Sleepbus is providing a bed to Melbourne’s homeless

To work with, Simon Rowe, the founder of Sleepbus was an absolute pleasure. His laser-like focus on solving the problem of homeless people having somewhere safe to sleep is also the way he works day to day. No obstacle gets in his way. Read about the first Sleepbus powered by lithium.

First Sleepbus Powered by Lithium

The project was to provide the electrical energy to a converted bus that will house up to 20 people who would otherwise be sleeping rough. The Sleep Bus mission is to help those sleeping out in the cold with a safe comfortable bed for the night.

Each of the sleeping pods has an integrated small TV, light and a USB charging point. Also, there are actuators that open the doors, all of these loads require 12V power.

The bus has two separate 240V AC air conditioners that provide heat or cold to keep the bus at a comfortable temperature for the visitors each night.

Technical Design

This is a large system. The batteries installed were 12V, 100Ah model with integrated BMS. Each battery is capable of delivering 100A and each battery has an external fuse.

LBS installed 10 batteries to provide a total of 1000Ah at 12V or 12kWh of capacity. Heavy cross-connect cables pulled the whole 12V array into parallel. When locked together they operate as one large battery with the LBS Battery Management System monitoring the individual lithium cells in each battery.

A total of 10 chargers were installed.

Each is a 25A unit and chosen because they are perfect for Lithium at 14.2V, electrically isolated on the input and output side and also, they don’t require to see the 12V battery to commence charging. This meant that they operate well when placed in parallel and if the battery bank was totally depleted, they will commence charging without any need to reset anything in the system.

The chargers are grouped into two blocks of 5 meaning they are each plugged into a 10A standard GPO. The design means that the battery bank can be charged from dead flat to full in approximately 4 hours.

AC Power

To provide the AC power, a 12V, 3300W Inverter was used. This unit can peak at 6600W for the inrush of the air conditioners and easily handled the load.

Simon removed some heavy steel bracing and installed flooring material to create a wall accessible from its own hatch. This layout gives easy access to change fuses or access the system should any service work be required.

LBS happily lent their expertise to help with such a worthwhile cause.

Well done Simon, we look forward to your next Sleepbus build!

https://www.sleepbus.org/ 

Sleepbus

Sleepbus