Solar set up beginnings

(Lloyd ) #1

Just acquired this Sierra Wave 30 W panel for 60 bucks, unused off CL, back here in south central penna. Newrly 300 bucks brand new on their website. Never even been or if box. Just got to get a 12v battery and inverter and it’ll be a good set up for my place. Should be a seeet setup for laptop and potentially lights at some point off of battery charge.


It will be interesting to see what they actually put out. 30 watts isn’t very much in laptop world as most chargers pull between 60 and 100 watts, and lots of times they don’t like the mod sine waves of cheap inverters. It’s definitely enough juice for a couple hours a day of use though, if your battery is properly sized for the load.

One thing to be aware of is that inverter-laptop/phone chargers sometimes don’t get along well. I recommend running the laptop battery dead, charging it on wall current, and timing it, then recharging it from dead off the inverter. If it takes more than 10% longer or gets excessively hot, you’ll need a different inverter, possibly a pure sine one.

(Lloyd ) #3

Okay good info. Since inversions and adaptations of electrodes etc is very foreign and hard to decipher for me, I appreciate the info. So your calling it a sine inverter? Which means what


The electricity that comes out of the wall makes a sine wave. It’s a smooth up and down pattern as the alternating current alternates between positive and negative voltages. There are “pure sine” inverters that output electricity that is extremely close to what comes out of the wall.

Most cheap inverters are “mod-sine”. In these, the transitions between positive and negative voltages are made in little steps. Since battery chargers and pulse width modulated power supplies also use steps, sometimes, depending upon the electronics designs of the components , a situation occurs where the inverter is between steps when the charger/power supply is needing current to produce it’s step. This raises the voltage in an attempt to flow the needed current but just ends up heating up the inverter and power supply.

If you can afford a pure sine inverter, I definitely recommend them.

(Lloyd ) #5

Man that is great information I am glad I made his thread. So good to know. I am able to make the funds for this and will spend the extra for a good inverter.

(Andrew) #6

At the same time, plenty of people have been running laptops off of regular inverters for years with no issues.

But yeah, most new-ish low-power laptops draw 45-60W. We have 200W of solar panel, and it is often not enough to run the laptop for more than a couple hours a day.

(Andrew) #7

FWIW, we have a $30 inverter from Amazon, and haven’t had any issues. Our neighbors have been running computers and satellite internet off similar cheap-o inverters for over a decade. Not saying pure sine wave inverters aren’t a good idea, but they’re not necessary.

Ideally, running DC-DC is cleaner to begin with. You can get a 12V “car adapter” for most laptops, which cuts the AC out of the loop. Not only is there less noise in the conversion, it’s also more efficient. Inverters always involve some power overhead. DC power supplies for laptops usually run around $20.

(Andrew) #8

Here’s how I’m currently running…

One plug (AC) comes off the inverter/generator. The other (DC) comes straight off the 12V battery bank. I just switch plugs when the sun goes away or the batteries get low. Then the internal laptop battery smooths out transitions until the sun comes back or I run the generator or switch on the inverter or whatever.

(Lloyd ) #9

Hmm alright. I guess though I definitely need an inverter tha hooks to 12v I learned that today just by looking at them. May ditch laptop idea and stick with typewriter and a tablet or two for electronic entertainment etc


Have you checked the efficiency? That could be why the 200w of panel isn’t keeping up. I’d read about it back in the 90’s but ignored it until I had a camera charger and inverter burn up. The inverter seemed to run everything else fine but that particular combo was just a fire waiting to happen. I tried it twice thanks to walmart’s swap the guts in the parking lot warranty policy.

I also had two different gateway chargers start melting themselves attempting to run them off a schumaker 400watt mod sine. It kind of worked for a while but they got hotter and hotter.

Now that I know why they do it, I always recommend a quick test. It’s just not worth the lost/wasted energy, or the potential fire.

(Lloyd ) #11

used a little car adapter inverter thing for my phone and tablet yesterday. Probably not most efficient setup but it wasn’t being used and I haven’t acquired other goods yet.