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: 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: 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 2-4 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.