36v battery charging

 For quite a while, I've maintained a 36v battery bank made up mostly of the surplus hoverboard batteries that I run in golf carts.  I have a golf cart charger that can supply ~9 amps that I have on a timer so it only charges when there should be good sun.

36v lead batteries can tolerate about 50 volts while typical 36v lithium batteries can tolerate no more than about 42v.  Two chemistries can be used in batteries.  Lithium Iron Phosphate, known as "LFP" and Lithum Cobalt which might be known as "Lithium Ion".  LFP cells, with nominal voltage of about 3.2v, can tolerate about 3.5v.  While LC can tolerate about 4.2v.  Four LFP cells in series can make a 12v lead replacement battery.  Twelve LFP cells can make a 36v battery while only ten LC are used.  For both LFP and LC, a charge voltage limit of 42v works nicely without killing the cells.  In both cases, it is best to use a battery management system to insure individual cells do not exceed their upper limits even when the total voltage remains below the 42v limit.

My 9 amp charger has been modified so as to not exceed 42v and I use it to charge both LC and LFP 36v batteries.

This post was stimulated by my observations this morning.  I took my spray golf cart out this morning to spray mesquite.  I nearly exhausted the battery as evidenced by the cart slowing down and stalling under load.  That condition is best detected by a volt meter but I have not configured an easy to use and reliable volt meter for that range.  Recently, I have been using a clamp on DC amp meter to detect charge current.  That is, to insure that charging is taking place.

So, this morning after I hooked up the mostly depleted golf cart, I noticed that a fully charged cart was discharging at about 19 amps while the depleted cart was charging at about 38 amps.  I should have expected that but I was surprised at the high current.  Most of the wiring connecting various batteries in the bank is only 14 gauge which should not handle current higher than about 20 amps.

Not yet delivered Model Y for sale

 Tesla tells me that it may deliver my long ago ordered Model Y in May.  With TSLA alarmingly low, I am unwilling to pay, as planned, with a sale of TSLA.

SO, I'm taking offers for someone to take delivery in my stead.

It is white, long range, dual motor, with FSD and (I think) a trailer hitch.  Tesla wants $69,990 above my $250 deposit before delivery.  Since I ordered, both the car and FSD have gone up in price.  If one were to order same specs today, I think the price would be about $75k and delivery would likely be in 2023.   If interested, I encourage you to play with the Tesla configuration found through http://tesla.com.

I am looking for offers of $77k+.  All numbers are exclusive of TTL; those should be around $5k.  I have told Tesla: no trade-in, no financing, payment in cash.  It may be possible to change those.

wmckemie4@gmail.com

I'm not sure what rigmarole is involved to get the buyer swapped but I believe it is commonly done.

Tesla now offers insurance in Texas.  Insurance acceptable to a lien holder will likely start around $60/month and may go down from there if Tesla decides you drive safely.  I've been paying AAA $300 +/- per year for minimum liability.

My hope has been that it will be a Austin made car with the new battery cells.  I don't know when/if that information will be available.

Recent news is that low range, about 270 miles, cars WILL have the new cells.  That implies that this car, even if made in Austin, will have the old cells.

 

Fiber to Dale

Yesterday, I noticed some construction along Barth Road between Fm1843 and FM672.  They made me come to a stop so I took the opportunity to ask what they were doing.  I was rewarded: "Installing fiber optic cable to the new cell tower in downtown Dale".  I have not previously noticed the technique being used:  They were using a backhoe to dig holes about 100 yards apart on the side of the road.  Then, they use a boring machine to bore from one hole to the next.  I imagine they were using an empty conduit to push through the borings.   I further imagine that they will somehow push a long continuous length of fiber cable through the conduit once they splice together the conduit segments.  I can not imagine that they would make cable splices every 100 yards.  That's because my perception is that making a fiber splice is difficult/expensive/lossy.

Five or more years ago a cell tower (tower only) was put up behind the Dale Volunteer Fire Department building.  I discovered that the chain link fence surrounding the tower had a sign identifying as "McKemie HomeGrown".  Finding that label surprised me.  The tower sat for years with the tower complete but no antennae or electric stuff.  A few months ago, activity resumed; first, electric service was installed.

I'm surprised that fiber is being installed to the tower.  I thought that all cell towers were served data only via radio. 

 https://photos.app.goo.gl/mKBGJxe2gCpfBrpJ6

Dust Bowl. And Stuff

 I recently decided to tour through both panhandles: Texas and Oklahoma.  Dust Bowl country.  After the dust had settled down, the government bought much of the eroded land that was available.  Now, it is a patchwork of "National Grasslands".  Most of the lands remain in private hands and is mostly farmed.

I was surprised to see so much center pivot irrigation in the area.  And I was more surprised to see "dust devils" scattered about.  It turns out that the "dust devils" were clouds of dust rising from farm equipment doing plowing.  So, there is more wind erosion in progress than I would have thought.  The dust creation is likely very short duration, occurring only between crops.  Maybe two or three times a year.

I have (or had) a very nice sandy asparagus patch of about three acres.  With asparagus, you have a single opportunity to mechanically control weeds.  That is best done a week or so before the asparagus spears begin to appear.  The entire field can be disked at a shallow depth.  Hopefully staying above the crowns from which the spears arise.  I remember one year when we had inopportune winds following the annual weed clean up.  It hurt to see great clouds of dust rise from the field.  Good and irreplaceable soil lost.

So, I've been reflecting on soil conservation.  Over freshly plowed soil, wind will pick up and carry away the smallest particles first.  Leaving behind coarse sand and pebbles.  That changes the character and value of the soil.

One good remedy to such soil loss is "low till cultivation" or, better yet, "no till cultivation".  Both require increased herbicide inputs.  That raises the cost but avoiding or reducing tilling lowers cost.  So, the farmers are inclined to use more herbicides and use less tilling for the purpose of preserving soil.  There are, increasingly, market forces that discourage herbicide use.  Certainly, there is a a conflict.   Think about that the next time you demand "organic" from your fresh produce source.

I notice that there are a lot of what appear to be sand dunes in the panhandles.  Vegetated over and mostly stable.  Road cuts and other excavations reveal much sub surface sand.   I suspect that most of the center pivot land is smoothed up sand dunes.

From personal experience, I know that farming may not be profitable.  It has many economic ups and downs.  Most beyond the control of the farmer.  I recall that when I started growing peaches in about 1983, I knew I had to make about three crops of peaches out of each five years in order to stand a chance of being profitable over the long term.  In my first five years of peach growing, I made a single decent peach crop.  And, I branched out into blackberries, tomatoes and many other "truck" crops.  NONE were long term profitable.  Most farmers have similar stories.

One great fear of our government is agricultural failures resulting in food riots and maybe even starvation.  Because of that fear, agricultural subsides are wide spread.  Most modern farmers are dependent on "feeding at the trough" for economic stability.    Without subsidies, market forces would push many farmers out of business.  That happened during the Great Depression and dust bowl era.  The declines in production due to farmers being previously pushed out of business results in shortages later.  Hence, the government strives to keep farmers in business when short term market forces tells them that they should not be in business.  

Recall that the Russians, under Stalin, starved millions of Ukrainians as a political control method. 

Because of low profitability, aggravated by government subsidies, agricultural land is of generally low value compared the value for other uses.  "Development".  Ass backwards, IMHO.  Farming should be reliably profitable.  Farmers should be valued and honored members of society.   Farm land should be so valuable that "development" occurs only on "waste" land.  Dream on, Willie.

tesla.com/blog

 In response to an old friend's Tesla questions, I've been reading the Tesla Blog:

http://tesla.com/blog

It is the first time I've read more than a post or so.  It covers near the entire history of Tesla.  Since the 3rd "Master Plan" is due to appear soon, I decided to locate the first two Master Plans:

https://www.tesla.com/blog/secret-tesla-motors-master-plan-just-between-you-and-me

https://www.tesla.com/blog/master-plan-part-deux

Tesla should have great credibility given how well they have followed previous long term plans.

Like everyone else I know, I have tried to inform my friend on Teslas.  Sadly, he remains surprisingly poorly informed.  Even to be uncertain as to the attributes of currently offered models.  So I offer:

1) Original Roadster 

2) Model S - a high performance, largish, four door sedan

3) Model X - a larger SUV type body on the Model S chassis.

4) Model 3 - very similar to Model S but smaller and cheaper.

5) Model Y - has about the same relationship to Model 3 as Model X has to Model S.

"In the works" are Cyber Truck and Semi with a cheaper smaller sedan expected to be introduced after Tesla has saturated the higher priced market. The original Roadster has been out of production since about the time the Model S was offered.  But is due to be replaced with a new Roadster.

High Line Voltage Interfering with PV Production.

 3/24/2022
I've long been aware that PV production raises nearby voltage.  High voltage causes inverters to shutdown.  I think the standard "give up" voltage is 260-265vac and may vary from one inverter to another.

I think typical Bluebonnet line voltages are about 245- 250vac.  Even though "nominal" voltage is 240vac

A couple of months ago, a neighbor's PV inverters mostly shut down due to high line voltage.  I think the utility, Bluebonnet, admitted that they raised his voltage to better serve other customers during a threatening weather event.

I recently discovered that I had two string inverters, serving up to 50 panels each, that were starting in the mornings but refusing to work mid day.  So, I went out (after 3pm and after peak sun) and measured voltages.  Here are the results:

House meter/transformer should be able to do about 37kw.  Wiring goes from main breaker to sub breaker box on rear of house to breaker box that serves the south field where I was having the inverter problem:

1) main breaker box: 256-257vac

2) rear of house breaker box: 257-258vac

3) south field breaker box: 257-258vac

Total production is just over 20 kw and I wish to add two inverters that will produce about 7kw more.  Those voltages tell me I probably have sufficient capacity to the south field breaker box.  Significantly higher voltage on one end than the other indicates the wire is nearing maximum current capacity.

The new "hilltop" breaker box is taking only 25 amps, about 10kw.  That is a 50kw transformer which should do about 125 amps.  I have problems there that need to be corrected for better production.  Line voltage was 251-252vac

The " across road" 50kw transformer is my best producer and was doing 122 amps.

1) main breaker box: 255vac

2) breaker box in "party shed": 261-262vac.  That tells me that the wire from main breaker is fully loaded.  So, I will not be trying to add additional capacity on that path.

3/25/2022  9am

All three breaker boxes chained to south field  near house show line voltages of 250-252vac with PV production of about 10 amp.  Full sun production from south field should be about 35 amps.

3/25/2022 3pm

This morning, I told our "renewable energy" Bluebonnet person, Brittany, of two problems:  I have no 1099 from Bluebonnet reporting my income from 2021 and that I have the high line voltage problem.  A Bluebonnet person came right out and reported ~252 at the meter and promised to "kick it upstairs".   Their target voltage is less than 250, 247 or so.   He reported that the source of my power is the installation near Bunton Cemetery and that he thought that there are no "regulators" between me and the power source.  A "regulator" is a place where they can step line voltage up and down as needed.  Brittany is of the opinion that Bluebonnet does not report amounts that they pay to customers for energy.

The visiting Bluebonnet guy seemed quite helpful but did not seem to fully understand "customer generation".  He opened the meter housing so he could measure line voltage as far upstream as possible.  He was holding a clamp on amp meter so I suggested he measure current at a couple of places including the not normally accessible meter housing.  He measured 80 amp in my breaker box and 100 amps in the meter housing.  I had not realized it but, apparently, my rooftop system does not go through my breaker box.  He exclaimed "how are you using all that power?!".  I had to inform him that that was power/energy I was delivering to the grid and not power Bluebonnet was delivering to me.

3/26/2022 7:30am

Line voltage:  246-247 before PV production

Even though I was not so informed, I imagine that my visiting Bluebonnet guy from yesterday reported the problem and something was done about it.  The ~247 is "normal" while voltages the previous two days, 252 and 257 respectively, were very much abnormal.  We are threatened by power outages that could result from heightened brush fire risks.  I suspect Bluebonnet had upped my voltage in response to that threat.

March 21 Tornado Storm

 Very little impact in Dale.  7/10" of rain.  A little hail.  Not much wind.  No PV panel damage yet noticed.

The tornadoes were mostly 20-40 miles north.  Round Rock and Elgin with others scattered about.

This is reportedly a once in 15-20 year event.

Interesting news videos:

1) A tall light tower falls near Round Rock at expressway interchange.

2) A pickup truck is blown over on it's side, then blown down the road sliding on it's side.  Then, blown back on it's wheels.  And the driver continues his trip.