# It is possible to use a 100W 12V solar panel directly to charge a laptop, using a buck converter for example?

I am planning to go off the grid due to the pandemia, to an isolated village. I am working remotely I am looking for a solar approach to power my laptop ACER A5 515. The charger is rated 40W.

I was considering using a 100 Watt panel, an inverter and the power charger. However I was wondering if its possible only adapt those 12 volts to 19 to use with my laptop. And which could be the best way to avoid damaging the electronics.

I think it should be a waste of power using an 100 watt panel from the solar controller, then a 120 v inverter to connect the laptop charger.

I could use the laptop battery to store any excess energy (I only the laptop to be on by 9 hours at day)

Also I will need to have my phone connected as I will using the data tethering and a rechargeable usb light to use at night.

Thanks in advance for any ideas or suggestions.I am looking for an starting point to start constructing this setup

• That won’t be easy. Is there any options for car charging or similar? May 24 '20 at 20:50
• It’s much easier with 19 to 24Vdc with a low ESR cap big enough to drive the laptop motherboard with less current. May 24 '20 at 20:55
• @winny my thought exactly. Why bother with any other solution as there are 12V input car chargers for the laptop available. May 24 '20 at 21:10
• to an isolated village ... that sounds like a totally irresponsible action on your part .... isolated villages usually do not have the medical facilities to handle the influx of covid cases when the virus has been brought in by people like you ... it endangers you and everyone else in the village May 24 '20 at 21:14
• I'd consider a 12V lead acid battery (second hand car battery? leisure battery if you can afford it) and a cheap solar charge controller to protect it. Then 12V to 19V adapters are easily available. All simple cheap (except the leisure battery) and works well together. May 24 '20 at 21:17

It might be possible, but not very reliable.

The reason is the input impedance is very non-linear to any DC-DC converter such as those used on Mobiles and laptops. This means the inability to match impedances from source to load (maximum power transfer theorem) which is the condition for MTTP. Worse yet, the surge start current might shunt the PV into a low power low voltage start condition that fails to draw sufficient current to reach an equilibrium , assuming sufficient power exists for a matched linear load.

PV’s are current sources with Vmpt ~ 82% of Voc with voltage limits.

This means the load instead of appearing as a positive resistance can start as a negative incremental impedance and result in unstable cycle of little or no charging. Boost DC-DC converters work with voltage source inputs it will then have a CC, CV cutoff profile. with low ESR and not with current sources.

Your best bet to make a linear load using the DCR of a battery pack using an array with 24Voc (open circuit and charging a 19V. A good charger with MTTP will match the charger impedance to the battery chemistry and you have a backup to To charge your laptop while charging the other .

Check around for battery specs or purchase a 19 to 20V roughly batt Pack to charge your laptop and emulate the 19.5V universal charger. Then find a PV charger that works on that.

If you plan to go off grid, get some 1kg jars of Vit C with C&L Lycene and Mg. 5,000 IU’s/ day and more if ill. There ought to be enough sun for Vit D. (10,000 IU tab/day )

A battery load is linear and works but a DCDC converter does not unless there is a huge capacitor in between. Your test mileage may. Vary.