Laptop touchpad unusuable when on AC power (via inverter) in vehicle

[Jeff Snyder]

I upgraded laptops a couple of chase seasons ago, and the problem has been around since then. I found a way around it, but I figured I'd ask about it here in light of the ongoing CB/USB port thread. I originally typed this up as a reply in that thread, but figured it was too much of a threadjack.

When I have my computer plugged into the vehicle's inverter, the touchpad is basically unusuable, as the mouse jumps around erratically; even not moving my finger, the mouse will jump around the screen many times per second. Before I got my DC-DC laptop power cable, I would need to unplug the laptop from the inverter/power cord in order to use the mouse/touchpad. Since only the trackpad is unusable when the comp is on AC power (via the inverter), I assume it's something to do with quality of the AC power (or the fact that the Dell power cable doesn't have a 3rd / ground prong). My old Dell laptop had a 3-prong AC power cable, and it had no problems in my vehicle, unlike the 2-prong AC power cable that came with my current laptop. The Duracell DC-to-DC adapter/power cable worked fine last year, but it stopped working a couple of months ago. FWIW, the Dell 2-prong AC cable also leads to occassional shocks when I touch the screws on the underside of the laptop. This secondary problem (shocks) has been reported on other sites, and it seems that a possible culprit (last I looked) was the 2-prong AC adapter.

Ideas to remedy the touchpad problem? I've thought about trying to ground the laptop to the vehicle, but it'd be a pain given that I take the laptop in and out of the vehicle so often (during chase season). This seems to be independent of any radio operation, and it only affects the touchpad. Of course, could be some RFI from on-board electronics (under the hood, in the dash, etc), but my strong suspicion lies with the inverter (since there are no problems when using the cig lighter / DC-DC adapter).

 

[Skip Talbot]

Jeff, you stated everything I was thinking about when I started to read your post, and I believe you are correct about the problem and remedy. I too get shocked occassionally from laptops with a 2 prong plug. I'm trying to think of a way that you could easily ground the laptop without sacrificing its mobility. Perhaps you could modify the power cable by making it three prong, or adding a ground wire to it?

 

[Mark Blue]

Jeff,

This may not be what you're looking for, but I found my touchpad on my Toshiba is basically unusable when in the vehicle, regardless of power options (AC or DC). I purchased a bluetooth mouse and a lap desk and have never looked back. I was to the point where I couldn't click on what I wanted because the cursor was all over the place once the vehicle was in motion.

Here's the lap desk I use: http://www.laptopdesk.net/laptopdesk2f.html

I just fold the lap desk in half and use a mouse pad with it in my lap. I use the Targus bluetooth mouse and it works like a champ. Nice and steady, unlike the touchpad which seems to have the mexican jumping beans installed as part of the payload with the driver! Best of luck.

Mark

 

[Robert Edmonds]

My mouse pad jumps around but that's only once it get warm from the sun. Then it becomes unusable. I have a dell laptop. The solution for me is to use a usb handheld trackball mouse. I actually think it's easier to use, given the situation. If you're not sure what it looks like I could get off my lazy end and take a picture.

But the occasional shock... can't help you there.

 

[Rob Wadsworth]

Maybe a USB optical mouse? I use that and a book for the mouse pad. Or a wireless mouse; I have one of those - too. Cheap, and works fine. Just a thought.

If you are getting shocked from anything in the vehicle, surely an issue that needs to be addressed first.

 

[Dennis Sherrod]

Jeff, I had a problem similar to this on one of the laptops I got. The mouse jumped like mad in the car. I went in and changed the touchpad sensitivity and it works great in the vehicle. Once I took it out of the car, I would need to readjust the sensitivity again. Other than that, I got a mini mouse with USB plug. That works too. Nice and small.

 

[John Diel]

A couple of years ago we had a very in depth discussion about the power quality that various inverter actually put out. I'm sure it's in the archives somewhere. Basically it falls down to the type of wave form the inverter creates in making the 12 V DC to 120 V AC conversion.

Though I don't know how this this wave type would affect the electronics (mouse pad, etc.) of a laptop, it stands to reason that the more "dirty" the power, the more degrading effect it would have. I believe we are seeing some of that evidenced in this thread.

One of the things I do with mine is I never power the laptop directly from the inverter. I have a high quality (power conditioning) power strip in between. I also have a high quality power inverter. It's a High capacity output inverter and has served me well for a few years now.

I tried the less expensive 150W cigarette plug types and they simply did not cut the mustard. With the laptops of today pulling even more power with faster CPUs, larger HD's, etc. You will need the power to feed them. Laptops aren't shielded very well these days. To get the bigger, better displays, and faster cpu's, a cut is made in shielding to keep the weight down.

Also, anything running with two prongs is not grounded. Personally, I would never place a laptop on an ungrounded connection. There's a reason they all have three prong connections. Circumventing that is asking for trouble.

JD

 

[JR Hehnly]

Jeff,

My mousepad does the same thing until I ground the PC to the vehicle's ground. This is accomplished for me by plugging in my USB accessories. I'm not sure which it is (probably the threatnet with it's 12v. power source), but at least one completes a path to ground. If I unplug all the USB devices my mouse again becomes unusable.

Try a jumper wire to ground and see if it helps. You could make a dummy usb that's just grounded on the other end for quick disconnect when you take the pc out.

 

[Jeff Snyder]

All,

Thanks for the thoughts and comments! It seems that my suspicion of ground or dirty AC problems are correct given what you all are saying. I'm not sure why Dell switched to 2-prong adapters, but between that (i.e. no ground) and the square-wave AC power (I have a cheapo inverter... the pure sine wave inverters are $$!), the touchpad isn't happy. I like the idea of a dummy usb cable with one end grounded (well, the ground wire grounded, obviously), so I'll check that out. If that doesn't work, then I'll look into a wireless mouse... I'd like to stick with the touchpad, though, since it's space-saving compared to needing larger surface to operated a traditional mouse.

EDIT: Well, I figured I'd contact Dell to see if I could get a 3-prong AC adapter. I bought the laptop in May 2007, and I did a 3 yr service plan. I did the online chat, and I told them that the screws on the bottom of the laptop occasionally shock me (it's documented with some other Dell laptops that went to 2-prong adapter - e.g. http://www.notebookforums.com/showpost.php?p=2547679&postcount=12 ). My cheapo multimeter (old, analog one) shows 6-35 V AC between most of the screws on the bottom and the house ground (a ground on a surge protector). It seems that the bad press they got from this in the past couple of years has made them quite generous in their fix... I basically just asked if i could get a 3-prong adapter. Instead, they said there may be other damage on the laptop, so, instead, they are sending out a new system that is "like or better" than my current one (my model is no longer produced). So, it looks like I'll be getting a new laptop entirely in a few weeks. Sure, and I spent a dozen hours last weekend upgrading my hard drive to a new 320 GB 7200 rpm one that I got for Christmas... Alas, I'll take it!

 

[Rob Wadsworth]

Sweet deal! I suppose you have to send your present one in to get the deal. Either way your dilemma is done; and you have a better, newer laptop. That's great news!

 

[Robert Edmonds]

I'd like to stick with the touchpad, though, since it's space-saving compared to needing larger surface to operated a traditional mouse.

That's why I like the handheld track ball mouse...

It doesn't require a mouse pad. There are several different types out there too.

 

[Mark Blue]

A couple of years ago we had a very in depth discussion about the power quality that various inverter actually put out. I'm sure it's in the archives somewhere. Basically it falls down to the type of wave form the inverter creates in making the 12 V DC to 120 V AC conversion.JD

I think this may be the thread John referenced in his prior post:

http://www.stormtrack.org/forum/showthread.php?t=13245

After reading the #14 post in the thread by Stuart Robinson, I officially converted to the DC to DC adapter and have been a very satisfied customer ever since. I wish I had known about these adapters before investing in a high dollar pure sine wave inverter from Lind, but what can you do? I am a big fan of the Lind adapters as they are very high quality and never run hot. They are a little pricey, but I am a firm believer that you get what you pay for. This link will take you to the page where you can find the model for your particular laptop:

http://www.lindelectronics.com/cgi-bin/store/shop.cgi/!ORDERID!/Special_DC_Adapters/x/dbx_gen_Special_DC_Adapters_mfgs/

Mark

 

[Robert Edmonds]

After reading the #14 post in the thread by Stuart Robinson, I officially converted to the DC to DC adapter and have been a very satisfied customer ever since. I wish I had known about these adapters before investing in a high dollar pure sine wave inverter from Lind, but what can you do? I am a big fan of the Lind adapters as they are very high quality and never run hot. They are a little pricey, but I am a firm believer that you get what you pay for. This link will take you to the page where you can find the model for your particular laptop:

I second that, I only use my inverter now as a backup. I keep everything on DC-DC. The most pricey thing was the dc-dc adapter for the laptop, but it works great. I even found a wifi router that takes straight 12V from the car, so need for an adapter.

 

[Chris Nuttall]

I'm glad someone posted this thread as it might help address a current question that I have. My new Jeep has an inverter built into the center console. It's a two-prong outlet, but my laptop's AC adapter is a three-prong. How safe am I to use a three-prong to two-prong adapter for this connection? The adapters are designed with a metal ring at the top that you are supposed to be the screw for a wall jack into, which then provides the grounding connection. If I do this, is this going to be an ungrounded connection? I mean, the Jeep itself is grounded.

I still have my stand-alone inverter stashed in the back, so I can always go back to using it. But, that would be one more piece of equipment I wouldn't have to get tangled up when I chase.