LocknCharge Blog

Getting Your LocknCharge Cart Ready for the New School Year: Quick Q&A

Q: Our schools are back from summer vacation and when we plug our Carts in to charge our Chromebooks, the circuit breakers keep blowing. Our Carts must be defective.

A: Not exactly. When charging 40 Chromebooks that have completely depleted batteries, they are pulling too much current for the ECO Safe Charge and the circuit breaker opens. Simply changing the charging mode to use the 3-hour cycle charging mode to get the cart and Chromebooks up and charging, but once the Chromebooks have some charge in them, the cart should be able to continue in the “ALL ON” mode to keep them charged during the day.

From our experience, once you get all of your devices up to a full charge, our cart is typically able to keep them all up to full charge using the “ALL ON” setting even with regular daily use. Chromebook battery life is predicted to be 8-10 hours, and a student using a Chromebook all day it may only deplete (at most) to 25%, and not usually every device is depleted even that much. To date, we have not had any reported issues with this, except in cases where the cart is left unplugged for a summer and the Chromebooks are again fully depleted.

We did implement the option for cycle charging, and we did incorporate the remote to make changing modes as needed easier for a teacher to manage since each deployment can be different than the standard. However, if you wish to not use either of these options, I would suggest just connecting half of the Chromebooks in your cart until those get charged to full (typically 3-4 hours) and then connecting the other half. This would reduce your instantaneous charge load on your new deployments without having to use the remote or having to change the charging mode.

Technical Explanation:

A typical home circuit is 15 amps, which equates out to 1800 watts. A commercial circuit can carry 20 amps which equates out to 2400 watts. When our cart was first designed, Chromebooks were supplied with 40-watt power supplies. That’s why we believed that our cart could charge 40 devices simultaneously without any issues, as 40 devices x 40 watts = 1600 watts. Since that time, Chromebooks have been introduced with 65-watt power supplies. Math shows us that 40 devices x 65 watts = 2600 watts, which can even exceed a 20 amp circuit, which is also why the breakers start opening when you have a cart full of fully depleted Chromebooks. Even our 30 unit cart can have challenges with a load of 65 watt Chromebooks (30 devices x 65 watts = 1950 watts).

For more information about ECO Safe Charge, click here

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