Michael Qulek

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since Oct 22, 2013
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Recent posts by Michael Qulek

I advocate the empirical approach, and just put out a sheet of plywood, or some other flat surface, and watch how the sun plays against it.  Figure that in the middle of winter, the sun will be about 30-35 degrees lower in the sky then right now.  That shouldn't be too hard to eyeball.

Here is something to think about in the design phase.  Modern MPPT charge controllers act like a transformer, taking raw high voltage solar and transforming down to battery voltage, making extra amps out of the extra volts.  What that means in the real-world is that you can now wire your panels in series to get high-voltage, then transform it down to battery voltage right at the controller.  Then you can position your array wherever you please and transmit the power to your system with little or no power lose.

Here is what I am doing.  I've wired four 30V 250W grid-tie panels in series to get 120VDC.  I run this ~130' from the array to the utility room where the solar electronics are.  My Midnight200 controller takes the 8A at 120V, and transforms it down to ~38A at 25V to charge my 24V battery bank.  Using 10 gauge solar cable, I see zero voltage drop at 130'.  

For you, you don't need to worry about shadows from the north hill.  Just build an array in the sunniest spot within a few hundred feet of your building, then run 10 gauge wire from your array to your batteries.  You can use this voltage drop calculator to predict exactly how much a certain distance will cost you.  https://www.calculator.net/voltage-drop-calculator.html

BTW, you don't want to do this with 12V panels.  You get far better results with high-voltage grid-tie panels, which are available on Craigslist right now for ~4W/$.  12V is just too expensive.

The Midnight200 charge controller is a bit pricy, so you might want to look at other controllers that can handle 200+V.  Take a look at Epever's Tracer 5420AN, which can also handle high voltage but is significantly less expensive.
5 days ago
I've found wood on the ground that I missed months earlier, and looked like what you are showing.  I got mine split and stacked to dry and it was fine.  No health hazard from breathing mycellium, after all, it's going into a fire.  The only thing that is important now is to get the remaining wood completely dry.  What you might see is fungus penetrating into the wood.  If the wood is more or less totally solid still, it will be fine, as long as it gets completely dry.

You are at a good time right now because it's the height of summer, and you still have a couple of months of warm weather to get it dried before you actually need it.
6 days ago
Do you already have a chimney poking through your roof?  What you will find is that installation (even self-install) will cost you far, far more then the stove itself.  I've installed two chimneys now (to code) and each one cost ~800$.  So, I'll guess at today's prices you are looking at ~1000$ of pipe/fittings on top of your 30$ stove.

I've made my own lampblack out out bacon drippings, and powdered charcoal.  Take some old bacon fat, and first do a hot water extraction to clean out the salt.  Then mix 50:50 fat to charcoal and keep it mixed until it solidifies.  Then you rub it into the cleaned steel to keep if from further rust.
1 month ago
You are over-complicating this.  There is no need to alternate different battery packs.  Just parallel multiple packs to get the number of Wh of storage you need.

I'm already operating a freezer on my smaller 24V workshop system, which is in the workshop, not a root cellar.  I find I'm consuming about 2.0 kWh of power per day, keeping the inverter on 24/7, and running the freezer, lights, and some power tools.

Here are my system specs....

8 245W YingLi panels, 1960W wired 4S2P
Rolls 568Ah battery, three 8V batteries wired in series
Schneider Conext 4024 split-phase 120V/240V sine-wave inverter/charger
Midnight200 charge controller.

Has worked flawlessly now for a couple of years.  I started out with just 4 panels, then upgraded to 8 as time and resources permitted.  I wanted the extra watts when I really needed lots of power, like running the lead furnace, for bullet casting.
1 month ago
Actually, both.  Some viruses are known to be transmitted via insects.  Control the insect and you can control the spread of the virus.
1 month ago
There seems to be some weird bug in the software of this website.  The string for the first formula should be...

200amphours divided by 8

200/8

Can't get rid of the smilely face.
1 month ago

norman launier wrote:will a  100amp controlier  handle 4  12volt  -100amp batterys connected  in a  parell  do damage  to  batterys  or inverter  t-y



It's not so much the controller itself as the number of amps passing through it.  As David alludes to above, too few, or too many amps is problematic.  Here are general rules of thumb for different battery chemistries, where "C" is capacity in Amphours (Ah), measured over a 20 hour period.  Battery makers will call this the "20 hour rate".  That means the TOTAL number of Amphours you get draining the battery slowly over a 20 hour time period.

Flooded lead-acid : charge at 1/20th of C minimum, 1/10C good, 1/8th of C max
AGM:  charge at 1/20th of C minimum, 1/8C good, 1/5th of C max
LiFeP:  no real minimum rate, 1/10C OK, 1/4th of C max

What is the size of your batteries, 100Ah?  Should be pasted right on the label if it is an off-grid battery.  If instead of Ah it is instead listed as "cranking amps", then you have selected the WRONG kind of battery for solar.  Let's do the math for a 100Ah battery.  Remember that in series volts add, while amps stays the same.  In parallel, amps add while volts stay the same.

If you take two 100Ah batteries and wire them in series, you get 100Ah of capacity at 24V.  If you take the second two 100Ah batteries and wire that pair in series, you also have 100Ah at 24V.  When you parallel the two 100Ah strings, you get a total of 200Ah at 24V.

The final bit of math you need to digest is how many amps you need to properly feed that battery bank without overdoing it.  Let's say you have 100Ah flooded lead-acid batteries.  The math is....

(200Ah/  X 25Vcharging X 1.175fudgefactor = 25 X 25 X 1.175 = 734W max.

Now, it you wanted to charge at an OK rate instead of a maximal rate, the math would be....

(200Ah/10) X 25Vcharging X 1.175fudgefactor = 20 X 25 X 1.175 = 588W.

If you try to squeek by with just bare minimum (NOT recommended) the math would be....

(200Ah/20) X 25Vcharging X 1.175fudgefactor = 10 X 25 X 1.175 = 294W.

The math will of course change as the type of battery changes.  Just plug in the Ah value of your battery with the capacity fraction for your battery chemistry, and you can figure it out yourself.

When you are ready to hook up everything, just tell us what controller you have, and what solar panels you got, and we can help you with the most optimal wiring scheme.  If your controller is MPPT, you need to keep your solar strings at least 40V, and the maximal Voc less than the limit of your controller.

1 month ago
Since this bike uses a lithium ion battery, not LiFeP, direct uncontrolled DC charging can potentially be dangerous.  All Li battery charging systems incorporate a Battery Management System, or BMS to control Li charging.  If you look carefully at the plug for your charger, you are likely to see three connections.  The outer cylindrical contact (usually negative), the inner cylindrical contact (usually positive), and then a center pin.  That pin is for the BMS to function.  Without the BMS to carefully regulate charging, Li-ion batteries can potentially rupture, and burst into flames.

This doesn't mean that you can't use solar though.  The safest way to do this is to have the solar panels charging the solar batteries via the solar controller, which feeds an inverter, into which the e-bike charger gets plugged.  There are solar charge controllers that can handle Li-battery charging, but they must be carefully programed for the charging regiment of THAT BATTERY.  If you don't have those exact factory specifications, the safest option is to rely on the factory charger that comes with the bike.

Here is a budget system that will work for you.  Get two 6V golf-cart batteries at Costco for ~99$ each that you wire in series for 12V.  Shop for solar panels on Craigslist instead of the internet.  I just got 260W panels three months ago for 65$ each.  One or two 250-260W panels will be enough to fully charge that size battery.  Then get a MPPT charge controller with at least 40A capacity.  The MPPT controller will let you wire the panels in series to get 60+VDC to feed the controller.  The higher DC voltage will cut down on wiring voltage loss.  The Epever 4220AN is an economical choice. Finally, a 12VDC to 120VAC inverter, in the 400-600W range.  This will power your bike charger, and allow for some extras like AC lighting, or even a TV.
1 month ago