How much proof do you need I'm wondering. You can drive those cheepos pretty hard. If you wire 2 of them in parallel how I mentioned before, you have effectively 0 chance of over driving them. Aside from that, their efficiency improves when they run cooler.
Oh boy..
First, the thing you mentioned about putting two of them in parallel, is kinda stupid; Using a resistor to "isolate" the regs from each other? Smart I guess, but it really doesn't work like that. You are also forgetting the fact that you will cause a very significant voltage drop this way and you are essentially just wasting power. That voltage drop means there is wasted power, directly related to the amount of current drawn by the sink (in this case the wii). Say we calculate the losses for the 1V line. We can roughly do that by considering how much it draws. That would be about 1.5A. (so about 1.5W, again these are all rough guesstimates) We could then represent the components attached to the 1V line on the wii as a 2/3Ω resistor. The entire circuit would look something like this:
See the problem? Those resistors there each will result in about a 0,06W loss. and a 0.08V drop.. Thats not insignificant. Considering the output voltage will drop anyways given the load and their
rated current, (which is usually inaccurate with these Chinese regs) you would need to set them at around a 15% or so higher voltage then the voltage you are trying to get to the wii in the end. Anyways, as
@Trimesh found, the highest efficiency you can expect from the best reg he tested is 78%.. Not that bad, but catastrophic in a battery powered device. given the fact that there's an 8% loss from these resistors by putting two regs in parallel, and there's a 78% efficiency overall, the total efficiency drops quite dramatically to just 72% (best case scenario, this gets worse the more current you draw).
Really the only risk is cooling the regs if you slightly undervolt, because undervolting the CPU or GPU either stable or simply not enough to power it. Over volting is where you get into dangerous territory.
Usually the LCD driver board has some tolerance level for over voltage built into the board, the same can be said for GC controllers if you are using an original controller, basically anything on the 3.3v rail can be undervolted.
You can't kill a wii by not providing enough voltage for it to turn on.
Then, there's the part about "undervolting the CPU/GPU isn't bad". This may be true to some extent, but not entirely. I don't think I can give you a good opinion on this however as I lack the knowledge or experience to properly say anything about this. What I do know however, is that having this much noise on the output is bad. Quite bad. This noise on the power line isn't just going to make the system unstable though, it radiates everywhere. You
will notice that on the audio and video output unless you shield everything very well.
Third..
A 001 model wii (the 45W one that shouldn't be used) can and has run off of 6 of these. That was before I had little thermisters to test for heat, and they stayed warm, but no more than a 30min old cup of coffee.
If your handheld went off like a hand grenade, my guess is you had 0 airflow, only one of those, and didn't check it before hooking it up. Measure twice cut once.
wat
The reason we don't use these 6 layer Wiis is because they use a lot of power. Inefficient regs combined with a system thats power hungry in the first place isn't going to get you a lot of battery life.. Other then that, a lot of power draw means a lot of heat output. 80% efficiency on regs with a system drawing 12W (not unreasonable for a 6 layer wii) means you waste 3W of power with those regs, and thats not even considering the resistor thing you had going on. 3W of heat is a lot of heat to just passively radiate. For reference, its more then what the GPU on a 4 layer Wii draws. I find it hard to believe these regs not getting this hot given the facts lol. But even then:
I have no issue with "Because it just works" but some people are in here for the DIY experience and don't mind tinkering to save $20 or more. Not to mention they should have a multi-meter and a work bench power supply/load.
You are saving 20$ with this? My b, the PTH regs cost 6$ a piece if you buy them from the right place - thats 18$ to power a full system. Even if these regs of yours are 2$, and you bought 6, well, you saved 6$.. And got a barely working inefficient setup. The reasons we stick with for example the PTH regs is not jxust because they work great and we were too lazy to find alternatives, its because they work
well, they are well priced, they are efficient, and they are
reliable. I think thats where the difference is most clear. I wouldn't trust these regs in a portable I would make, especially considering everything else that can go wrong in a system as complex as it. If I have a PTH in there, and something breaks, I can expect it was my fault because, and I would be able to fix it. I won't have to fully disassemble everything to then figure out the reg blew on me. We take pride in our work, and we would like it to keep working. Using reliable parts makes that a lot easier. It really isn't like these PTHs are the only way. Look at PowerMii, the Wii PMS, or even some of my own things. They are all using different regs. Some examples, like the Wii PMS, are even more economical for most people (still) given the features it has and the size of it. I agree with the part about the DIY experience, but there's a difference between going for the "diy experience" and plain ignoring research other people have done already and doing something else. While this may work for you right now, if you are serious about making a portable and making it any good, please get better regs.. Then I'm sure we'd all love to see it.
Sorry for the rant btw, I just got triggered and started typing..