30:29 Peter Lindeman gave a presentation on advanced solar methods, where we're showing a successful system implementing the concepts that we have been teaching for years. And it's a friend of ours Al Francor up in Yakbc and his batteries are all charged by 2 p.m in the afternoon regardless of how much sun there is And so with the batteries, what's been known for about a century and this came out of a book that John Bodini and Peter and the rest of us called The Battery Bible. It was written by somebody who is teaching farmers how to keep their batteries pretty much indefinitely good for powering milking machines on the farm, for example. What they see is that as the battery is getting charged... For example, an alternator in the car might push your battery to 13.8
31:19 Some solar charge controllers and battery chargers might charge the battery to the low 14s, and people are conditioned to believe that when you're done charging it. And you see the voltage come down if it's 12.6 and above then it must be charged but nothing could be further from the truth because the voltage is not an indication of how much capacity that battery actually has. And so what we see is that once you start charging the voltage, you start bringing the voltage up to high 13s and get it up into mid-to high 14's the voltage level starts to kind of plateau a little bit. And if you push it to 15, 15-1, 15-2, 15-3 right around there it'll plateau and then what you see is that the voltage actually drops
32:10 little bit. And when you see that voltage drop, that means that the final layers of sulfation have dissolved back into the electrolyte and you basically reverse the chemistry to a like-new status. What that voltage drop indicates is that the impedance which is like a resistance in the battery has dropped because if you still have sulfation on a plate, that means there's less electrolyte in this solution and you have more distilled water than you do the sodium or the sulfuric acid solution. The more sulfuric acid is dissolved in the solution, the more conductive it is which means there's less resistance to the current moving through the battery but when that sulfation goes onto the lead and that means the battery is sulfated so to speak
32:55 There's less sulfuric acid in the solution, which means it makes it harder for the current to move through the battery. So when we see that little voltage drop in a low 15 volt range for a flooded cell lead-acid battery... ...which would be like a battery in your car that you actually have little caps you can take off and add distilled water to it.... that kind of battery at that low 15 volt level, you will see that little voltage drop which means the final layers of sulfation dissolve back into the solution making it more conductive. So that's why the voltage drops. Not only does the current move through more easily, but the voltage is moving through the battery more easy as well so it's like there's less back pressure to it you know if you put a potato in a tailpipe of a running engine It'll stall it out because there's so much back pressure that the engine can't turn over Because there's too much back pressure holding it back But the pressure will go up
33:49 quite a bit and then it'll just stall out. And that's kind of what the sulfation is in a battery, is kind of like putting a potato on a tailpipe where you have too much back pressure to the flow of electricity so the pressure goes up and the voltage is up but if you remove that potato that pressure would suddenly drop and that's what that little voltage drop is. So all of Bidini's Battery chargers and rejuvenators took the lead acid batteries through that process to bring it up, look for that little drop. And then you can reuse the battery and as long as the battery was constantly charged by that method it would just stay good I mean he had car starter batteries over 20 years old that still worked like new