulses to make the DC current more smooth. As you mentioned the battery itself when connected to a converter or alternator powering the trailer/vehicle can help fill in the pulses and make the DC more smooth. That might help in the case of a Wii.

As the Wiki article pointed out, a capacitor can deliver a nasty shock to a person even after power is removed, until the capacitor's internal charge bleeds away. I believe a resistor is sometimes added to hasten bleeding off the charge. The little green LED on my computer power adapter stays on quite a few seconds after I pull the plug.

Bill

[wannabefree]

Actually, a bridge rectifier takes the bottom half of a sine wave and flips it upside down. The result is often referred to as pulsating DC, but it's more like an endless string of McDonalds logos. Now that's an image for you. The capacitor is the filter and works as you describe. It stores energy as the voltage ramps up and releases it to the load on the down slope. While it does store energy when the power is removed, it's only 12V in this case, so no need to worry about a nasty shock. Maybe a little zap if you hands are wet.

[MceeD]

I'm pretty sure the Wii is a 12v device, though the 12v transformer it uses is surely regulated...has anybody had the courage to just plug it in direct to their 12V system without an inverter and the Wii's own regulated power supply? Does it work?

From the looks of this post http://forums.benheck.com/viewtopic.php?f=23&t=24698 You can do it. even with the car running. Although without the adapter "dreadcptflint" pointed out you might run into electrical/radio interference. You can always hack the adapter to hook up directly to a battery or terminals.

Do you mean using something like this: http://www.ifuncity.com/wii-12v-car-charger-adapter-power-supply-nintendo-n12.html