11 replies to this topic

[DirtyDog]

Star 152 came up with this spreadsheet to calculate amp use per day. Pretty cool! The file uses default values for his camper - update as needed.

Amps Per Day Spreadsheet

[Star152]

OK thanks DD. the values in red you can change. the equipment values if you give to me I can change. or you can do the calulations your self.....

[benburnett]

Great chart. One thing to keep in mind though is that some of the ratings are the start draw of the unit and not the running draw. So actual amp time will be slightly longer.

[Star152]

Ben again your knowlege is always welcome. I made this chart because I am a lay person and all the information that I got was above my head...... I hope this is something that anyone can use to give a ball park figure of AMPS used......IMO.

[benburnett]

Star,

Your chart is great. I will actually point some folks to it so that they can get an idea of draw. I get questions all the time that the chart will cover for them.

Most of it is over my head also. I just remember in talking to a few of the vendors about amp draw of the products that the listed amp draw was nomally a start up draw and that the units used less power while running that what was stated.

I know that I can use a camper for more than 3 days sitting still and still have plenty of battery left, so that works for me.

[EdoHart]

I'm looking seriously at solar systems, so I modified Star 152's spreadsheet to allow me to calculate the wattage rating of a solar panel I need to keep my batteries topped off. I changed the format a little to make it easier for me to read: slightly different column headings, added and deleted appliances, and I replaced the amperage values with actual numbers I measured in my Hawk. I made the above changes before I thought to post them here, otherwise I would have kept it in the same format except for my additions. Although I don't camp with a blender, I kept that in there because it seems like a great idea. :thumb: Also, my amp values are for the running state, not for the start up.

At the bottom, I added 4 rows which I think are pretty self explanatory.

Attached Files

•  Solar Calculation.zip   2.84K   878 downloads

[Lighthawk]

Thanks everyone for helping me get a better handle on our electrical needs.

 

I'm in the beginning stages of designing/executing a charging center for our camper; with multiple 12v and USB ports.

I'm debating whether to add an inverter.   Complete project will include a bluetooth sound system, and (future) solar supply.

[craig333]

I'm planning on adding a second inverter some time. I'd like to have  small true sine wave inverter for those things that aren't 12v, laptop and certain other chargers that aren't happy without it.

[MarkBC]

.... I'd like to have  small true sine wave inverter for those things that aren't 12v, laptop and certain other chargers that aren't happy without it.

 

Do laptops really care if it's "true sine wave"?

Maybe they do...but I wonder why it would matter since laptop chargers process the AC through a brick that converts it to whatever voltage DC the laptop needs.  The laptop never sees the AC directly.

 

So, I don't really know -- not an electrical engineer -- I'm just wondering why the purity of the AC would matter after being rectified to DC. 

 

(I haven't experimented with this personally in a long time -- I have a 12-volt charger for my laptop)

[craig333]

I'm just going on info that says chargers, especially small ones are particular. I mean, I read that on the internet, it must be true right?