As far as seeing it in operation, you and me both.
The big fork lift drive motors are those big beasts that probably weigh 150lbs. They could probably stir a 1000 gallon papercrete tank without breaking a sweat.
I was thinking more along the lines of the smaller, but still very powerful hydaulic lift motors that are more like 75lbs. One of those from a salvage yard can be purchased for $50-$100 if one is willing to take it apart, clean it out (they are almost always nasty), dressing up the commutator, and throwing in some new brushes if necessary. That will have more than enough power to handle a more modest sized mixing tank. Two of that class of motor are what powers John Waylands White Zombie Drag Racer. As I have said, one of those at 36-48 volts should still be overkill for a modest sized mixer.
I think you overestimate the amount kwh required to accomplish the task. Peak power is only required for a short time. Much less power for most of the mixing time. Lots of torque and power are required to break up big chunks of paper, like phone books or big grocery bags full of newspapers. That first minute or so (+/-) of mixing will require the highest amperage draw to the motor to provide that initial torque. Once the mix is beyond that initial stage, the power required to keep the mix churning drops. If you don't cut the power back, you'll throw the mix out of the mixer. I'm certain you have experienced that phenomon before. You've posted about it. The amperage should drop as well once the mix is beyond that first stage. That has been my consistent experience in the very tiny 5 and 10 gallon mixers I have used for experiments. The power required will also vary with how watery the mix is. The more water the thinner the mix the easier it is to churn and the lower the amperage required on the motor. Nothing comes for free though, the more watery the mix, the more batches will be required to finish the same job. Such is life. Everything requires balance.
Also, I can buy a brand new 48 volt pulse width modulated 500 amp Golf Cart motor speed controller for one of these motors for $500. If I settle for less power, like a 250amp version I can get a new one for $150. However I have no intention of buying a new one. I'll get a used one for under $100 easy. Probably much under. The same salvage yard in Kansas City that has old dead elecric forklifts also has old dead electric golf carts. It's trivial to dig through the yard and test the controllers to find a good one.
With an efficient blade design I should be able to punch the motor hard for the first minute or so to break up the big chunks, then throttle back to a liesurely pace to thoroghly churn the mix for a while to a frothy yummy oatmeal goodness. (mmmmmmmmm frothy yummy oatmeal goodness mmmmmmmmmmmmm)
Also, I don't have a problem mixing up two or three batches in a day, then waiting a week or more before I run more batches.
The key is that I want an efficient mixer, regardless of how it is powered, that allows me to dump the papercrete directly where I want that papercrete to go without ever needing to handle the papercrete ever again. If I can dump directly into forms directly on the wall, I have saved myself a ton manual labor. I can afford to kick back and drink lemonade while the batteries recharge and still finish a structure faster than if I had worked like crazy to make thousands of blocks for weeks and months only to spend more time mortering them into place.
At least, that's the theory.
Whether I can make it work in practice? I'll be as excited to discover that answer as anyone.
Dang. Now I'm hungry. I think I'll cut up an apple and have some oatmeal... the real kind.
Spaceman wrote:
A typical household system is in the range of 600 to 2,000 watts of panels, which is what that photo appears to be, perhaps 20 100watt panels. Even the larger system would only run a 20 hp motor for an hour or so after a good day of full sunlight and charging, with no other loads connected like those power tools and machinery. The numbers (blah blah blah) are what matters when you are talking about powering a large motor. Assuming that one panel will charge one battery in one day is nonsense. How large is the panel, how large is the battery, how much sunlight hits the site? A typical residential solar system is not big enough for what is needed to mix papercrete unless you are in no hurry. A couple of mixer loads a day will take a long time to make a house. Tripling or quadrupling the size of a solar system would be expensive.
I still think a forklift motor would make a great mixer if it could be powered easily. I don't see it as an advantage over any other kind of mixer from a safety standpoint, or a convenience standpoint. I see disadvantages in the expense, in the huge battery bank that you will have to place next to the mixer or run large expensive cables to. The amperages involved are large and potentially dangerous. A forklift motor may weigh 100 or 150 pounds, not exactly portable by itself even without the batteries and controllers.
I'm starting to repeat myself, so I'll stop. I look forward to your video showing your mixer in operation.
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