EVTV Power Safe 15kWh RV and Marine Edition User Manual

EVTV Power Safe 15kWh RV and Marine Edition

Product Information

• Product Name: EVTV PowerSafe 15kWh RV and Marine Edition
• Version: 1.01
• Release Date: October 2019
• Manufacturer: EVTV
• Copyright: 2019

Legal Disclaimer

• The EVTV PowerSafe 15kWh RV and Marine device is an experimental solar energy storage device that utilizes used Tesla Model S Battery Modules obtained from salvaged and wrecked Tesla Model S automobiles. EVTV does not have authorization from Tesla Motors to use these batteries for any purposes. The warranties on Tesla batteries are voided once the vehicle is declared salvaged, and neither EVTV nor Tesla warrant or guarantee these battery modules for any purpose or use.
• The use of the term “Tesla” or “Tesla battery modules” is strictly descriptive of where the battery modules originated and the original manufacturer of the salvaged devices. EVTV has no claim or right to the Tesla brand or name.
• The PowerSafe RV is an experimental device intended for DIY experimenters with advanced technical skills. Lithium batteries, especially those sourced from salvaged vehicles, pose inherent dangers and an extreme risk of fire or explosion. The purchaser assumes all risks associated with the use of battery devices purchased from EVTV.
• EVTV offers no guarantee or warranty on these devices and does not assert fitness for any particular purpose. The PowerSafe device has not been tested or approved by any regulatory authority. In some jurisdictions, connecting this device to a public utility electrical service may be illegal.
• EVTV has no connection or association with Tesla Motors and these devices are based on used and salvaged components.

Product Usage Instructions

• The EVTV PowerSafe 15 is a 15kWh solar storage device designed to be the central component of a personal solar power plant. It can provide a continuous output of 6kW of 240V AC power at a frequency of 60 Hz for up to two and a half hours. Additionally, it can deliver an instantaneous surge power of up to 18kW, which is useful for activities such as air conditioning startup
• This specific version of the PowerSafe device operates at 24V DC and is specifically designed for use in Recreational Vehicles (RVs) and Marine applications. It serves as a self contained portable hotel power production system. It is compatible with various solar photovoltaic designs and 24V vehicle systems. The device allows for recharging operations from shore power, solar photovoltaics, onboard 240V AC generators, or vehicle DC systems.
• It is important to note that the PowerSafe device has not been tested or approved by any regulatory authority, including Underwriter Laboratories. Furthermore, in many jurisdictions, it is illegal to connect this device to a public utility electrical service. Users should exercise caution and ensure compliance with local regulations and safety guidelines when using this experimental device.

Legal Disclaimer

• The EVTV PowerSafe 15kWh RV and Marine device is an advanced EXPERIMENTAL solar energy storage device based on USED Tesla Model S Battery Modules obtained from SALVAGED and WRECKED Tesla Model S automobiles.
• EVTV has NO authorization from Tesla Motors to use these batteries for these or ANY purposes. All warranties on Tesla batteries are voided at the point the vehicle is declared SALVAGED and neither EVTV nor Tesla warrant or guaranteed these battery modules for any purpose or use whatsoever.
• In using the term Tesla or Tesla battery modules as a descriptive term, EVTV makes no claim or right to the Tesla brand or name. Use of such terms is strictly descriptive of WHERE the battery modules originated and the original manufacturer of the salvaged devices.
• The EVTV Tesla Battery Module Controller again is a strictly descriptive term for a module controller used specifically with battery modules sourced from wrecked or salvaged Tesla automobiles.
• Tesla Motors in no way endorses, supports or otherwise acknowledges EVTV nor approves, supports, or endorses the use of salvaged Tesla vehicle parts of any kind for these purposes.
• The PowerSafe RV is an EXPERIMENTAL device using USED and SALVAGED batteries and is intended for Do It Yourself (DIY) experimenters with advanced technical skills.
• Lithium batteries are INHERENTLY dangerous and pose an extreme risk of fire or explosion starting at the point of manufacture. These risks are dramatically increased in the case of batteries from vehicles that have already been wrecked or damaged and sourced from salvage yards.
• The purchaser assumes ALL risk from the use of battery devices purchased from EVTV.
• Because of the experimental nature of these devices and the use of salvaged components, EVTV offers NO guarantee or warranty on these devices of any kind, nor asserts fitness for any particular purpose.
• The PowerSafe device has not been tested or approved by ANY regulatory authority, including Underwriter Laboratories or any other approval agency. In many jurisdictions, it is ILLEGAL to connect this device to a public utility electrical service.
• To reiterate, EVTV has NO connection or association to Tesla Motors of any kind. These devices are based on USED and SALVAGED components. And are intended solely for EXPERIMENTAL use by the purchaser who assumes ALL risk of doing so.

INTRODUCTION

• The EVTV PowerSafe 15 is a 15kWh solar storage device designed to serve as the heart of a personal solar power plant. It can provide 6kW of continuous 240vac 60 Hz power and it can do so at that rate for up to two and a half hours. It can provide up to 18kW of instantaneous surge power useful, for example, in air conditioning startup and initial surge.
• This 24vdc version of the PowerSafe family is specifically designed for use in Recreational Vehicles and Marine applications as a self contained portable hotel power production system. It is compatible with a variety of solar photovoltaic designs and 24v vehicle systems. And it easily allows recharge operations from shore power, solar photovoltaics, onboard 240vac generators, or vehicle dc systems.
• While it can be charged from grid utility or generator power, it is intended for off-grid operation. And it’s most unusual feature is that it is designed specifically to charge from solar panels featuring grid-interactive microinverters such as the Enphase Power IQ series.
• This means it uses AC coupling to charge the storage batteries from 240Vac provided by the rooftop solar microinverters and it enables that rooftop solar installation to operate with no utility grid available.
• The way this works is that the grid-interactive microinverters detect the PHASE and FREQUENCY and VOLTAGE of the PowerSafe, and then carefully synchronize their output to match all three of those characteristics. This causes them to act as the power SOURCE to power the vehicle during sunlight hours. In the event the photovoltaic power is insufficient to provide ALL the power needed, their voltage drops slightly and the PowerSafe15 becomes the source for the difference needed.
• If the rooftop array produces MORE power than needed by the RV or boat, the excess is pushed to charge the 15kWh battery.
• It is key to note that while the continuous output power of the PowerSafe 15 is 6kW, more than enough to power most RVs, it is NOT the limit of power available. The grid-tied microinverters producing 240vac from the photovoltaic array are wired DIRECTLY into the hotel loads panel for RV. The power they produce of course goes to that panel and DIRECTLY out through the various circuit breakers to the power loads in the vehicle. It does NOT go through the PowerSafe 15.
• And so in full sun, a 2.5 kW photovoltaic array might produce the 2.5 kW of solar power AND the PowerSafe 15 can provide an ADDITIONAL 6 kW continuously or 18 kW momentarily. And again, the 2.5 kW from the array does NOT go through the PowerSafe 15 device at all. This then is the CENTRAL advantage of AC coupling. Solar produced power BYPASSES the enabling device.
• The PowerSafe 15 uses a control system that communicates with the Battery Management System board designed by Tesla on each of 3 Tesla Model S battery modules.
• The PowerSafe 15 features an optional 7-inch interactive display depicting the voltage of each cell of each module, total power in and power out, battery current, state of charge and provides historical graphing of power and state of charge.
• The PowerSafe 15 requires a local WiFi router or Access Point for communications and features the ability to send data to a second remote display located anywhere in the world with Internet access. the lithium ion storage batteries.
• In the event that the photovoltaic array produces more power than can be stored in the battery, on reaching 100% state of charge, the PowerSafe 15 will signal the microinverters to shut down operation and stop producing power. The microinverters will do this typically for 300 seconds and then come back up. During that period, the PowerSafe 15 will produce all necessary power from the battery, decreasing it’s charge state. If it again reaches 100% charge, it will once again signal the microinverters to shut down. This is repeated as often as necessary until the sun goes down.
• The PowerSafe 15 features very advanced transient voltage suppression to harden both input and output to guard equipment from high voltage transient pulses caused by lightning or other disturbances.

SPECIFICATIONS

• Continuous Power Output: 6 kiloWatts.
• Surge Power: 18 kiloWatts
• Output Frequency: 60 Hz.
• Output voltage: 240Vrms
• Output connections: L1, L2, Neutral, Earth Ground.
• Length: 36 inches
• Width: 24 inches
• Height: 10 inches
• Weight: Approximately 300 lbs.
• Storage: 3 used Tesla Model S battery modules 5.3kWh capacity each. Display: 7-inch touch interactive color display
• Microcontroller: Espressif ESP32 240MHz 32-bit microcontroller with WiFi and Bluetooth capability.
• Transient Suppression : Midnight Solar 300vac metal oxide varistor transient suppressors on AC output.
• Two Littlefuse MOV 39vdc transient suppressors on the DC output.

INSTALLATION

• The PowerSafe 15 is NOT weatherproof and intended for inside installation.
• The connection to the site power system is important.
• We would recommend you install a dedicated NEMA 14-50 cable to the AC output of the PowerSafe 15 and the master input switch on your hotel AC distribution panel on the vehicle..
• Use a heavy duty 4-wire cable capable of at least 50 amperes current with a NEMA 14-50 male connector on the PowerSafe 15 end.

NORMAL STARTUP

1. Make sure all utility grid power is disconnected from system.
2. Make all installation connections.
3. Set power to OFF on the inverter control panel.
4. Pull the ON/OFF switch to the ON position. It should light up.
5. Wait until both the NEGATIVE CONTACTOR and POSITIVE CONTACTOR LEDs light.
6. Set the inverter control panel switch to ON.

CONNECTIONS

• 240Vrms SPLIT PHASE INPUT.
  • A NEMA14-50 four prong 50Amp electrical connector is provided on the end of the PowerSafe15 specifically for connection to shore power. This is a standard U.S. L1, L2, Neutral, Earth ground connection at 60Hz.
  • The PowerSafe15 is configured with a Sigineer 6kW inverter set to AC PRIORITY mode. This means if AC shore power is available, it will be used both to charge the battery AND is passed directly through to the AC OUTPUT of the PowerSafe 15 and thus to the hotel wiring of the vehicle. And so when you are plugged into shore power, shore power is used to power the vehicle WHILE also charging the batteries. Of course, a 240vac 60Hz generator could be plugged into this input as well. Note that 120vac single phase cannot and should not be used on this input.
• 240Vrms SPLIT PHASE OUTPUT.
  • A NEMA14-50 four prong 50Amp electrical connector is provided on the end of the PowerSafe15 specifically for connection to the vehicle AC power circuitry. This is a standard U.S. L1, L2, Neutral, Earth ground connection at 60Hz and it features excellent built in transient protection.

DC INPUTS

• Access to the 24vdc battery voltage is provided through a pair of camlock welding cable connectors rated for 315 amps continuous current.

• This 24vdc connection is switched by an internal contactor to prevent overcharging or over discharging. And so this can safely be used as a charging power input normally from a 28vdc alternator on the boat or RV normally used to charge the vehicle DC battery.

• In this way, you can recharge your batteries simply by running the vehicle engine during normal operation without fear of overcharging the battery. Once the proper CHARGE CUTOFF voltage you have set is reached, the internal 600 amp 800V contactor disengages, disconnecting this 24vdc input from the vehicle alternator.

• Similarly, this could be used with appropriate DC coupled Solar MPPT charge controllers to maintain charge on the PowerSafe 15 battery. These charge controllers vary in operation, output voltage, and quality and the PowerSafe 15s switching of this load on and off may cause problems with some inadequately protected MPPT charge controller models. 

• INVERTER DISPLAY
  Provides information on operation of 6 kW inverter. ON/OFF switch allows inverter to be powered off or on independently. See the Sigineer 6kW inverter user manual for more details. http://store.evtv.me/proddetail.php?prod=15kw

• BATTERY DISPLAY
  Provides information on battery system operation, state of charge, power levels, voltage, etc. See the EVTV Battery Display User Manual for more details. http://store.evtv.me/proddetail.php?prod=BatteryDisplay

USB PORT
This Universal Serial Bus port allows access to the microcontroller that operates the PowerSafe 15. Connect at 115kbps, 8N1, using any ASCII terminal program from a laptop or other computer. Provides detailed operational data on each cell of each battery module, operational state information, and allows configuration of detailed elements of operation. See the EVTV BMS Controller V2 Manual for more details. http://store.evtv.me/proddetail.php?prod=esp32bms

CONTACTOR LED
Two contactor LED’s are provided. On startup, the PowerSafe15 will go through a precharge procedure to bring battery power to the Inverter. The NEGATIVE CONTACTOR LED (red) will come on first, followed by the POSITIVE CONTACTOR LED (green) about 8 seconds later. This precharges the input capacitors on the 6kW inverter. Once both LEDs are lit, the Inverter may be switched on safely.

MASTER ON OFF SWITCH
The master ON/OFF switch is used to startup the PowerSafe 60 device. It switches the 24vdc battery voltage to a 12vdc converters to operate the microcontroller and contactors. This will initiate the precharge sequence.

120VAC QUAD
This is a standard four outlet NEMA 5-15 type B outlets. Each provide 120vac 60 Hz power. This is a convenience outlet just used to plug in laptops, WiFi hubs, or lights as necessary.

ISSUES WITH 24VDC ALTERNATORS FOR CHARGING

• The PowerSafeRV is designed to SUPPORT charging from a vehicle 24vdc alternator. The device offers a pair of high current camlock connectors to support connections to MPPT DC solar charge controllers. These can theoretically allow charging from a 24vdc alternator.
• But there are issues with such systems a bit beyond our ability to address.

These issues include:

1. Alternator voltage.
2. Alternator power capacity and cooling
3. Alternator output diodes and voltage spikes.

• Our first such installation was with a marine yacht application that already featured a 24vdc system with AGM batteries and two alternators. The existing batteries have the ability to buffer voltage spikes and help produce current to charge the PowerSafeRV device.
• But many Recreational Vehicles actually feature 12v systems with a 24v alternator add-on. While this sounds good, these tend to be inexpensive and failure prone anyway.

1. Alternator Voltage. Generally, most high quality 24vdc alternator add-ons feature adjustable voltage regulators. These should be set for 24.0 to 24.5vdc.
2. Alternator Power Capacity and Cooling.

• Automotive alternators are generally designed to be inexpensive, not efficient. And so efficiency of such devices generally runs about 50%, unusually low for power generation devices.
• What this means is that for every 1000 watts of electrical power output, they also give out about 1000 watts of heat. Cooling is provided by internal fan blades attached to the rotors.
• And so cooling is better at higher shaft speeds.
• And so in driving down the road at highway speeds, alternator rotation speeds are higher and you have much improved airflow within the engine compartment simply because of vehicle movement.
• Lead acid and AGM batteries have quite high internal resistance. And so they present a fairly limited load to the alternator.
• Lithium batteries generally speaking are QUITE different in that they have very low internal resistance and are generally designed for quite high charging currents – several hundred amperes in some cases and particularly so with Tesla Model S batteries.
• As a result, lithium batteries will present a very HIGH load to the alternator and in fact will generally put it at maximum output immediately on connection.
• If you combine low shaft speeds encountered at engine idle, with maximum output demand loads, you can quickly burn out a 24vdc alternator. And by that read literally burn the insulation off the field windings causing smoke or even fire.
• Higher end add-on alternators will feature a field weakening controller and temperature sensors. The controller monitors alternator temperature and decreases field winding voltage and hence current if the temperature exceeds a threshold. This has the effect of limiting power output of the alternator to maintain a safe temperature.
• Using less expensive 24vdc alternators that do not feature an adjustable voltage regulator and temperature compensating field weakening is generally going to result in almost immediate failure. Larger alternators are also generally better.
• At 15kWh, the PowerSafeRV is an unusually large battery and can place an enormous load on a small inexpensive alternator.

Alternator Output Diodes and Voltage Spikes

• The PowerSafeRV will allow dc-input charging until the configurable CUTOFF voltage is reached. At that point it abruptly de-energizes a quite large Gigavac contactor on the positive terminal of the DC input. This disconnects 24vdc from the battery to prevent further charging.
• At the point where the voltage falls to the RESUME voltage it will again close the contactor, connecting it to the DC source for further charging.
• Again, this is designed for MPPT charge controllers from solar panels, which automatically regulate their current output.
• The problem is that with inductive devices such as alternators and the inductance of the connecting cables on large current flows, this sudden disconnection can cause very high voltage spikes. These are termed transients as they usually last just a few milliseconds but can be several hundred volts in magnitude.
• An automotive alternator is just that, and an alternator produces an ALTERNATING CURRENT. But it also features a set of rectifying diodes that rectify this AC to the correct

24volts DIRECT CURRENT or DC.

• These diodes generally can withstand a relatively low transient voltage, usually under 100volts and even on very good alternators 200vdc, even very briefly.
• So suddenly disconnecting the alternator while it is producing several hundred amperes of current can cause significant voltage spikes that can destroy the alternator output diodes – rendering the alternator inoperable.
• This is analagous to pulses caused by lightning nearby in power systems. And to protect from that you generally use a surge suppressor protection circuit. This device is almost always a metal oxide VARISTOR or MOV that shorts at some threshold voltage, shunting the voltage to the return briefly. It then immediately recovers and resumes normal operation. Often these can do several thousand amperes for a few milliseconds. And so they act as a shunt to voltage transients protecting the circuit. 
• These should be physically located as close to the alternator as possible and connected between the positive and negative output  terminals. There is no polarity to these devices, they can be installed in either direction.
• Little Fuse makes an excellent line of automotive MOVs. Their V20E25AUTO device is for an operating dc voltage of up to 39vdc and clamps entirely at 77v at up to 20A for 2 milliseconds. These can be paralleled for greater protection. This may offer some protection for alternator diodes.

POWERSAFERV ALTERNATOR CONTROL

• Most alternators feature a control input to turn them on and off using the normal 12v ignition voltage signal. The PowerSafeRV features a small two pin CHARGE ENABLE connector that can be used to control the alternator.
• Pin 1 of this connector has a constant 12vdc while Pin 2 is switched ground enabled when charging of the battery is enabled.
• This output can be applied to the coil of an ordinary BOSCH style automotive relay. The Common pin of the relay would normally be connection to 12v or 24v ignition voltage and the Normally Open (NO) pin of the relay to the alternator.
• In this way, when CHARGE ENABLE is true, the relay is energized and the ignition voltage is switched to the alternator. When CHARGE ENABLE is disabled, the ignition voltage would be removed from the alternator turning it off.
• In this way, you can shut off the alternator entirely when CUTOFF is reached and restart it when RESUME indicates charging should start again.

References

• EVTV Tesla Model S Battery Module V2 Controller – EVTV Motor Verks Store

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