I didn't say an 8 volt converter wouldn't work. What I said is it was the wrong chip to choose, and I stick to that. Why? Easy. If you're going to sell an adapter described as a 12 to 6 volt device, at least be honest and use the 6v chip. Otherwise call it a 12v to 8v device and don't fib about what it is because you think you'll be able to sell more of them to people looking for a 6v something or other. And also, take a look at how the runtz gizmos are being marketed today. Whoever is selling them has recently decided to claim they can handle 4 amps. Is that the truth? If they are still using the 7808 chip, it can't take 4 amps for even a nanosecond before shutting down and/or internally frying. Even if they've changed the chip, ask anyone...4 amps is not a piddling slug of current for a chip like that. It will require a heat sink which the runtz thing doesn't have.
Why are they failing? Not sure, but I have an idea. Take a look at the circuit. It has the 7808 chip, one capacitor on the input side and one on the output side with a single diode forward biased back from the output side to the input side. To me it looks like you sort of have protection for short circuits, but what about protection from capacitor discharge? The makers of most voltage regulator chips suggest various "typical circuits" in their data. I've yet to see a diode protected circuit with only 1 diode. To me that's like a doctor saying "Mr Hodpecker, we set your broken leg with a nice plaster cast and normally we would give you 2 crutches to get around with, but today we only had a termite-eaten piece of 1 x 2 and nurse Scooterpie coated one end of it generously with axle grease for fun. Good luck...you're on your own."
What I also said was it was likely the voltage mattered less than may be expected for the fuel gauge (and I explained how that gauge would work and why I believe current will be more important than voltage). But will it work on 6v? Without question it will. Please remember the 6v battery is made of 3 cells. Each of those when brand spanking new outputs 2.1~2.2 volts and whatever amperage the battery was designed to provide. As it ages, you can say adios to the 2.1v and the "new battery" amperage. That's what happens when any battery gets old, and it matters not whether you have an 8v battery (4 cells) or a 12v battery (6 cells)---and if you're curious why a 12v battery when you get it home registers apx 13.2 volts, multiply 6 times 2.2. They all go south when they start showing age. Just like the alkaline cell in your digital clock, remote control, Maglite, etc.
Yes, more investigation is always good. So is more knowledge. If you recall I had about 3 things I wanted to achieve in a "new design" voltage regulator and all of those have been accomplished. It has unavoidably taken longer and cost more, but it is going be able to handle 1.8 amps continuously and it will even be adjustable (something else new) so that you can make it run at any voltage you want (below 12v, naturally). Hopefully in a couple of weeks I'll have something to show you.
