Perfect Switch Power-Gate solid state Bi-Directional DC Relays used as a Battery Management System (BMS) for lithium titanate oxide batteries (LTO)

Lithium Titanate Oxide Battery (LTO) BMS: Bi-Directional DC Relay (Gen 3.0)

This is a new device developed by Pinnacle Innovations and built by the engineers at Perfect Switch. The basic use of the device is to provide both over-charge and over-discharge protection to a custom made Lithium Titanate Oxide (LTO) battery system with 13.8 Volts nominal and 880 Amp hours capacity that will be installed in an all-season RV trailer that will be used in temperatures as low as -40 Celsius. The LTO battery cells are unique in that they can be easily used for cold temperature applications like this - eliminating the need for battery heaters that would be required for lead-acid, AGM or conventional LiFePO4 (lithium-ion) batteries. The beauty of this product is that it is very simple to install within a sealed battery enclosure or in our case, inside the trailer where it is accessible in case the Breaker Switch trips. In addition, we are using active cell balancer boards for each of the 27 packs of 6 LTO cells wired in Series.

On the surface of the Perfect Switch device is a push button breaker that will trip if there is an over-current event. It can also be used as a master on/ off switch. In addition, this device comes with a 3 wire harness (as well as external LED wire harness if you plan to connect external indicator LEDs). We have connected the small orange wire of our BMS device to the battery pack's + 13.8 Volts and run it to a remote toggle switch so that we can remotely turn the device on/ off (orange wire is the "Excite" or "Trigger" wire that powers up the device). The other two small wires (blue or brown) connect to another SPST toggle switch which controls the override features. With this switch on/ connected, our Voltage protections are active. If we turn this switch off it disables things like the over-Voltage charging protection. The external single pull, single throw toggle switches are not included - we can provide a variety of high quality marine rated and waterproof toggle switches at minimal extra cost.

On the device itself, we wire all loads and charging devices to Terminal 2. Terminal 1 connects to our battery system positive bus bar. NOTE: We may be able to offer a "Twin Path" BMS whereby both the charge and discharge paths are separated so that if a charging error/ event occurs you can still power loads and vice versa.

Below is the programming/ specifications that we used:

• Stand alone Bi-directional Solid State Relay
• Large enclosure
• Generation 4.1
• 12 Volt system
• All LEDs active - we will also connect/ install remote LEDs
• On-board and active-high remote main trigger
• Active-low non-isolated override trigger
• Specification code 1053A denoting the following:
  • UnderVoltage Shutdown: 9.6 Volts
  • UnderVoltage Shutdown delay: 30 seconds
  • UnderVoltage Reset: 10.5 Volts
  • UnderVoltage Reset delay: 5 seconds, Terminal 1 only
  • OverVoltage Shutdown: 16.0 Volts
  • OverVoltage Shutdown Delay: 1 second
  • OverVoltage Reset: 15.9 Volts
  • OverVoltage Reset delay: 5 seconds Terminals 1 and 2
  • Sleep Mode Enabled - Immediate sleep mode entry upon UnderVoltage lockout
  • Circuit Breaker Shutdown: 500 Amps
  • Circuit Breaker Shutdown delay: 2 seconds
  • Circuit Breaker in one direction (battery to load)
  • Circuit Breaker Reset: Toggle Button Switch

We are able to offer this "BMS" style product for LTO battery Voltages up to 48 Volts. Learn more general information about the POWER-GATE bi-directional solid state relays on the Bi-Directional Relay Main Page.

Devices can be customized for opto-isolation, latching, external Vcc, external status, logic feedback, and other various features. If you need to switch from a source to a load, and mechanical relays won't cut it, POWER-GATE may be your solution.