Planning the Ideal battery Mix

There is a choice of Circadian 80, 160 and 200Wh batteries. Making the right choice for your application impacts the long term reliability of your operation and satisfaction of your staff. Since you ideally want to avoid Swapping Batteries during shift for at least 3 years, we recommend the following based on your cart load. The cart load is the power required by the Monitor, the PC or laptop and any accessories now or planned in the near future. This figure is key and really difficult to assess, best is to err on the high side!

Example - Let’s assume:

Cart Load is 40W and a Nurse Shift is 8 hours = 320Wh requirement per shift.

But the Cart is not in use full time. Assume 60% usage = 192W requirement

But the Circadian battery might decline to near 80% over 3 years.

That’s a factor 1.25 which you should plan for:   192Wh x 1.25 = 240Wh

 

Thus the requirement is 240Wh Circadian battery power on the Cart and also on the Charger to run the Cart 24-7 for 3 years without the need to Swap batteries during shift.

  • 4 Circadian 80 batteries are not sufficient
  • 4 Circadian 160 batteries: 320Wh on cart: 320Wh on charger are perfect
  • 4 Circadian 200 batteries will do the job, but are overkill.

 

NB: if you use an inverter (DC:AC:DC)  rather than a DC:DC options you need to assume a minimal additional 25% loss of Battery capacity since power efficiency is lost on both the up and down conversion. Then the 240Wh needs to be multiplied by a factor of 1.33

240 x 1.33 = a 320Wh requirement. Again the Circadian 160 achieves this, but it is a tight margin.

If the load, usage or shift times were to increase extra batteries or the 200Wh Circadian batteries would be required.

Summary:

What do you need to know?

Example

For you

Estimated real Cart Load in Watt

40

?

Nurse Shift in hours

8

?

Estimate Cart Usage in Percent

0.6

?

Factor in Aging - based on warranty %/years

1.25

1.25

Factor in Inverter

1.33

?

WATT HOUR requirement on Cart

319.2

 

WATT HOUR requirement on Charger

319.2