Overland Journal: Discovery I, 5-speed

[craig]

For powering a simple laptop, why not go with an Auto/Airline power brick?

Without doing any research beyond an old mp3car.com thread, I believe it is much more efficient to go

DC->DC than go Car DC->Inverter AC->Laptop DC.

A lot of energy is lost to heat during each of those conversions.

 

[craig]

If it's just for your laptop, I've been using one of these for about 8 years. It works well, and also works with airplane power sockets.
http://www.targus.com/US/product_details.asp?sku=APD10US

Exactly... that's what I've used for years too. Simple and efficient like all good mods.

 

[michaelgroves]

For powering a simple laptop, why not go with an Auto/Airline power brick?

Without doing any research beyond an old mp3car.com thread, I believe it is much more efficient to go

DC->DC than go Car DC->Inverter AC->Laptop DC.

A lot of energy is lost to heat during each of those conversions.

For a single DC application, this is by far the best route. But an inverter allows you to use all sorts of Mains-voltage equipment.

 

[R_Lefebvre]

For powering a simple laptop, why not go with an Auto/Airline power brick?

Without doing any research beyond an old mp3car.com thread, I believe it is much more efficient to go

DC->DC than go Car DC->Inverter AC->Laptop DC.

A lot of energy is lost to heat during each of those conversions.

I agree, just, an inverter is more flexible for more applications.

And BTW, DC-DC also supply "dirty power" with voltage fluctuations, but they still work too.

 

[Hank]

Direct current is direct current. The wave has to do with the efficiency of the voltage step up (or down) of the AC that presents to the device rectifier. If the laptop is expecting AC voltage in a sine and it gets a saturated square, it will probably be handling more current than it expected. Cheap inverters will very likely cook unless the inverter supplying it is properly regulated. That's why you see "Regulated Modified Sine", and "Modified Sine". Although Regulated Modified Sine is nothing more than a sales gimmick, IMO.

With a squared output of modified sine wave you have a sudden voltage surge, and you place that to a capacitive load within the power supply of the computer. In other words, it's a short. So you are only replenishing the charge at the top of the cycle. In Laymans terms, it's like turning a light switch on-off-on-off-on-off........ This is dirty power.

Modified sine wave inverters are fine with resistive loads. You can run a drill all day long with a modified sine inverter and never have an issue. The "surge", or "blowback", is dissipated in the motor (it gets hot).

What happens if your computer processor fan gets hot?

Like I said, a modifies sine inverter will work. It may even work forever. But there is a much better, safer, option. Hell, I could run re-caps on my truck instead of the BFG's; I could have installed a Rover Racks roof rack instead of my Safety Devices rack; I could be using an Acer computer instead of my Toshiba. But I don't.

 

[craig]

Yep, an inverter is more flexible. Scott mentioned that his power need was for his laptop. Until that requirement changes, IMO an inverter seems like an over-engineered solution.

Craig

A new photo from a recent trip in Arizona


Originally, I was going to permanent mount a big inverter, but now I am reconsidering. For this truck, my greatest power requirement is 100 watts for the MacBook Pro. So I am going to buy a two smaller inverters, like this one from Xantrec:

 

[michaelgroves]

I suspect one reason there's a difference of opinion on this point, is that there's no firm distinction between "true" and "modified" sine waves. Nothing produces an absolutely perfect sine wave. There's a continuum between a square wave and a sine wave, and improved electronics in recent years has narrowed the gap and made "MSW" much closer to what perhaps used to be considered "TSW". Ten years ago, it was a big issue. Now, not so much.

 

[michaelgroves]

Yep, an inverter is more flexible. Scott mentioned that his power need was for his laptop. Until that requirement changes, IMO an inverter seems like an over-engineered solution.

Craig

His greatest power requirement. I suspect he's thinking it would be handy to have 115V on tap for secondary and/or unforseen requirements. But I agree with you, if that's not the case.

 

[Scott Brady]

Well, my trusty little DI is still sick. I am starting to diagnose the problem, but could use some help along the way.

Original issue: Truck died in Flagstaff. Died once on the highway and then ran again. Died completely on the trail, north of Flag. Towed back to flag. Ordered fuel pump and replaced. Truck ran great all the way back to Prescott, a few days of driving and even a day on the trail.

New issue: Truck died while coasting down hill into Jerome. It started once and idled fine for 5-10 minutes. Started to drive back to Prescott, died under power after about 100 yards. Coasted into a parking spot. I purchased a new fuel filter and replaced. Truck idled for 10 minutes while packing tools and cleaning up. Drove around the corner and it died again.

Got a tow from friends to the top of Mingus mountain. Coasted down to the flats and tried to restart it. It started and ran for 15 miles! Died as I pulled into the shop parking lot. Will not start this morning. Does not sound like the fuel pump is running.

I am off to get a fuel pressure gauge and connect it to the fuel rail to assess. Might be a relay too. Need to find my RAVE cd

Will report back fuel pressure results in a bit...

 

[Pskhaat]

...truck died while coasting down hill into Jerome

That is no fun hill for which to have a vehicle die; sounds like you were able to brake safely away.

 

[dieselcruiserhead]

Sounds like an intermittent pump failure issue. Fuel pressure gauge is a good idea to diagnose. It could either be the new pump though doubtful, or possible a faulty oil pressure sender or possibly even an air leak somewhere in the fuel system. If it is a faulty oil pressure sender this could have also been the source of the original pump failure. Most modern vehicles are designed to kill the fuel pump in the event of a roll over accident which makes fuel issues susceptible to pressure sender and intermittent pressure sender failures.

good luck,
andre

 

[nwoods]

If it was an LR3, I'd say to check your gas cap, as such things have been known to happen. No idea about a D1 though

 

[R_Lefebvre]

Most modern vehicles are designed to kill the fuel pump in the event of a roll over accident which makes fuel issues susceptible to pressure sender and intermittent pressure sender failures.

That's interesting... and along that line of thinking, does the truck have an inertia sensor? Modern cars have one of those too, which kill the fuel pump. Maybe something flaky in that circuit.

 

[Antichrist]

I'd also check the connections at the pump. You may have inadvertantly damaged one during the work and it's making intermittent contact.

 

[cruiseroutfit]

Fuel pump relay failing or intermittent short in wiring?