Laptop DC-DC auto/air adapter heating problem!

nickfer3 · 06-22-2008, 08:44 AM

hi guys, I've searched for a few hours but couldn't find anything related to my "problem"...

I'm powering my laptop setup through one of those ebay auto/air dc-dc adapters, and cut the cigarette lighter plug off and hardwired it using 6 gauge wire directly from the car's battery...

I'm worried because the adapter gets very HOT when charging the laptop, hot to the point that I can't hold it in my hand for 3 seconds...is this by any means normal?

Could the 6 gauge wire be overkill? since it puts out a lot of current through it, only to find a 16 gauge wire going into the adapter...

any comments would be appreciated.. thanks!!

nickfer3 · 06-22-2008, 08:58 AM

oh, by the way, the adapter puts out 18.5v 3.5a 80w max

it powers my laptop, and my laptop has usb dvd drive, usb radio, an express card 4-port usb hub for the touchscreen and a bluetooth dongle...on the wall power brick for the laptop it sais 18.5v 3.5a 65w power consumption...

could the laptop be drawing more power than the adapter can handle, thus causing the (over)heating??

FusionFanatic · 06-22-2008, 08:40 PM

I used a cheap eBay adapter with my old laptop install. like yours, the one I had would get extremely hot after a few minutes of use. under the plastic 'shell' is a large metal heatsink. this heatsink presses right up against the plastic shell which is why the entire unit gets so hot. there were tiny 'vents' in the plastic shell but they were pretty much useless. the way it was designed, the plastic shell basically trapped all the heat inside.

due to the poor design, It does seem to be "normal" for it to heat up like that, but I was not comfortable with any [external] component heating up that much. my solution was to remove the outer plastic shell and mount the 'naked' DC-DC adapter in an empty ATX PSU case (with 120mm fan). I wired the fan to the 12v input line (which was switched on/off with a relay). after that it ran nice and cool

nickfer3 · 06-23-2008, 04:06 AM

thanks for the reply!!

I remember seeing somewhere someone that had this heating problem, but I just couldn't find it anywhere on the forum... come to think of it, I think it was you!!

lol

so after you changed the actual plastic casing to a metal one the heating got cooled? i think that's what I'll do. You put it in a way that the soldering on the adapter couldn't touch the metal, right? what did you use?

and what about the power load on the adapter? as from what I specified, my laptop says it consumes 65w but I have usb devices connected to it...usb dvd, radio, 4-port express card, bluetooth and 4-port external hub.... do you think that my 80w ebay adaptar can handle it? or am I asking too much from it?

thanks again!!

nickfer3 · 06-24-2008, 04:09 PM

Just so everyone knows, I pretty much solved my problem by adapting a mini-fan from an old cooler I had laying around onto the laptop psu. It cools down the temperature quite well

Here's what it looks like now:

Sorry for the blurry phone picture, and I still have to do some cleaning up on the fan, but it works