Reddit reviews Sunforce 7 Amp Charge Controller

No

60 Watt Panel

Charge Controller

Battery

Light

12v Cig Adapter

This RENOGY 100w Monocrystalline Photovoltaic Solar Panel on Amazon is a much, much better deal. Combine it with a Sunforce 7 Amp Charge Controller, deep cycle battery and a small power inverter for a complete system.

The battery is a good one but you don't want to skimp on that part. If you want to expand to 4 of those solar panels you need to upgrade to a Sunforce 30 Amp Solar Charge Controller. I would not go for too much larger of an inverter unless you decide to enlarge the battery bank. It's much too easy to overtax batteries.

For the controller, a quick amazon search comes up with several models, this being one of them.

The panels can be a bit trickier to find at reasonable prices, but here's one.

If 15W isn't enough to keep the battery going with all your accessories, Harbor freight sells a full-on 45W kit for about $170. However it's probably a lot more than you'd really need.

You can get panels in less than 15W, but it needs to be able to charge the battery up durring it's (we'll assume here) 10 hours of usable light.
You'll probably want to do some actual math on how much you're using. Your typical lead acid battery varries from 12-14.2V, and could go up to 17+ when it's charging (i'm not exactly sure on the circuitry inside the charge controllers). So make sure whatever 5V regulator you're using can keep up with your current draw.

Regular car batteries are made to have a lot of cranking power, and then stay on a trickle charge once the alternator gets going. Running the battery voltage down each night and charging it daily will kill the life of your battery (if it's not deep cycle).

Honestly, charging a phone (5w), running some small LED lighting (8w), and a couple 12VDC fans (6w) can all be done through your cigarette lighter port and won't be drawing more than 20watts. If you ran that all night, you would only be using 15amp/hrs or so of your battery; and if you get 8 hours of sunlight, you only need a 30watt solar panel to charge it back up. Whenever you are talking about solar though, you should plan on doubling your capacity to account for non-optimal performance, cloudy days, long winter nights, etc.

kieranmullen gives a pretty good rundown of what you would need to setup a separate 12v system but seems like overkill for what you are asking (and would run you about $300-400).

Personally, I would get a 100 watt panel, 7 amp charge controller, the cheapest 12v deep cycle marine battery from walmart, and maybe a 3-400w inverter (for a laptop charger or any other AC devices). Also, I'd put an inline fuse between my charge controller and load, and maybe another between the battery and charge controller.

I recommend moving to 12v components and then regulating the power back down to 5v for the Pi. There will be many more options and prices will be better.

Start with a solar panel:
http://www.amazon.com/HQRP-Mono-crystalline-Anodized-Aluminum-Radiation/dp/B002HSUT40

Use a charge controller to attach it to your battery(s):
http://www.amazon.com/Sunforce-7-Amp-Charge-Controller/dp/B0006JO0XI

Attach a voltage regulator to the battery and your Pi:
http://www.amazon.com/Ship-Hobbywing-Switch-mode-UBEC-Lowest/dp/B008ZNWOYY/

As far as batteries go, buying local will save you some shipping. If this is an outside battery you can use a deep cycle/RV battery. If inside then you need something sealed. You should have several days of reserve for bad weather. Maybe something like this:
http://www.amazon.com/26-SEALED-VOLT-DEEP-RECHARGEABLE/dp/B007GCDDOA

For something this small a simple dumb (non MPPT) would work fine.

http://www.amazon.com/Sunforce-7-Amp-Charge-Controller/dp/B0006JO0XI/ref=sr_1_2?ie=UTF8&qid=1381095592&sr=8-2&keywords=solar+charge+controller

Hi, this is pretty much what I have, cheap.

Edit: Just noticed this one doesn't have a load connector so this one depends upon you connecting a load directly to the battery - this is bad as it won't protect the battery from deep discharge, so avoid this one linked above. ainstead, opt for one which has all three connectors.

The reason you need one of these is that solar cells don't actually output precisely 12v, they have an open circuit voltage which can go up to 20v in some cases, and connecting this to a battery directly is likely to damage the battery and possibly the cell too.

The charge regulator cuts this excess voltage down into usable current and shunts it into your battery/load.

When your battery is full, the regulator has to shunt the excess energy produced by the solar panels into a heat sink.

Have a read of reviews before picking a regulator to be sure, mine isn't on there since I am from outside of the US so I cant 't actually vouch for it.

https://www.amazon.com/gp/product/B01MY0875V/ref=oh_aui_detailpage_o01_s02?ie=UTF8&psc=1

https://www.amazon.com/gp/product/B0006JO0XI/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

I got these charge controllers they worked great as far as i can tell. no noise

Use something like this:

http://www.amazon.com/Sunforce-7-Amp-Charge-Controller/dp/B0006JO0XI (will prevent overcharging or discharging)

Edit: You already have a controller bundled. No need for the above.

with something like this:

http://r.ebay.com/wFDuiC (or bigger depending on your need).

What current (or power if that's more handy) rating do you need?

Number 1 best seller on Amazon.

You did specify 30V - is that the actual voltage you need or did you round up? A 36 cell solar module is fairly common - you'll have an open circuit voltage of about 22V in that configuration, less after the panel heats up.

Second best seller on Amazon.Its becoming more common to claim "12V panel" as a way of saying "panels intended to charge 12V batteries" - it has nothing to do with the actual open circuit voltage of the panel.


To be honest, if you can't easily get replacements, I wouldn't go cheap on this component.