Generators and Inverters

[MikeT]

Thanks everyone for the valuable advice.  I should have paid more attention in that circuits class 20 years ago!  So this all started with the realization that the 12v car battery that was supplied with my trailer was not going to cut it when it died after 2-3 days of camping.  After reading all of the posts on the old site and this one it was clear that 2-6volt GC batteries was the way to go.  That and a solar panel to top things up.  Charlie, I realized the 2/0 welding cable to join the batteries was overkill, but that's what came with it so I didn't argue.

I liked travelling with this trailer so much I decided I could do my work on the road.  I really thought that I could simply pack up my laptop, portable drives and head out.  I did try to locate a dc power supply for my pc but no luck.  Charlie, I have an HP Envy TS 17 Notebook.  Hopefully, the picture I took is attached here.  If not the output is 19.5 V  6.15A.  The power supply also states "wide range input 120W".  If you know of a compatible dc-dc inverter it would be greatly appreciated.
 
This is when I thought that an ac to dc inverter would do the trick.  I figured that if I could drive an 18 hole course on a golf cart there should be no problem running my laptop.  Obviously, I was wrong.  So, in summary, I really just want to run my laptop and hard drives.  FYI, the programs I run are very CPU intensive and do an incredible amount of disk I/O. Imagery is read from one hard drive, processed and written to the second hard drive.

When I thought I could do everything I started thinking about my fridge issue.  I have always been of the understanding that it was a strict no to run the propane while driving.  If this is not the case I will fire it up before I leave.  I have always cooled the fridge prior to departure (usually do this a couple days prior).

Thanks David for the calculations.  I will work through the numbers and get a better understanding of this and rethink the batteries and solar panel.  Another glitch will be the fact that the sun rarely shines in Haida Gwaii!!

I did work from the trailer last year in Fort Stevens, OR but we had power there.  Only problem was that Linda crushed the cord when she caught it in between the fold down frame of the bed.  Aluminum really does conduct electricity well! I guess I'll be a newbie for a while yet.

Cheers

Mike

[charliem]

Mike,

Your laptop is very similar to my Dell XPS L502. It comes with the same 19.5V @ 6+A adapter but runs fine with the 90W car charger. The laptop gives me a warning that it has detected a lower powered adapter but continues chugging along without complaint. It may require higher current during high workload periods like bootup, but that just means it dips into its internal battery for those peaks. On average it maintains the battery just fine. For the price it's worth a shot but make sure the connector is compatible.  You should add a line directly from an unused fuse slot on the converter panel using #12 or #10 AWG wire. The PWR+ adapter can be used with a cigarette lighter plug.

https://www.amazon.com/Pavilion-TouchSmart-HP-Envy-15-Slatebook-14-HP-Turbo-14-15/dp/B003LZK89Y/ref=sr_1_8?ie=UTF8&qid=1492778029&sr=8-8&keywords=laptop+car+charger

If you're uncomfortable with that approach you could go to a small true sine inverter. The Morningstar 300W unit gets very good reviews by knowledgeable RVers and it has a large heatsink so it doesn't have an annoying fan. The Morningstar should be wired directly to the battery with #8 or larger wire and a 30A fuse. Anderson PowerPole connectors are nice if you want that convenience. 

https://www.solar-electric.com/morningstar-si-300-115v-ul-inverter.html

https://www.amazon.com/Morningstar-Morningstar-SI-300-115V-UL/dp/B007IAFN16/ref=sr_1_1?ie=UTF8&qid=1492778747&sr=8-1&keywords=morningstar+inverter

https://powerwerx.com/anderson-power-powerpole-sb-connectors?utm_source=google&utm_medium=cpc&utm_term={keyword_text}&utm_campaign=Anderson+-+Exact&utm_adgroup=Powerpole+Connectors&mkwid=socT3NeWY_dc&pcrid=105083329682&plc=&pkw=power%20pole%20connectors&pmt|=e&gclid=CMr3qNTQtdMCFQ6NaQodqIwPzg

Your 7cf Dometic has a frame heater that draws ½ Amp 24/7 from the 12V battery. Another bad idea from Dometic. It must be disabled when boondocking. Check the archives on this forum for how to make this mod. Travelling with the fridge on propane is no problem. Every RV with a fridge over 4cf does it. Today's propane bottles have flow limiting safety shutoff valves the take care of emergency conditions.

[DavidM]

Several years ago I used a laptop as the gps/chartplotter on my boat. At first I powered the laptop with a small, 150 watt inverter that plugged in to the cigarette lighter outlet. It used 4-5 amps at 12V. Then I bought a cheap, Chinese made 12V to 20V DC converter to power the laptop directly. It used 5 amps at 12V. So I concluded that the inefficiencies of that DC converter were more than the inefficiencies of the inverter and the laptop brick's DC power supply.

This was one example and admittedly using a cheap Chinese DC converter, which ultimately failed and I went back to the inverter. YMMV.

David

[charliem]

Chinese=cheap=inefficient=unreliable=buy again=maybe not so cheap!

YGWYPF

[MikeT]

Thanks again for the advice and links, I will check them out later today.  I will disable the fridge frame heater this weekend, I had seen this before and wondered how you guys ever knew it was in play.  Thank goodness for these forums and the people who take the time to contribute.  I do hope that one day I will be able to provide advice!

Cheers

Mike   

[DavidM]

Hey, what can I say. It was really cheap -;).

David

[Capt J-rod]

Remember your laws of electricity.... Volts X Amps = Watts..... Watts / Volts = Amps... Yamaha makes a 2500w Generator that is enough to run the A/C. 2000 watts / 120 volts = 16.66 amps. This is why the Honda 2000eu comes up short. 1000/120= 8.333. This is why that cute little 1000eu Honda won't run anything. 3000w/120=25amps. This is why a 3000w generator hits the sweet spot for camping. 2500w gives use solid 20amp circuit. It will handle the A/C but nothing else. As far as other brands of generators, the Honda has the cleanest sine wave of all the generators that I'v seen. The A/C doesn't care, but your laptop and sensitive electronics will not like dirty electricity.

[Pinstriper]

Woot is selling the WEN 2k for $399 while they last.

https://tools.woot.com/offers/wen-56200i-2000-watt-inverter-generator-1

[catmanriff]

thanks. I like mine, would like another for parallel possibilities.

[planemaker]

Just bought a Hyundai HY3200 Inverter Generator at the Toronto Spring RV Show this weekend.  Anyone have any experience with a Hyundai generator product?

Paid $999 for it, on a power sale promotion.  I will let everyone know our thoughts when we use it this spring!

[Merlin]

Looking forward the your report!  Especially on noise.