Laptop Power Supply Adapter - Electrical Engineering Required! :)

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htwingnut

htwingnut

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I have a Dell PA-9E 19.5V 230W power supply with a 7.4mm/5.1mm outer/inner barrel connector and have an adapter taking it down to the 5.5mm/2.5mm outer/inner barrel connector on my laptop.

The adapter I'm using is here: http://www.bixnet.com/cntx75.html

It indicates it uses 16AWG wire.

Now this adapter works great, and allows me to overclock and draw more than the 180W that the stock power supply can provide. But I was curious about any concerns or current capacity with the adapter.

It's 16AWG at 19.5V but I can't find any straight answer as to what the rated or peak current draw should be or other considerations by running peak 12A draw periodically is of any concern, and running 8-9A consistently when gaming.

Thanks for any input on this.
 
Solution
volcanoscout
I'm not an EE, but I stayed at a Motel 6 last night - 16GA multi-strand wire at 12V is conservatively rated to handle 20A over a short run (6-10ft) with a wattage of 240. Using Ohm's Law, at 19.5V it works out to 12.3A. Your peak amperage at 230W and 19.5V works out to 11.79A. You're at the edge of theoretical max, but again, these are conservative numbers.

Considering the length of the adapter, 7.5", I would postulate that it provides considerably less resistance than a 6' length would, and so should be able to handle more. I would recommend that you apply a complex and dangerous, but relatively accurate, practical application test: run your system at max draw for decent amount of time, then...wait for it...feel the adapter. If...
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volcanoscout

volcanoscout

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I'm not an EE, but I stayed at a Motel 6 last night - 16GA multi-strand wire at 12V is conservatively rated to handle 20A over a short run (6-10ft) with a wattage of 240. Using Ohm's Law, at 19.5V it works out to 12.3A. Your peak amperage at 230W and 19.5V works out to 11.79A. You're at the edge of theoretical max, but again, these are conservative numbers.

Considering the length of the adapter, 7.5", I would postulate that it provides considerably less resistance than a 6' length would, and so should be able to handle more. I would recommend that you apply a complex and dangerous, but relatively accurate, practical application test: run your system at max draw for decent amount of time, then...wait for it...feel the adapter. If it's cool or only slightly warm to the touch, I think you're good. If it's hot, quit maxing it out until you can find a more robust adapter.

Hope this helps, and for God's sake be careful :)
 
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htwingnut

htwingnut

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I'm using Prema Mod BIOS and just have the i7-4710HQ CPU which I can run at 3.5GHz with 4 cores, but can OC my GTX 970m to 980m performance levels and can draw as much as 200W from the PSU from the wall, so it's near the 180W limit (if you take into account inefficiencies), and don't want it to throttle because of power.
 
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volcanoscout

volcanoscout

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I've been considering a Prema for my NP7338, but just haven't had any time. Sounds like you're getting decent OC numbers - any stability issues? How have your temps been?

Prema's got a very good rep, but I use my laptop for work so can't get too crazy with it.
 
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htwingnut

htwingnut

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You don't need to OC if you don't want to, but it removes the +135MHz overclock limit typically found on notebooks. At stock voltage most GPU's can get well past the +135MHz nVidia cap. I've posted tons of stuff at notebookreview forums, not sure if you've seen my reviews there on the Sager/Clevo models. But NBR is down at the moment, but I did post my max OC (well near max) over at TechInferno: http://forum.techinferno.com/clevo/401-%5Bbenchmarks%5D-official-thread-23.html#post116836
 
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volcanoscout

volcanoscout

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Technically, I don't need the performance of the stock system let alone overclocking it. But there's "need", and then there's "NEED".

I didn't make the connection to NBR until you mentioned it - I've read a number of your reviews. In fact, your 7338 review was one of the things that decided me on the model. I would have preferred a larger model, but traveling with anything over 13.6 is a major pain. Awesome work! Pleased to make your acquaintance.
 
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