Frequently asked questions: In this section we will list everyday user questions we actually receive from customers and will aim to put the most asked question at the top. 

Q: What is a toggle? and why is it needed?

A: This is basically a reset. When a Circadian battery has gone into low voltage sleep mode, it closes down circuitry responsible for an automatic restart, this saves power and increases life. The Battery needs to see a charger, which is effectively a magnetic signal and a power input. if using a charger this is automatic. When using power supplies the user must make sure it is plugged in, remove the battery from the C-Mount and return. At his point the magnetic activation and power input wakes the battery and charging can resume.


Q: Why do the batteries discharge simultaneously and not sequentially?

A: Sequential discharge has many disadvantages. The load is double which shortens battery life by a significant percentage ( think of the life of a car engine, constantly driven double the speed). The voltage is lower, which effectively means less overall run-time. The first battery will usually be fully discharged - again reducing battery life.  The nurse will have double the amount of empty battery messages. Usually two Circadian batteries will be chosen to run a complete shift. Most sequential systems do not have the large LCD display, such as the Circadian system, so the nurse does not have the easy visibility of battery status. We cannot think of a single advantage to the hospital of choosing a sequential system. The Circadian system has a much longer warranty than any other hot swap system we know of- and we achieve this by optimizing all aspects of battery technology.


Q: the new Laptop has a 240W power supply, will it work with the Circadian system?

A: Some thought is required to make this work. 1st the Hot swap PCB has a max load of 175W. Therefore a 2nd Piggyback PCB at the same voltage is required, so that the system can handle the peak load. 2nd if a power supply is used as a charger, the standard 220W GSM might be limiting, especially since it requires circa 100W to charge 2 batteries. 3rd, If hot swapping there are moments when only 1 battery is operational, This raises several issues around time, and also the sort of battery and its age. 4th if an inverter is on board, it also needs to be able to handle higher loads. The standard inverter is a 200W, however there is a 400W version available.

Our best advice is to contact a technician or DCPower4C support to discuss. We can usually resolve this, but need to understand any potential consequences and limitations. In some case a lower rated power supply can be used.


Q: Can we have an Audio signal to indicate low battery?

A: Yes there is an LCD display available that includes a speaker; it can be programmed to beep at various Near End or Eng settings.


Q: How long can I leave my batteries empty?

A: This is a more complex question and it depends on the capacity of the battery.

Stock shelf life

30% Full

100% Full


















The above chart gives the calculated safe storage times. When a battery is shipped it must be below 30% full. Idealy anyone storing batteries will leave them in the box and will charge them up to full if the stock time is likely to be longer. It is clear that the Circadian 80 Battery requires more management than the high capacity types. 

If the battery is left on a C-Mount or Quick Connect (bracket) on cart, the magnetic connection still activates the battery. All internal systems such as Safety Management, Hot Swap and LCD Display are running. The LEDs will light up. The battery will discharge over 2-5 days, before going into sleep mode and then deep sleep. The LEDs are deactivated and the battery shuts down just about all internal circuitry bar safety control to minimize power draw. BUT - dependent on capacity and age, the battery will open its safety circuit after circa 2 months at which point the battery will no longer respond. This is a feature not a bug! Over discharged Lithium-Ion batteries are a safety hazard. For that reason such an overdischarge failure is not covered by warranty. So if you are not planning to use the battery, charge them up, check every 3 months and don't leave them on the Cart.

Hospitals in the Pre-set up phase are especially vulnerable to this. Often the Carts are ready to go in the cellar for months on end. 


Q: Is it safe to leave batteries on the Charger for long periods? 

A: Yes, as long as the charger is plugged into the mains and switched on. The batteries will remain fully charged and ready to go. The status is managed- there is no trickle charge  or heat  build up that could represent a safety concern.  


Q: Can you provide Hot Swap power direct from the Battery C-Mount for our on cart laptop which takes a 19V input?

A: Yes there are several options for this depending on the brand and model of your Laptop. In most cases one Circadian 80 battery is sufficient, it will keep the Laptop battery 100% full as it discharges and can then be swapped giving around the clock power. Contact This email address is being protected from spambots. You need JavaScript enabled to view it. for details. The new Quick Connect is also a suitable option.

Q: Can we power PADs with a 5V DC input?

A: Yes, this is easy to implement.  Contact This email address is being protected from spambots. You need JavaScript enabled to view it. for details. See details on the Quick Connect.