February 18, 2016

Juice: Mtnforge sends.

Pay attention.  Good info here.

h/t mtnforge
I did all this. Some thoughts on power hope helps anyone interested.
Built me a solar/wind off grid system with a big ole fork truck battery. (1250 amp hours on a 20hr draw, after messing around for awhile to figure out how it all works). Keep your battery above 20% depth of draw, (based on 80% draw over a 6 hour period), and your battery will love you long time.
I fooled around various with PMA alternators:
The best pedal powered Permanent Magnet Alternator’s are 12volt ones wound for wind power, the slant core or non cogging are ALOT easier to crank. Usually you can expect a net charging current/voltage of 150-300 watts output at around 200 rpm. Don’t sound like much, but it is constant, it is a good kind of current too, nice square wave, what batteries like. If your people powering, rig into it a flywheel of some sort, the inertia really makes a difference. If your pedaling it, you don’t need a charge controller, a simple analog volt meter will do. Mount it to you grab handles, and when you reach 14.2 or so volts, your charged, stop pedaling. Simple, one less piece to break or wear out. The Delco cased PMA’s are easy to mount, they have a belt pulley already, no field to excite, just a positive terminal, the case is negative ground, they have the rectifier built in, though some models don’t, and you get 3 phase wild crazy AC, which is good if you want to send your output over long distance, you can use much smaller gauge conductor, and rectify your 3 phase into DC at your battery. Don’t have to worry about overheating if you have the auto style pulley fan, might find a larger size PMA pulley an advantage, depends on your ratios you are using. Use a notched half inch shallow Vee alternator belt if you can get one. Ask to mooch around behind the counter, get the thinest belt you can. Lot less friction. Your legs will thank you.
Its theoretically about 748 instantaneous watts to the horse power in a perfect world. 1HP is a lot of pedaling. How long you can pedal is the right question. Add in line losses, manufacturing inefficiencies mechanical losses, its probably 500 watts per horse power. But your talking pretty high amps output. And the voltage on a wind PMA is optimized by how the windings are set up, they have neodymium magnets so high flux is produced, it is good charging current, a regular car alternator doesn’t compare, and they use precious juice to run. A PMA puts all it’s current out the line. The lower the discharge voltage on your battery set the more it draws off your charging device, that decreases as full float charge is approached, (less current-more voltage-less drag on your generator/alternator you are powering).

Or you can go with the best. I know its large, but for a home base, this puppy below is the Bee’s Knees in PV cells:


These are the no shit cream de le creme of solar cells. Nothing comes even close, and this is the only high output panel made with a junction box. A really practical feature. These fuckers are hotrods with a true 25 year lifespan and don’t fade as the silicon wafers heats up in the sun. I got a rack of 4 and a rack of two, (with a 1200 watt turbine on a 40ft tower), the 4 rack puts out 34 amps at 21.7 volts (DC) as long as the sun is direct on them. That is what the meter reads with these connected to a charging battery. Let me tell you, one panel at 8 amps and 21.7 volts hooked to a charging battery is serious power, you can cook a 24 series 1000 cold cranking amps car battery to death from a dead flat discharge in 20 minutes. It will be smoking and the case will be ready to give up the ghost.
These panels are made like a piece of jewelry. Nothing is even in their class. No repurposed silicon in them either. Made in the US too. This size ships UPS.
Get one, you have a panel that will outlive you. For $289 bucks, and shipping from AZ to WV total is $309 for power that will not shit the bed on you. A charge controller, a switch, some crimp on fittings, a fuse block, 6 ga welding cable and a battery, you got real power that nothing can top or be as reliable. It is a no maintenance put up and run system.

I’m Running a big ole motive power battery, company in Chicago has a great deal on this size, weighs 850lbs with a beautiful armored powder coated liquid tight 1/4″ welded plate steel case, hinged cover, 00 cables with connectors, puts out 780 amps on a 6 hour rate to 80% depth of draw, 1280 amps at the 20hr rate.
Secret to batteries, is weight, everything else is a sales gimmick. Weight =’s plate materials. The more weight the better the plates the more capacity the longer the life. All else is BS. Gel cells, glass matt, space age metal batteries, deep cycle etc. Forget them. Nothing is better than an industrial motive power battery using wet lead acid cell design. (Cat makes some of the finest lead acid cell batteries in the world, maybe the best. Their generic model heavy equipment batteries are world class, they have pioneered a 20% increase in capacity in the same given case size, with a unique arrangement of grid composition.) It ships FedEx, to their commercial loading dock, you pick up, they load in your pickup, strapped on a pallet, total cost was $1650, fully charged with acid. Lot of power in that baby, and keeping the depth of draw above 20-30%, its a 30 year battery. A old fashioned MOTIVE power wet lead acid cell battery can not be beat. No matter what anyone tells you, these are the only battery to run if you can. They are specifically made to have the crap beat out of them, every kind of neglect and abuse imaginable, and keep taking and holding a charge. You put one of these in your off grid shack, its like Mount Rushmore, it lasts forever. They are made to go 1200 cycles to 80% DoD. 3.2 years of abuse. And they still have a ton of life left in them for other uses. If you can get a used one, they won’t have the depth of draw left as specified, but with proper use, keeping your DoD at 20% or around there, they are 10+ year batteries, for the price of scrap metal weight. You got to check all the cells, a dead cell you don’t want, unless you have enough cells to rewire back to 12 V.
Ask me anything, i’ll share what i know. I’m starting to get into comms, and figured a good off grid system was paramount. I figured all this stuff out myself, I’m just a regular guy. If i can help anybody be great.

PS, Lot of great 12 volt products on the market. We have been going that way. Lights, appliances, just got us a 24 inch LED TV, runs on 50 watts, has all the inputs/outputs, no smart TV bullshit, no spying on you crap. Half the price of a 110VAC TV. Whats not to like? A 12 volt freezer is next. Doesn’t even require a battery, runs on one 140 watt solar panel, has enough insulation to keep it cold over night and a day or so if its very cloudy.
Then there are “Dump Loads”, which are devices which are powered by excess current your system produces when the batteries are charged. Built a hot water system, uses 12 volt heating elements, screw in like your regular AC powered water heater elements. Got this rig so it convection heats my AC power heater, and draws the 12 volt heated water into the AC unit when we turn on the tap. There are so many thing you can do. It is a holistic operation. Besides, the second you produce power, every penny you put into it is now paying you. Awesome shit.


  1. One more comment: Doug, 8 amps charging is TRIVIAL to decent battery. I love you, brother, but your example doesn't hold water. Kyocera makes fine panels, but pretty much all of them are guaranteed to still be producing 80% rated power after 20 yrs. All panels have the connectors so they can be easily plugged together. Finally, ALL photovoltaic panels are impacted by temp. There is no magic! Output falls as they heat up...AND rises in the cold. Calculating proper string size is important as you can overdrive a charge controller on a cold day. My panels are nominally in the 40-something volt range, and I was planning to string 3 in series. The charge controllers have 150v max input, and I realized that on cold winter mornings they would be running over 50v each. So I had to recalculate the strings for only two in series.

    Read a bit on the good solar energy forums (solarpaneltalk.com and solar-electric.com are good, not Homepower as there is little real knowledge there) and learn and plan before just jumping in!

  2. Buddy, you should make accusations of naiveté from a position of actually having a set up in real life a unit and using it. I built a pedal unit, I actually use it. Make a pedal power unit with the components I employed, then come back with a factual accounting based on real world experience, not conjecture on assumptions and fancy anectdotal sports medicine. It IS a very difficult device to operate. I tried to make that clear. The calories required alone probably makes it inefficient from an austere perspective. But it is expedient. That is why I made the comment about getting solar panels.
    And just so you know, Lance Armstrong wouldn't last a day at my homestead. He would be sucking wind before the day is out chopping firewood, digging a garden, or going to work with me in a coal mine. That's pretty muscles that guy has, and he needed drug enhancement to get it. Not the build and stamina a working guy or a farmer has, not to mention the mental stamina.

  3. If your running a 24 or 48 volt system you can not equate your system output with the 12 volt system I am running. It is comparing apples to oranges. 12 volt is current heavy. Ohms Law dictates that.
    And why the negativity Buddy? What is that all about?

  4. Can mtnforge shoot us some of the links he has for the applicances he's eyeballed? For example, the LED TV, and definitely the best 12V freezer he's found.