21 replies to this topic

[smlobx]

We are in the process of spec'ing a new Hallmark Everest but I think this question would apply to any camper.

Our goal is to make the unit as self sufficient as possible.
We are adding PV panels, extra battery, 2 way fridge etc. to allow us to stay off the grid as much as possible.

We don't anticipate much 110v electrical use other than a laptop. When we questioned Matt he said they could install an inverter (for around $800-1000) but reccomended we buy something like this instead:

http://www.donrowe.c.../pst-300-12.htm

I'll be the first to admit my electrical ignorance so I am looking for advise from those of you that have some experience in this department.

Thanks!

[Happyjax]

I have heard good things about Samlex but have not owned one. The pure sine wave is a cleaner power version that the lesser expensive modified sine wave. It is better for electronics. This is a small inverter but should power your laptop and a few small items with no problem.

[iowahiker]

My understanding (not an expert) is "clean" power inversion is only important for non-battery powered electronics like desk top computers or display monitors (digital TV).  We carry a small inverter ($35) to charge our laptop and and cell phone.  We also purchased a 12 volt cell phone charger which is more efficient than using an inverter.  If you get a large inverter, then you need a larger battery pack to supply it and a larger fuse in the campers 12 volt system to supply it.  Our inverter has a 10 amp/12 volt fuse or 120 watts.  Our laptop charger has an output of 20 volts and 4 amps or 80 watts.  At startup (but not while charging), we slightly over amp our inverter so a 15 amp/12 volt inverter fuse would be better for us.  Check the labels on your device chargers, convert to watts (amps x volts), and pick an inverter which has larger watts (fuse amps x 12 volts) while not exceeding the amp fuse rating on the 12 volt camper circuit you will connect to.

[Lighthawk]

Consider leaving 110v behind!  Inverters are inefficient and from my limited knowledge either expensive or cheap.  

 

We picked up a 12v adapter for our laptop, and all phones, GPS, bluetooth speakers and camera battery chargers are also 12v.

I modified our Hawk to make a charging station two years ago and it's been perfect for us.  

 

FWC typically puts in one 12v outlet, usually on the face of the cabinet below the stove/sink, which doesn't really provide a platform to charge your device.   I opted to put our charging station on the opposite side of the camper and added a shelf where we can place all those hungry electronic devices to get their fix. 

[Casa Escarlata Robles Too]

I have a small 150w wired right at the battery. Easy to get to and use,Just charging lap top,camera and other battery's.

Also I use it to plug my coffee grinder in.It's just a bald grinder and works well.

Also I picked up a portable inverter that I can use in the truck cab or in the 12v outlet in the camper.

IMO I wouldn't spend a bunch of money on one. Wow $800/$1000 for that install!

Frank

[ntsqd]

I second Lighthawk, leave 120 VAC behind if you can. I tried and couldn't (at the time) so we have a couple small inverters. One that is mounted to run the navigation notebook and another loose one to charge camera batteries & occasionally run the string lights. Neither of these is a pure sine wave device and I've not had any issues in a couple of years. When it's time to replace the notebook I'll be revisiting this.

[wuck]

Generally speaking, a pure sine wave inverter is required for devices that use line transformers or AC motors. A square/modified sine inverter will cause these things to overheat and be noisy.

 

These days, nobody builds AC adapters for phones/laptops/etc with 60 Hz AC line transformers. They are all direct line switching supplies, there is a transformer involved but it is a high frequency, compact, lightweight design. How can you tell? Pick up an old AC adapter, compare the weight to your newest phone charger. The new one will weigh almost nothing. These type of adapters will usually operate fine off a modified sine inverter, with one caveat: Because of the waveform shape, the PEAK voltage output of a modified sine inverter will be larger than a pure sine inverter in order to keep the RMS output voltage at ~110 to 120 volts. This could cause problems with some adapters.

 

All that said, 12 volt adapters are pretty easy to find and way less expensive than a big pure sine inverter, I'll third the motion of going straight 12 volts.

[Bad Habit]

I opted out of a built on inverter on ours.  In some ways I do wish I had one built in but it's not a big deal.  We have a good portable one, ~350w I think that covers our needs.  The only small down side is it's awkward for battery chargers, etc as to how they plug in in some case (i.e. the camera battery charges are always direct plug in units that sit at strange angles to the plug).  My truck also has a built in ~150w inverter so I end up using that more times than not.  Having something built in is nice because it's one less thing to store, deal with but for the, not worth it in my opinion.

[PaulT]

Add me to the list of losing AC 120v.

Converting between AC & DC, in either direction, involves loss of energy as heat. Losing battery energy hard won from solar as heat in the warmer months is strong incentive to find alternatives to inverters.

This may be as simple as choosing as your next laptop one that can be run directly from 12 volts DC.

Paul

[smlobx]

Thanks for all the replies! I've really learned a lot.

I read Lighthawk's previous posts and that got me to searching and I discovered a few things I didn't know before.

1. Laptops and iPads etc actually run on 12 volt
2. Going from 12v>110v>12v results in a loss of efficiency at each stage.
3. The iPad's actually need a different (stronger) charger than iPhones.

So it sounds like we're going to join the 12v club and just get the proper plugs!
Thanks again...