Charging a Laptop

RichardS said:
Come on guys. This seems to have gone the same way as the "GM10 overheating" thread.

Richard
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I hadn't previously read that thread Richard, but i think you have a point. Posts #7 and #9 were perfectly polite corrections of previous statements, but as with the engine thread, some people just don't like to be corrected.
 
Back to OP question and the reason the answer is no. A 120 w solar PV panel (for 12v system) will typically deliver 20v with no load dropping to about 16v at 6 amps load.
Higher output voltage at less load lower with more load.
Your laptop I think will have 4 lithium cells in series. Nominal 3.7 volts each up to 4.1 volts fully charged and needing 4.2 or more volts for charging. So at 18volts in you need about 17.2 volts on the batteries. The controller drops .8volt in the control transistor. So max around 4watts of heating in the control transistor.
More voltage than 18v in, may cook the charge controller in the laptop.
If you connect the solar PV direct the voltage may tend to drop below 18volts. In that case charge current will fall until solar volts rise, sort of self limiting but perhaps slower charge.
Unfortunately the current drawn by the lap top depends on charge current to the batteries (depending on charge state) and actual computer drain depending on usage type. So with variable drain you end up with variable input voltage. Often under volts potentially also too high.
So conceivable that direct connection would work it is not worth the risk of introducing your computer to smoking. Best use ships batteries or if really necessary feed the panel in to a 12v to 18v buck boost regulator. You might only smoke the regulator. ol'will
 
If the laptop does support USB-C PD then you may want one of these. I fitted one and it's perfectly fine for my laptop, which uses between 5-13W while running (it's relatively high end!). The socket can deliver 18W which is enough to run and charge the laptop at the same time. https://www.amazon.co.uk/gp/product/B07R8JV1LX/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Cheaper or older laptops will generally use more power as they're less efficient so the solar panel may not be sufficient to keep up with demand if you're planning to use it all day and the laptop isn't efficient. Obviously it's insignificant next to the load from the fridge while making ice for your post work G&T :)
 
PaulRainbow said:
Looks like you are mixing your terminology up, which is bound to cause confusion.

Solar panels have connections to go to the controller. Some controllers have USB sockets on them. If your laptops can be charged from a USB socket, then you can plug them into the controller.

It sounds like you might have a "briefcase" portable kit, with built in controller, if so, and it has USB sockets, you can use those, again, if the laptop can be charged by USB.
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yes, that is exactly the situation. However, the laptops cannot be recharged with a USB socket (I think), but I could use the other "plugs".
 
lustyd said:
If the laptop does support USB-C PD then you may want one of these. I fitted one and it's perfectly fine for my laptop, which uses between 5-13W while running (it's relatively high end!). The socket can deliver 18W which is enough to run and charge the laptop at the same time. https://www.amazon.co.uk/gp/product/B07R8JV1LX/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Cheaper or older laptops will generally use more power as they're less efficient so the solar panel may not be sufficient to keep up with demand if you're planning to use it all day and the laptop isn't efficient. Obviously it's insignificant next to the load from the fridge while making ice for your post work G&T :)
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My 2015 Macbook air has a 45W mains charger. Do you think that one of these 46W USB-C PD chargers, going through a USB-C to Magsafe connector would work? I'm pretty sure it would be OK from a pure power perspective, but its the communications between the mac and the USB-C charger that I'm concerned about.
 
neil1967 said:
My 2015 Macbook air has a 45W mains charger. Do you think that one of these 46W USB-C PD chargers, going through a USB-C to Magsafe connector would work? I'm pretty sure it would be OK from a pure power perspective, but its the communications between the mac and the USB-C charger that I'm concerned about.
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There is a common misunderstanding about chargers for PC's etc. The power stated on the charger is its max output .. but the actual output will be set by the demand of the PC .. therefore as long as voltage is in the required range and regulated - the PC will draw the amps its requires.
Second - the most power is used to charge the battery - not power the actual computer.
 
It’s definitely got enough power, but I couldn’t say whether Apple will allow you to charge from it or if they’ll require you to buy something from them. From what I’ve seen of recent MacBooks it’ll be expensive Apple chargers only
 
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