Worried about keeping electronics charged... power inverter?

We are renting a 30 ft class C RV from Cruise America next month and are going on a long trip. I'd like to avoid using the generator as much as possible and don't know how often we'll be plugged into shore power so I'm a little worried about keeping our electronics charged (we're talking phones, GPS, camera battery, laptop, etc). Since I'll have power from the cig lighter any time I'm driving, I've started looking into power inverters but I know nothing about them. I'm reading reviews on Amazon, but I thought I'd ask the experts here. Does anyone have any suggestions? Thanks!

Some of those things can probably be charged from a USB (5V output) connection and many such plugins are readily available and can be plugged into a cigarette lighter or 12V (similar) connection available in many modern vehicles. The possible exceptions may be the laptop and portable (handheld) GPS units. These may likely require an inverter and there are many of these available, an .8-1k output unit would be adequate but make sure you are underway when using it to avoid killing the engine battery.

Generally Laptop computers need some serious voltage, as much as 20 or more DC, you can get a DC/DC converter at most Major Computer stores, and occasionally (though over priced) at Radio Shack.  (Micro Center is a decent vendor)

Phones, Tablets and the like often run on USB,, Big Lots sells a 12 volt to USB adapter that is shaped like the Letter Y,  I have one in my car.. I have several otyhers lying about You can pick up these most anywhere.. I like one that has at least 2 amps total out though,  1 amp WILL NOT maintain my phone in GPS mode screen on

If it says 30 miles to next turn, I can kill the screen,, it will still say "Turn right in a quarter mile".

You may be worring about the wrong thing. Even the interior lights can put as large a drain on the coach batteries as the items you listed.  The furnace and refrigerator/water heater/propane detector and other things that may be on full time are even larger loads. I'd suggest you bite the bullet and run the generator at least 2-3 hours a day when not at a park or traveling(when boondocking).

Ernie

To tag on to this discussion I am not new to RVing but have been out of practice for about a year so feeling like I am starting anew.  My concern is similar in that I have totally forgotten how I keep the house battries charged.  I have a 2005 County Coach and it has all of the basics...my question is how do I know when driving that the house battries are being charged.  It is my understanding that when driving the house battries will be charged through the inverter. First is that correct?

Does the electrical indicator panel I have in the coach  tell me the house batteries are being charged and is it a simple on off switch on the indicator panel the shows the inverter is on? Or is in on all the time if I have the house battery switch on.  Simply concerned while driving that I am charging the house batteries.  Trying to get back in the swing of  RVing. This relearning  process is frustrating to be sure.  :-\

Thanks for any help.

Chuck

Chuck, I'm not familiar with Country Coaches but to the best of my knowledge when driving down the road the house batteries are charged directly off the engine alternator. The only time the inverter/charger comes into play is when you're plugged into shore power.

Plugged into shore power the charger part of the inverter/charger charges the house batteries.

When you're boondocking the inverter part of the inverter/charger changes 12VDC from the batteries into 120VAC.

You'll have to have someone with a Country Coach explain how the electrical indicator panel works. I haven't a clue.

Hi 1osfan, a cigarette to multi-USB charging adapter will work for most of your list.  For the laptop, a 200 watt inverter should suffice. You should be able to look at the laptop or power chord to confirm.  A pure sine wave is the best and will work with most any device. A modified sine wave will probably work fine for your laptop.

Are you certain the RV does not already have an inverter installed?

1osfan-Why don't you want to run the generator?

You make want to get a couple of extended batteries. They will help keep things running, then charge everything when plugged in or running the generator.

TheNewhalls said:

1osfan-Why don't you want to run the generator?

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Maybe because of the noise, smell, and expense.

Maybe because of the noise, smell, and expense.

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YAY!! It warms my heart to know that some potential neighbors think similarly to me about such things.

howellad:

Allow me to define a couple terms that are frequently confused.

A  CONVERTER  takes 120V AC and converts it to 12VDC to charge batteries and run 12VDC "stuff" when 120VAC is available.

An  INVERTER  takes 12VDC and inverts the current to 120VAC, so the batteries can supply 120VAC power when not connected to shore or generator power. 

Some RVs have one or the other.  Some have both.  Some have both in one unit.

When traveling, neither of these are needed,  as the 12VDC from the alternator is fed directly to the house batteries, assuming shut off switches allow.

kdbgoat said:

You make want to get a couple of extended batteries. They will help keep things running, then charge everything when plugged in or running the generator.

Maybe because of the noise, smell, and expense.

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That's the trifecta! Because we are renting the RV, there is a $3.50/hr charge to run the generator. I figure we'll need to run it at times, but I'd like to run it as little as possible because we're renting the RV for more than 3 weeks - the hours will add up.  Add to that the noise and smell and I'd like to be a good of a neighbor as I can be.

JFNM said:

Hi 1osfan, a cigarette to multi-USB charging adapter will work for most of your list.  For the laptop, a 200 watt inverter should suffice. You should be able to look at the laptop or power chord to confirm.  A pure sine wave is the best and will work with most any device. A modified sine wave will probably work fine for your laptop.

Are you certain the RV does not already have an inverter installed?

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Thank you! This is exactly what I was looking at. I'm amazed at the price difference between the pure and modified sine wave types. I can get a 300 W on amazon that gets good reviews for $30 but the cheapest pure one is $100.

No, I'm not certain the RV doesn't have one but I was told there are three cigarette outlets so I figured there wasn't both.

You probably cannot get 300W of power from any cigarette lighter or utility socket. They are seldom rated for more than 15A and 10A is more typical. That's 120W-180W max. Even a steady 120w is likely to overheat it, even if the fuse doesn't blow. And an inverter typically draws 5-10% more power from the batery than it produces in 120v output, so your available power is probably going to be around 100W.

You may want to wire the inverter direct to the  battery with good quality clip leads and some fairly heavy wire, maybe 14 ga or 12 ga automotive primary wire.

Gary RV Roamer said:

You probably cannot get 300W of power from any cigarette lighter or utility socket. They are seldom rated for more than 15A and 10A is more typical. That's 120W-180W max. Even a steady 120w is likely to overheat it, even if the fuse doesn't blow. And an inverter typically draws 5-10% more power from the batery than it produces in 120v output, so your available power is probably going to be around 100W.

You may want to wire the inverter direct to the  battery with good quality clip leads and some fairly heavy wire, maybe 14 ga or 12 ga automotive primary wire.

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I am completely illiterate when it comes to electricity and power. We have a couple of phones with USB plugs, a couple of rechargeable camera batteries that plug into an outlet, and a laptop. I don't expect to need to charge the camera batteries often and I doubt I'll charge the laptop often but I will charge the phones using the USB regularly. When you talk about not being able to get 300 W or about blowing fuses, are you saying this type of inverter won't do what I need it to?

Thanks again for your help!

A cigarette lighter socket can only deliver around 200 watts.  Draw more than that and you'll blow the fuse.

Look at the charging brick on your laptop and see how much power it uses.  It's Input Power will be printed in small type on the back, either in Watts or Volts and Amps.

If it's Volts and Amps, multiply them together to get Watts. For example, 120 volts x 0.5 amps = 60 watts.

Add about 20 watts if you want to charge your camera batteries at the same time as the computer.  Get an inexpensive inverter that plugs into a cigarette lighter and is rated at or above that power.  Use a cube tap or plugstrip if you need more outlets.  You don't have to spend more than about $30 for the inverter.

For your phones, get a dual, triple, or whatever cigarette lighter to USB multiport adapter and charge them from it. 

The important specification is how much current the adapter delivers TO EACH OUTLET.

Your phones may be happy charging from a 1 amp outlet, but larger devices like an iPad, a tablet or the GPS could need up to 2.4 amps each to charge.

The prices on high power multi-port adapters are low enough I wouldn't even bother using the lower rated ones.  There's nothing wrong with plugging a low current device into a higher current outlet.

For example, here's a dual port charger that delivers up to 2.4 amps to each port.

Here's another good one that delivers 2.4 amps to each of it's 4 outlets.

When you talk about not being able to get 300 W or about blowing fuses, are you saying this type of inverter won't do what I need it to?

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No. I'm saying the 12v outlet cannot deliver all the power needed by inverters rated for more than 180W.  You can buy a higher rated one and it will still work fine up to some point, but if you plug in too many things at once, the power needed will exceed what the outlet can handle and a fuse will probably blow. The phone and camera battery chargers won't be an issue, but a laptop will draw more power. Mine is about 100 watts.

I was merely cautioning you to avoid getting carried away and thinking you can run lots of things once you get that inverter. Just as with awall outlet at home, there is a limit on how much power you can get from one.

I picked up an inexpemsive inverter at Costco several years ago. From the.cigarette lighter plug, it will supply "up to" 150 watts,  but wired to the battery (or connected with clamps) it will provide "up to" 400 watts.

When travelling/short-term boondoxking, we just use the 12v outlet to charge personal electronics.