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Electrical Laptop battery as standalone/diy-power source.

  1. Nov 13, 2011 #1
    Hi. I'm investigating the idea of using a laptop battery for energy storage in a portable solar setup. The idea is charging the battery from solar panels, then power/charge other devices from the battery in low light conditions.

    I would like to be able to power/charge laptops and usb-devices.
    The macbook pro 13" battery is tempting... (60wh, 11v, li-ion)
    datasheets on these batteries seem impossible to find...

    Is using laptop batteries in this fashion a feasible option? Has this been done before? I can't seem to google anything on it... Are there better alternatives simplicity/capacity/weight?
  2. jcsd
  3. Nov 14, 2011 #2
    I would advise against laptop battery packs for your project. You can't find data sheets because the battery packs are purpose-built devices. In the case of modern lithium-type packs, using them outside of the design envelope can have serious, and potentially lethal, consequences.

    Do you understand that the scenario you present involves cascading energy losses? The initial "backup battery" will retain much less than 100% (probably much less than 90%) of what you feed it (in addition to the losses inherent in the charging circuitry). Then, the battery pack continues to self-discharge as it sits idle. Multiply those losses by however many devices you intend to recharge from the backup battery.
  4. Nov 16, 2011 #3
    Hello Magnus:

    Cost per energy stored - it is still a little hard to beat a lead acid battery. The big benefit of the Li-ion bats is weight and size per energy stored. Since the solar panels are probably stationary - then the battery installation probably is as well.

    The key to battery success in energy storage applications is the charging cycle - the Lead Acid is much more forgiving

    Most Li-ion batteries have a dedicated charging management circuit that also has a thermal sensor on the battery to prevent overheating.

    The Lead Acid is like a work horse - easy to maintain and care for - the Li-Ion is a Thoroughbred - picky eater, and you need to know what you are doing or your will ruin it.
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