The Circadian® system has been designed with multi level control and management in mind.

The Batteries themselves are smart and measure and record multiple parameters. A bidirectional communication circuit has been established so that batteries, Hot swap module and chargers can access data. CAN-Bus has replaced SM-Bus to avoid the well documented communication issues of the SM-Bus which is vulnerable to noise artefact outside short range on-PCB communication 

Level 1 On Battery:

Circadian® batteries have 5 green LEDs indicating the State of Charge (SOC) which is is active when the battery is on Cart or on the Charger. If the battery is not connected push the DCPower4C logo button shortly to activate the LEDs for 1-2 seconds.















The SOC informs the user on how fully charged the battery is in percentage terms. This is standard on battery displays. However be aware that this can be very misleading since with Lithium Ion batteries the full rating constantly declines with age and cycles. For example a new 100Wh battery shows 100% full meaning it has 100Wh available. The same battery when 5 years old and now really a 20Wh battery will still show 100% full after charge, but meaning 20Wh is now available. Therefore SOC is not a good indicator of run time, battery age or real capacity.

If the DCP4C logo button is pushed and held for longer than 2 seconds the (SOH) State of Health info is given. This is for age control, indicating when the full Battery capacity has declined in percentage terms. Circadian batteries have an unusually strong warranty. If the SOH is below 80% within 3 years -it is a warranty case. This SOH tool allows maintenance to control both Warranty and End of Life control. It is a unique on the market and gives clear guidance on battery Health. As a rule of thumb batteries are fully operational above 80% and depending on circumstances increasingly limited on loads down to 60%. Below 60% Lithium Ion batteries experience a high increase in internal resistance and their reliability becomes poor and thus unacceptable in a professional medical environment. In the SOH mode the battery LEDs show:



















 This Circadian SOH mode is also calibrated to ambient temperature and current load in order to ensure accuracy in all circumstances.

Level 2 for nurses or cart users

A colour LCD display can be plugged into the Hot swap module and mounted anywhere on the cart. With a 2.8 inch screen the nurse can always see the remaining run-time in Hours and Minutes. For example on a 30W load with 2 fully charged 160Wh batteries the display will show 10 hours 45 minutes. This number runs down during the day, it will adapt and vary as the actual load falls or rises. 

This Remaining Run-time is known as SOF, State of Function which is the SOC times SOH expressed in time in relationship to the current load. It is the most pragmatic information for nurses during shift.  Of course Computers are subject to massive sudden changes in power consumption, spikes and troughs. The Circadian battery implements an algorithm to monitor average power during an ongoing discharge, thus giving a more consistent and overall accurate remaining run-time reading.

As the battery empties the LCD display will change colour as an extra warning to the Nurse.

There is also an Audio version of the LCD display that will beep as the battery reach selected low capacity thresh holds.

Level 3 On charger

On chargers the 5 battery LEDs light up according to state of charge, when all 5 are on the battery is 100% or fully charged. The charge mode also can show the uppermost LED flashing. For example if 4 LEDs are on and LED 5 is flashing, the SOC is between 90 and 100%, when the top LED is steady on, the battery is 100% full.

 If when, LED 1 is full and LED 2 is flashing, it changes to LED 1+2 on and LED 3 flashing the battery is exactly 30% full which is the current transport regulation criteria.

 Level 4: On the Cart’s IT screen.

The Hot Swap module can be connected to the cart SOC system or the PC Battery management software which typically use standard USB communication protocols. DCPower4C also provides 3 different software options for Nurses or Maintenance IT on cart.

  1. DCPower4C windows bar Icon, which if clicked expands to replicate LCD data: SOC / Remaining runtime etc.
  2. A Battery parameter read out software, showing all key data, including SN, Cycles, SOH, D.o.M.
  3. A Firmware upgrade software for Batteries, Hot Swap electronics and LCD displays. This allows improvements, service fixes or Hospital specific requirements to be implemented.

The last two software are only recommended for IT/maintenance use. Some customers equip a central cart  for this purpose.

Level 5 WI-FI / LAN module upgrade for Carts and Charger to Dash Board

All chargers and Hot Swap PCBs are pre-wired for this upgrade which is under development.

Batteries should either be on the cart or on the charger. With this WI-FI / LAN system every battery can send its data to a central Dash Board. So all key parameters on battery life and performance, their aging and probable need for replacement Budget can be viewed centrally.

The chargers have fixed locations and can communicate the status of each battery. If a nurse calls IT, they can direct her to the next fully charged battery. If the charger is unplugged or switch off an alert can be raised.

The cart will also communicate – even if the on-cart IT is turned off. If nurses forget to charge, it can be seen and acted on.

Both Cart and Charger send data at intervals requested by the central Dash board. The Data ouput formats are flexible. DCPower4c can organise a Dash Board, however, understandably, most Hospital IT departments want to control this themselves or via a local partner, so that their system is responsive to their needs, encompasses other cart equipment and is controlled and secure.

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