Community Forums

Wanabee FTer · 12-02-2010, 10:39 AM

I think I will buy a good quality 300w inverter for this purpose.

wa8yxm · 12-02-2010, 10:42 AM

A lot of folks use an inverter and plug the power brick in.... I use a DC/DC converter I got at Radio Shack, There are others you can get from any good computer place (IE: Micro Center) or Igo.com.

The best inverters I have seen are around 90% peak effiency
The best power bricks are likewise 90% Giving a final effiency of 81% or less.

The DC/DC converter.. again, about 90 percent

NOTE Efficiency on any converter drops as the load drops and since the DC/DC converters are operating closer to design load.. They are way better than Inverter then converter systems.

WOODYDEL · 12-02-2010, 06:19 PM

Whatever brand pc laptop you have, the easiest way is to simply charge it and use it. Head on down to a local pc store and buy the power supply which plugs into a cigarette lighter WITHOUT an inverter. I see on your site that you sit outside using your computer. Charge doesn't last long enough? Get a bigger battery with more cells. 12 cell battery packs last long enough for you to get a square A. Bottom line is laptops are by design efficient users of electricity and charging those batteries are not an impact on your battery reserves. They do not have to be plugged in to operate so why do it?

WheelingIt · 12-02-2010, 07:03 PM

Well...thanks everyone for the replies. I see a couple of options in here based on what I'm looking for so appreciate that. I like the option of powering our laptops off the 12V simply to avoid always turning on the inverter, so thanks for the options there.

Now we have been reading alot on Solar (incl. the threads here) and are pretty fixed on what we want to do on a macro level. I do understand (to a decent extent) the various power losses and draws, but I like the idea of maximizing as much as possible, both for the fun of it as well as the functionality. Thanks again, folks!

JeepTJ5 · 12-06-2010, 12:04 AM

If you look on Ebay you can find "universal" 12volt laptop charger/converters for much less than the $100 or so at places like Best Buy. I have a couple of them, one in my off-road jeep and all work great. They are adjustable to the input voltage of your laptop and come with numerous tips to fit the laptop connector. I got all of mine for less than $30 each.

I like to use the 12V unit when I'm dry camping because I use less power from the RV's batteries - and there's only one voltage conversion.

Don

bldrbob · 12-06-2010, 07:20 AM

I went for the small inverter instead of the 12 volt cord. That way I can use it for other things like charging my cordless tools and running other small electric appliances.
BOB

Dave Rickey · 12-08-2010, 12:52 AM

The risk of plugging directly into your "12V" is that it usually *isn't* 12V, it's generally a bit more and can be as high as 14.5V. Your laptop assumes it's going to get a steady, regulated 12V input, and depending on the design it may do just fine, or it may do very badly (like "my laptop battery is exploding in flames" badly).

A regulated 12V universal adapter is a better bet, or if your laptop manufacturer sells a automotive version of their power brick (Dell, for example), get that.

On LEDs: For most 120V applications, compact fluorescent bulbs are better. LED's at home are only justified for bulbs you're never going to turn off (I have three fixtures using them, all the others are CF). But there's no such thing as 12V CF's, while there are LED's that run natively on 12V, and plug right into the automotive sockets used in RV's. They are 8-10 times as efficient per lumen as incandescents, they don't generate nearly as much waste heat, and they last 20 times as long. For 12V, it's a no-brainer to use LED's everywhere you can.

I'm not going to replace all the bulbs in my rig at once, just as the incandescents burn out. But the most used interior lights have already been replaced.

As for color: You can buy "warm white" LED's that look more like incandescents or natural sunlight. They don't have to look bluish (actually, our eyes are tuned for sunlight and true white light looks blue).

--Dave

WheelingIt · 12-09-2010, 09:58 AM

Dave - thanks! That was exactly my worry...the fact that the 12V is not *really* 12V, but a variation based on the state of the batteries and what they're putting out. And yes, we've been looking at the "warm LEDs"...seem to be some good options out there. I'm going to buy several and try them out to see what my eyes like best.

leadman · 12-20-2010, 08:31 PM

We boondock alot and I added LEDs and kept the incandescants also. I measured the draw of 3 incandescants and it was about 4.5 amps, 4 of the LEDs was about .5amps.
I also added solar from Harbor Freight that has a controller with outputs for USB, 3,6,9, and 2 different style 12 volt outputs. We use this to charge many of our devices.

The LED lights have improved significantly recently and if you search can find them at a decent price. I also was at PEP BOYS automotive today and they have added a line of automotive LEDs.

wa8yxm · 12-21-2010, 01:39 AM

Micro Center at one time had a "Universial" Laptop power supply thing, would take either 12vdc or 120vdc in and put out assorted voltages. Like the 16 this laptop eats. FIFTY BUCKS.. Wish I'd bought one.

I had, however, at the time, two other DC-DC converters.

As for the "Loss is insignificant" it's about 10% So if your laptop's power supply is eating 50 watts. your inverter eats at least 55, and odds are the laptop itself is only getting 45.

With the DC to DC converter.. You'd only be eating the 50... Saving 10%. In truth, in the larger scheme of things 5 watts is not much.. But.. it's still a savings. I'm running on a DC-DC as I type this.

heritage2006 · 01-30-2011, 06:12 PM

Was drawn to this thread as my only problem with boondocking is keeping my computer charged. I've read all the comments and gotta tell you I now have a headache.

My poor old brain simply won't absorb it all. I hate turning on the generator but have no choice. I'm on the computer A LOT. But the battery will only give me less than 2 hours and then the generator has to go on to re-charge it.

I have a small (200W) inverter that I used to plug it in to the cigarette lighter to keep my computer charged - but ended up with a dead engine battery. Obviously I left it on for too long ??!!

I'm new to fulltiming and there's lot to learn. I don't even know what an inverter or converter is !!! I have two coach batteries.

Any help in very simplified terms is appreciate. LOL

TXiceman · 01-30-2011, 07:56 PM

Any inverter has an efficiency loss and there fro is not as efficient as going direct from 12 VDC to 12 VDC. I use a 12 VDC adapter in the power plug in my truck to run the netbook in GPS mode and it works fine.

Ken

Dave Rickey · 01-31-2011, 12:22 AM

Quote:

Originally Posted by heritage2006

Was drawn to this thread as my only problem with boondocking is keeping my computer charged. I've read all the comments and gotta tell you I now have a headache.

My poor old brain simply won't absorb it all. I hate turning on the generator but have no choice. I'm on the computer A LOT. But the battery will only give me less than 2 hours and then the generator has to go on to re-charge it.

I have a small (200W) inverter that I used to plug it in to the cigarette lighter to keep my computer charged - but ended up with a dead engine battery. Obviously I left it on for too long ??!!

I'm new to fulltiming and there's lot to learn. I don't even know what an inverter or converter is !!! I have two coach batteries.

Any help in very simplified terms is appreciate. LOL

Somewhere in the rear you should have 12V sockets, like the one for your cigarette lighter but without the lighter widget (they may have a plastic cover over them). Plugging your inverter into them should at least let you run from the coach batteries rather than killing your engine battery. They'll probably last considerably better, as well, the engine battery is designed to put out a lot of current fast, rather than a trickle for a long time.

--Dave

pa0gri · 01-31-2011, 12:43 AM

Laptop users using 12 volts (from the coach batteries, do not use the engine 12 volt unless traveling).
Most laptops have a supply of larger that 12 volt comming from the net (110 volts) supply.
If you want to use a 12 to "12" volt converter read what the net supply gives and adjust the 12 to 12 volt inverter to that output, often 19 volts.
Most DELL chargers have a 3 wire connector and a chip in the charger telling the laptop what kind they are. If not genuin, it will not charge the battery but allow running the laptop.
I always carry the original charger and a small 150 watt converter 12 to 110 volt
where I connect my charger to. That way I know it charges too.
When on shore power I just plug in the charger into the normal outlet.
My experience is that not all 12 to 110 (or 220 - I live in Europe) can handle a laptop charger's load and trip or make funny noises. The one I found does a great job and I carry it with me when I travel with my Tioga trought the USA. (AK)

-- Gerard