I live in a place that suffers from electricity shortages, I have a 12V 20AH battery and I want to charge my laptop using it, rather than buying an inverter I thought it would be more efficient if I use a DC-DC step up module

I got the XL6009 4A max it does provide the wanted voltage (19.5V) but then I checked my laptop charge adapter and it says 4.62A MAX.

Is this a real problem or I'll get away with it if I provide decent ventilation?

Details of my XL6009



closed as off-topic by RoyC, Sparky256, laptop2d, PeterJ, Andy aka Jan 26 '18 at 17:09

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  • \$\begingroup\$ Could you please reduce your font or image size by a factor of ten-or at least five. Such a visual overload chases people away. \$\endgroup\$ – Sparky256 Jan 20 '18 at 1:36

4.62A is out of spec even for the XL6009 itself, so you will need a more powerful converter. In practice, the actual current you can get from these pre-fabricated DC-DC converters is further limited by their design. The cheapest ones and the smallest ones can barely deliver 2A continuously, before they start getting too hot and eventually shut down thanks to thermal protection. Websites selling them will still advertise them as 4A converters, without mentioning that 4A is in fact a spike value.

If you're lucky your laptop only pulls 4.62A occasionally, and a well-designed converter based on XL4015 or LTC3609 may suit your needs. Pick a module with a toroidal coil: these coils heat up quite a bit, so you don't want a coil which has good thermal contact with the PCB and contributes to the overheating of the converter chip.

If you don't want to guess, buy a real power supply rated for 5A or more of continuous load.

  • \$\begingroup\$ A 150W 10A would do the job? I've attached the information above, thank you. \$\endgroup\$ – Seraj Jan 15 '18 at 12:05
  • \$\begingroup\$ @Seraj Yeah, that should do it. It even says it can drive a 90W notebook. \$\endgroup\$ – Dmitry Grigoryev Jan 15 '18 at 12:08
  • \$\begingroup\$ It says the module temperature is 45c at 19V 3.42A, should I take any precautions at 4.62? \$\endgroup\$ – Seraj Jan 15 '18 at 12:11
  • \$\begingroup\$ @Seraj No, unless you will put it next to heat-sensitive parts, like Li-ion batteries, LCD screens etc. \$\endgroup\$ – Dmitry Grigoryev Jan 15 '18 at 12:27

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