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Clinton Blackmore
Asked: 2010-07-14 08:42:06 +0800 CST

Any tips on wiring up a laptop cart?

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We are shuffling laptops between schools during the summer and rearranging laptop carts. We've used various methods of wiring in the laptops (some of which depend on the specific model and power adapter, but surely some of which doesn't) with reasonable results.

However, with laptops getting older (and the batteries not necessarily having been replaced), students will take the power adapters out of the cart so that they laptop will remained powered-up through class.

Does anyone have any tips on:

  • wiring up laptop carts in general
  • wiring up laptop carts so that the power adapters can be removed and replaced in the cart easily, and without creating a tangled mess?
laptop

2 Answers

  1. Best Answer

    K-12 district here. We have 8 schools with 43 notebook carts (both 15 and 30 unit models) throughout the district. Buildings have [or will soon] eschewed traditional computers labs in favor of notebook carts.

    A couple things we've discovered over the years using these carts:

    1. Standardize your notebook model.

    One of our earliest issues was the varying location of power/network ports on the notebooks. Each vendor [in a seemingly random fashion] selects different locations for these ports. Having both power and network on the same edge was an important requirement for us.

    2. Wire carts for power and network.

    This helps greatly when imaging the laptops and deploying software. We also have the carts "parked" at the end-of-day. We can WOL the laptops at night and apply updates, etc. For year end re-imaging of staff/teacher notebooks, the carts serve as a drop-box. No need hand collect the notebooks.

    3. Invest in an integrated DC charging system for the carts.

    Our cart vendor builds custom PSUs with integrated charging units. These units feature model-specific adapter-ends but can be reconfigured without replacing the PSU. We do not need to "donate" the AC adapter for each laptop to the cart. You can store the unused AC adapters in a central location (Library, Office) where users can self-serve.

    4. Pony-up for a battery replacement warranty

    Regardless of any end-user education, staff/students are going to abuse the notebooks when it comes to charging cycles. Some of our older deployments had batteries failing after only 1.5 years. If you're buying a sufficient number of notebooks from a vendor you are in a great position to negotiate a deal on battery warranty. Also, look for bay-battery options if you do not require optical drives.

    Edit:

    Additional stream-of-conscious notes...

    • Skip the zip/twist-ties unless you enjoy using dikes. Velcro Hook-and-loop wraps can save lots of time when re-wiring.
    • Devise additional physical security. Every model cart we've used has useless built-in door locks.
    • Protective [non-conductive!!!] enclosures for on-board wireless APs. We had a Cisco AP destroyed by someone stuffing it full of paper clips, staples and other debris.
    • Publish some picture-heavy/word-light Ikea-style docs for user. How to charge cart, connect to network, access printer (if one is on cart), general connectivity troubleshooting.
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  2. There is a big gotcha with this setup and that is with what model laptop you want to support. We have some "consumer model" HP 3125 laptops that will only maintain their connection to the wired network if they are shutdown with both power and network cable connected. If you shut them down while they are wireless, and then plug in the network/power cables, the will not connect to the switch and thus cannot be woken up.

    Our Lenovo X131e laptops will reconnect to the switch after it is shutdown as soon as you plug in the network cable/power.

    So bottom line, get a sample machine and make sure you can wake it up if the cables are plugged in after it's shut down.

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