If you do a search on EPEVER charge controller settings you will see there is general confusion about them.  I attribute this to:

• Chinese to English translation problems.
• Differences in naming conventions of the different stages of battery charging.
• Confusion as to whether a setting refers to battery charging vs power to the load terminals on the charge controller.
• Slight differences in voltage measured by
  • The charge controller
  • The MT50 monitor.
  • A multimeter
  • A shunt battery monitor

Let me preface this article with the fact that I am not an electrician, electrical engineer, or solar energy expert.  I am just an ordinary end user like many of you.  The information here is derived from reading the EPEVER documentation, web searches, and careful observation and monitoring of the behavior of my 2 EPEVER 4210 charge controllers using the EPEVER charge controller screen, the MT50 monitor, and the EPEVER software with the controller connected to a PC.  Using a PC was the only way the controller would specify if it were in Raise/Boost vs Float mode.  Please comment if you think anything stated in this article is incorrect.

I don’t use the load terminals on my charge controllers.  I will limit my comments about them to the following list of settings that apply only to the load terminals (not the battery charging).

Load Terminal Settings:

• OVCutOff
• OVRcv
• LVRcv
• WarnRcv
• LVWarn
• LVCutOff
• DischaLmt

I am also going to limit the discussion to lithium iron phosphate batteries, since that is what I use and from which my observations were made.

EquilDur:

Since LiFePO4 batteries don’t need the Equalization function, the Equalization Duration should be set to zero to disable it.

Charging a LiPO4 Battery:

Most Solar Charge Controllers use a 3-stage process.  The 3^rd stage (FLOAT) is not technically required because, in contrast to lead acid batteries, their spontaneous discharge rate is relatively slow. However, since the discharge rate is not zero, a FLOAT is generally implemented.

• 1^st STAGE = Constant Current (Bulk) – The charger supplies the maximum current until a target voltage (RaisV) is reached.
• 2^nd STAGE = Constant Voltage (Absorption) – The charger varies (generally decreasing) the current to maintain a constant target voltage (RaisV).

Now pay attention here!  What EPEVER variously calls “Boost” or “Raise” refers to the 2-stage process above.  That is, when in “Boost/Raise” mode, it does 2 stages; constant maximum current until “RaisV” is reached followed by Constant Voltage for “RaiseDur” (Raise Duration) minutes. This constant voltage portion of the “Boost/Raise” mode corresponds to what everybody else calls the “Absorption” phase. After that it enters Float Mode.

• FLOAT

Fortunately, float means float. It is a constant voltage algorithm like the 2^nd stage/absorption portion of “boost/raise”, however, this is set to a lower voltage (FloCharg).

• RaisRcv

If at any time while in FLOAT mode the battery voltage drops to RaisRcv (Raise Reconnect Voltage), the charge controller switches back to RAISE/BOOST mode and the process starts all over again.

As of the time of this writing, if the battery type is set to LiFePO4, then many of the above parameters cannot be changed.  If you need to change those parameters, you need to set the battery type to “USER”.

My setup consists of:

• 2 EPEVER Tracer4210AN charge controllers in parallel
• 4 – 100ah 12V LiTime LiFePO4 batteries in a 2S2P configuration (24V 200ah)
• Giandel 3000W 24V inverter

I had to tweak my settings because I was getting voltage surges into the 30s (exceeding “ChrgLmt” which would cause my Giandel inverter, charge controllers, and battery BMSs to repeatedly go into overvoltage protection mode.

I believe this resulted from the following factors:

1. Differing voltage readings of the batteries from different devices
2. The EPEVER charge controllers could not respond fast enough to rapid changes in solar output (sun emerging from under a cloud) when in Boost/Raise mode and the batteries were full.  (e.g. Web search results suggest that Victron Controllers do not have this problem)
3. Slight differences in the batteries in the battery bank.

As of this writing, I am using the following settings which seem to have eliminated (or at least greatly mitigated) the problem:

• ChargLmt = 27.7
• EquilV = 27.7
• RaiseV = 27.7
• FloCharg (voltage) = 27.2
• RaisRcv = 26.4
• RaisDur = 120

Thanks for reading.  Please leave your comments and suggestions below.

The post EPEVER Charge Controller Settings appeared first on Arnold Solof.

Vaccine Readiness

It is estimated that at least 70% of the population needs to be immune in order to begin to see significant herd immunity.  Currently, only about 50% of Americans are willing to get vaccinated.  At this point in time, we have 2 vaccines completing phase 3 trials with emergency use authorization pending.  Pfizer’s mRNA vaccine on 12/10/2020 and Moderna’s mRNA vaccine on 12/17/2020.  Both these vaccines have demonstrated safety and about 95% efficacy in preventing symptomatic disease and about 99% efficacy in preventing severe disease.  We have been told that once given authorization, they can be immediately distributed and ready to be given with 2 days.  The details of the distribution plan are not yet available.  Other vaccines will become available soon afterward.

Initial Distribution

The initial supply of the vaccines will be severely limited and with 50% of Americans willing to receive them, the demand will far exceed the supply.  Therefore, those that refuse the vaccine will not slow the initial effort to protect the country.  The limited supplies will be prioritized to health care providers and other front line workers at high risk of exposure and the elderly and those with co-morbidities predisposing them to severe disease and death from Covid-19.

Hidden Problem

Most companies have not yet begun studying the vaccines in children.  Children make up 25% of the population in the USA.  Although children are at statistically lower risk than adults for severe disease, they also can become seriously ill and die from Covid-19.  In addition, although they are less likely to become seriously ill, they are just as likely to become infected and spread the infection.  Because they are more likely to be asymptomatic or mildly symptomatic, they are an unseen, concealed danger to everyone.  The American Academy of Pediatrics recommends children under 2 years of age not wear masks due to concerns about interfering with breathing.  Adults do not normally isolate themselves from infants and children.  During office visits, my greatest fear is not taking a nasal swab from a possibly Covid-19 positive patient, but instead, examining an unmasked, crying, struggling infant or toddler who is spraying his respiratory secretions throughout the room.  I wear an N95 mask and face shield for those exams.  Vaccinating children for Covid-19 is not the first priority and current vaccine supplies are very limited.  I expect that by the time the vaccine supplies increase substantially, the studies on children will have been completed.

Mid and End Distribution

After the first 100 million doses of vaccine are given an increasing majority of the remaining people will be unwilling to be vaccinated.  Assuming the safety and effectiveness of the vaccines hold up following the initial mass distribution, what strategies are likely to work to allow us to achieve herd immunity? 

• The safety and effectiveness data need to be clearly communicated to the public.
• Comparison data of infection rates in contained groupings like nursing homes, prisons, hospital employees, police force, etc. before and after vaccination.

Guaranteeing Herd Immunity

I never cease to be amazed by how many parents don’t have their children receive routine child vaccinations because they want to protect the health of their children, but rather do it because it is required for school or daycare attendance.  The same holds true for hospital employees, many of whom would refuse influenza vaccine if it were not required for their employment.  Given that is “standard behavior” for our population I propose the following as examples of entities that should require Covid-19 vaccination for their employees:

• Hospitals
• Medical Offices
• Nursing Homes (employees & residents)
• Federal, State, Local Government employees
• Police departments
• Fire departments
• Schools (employees & students)
  • College
  • High School
  • Middle School
  • Elementary School
  • Preschool/Daycare
• Prisons (employees & inmates)
• Public Transportation (Even better if you include passengers)
  • Airlines
  • Buses
  • Boats
  • Taxis, Uber, Lyft
• Delivery Services (UPS, FedEx, Amazon, etc.)
• Gyms
• Restaurants
• Bars
• Personal Services
  • Hair Salons
  • Nail Salons
  • Tattoo Parlors

Until Herd Immunity is Achieved

In the meantime, while we wait to achieve herd immunity, we must do our best to prevent infection spread (Don’t Share Air):

• Avoid contact with people whenever possible
• Social distancing (6+ feet apart)
• Wear a mask if around people
• Meet outdoors instead of indoors if possible
• Wash/sanitize your hands frequently

Conclusion

Many questions remain to be answered:

• How long will immunity last for each vaccine?
• How long will immunity last following a Covid-19 infection?
• Will there be rare serious vaccine side effects found after we have more experience with the vaccines?

Achieving herd immunity is readily achievable, but only if we “put our foot down” and insist it be done.  As of this writing, Worldometer shows 266,016 people have already died in the USA of Covid-19.  We now have the tools to stop it.  Let’s get it done.

The post Covid-19 Vaccine Acceptance and Achieving Herd Immunity appeared first on Arnold Solof.

The thermometer is well made. Constructed of stainless steel it should not corrode when exposed to moist soil. I tested its accuracy comparing it to several other thermometers and it was accurate. It equilibrates/stabilizes after just a couple of minutes when moved to a new location.

Accuracy

Determining the Probe Sensing Area

I did the above experiment to determine what part of the probe was the active sensing portion of the thermometer. I found that it wasn’t the tip of the probe or the entire probe, but instead was the distal/last 2 inches of the probe. Therefore, if you want a reading at a specific depth you should insert the probe at a depth 1 inch greater than that you want to measure so that the last 2 inches of the probe are centered at your target depth (1 inch above and 1 inch below target depth). If you were to insert it only 1 inch deep then 1 inch of the sensing portion of the probe would be reading air temperature.

Other Options

After getting the thermometer I began to wonder if people provide this information via something like a weather report and guess what? They do. Here is a report from Rutgers on New Jersey Soil Temperatures:

https://www.njweather.org/maps/nj-statewide-soil-temperatures-10cm

You can view the report at 5cm, 10cm, 20cm and 50cm depths at various location around New Jersey. The same type of report is available for pretty much anywhere. Below is a sample report at 5cm (2 inches) depth on 3/16/2019.

Still, it doesn’t hurt to have your own thermometer because there are local variations due to differences in shading, wind exposure, etc. If you have your own outside thermometer or rain gauge you know what I mean.

Below is a video review of this thermometer I uploaded to my YouTube channel “Arnold Solof”.

Conclusions

The thermometer works well and helps you time gardening tasks to allow you to get the most bang for your buck from the products you purchase and optimizing the results for your gardening efforts.

It is available on Amazon but its price fluctuates widely between 15 and 25 dollars. I paid about $20 for mine.

The post Stainless Steel Soil Thermometer by Smart Choice Review appeared first on Arnold Solof.

It seems like lately, every mother is having a 5-minute conference with the school bus driver every time her child boards the school bus.

It is hard for me to believe that every day they have such important matters to discuss that it justifies holding up traffic.  The school bus laws that prohibit passing a school bus in either direction while children are boarding are important for the safety of our children.  These parents seem to be abusing the law for frivolous reasons and they appear to be inconsiderate and totally oblivious to the world around them.

In some ways, it reminds me of people talking loudly about unimportant chatter on their cell phones (especially with Bluetooth devices) in confined public places like restaurants, totally unconcerned with the noise pollution they create.

The other day one bus stopped 5 times within 5 blocks with each stop taking about 30 seconds for the child to board the bus and another 4 1/2 minutes for the mother- driver conference/conversation.

I know it has been a long time since my kids were school age, but am I missing something here?  Is there some valid reason I don’t know about to explain this behavior?

And what about the drivers?  Aren’t they instructed in how to deal with parents who won’t stop talking and who are tying them up?  They also should know better.

The post Mother-Driver School Bus Conferences appeared first on Arnold Solof.