Month: November 2019

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QUALITY OF SOLAR PANELS IS IN THE MATHS

QUALITY OF SOLAR PANELS IS IN THE MATHS

SAFIERY UNIVERSITY

SOLAR PANEL QUALITY IS SO EAZY TO CALCULATE "THERE IS NOWHERE TO HIDE"

NO WHERE TO HIDE: CALCULATING TRUE SOLAR PERFORMANCE

We have read many websites advertising caravan and 4WD solar panels at lower prices. They nearly always brag about having the “high or even highest efficiency solar panels in the market”.

We simply do the maths to find out the “pork pies” and its “porkies” on nearly every occassion.

How is this done?

It’s very easy you see. Sunpower publish the Voc of their solar wafers. Simply take the number of wafers on the panel and then divide the panel Voc by this number to get the Voc per wafer. Then look up the tables above to determine the quality.

There is a slight complication: If the panel has bypass diodes then the forward voltage loss has to be taken off (one reason whigh high voltage panels have an advantage as the loss is a much smaller pecentage). There will also be a very small voltage loss on the junctions themselves of say 0.1V. We use a 0.8V Diode loss.

Lets look at an example.

Safiery’s highest grade panels are 190W. They have a Voc of 38V. There are 54 wafers in a panel. The Calculation is:

Voltage of Wafers before Diode: 38V + 0.8V +0.1V = 38.9V.

38.9V/54 Wafers = 0.7203V/Wafer

Looking up Chart above these wafers are Maxeon III Bin Le1 which is 0.721 per wafer. This shows the diode and junction drop to be a little more than 0.9V.

Checking the power against the same chart:

54 Wafers x 3.62 Wp per wafer = 195.48 Watts

Loss of 0.9V x 6.15Isc Loss on Diode/Junction = 5.535 W

195.48 – 5.535 = 190.013Wats

The Maths Check out. No Porky Pies here!

To check out your own panels follow this proceedure. If the wafers are not Sunpower, use the above as a guide. Here is the Summary of Sunpower Wafers/Cells.

    Sunpower Bin Number Voc Watts Peak Temperature Co-efficient of Loss per Degree C > 25Deg C Efficiency
Highest Performance Me1 0.730 3.72Wp 0.29% 24.3%
Le1 0.721 3.62Wp 0.29% 23.7%
Ke1 0.713 3.54Wp 0.29% 23.1%
Kp 0.68 3.48Wp 0.35% 22.7%
Jp 0.68 3.46Wp 0.35% 22.4%
Lowest Performance Hp 0.68 3.43Wp 0.35% 22.3%
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Smart Hotwater from excess Solar & Vehicle Charging

Smart Hotwater from excess Solar & Vehicle Charging

SAFIERY UNIVERSITY

SMART HOT WATER SYSTEM POWERED FROM EXCESS SOLAR AND VEHICLE CHARGING – NO LPG.

This article is designed to give assurance to the reader that the Safiery 2kW Electric Hot Water System can operate automatically from the Victron Smart 2,000W Inverter and a single 200Ah Lithium Battery.

This is a solution suitable for OEM’s, Body builders and DIY customers. It is NOT a retail product.

Automated Charging Only When Batteries are Charged

Electric hot water is not new. With heating systems at 1500-2000W, there is a problem that use a lot of power to run. Even so they are more efficient than LPG hot water where a lot of heat still goes up the chimney.

Now there is an automation solution from Safiery and Victron that:

  • Heats the water once the batteries are over 90% State of Charge (SOC)
  • This may occur while driving with the DC to DC converter, or
  • While camping with the excess power from Solar once the batter are over 90%, which is generally by mid day.

Benefits are simple:

  • You arrive in camp with hot water to go,
  • It’s created very efficiently.
  • It stores the hot water very efficiently.
  • No need to worry about LPG bottles.
  • Piping hot water at the sink or shower.
  • Compact and Simple to Install.
  • No user intervention,
  • Manual switch “on” available.
  • Its Free Power.

Size the Electric Hot Water to your requirements:

  • 10L 2000W German System,
  • 28L 1500W (Rheem Equivalent) System,
  • Any other tank system less than 2000W

We show the German System in the test video because of the high power requirement.

However, there are two important requirements:

1. Solar Replenishment Capacity needs to by 500W Plus on the roof and 250W Plus as a portable for boosting in difficult weather.

  • Victron 3 x 175W Glass Panels 1485 x 668 x 30mm each
  • Safiery Ultra Slim Portable

OR

  • Bring your own, but we will swap your present solar controller for a Victron 98% efficient controller.

If you can NOT carry solar of this capacity or greater, this system is NOT sustainable.

2. Lithium Batteries

At least 200Ahr, 2 x 125Ahr is better.

  • AGM batteries just dont hold up to the high current demads of an inverter.
  • Solar efficiency is 98% with Lithium, but only 75% with AGM batteries

Ditching LPG gives you improved cooking options”

Cooking: Ditch the LPG for Induction and Charcoal – Old and the New!

  • Gas cooktops are 40% efficient. In the wind, even less.
  • An induction cooker uses electricity and magnetism to make your pan the source of heat. They are 94% efficient.
  • They heat 3 times fater than LPG and 10 times faster than electric.

A simple demonstation of the high efficiency is the “cool to touch” induction glass top after you remove the cooking pot. The pot is hot but the glass top is cool!. Little energy wasted!

Induction cooking is:

  • Fastest way to cook – 2min for 0.5L Water at 1800W
  • 94% Efficient; compared to 40% for LPG and 70% Electric
  • Safe and cool to touch after use
  • Ceramic glass top – easy to clean
  • Cool to touch immediately after use
  • Induction pots and pans now commonplace and inexpensive
  • Can be set at “slow cook” – walk away and enjoy the day without worry of open flame.

However…..

  • Early models would cut out without large inverters
  • Early models did not have temperature control for safe low temperature and “walk away” cooking.

And….. TWO Hot Plates may be needed Inside – not just a single.

  • But there is a problem with an induction cooktop and two hot plates…

Induction Cooktop Problem

Hot Plate 1 Size

1,800W

If On at 1,800W

Hot Plate 2 Size

1,500W

If On at 1,500W

Total Power Size

3,500W

Total Power 3,500W

Inverter Power

3,000VA

INVERTER TRIPS (MAYBE AFTER A WHILE)

Cooking Stops, Family not happy!
  • Another problem is your 4WD/Camper trailer/Caravan may not be wired for more than 2,400W (10A).
  • Electrical problems may follow.
  • Maybe a serious safety hazzard.

Introducing the Safiery 2 Hob Induction Cooktop

  • Built-in
  • Double induction built in
  • German IGBT control
  • German Schott Ceran High grade black crystal plate
  • Touch Sensor controls
  • Size: 520 x 290 mm

Power

  • Power Watts: 1800W+1500W
  • Has Maximum combined output of 2800W to suit Victron 3000VA Inverter.
  • Individual Controls
  • Smart Power alert with Inverter

Automation

  • Timer
  • Child Lock
  • Booster  function
  • Auto Safe Switch off
  • Over heat & empty pan safe off
  • Cookware detection

Smart Dual Hob Induction Cooktop Manages Inverter Power Limit Automatically

Demonstrating the Smart feature of balancing the dual hob controls to stay within either 2000W OR 3000W Inverter capacity using 1800W and 1500W Safiery Dual Induction Cooktop (built in only model).

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Smart Lithium Battery Protection with Inverter

Smart Lithium Battery Protection with Inverter

SAFIERY UNIVERSITY

PROTECTING LITHIUM BATTERIES FROM TOTAL DISCHARGE WHEN USING INVERTER

The biggest issue facing users of battery powered Inverter systems is running the batteries flat. Voltage Sensitive relays are fine for small currents, but running an Induction cooktop or a espresso coffee machine draws 100+ Amps.

Safiery solve this problem in a simple way with smart technology. Bullet proof, Safe, Easy to use.

Battery Protection Problem with Inverters

Traditional methods for protecting a battery from total discharge was to place a Voltage Sensitive Relay in the power feed between the batteries and the inverter. Inverters can draw a very high current, beyond the safe limit of most relays. Because this feed is two-way for charging and discharging, digital relays need complex twin path control as these are uni-directional. Either way you end up with a complex wired white board kit.

One problem with a Voltage Sensite Relay with Lithium Batteries is the voltage profile is very flat. Although it will drop while under a sizable inverter load, it wont continue to drop until the battery capacity is 5-10%. Even if it can be tuned up to very sensitive levels, the surge that can occur when starting up some devices with trip the VSR.

The best way to protect Lithium Batteries is with State of Charge. This is bullet proof.

Safiery Solve this Problem

HALL EFFECT CURRENT MEASUREMENT BUILT INTO LITHIUM BATTERY

The true capacity of a Lithium battery is referred to as “State of Charge”. It is arrived at by measuring the total net current into and out of a Lithium battery. Once the Lithium Battery is fully charged, SOC starts at 100% and counts from there.

Tradional measurement of current flow if done with “shunts’ that consist of a huge piece of metal with tapping points on the side of a metal bridge. By measuring critical voltage changes, the shunt determines current flow. Installing shunts in Lithium batteries would add weight and possibly cause harm when off-road or at sea from vibration.

The alternative is to use a “hall effect” device that measures the magnetic effect from a high current flow and then calculates the current. These are highly accurate.

The current Sensors in our 48V Lithium batteries use Hall Effect technology.

Hall effect sensor benefits:
  • Galvanic insulation
  • Can be placed anywhere on the current path (voltage is not a problem)
  • Do not affect the measured current so they are great within a Lithium Battery.

CANBUS ENABLED LITHIUM BATTERIES

With the Hall Effect current measurement built into the battery, the State of Charge can now be calculated inside the Lithium Battery and communicated ….

  • Communication is done using Canbus.
  • This is the most common bus used in automotive with a similar bus used in marine.
  • Victron Venus is programmed by Safiery to read the Canbus communication

Information Available from the Canbus connected Lithium Batteries

  • Sate of Charge of the Batteries
  • Charging Limits : high and low
  • Battery temperature
  • Battery Voltage and Current

With these Smarts that save power and protect your battery:

  • You see and can set:
  • % SOC that will turn off Inverter
  • Change it to a level that suits
  • Set the level when Inverter re-connects
  • You get the benefit of:
  • Accurate SOC disconnect
  • Preserving your Lithium Battery life

ONLY 3 COMPONENTS

  1. Victron Inverter/Charger or Inverter
  2. Victron Venus
  3. Safiery Lithium Battery

No Complex Whiteboard kits!