Too much or too little Solar?

[Canine]

Many of those CPAPs run off DC and AC. You lose energy when converting from AC to DC or visa versa. If your CPAP is DC capable, plug it directly to DC and that will help with efficiency.

If you find you don't need your inverter on all the time, you may want to only hook it up when you need it as it has a phantom draw. Or if you do need one all the time, perhaps use a smaller one as it will have a smaller phantom draw then hook up a large one when larger electrical usage is demanded. I read about a guy doing this, but have never done it first hand, so I can't speak authoritatively on this. It's an idea worth thinking about.

While I prefer using a BluRay, I have become accustomed to watching old fashioned DVD's on my laptop. It is much more efficient. Losing screen size and high definition is the price I pay for being miserly with my electricity. It took me a while to get to that point and enjoy it. I really wanted to smoosh everything I had in my previous lifestyle into my new lifestyle. Boy, did I try! It just didn't work that way for this poor boy. Interestingly, while I appreciate the view of true high definition, I miss it only a little. I much more enjoy having the lifestyle I have now and it's getting better.

 

[AuricTech]

A couple of minor thoughts:

1. Keep in mind that Amps and Watts are rates of power draw. The proper units for discussing how much power a given device uses over a period of time are Amp*hours (Amps times hours used) and Watt*hours (Watts times hours used). It will help you keep this straight if you remember that your electric utility bills you for each Kilowatt*hour you use.

2. When you're off-grid, have you considered replacing the 36-Watt fan with one or two USB-powered fans, each of which draws only 2.5 Watts (500 Milliamps times 5 Volts)?

 

[akrvbob]

With 570 watts I never have to use my Honda 2000 generator. I'm actually considering selling it since I can't justify having it. the only times it ever runs is when friends borrow it.

I think you have a really good plan! With 630 watts of solar you should never have to use your generator except for wanting the AC or long times of bad weather.

People who try to do too much off the alternator can put a strain on it and cause it to wear and fail prematurely. But with that much solar I can't imagine that happening. I'd go ahead and connect to the alternator just in case of bad weather.

I'd probably suggest another set of golf carts. Sternwake will tell you you may not be able to put a fast enough charge on them for their best health. And he is 100% right! But as much as you are going to drive I think you'll be fine. Plus, you aren't really thinking long term, just this one long trip. In other words, giving them their best they will last 6 years and maybe not giving them there best they will last 5 years. Do you really care?

I think I'd rather have the extra set of batteries to get me through rainy days and give up that extra year. Plus, giving them their best is a very time consuming job, I don't think you are going to want to do that on this trip--you'll be too busy having fun! Of course you have to pay for them up-front and find a home for them, plus its another 120 pounds. Your van will be very heavy so that's something to consider.

You are going to be very happy with your solar system!!
Bob

 

[rvwandering]

Matt, while I'm a complete advocate of solar power and your plan for a 600 watt system is very good I don't think that you really need it. Most of your time will be spent in parks with full hookups and when you're in national parks without electricity you'll be driving enough to charge your house batteries. Most likely house two batteries will be enough if you get a more energy efficient computer. I hate to see you spending money that you could use to travel when you could manage fine with a generator, park electricity and charging while driving. What you have planned is excellent for extended boondocking. If your trip goes well and you decide that this is a workable life you and your wife then go for a big solar system.

 

[Matt71]

I was thinking the same thing. Originally I didn't think we'd be able to use the alternator.
We may not have a choice because our starting expenses are almost a third of the annual budget right now. We might dump the generator instead and pick one up later if we really need it.

Also, keep in mind that the solar panels are 18.5v not 12v, so in the end I think it comes out closer to a 410W system

 

[akrvbob]

Get a MPPT controller and you'll get all 600 watts.
Bob

 

[Matt71]

Planning to get a Renogy® Tracer 4210 40 Amp MPPT Charge Controller

 

[akrvbob]

Then you'll get all 600 watts into the battery. That's what MPPT does, it steps down the voltage and ups the amps. A PWM just throws away the volts and their amps so you would only get the 400.

Bob

 

[Matt71]

Thanks Bob, that gives me quite a few extra amps to work with. Quite certain I won't need the generator now

 

[akrvbob]

I have 570 watts and I'm ready to sell my Honda 2000 because I never use it except to exercise it. However, if I remember right you had some very high draw draw items that we thought wouldn't be realistic on solar. Do I remember wrong or did that change?

Forgive me for not remembering, I love these long threads but by the end you don't remember the original question!

Bob

 

[Matt71]

This is what I'm looking at right now
https://docs.google.com/spreadsheet...lWhpJ4WNEuT1wwpevMw07tfLM/edit#gid=1283376365

The air Conditioner is the only thing that we'd really need the generator for.
My current calculations put us at 218Amp per day and the solar should pull in from 158Amps to 263 Amps per 5 hour day assuming good weather.

I dropped the projector idea because there was no room for a screen after putting in additional storage. Going to use my 24" monitor. Not sure I got the amps right on that. The tag on the back says 1.5A, but the specs say it has a max draw of 49 Watts which is only about .41A @ 120V

 

[jimindenver]

We have left the generator home for two years. I only do it because we can cherry pick the times we go camping and let me tell you, I find nothing appealing about being cooped up in a small box during the monsoon season and the rig can't handle extended time below freezing so winter's out too. I would take it if I thought it was going to be hot enough to need the big AC or we had to be out in a bad condition. It worth the piece of mind if nothing else.

You on the other hand need to set up to deal with what ever you think life will throw at you. Solar doesn't play well with over cast or shady conditions. Have your controller go out and the best can, you will have no charging at all. I consider the truck as a back up in a last case scenario.

 

[akrvbob]

The bottom line is you aren't going to have room for a genny, even a Honda 1000. 600 watts is a lot of solar and I think it will have to do.

I think the key thing is that as a vandweller you have to embrace more discomfort and inconvenience in your life. You need to monitor the weather and if a storm is coming you need to go into conservation mode ad do without some things. If it lasts for awhile, you go into rationing mode. If it drags on-and-on, you go into emergency mode.

Being truly, deeply alive means embracing and welcoming hardship. Only the dead never suffer! By chasing a life without any suffering, we are chasing death and rejecting life.

I absolutely guarantee you that in 5 years you will look back with the biggest smiles and most joy at the hard times!! That's when you were most vibrantly alive!
Bob

 

[wagoneer]

Holy Sh##t. imac going mobile?? Mac mini perhaps. Trim some fat buddy or haul a large battery bank around.
Lotta free advice here and take it for what it's costing.....0 love and out Wagoneer

 

[highdesertranger]

great post bob(#93). I totally agree. highdesertranger

 

[Wabbit]

...great post bob(#93). I totally agree...

Ditto!

 

[Matt71]

Holy Sh##t. imac going mobile?? Mac mini perhaps. Trim some fat buddy or haul a large battery bank around.
Lotta free advice here and take it for what it's costing.....0 love and out Wagoneer

I cut the iMac and will go with a macbook pro