Essential bit of kit for your EV conversion. This trully robust and quality item will keep your 12v accessory battery charged even if you have a high draw devices such as heated seats and electric power steering units.
 
Thunderstruck Motors 96-144V (nominal) Isolated DC-DC converter has 13.8V output with a max of 50 amps (burst at 12V).  8"x5.5" Footprint. 5kg. 

Input:
Yellow 144V B+
Grey  144V B-
Green 144V B+ (On)
Output:
Red 12V +
Black 12V-

Specs:
The ipDCIS series isolated DC-DC converter utilises advanced high frequency power conversion technology and is designed to transfer high power battery voltage to a lower 12V, to supply vehicle mounted devices such as lights and audio systems.
 
Its features include small size, high efficiency, stabilized output voltage, and completely protected functionality.

This DC-DC converter is completely electrical isolated from input to output to ensure safe use; stabilized output voltage can charge 12V batteries; multiple DC-DC converters can be used in parallel directly to increase output current.
 
If using for a 96v application, be sure that your system will still function without problems at a low state of charge, as this unit's low voltage cutoff is 80V. 
 
Maximum Efficiency: ≥88%
Environmental Enclosure: IP65
Operating Temperature: -20℃-+60℃
 
Protections & Functions
Water & Vibration Resistant: Enclosure is sealed by silica glue to protect from water and vibration.
Key Switch Control: The converter can be controlled by a key switch control wire instead of an input relay.                                     
Over Heat Protection: Automatically reduces output current if the temperature is over 65°C, but it does not shut down to ensure the continuous power for your accessories.
Short Circuit Protection:  Shuts down and auto-resets with little pulse current.
Under Voltage Protection: Shuts down when the voltage of Hi-V battery is too low to avoid over-discharge ofthe battery.
Output Voltage: 13.8V±0.2V @0A, >12V @50A
Actual recommended input voltage range 100-180v
Low Voltage Cutoff  ~79V
 
Notes:
(1) Be sure you don't have input wires and output wires reversed, otherwise it will cause damage!
(2) Don't open the shell of the converter; there is a risk of electric shock!