4.5A Charge Controller (RA-9)

When I ordered this controller, I thought that it was essential to prevent the solar panel from draining the battery at night. What I discovered when the flexible solar panel and this controller were delivered is that the panel output wiring contains a diode to prevent the panel from draining the battery at night. The documentation says that the real purpose of the controller is to prevent overcharging of the battery. The only drawback to using both the controller and the diode in the solar panel wiring is the small additional voltage drop of a few tenths of a volt, which should not be a problem, because the open-circuit output voltage of the solar panel is far above (20 volts or more)the approximately 13 volt level of a fully charged battery.

Directions do not state that the unit is powered by the battery side connection before it will allow solar PV current through to charge a battery. So at first I thought I had a defective unit. Tech support at MorningStar Corp. was very helpful to clarify how it works. So make sure that the battery being charged inside a device does not have a resistor in its charging port that will NOT allow backflow of energy or the charge controller will not operate. It would be handy if the SunGuard unit had a "charging" indicator light on it so you know its actually charging so when the sunlight is too weak you know to reposition the PV panel or pack it up.

Looks like good quality will leave it to charge the battery of my boat year round lets see how it resists...

I bought a Powerfilm 15-1200 20-watt folding solar panel and this charge controller to go with it. I took them to Haiti with me for a 3 week missions trip. I needed to charge my little Netbook computer plus a few dozen AA batteries that were in everything I used: flashlights, cameras, air mattress pumps, etc. Since the 12 volt 20 watt panel won't directly run the 19 volt 16 watt Netbook car adapter (I'll explain why later) I also brought two small 48 amp-hour 12 volt lead acid Gel Cell batteries along. This controller was used between the 20 watt panel and the 12 volt batteries. (These were 12 volt batteries I had bought for a computer UPS which ended up not needing them.)The Ra-9 charge controller worked as it was supposed to work and was reliable. I only give it 3 stars because of its design. The folding solar panel is small and light weight and is "obviously" intended to be portable. However, the charge controller built specifically for this application is a "permanent", "screw it to the wall" construction. If you look at the picture of the device, it is about 2 inches by 2 inches on the square top. BUT, it is about 1.5 inches high with two big ears with screw holes in them. Internally, the "potted" resin filled chamber with the electronics is only about 5/8 of an inch. the extra 3/4 inch or so of empty space and the big screw hole ears is just wasted space! Before I left for my trip, I took wire cutters and chopped away all the bottom plastic that was empty space and lopped the ears off with it. Now my "customized" controller is about 1/2 as big as it was when it arrived and is much more of what a portable solar panel should have.With Powerfilm branded panels, they add what appear to be totally custom / proprietary "marine grade" connectors on everything. This connectors appear to be very high quality and are great if you want to buy only their branded things, but to adapt to any other non-Powerfilm device, you will need to chop those connectors off and improvise some other connector arrangement.My Powerfilm 20 watt panel combined with this charge controller worked great for the solid 3 weeks of charging I used during my trip to the outer reaches of Haiti well beyond the run of the power lines. I had more power than I knew what to do with. However, they should make a charge controller that fits their panels with a more "portable" design and not only supply one that is intended to be bolted to a wall somewhere.Oh... the 12 volt 20 watt to 19 volt 16 watt conundrum with my Netbook. The problem isn't the "average" power requirement, it is the way the power it made. To get 19 volts from a 12 volt supply, what is called a "charge pump" is used in the 12 volt adapter. This is a high speed oscillator circuit which charges a tiny capacitor to 12 volts. Then it quickly reverses that capacitor and connects it in series with the original 12 volt power source. This give 24 volts. This 24 volts is then used to charge yet another capacitor to the needed voltage; in my case for my Netbook it was 19 volts. This 19 volts is then sent out the output to power/charge the Netbook computer. This oscillation of charging the tiny capacitors and flipping their polarity occurs hundreds of thousands of times per second and even up to a billion times per second. The problem is that this oscillation causes the power to be drawn from the 12 volt source only part of the time. While the tiny capacitors are being charged, the 12 volt power is being used. While the circuit is flipping the capacitors around, it is not being used. Therefore, during the charging time, up to double the "average" draw is being taken and is "made up for" by not drawing anything while the capacitors are being flipped. So, the average power needed is only 16 watts in my case, but about 1/2 the time 32 watts are needed and the other half of the time 0 watts are needed. This panel can produce 20 watts peak even for the tiny fraction of a second that more is needed, it is not there.Therefore, this panel cannot power a charge pump "car charger" that is required to produce more than 12 volts on its output. Theoretically, though I have not tried this, just a small capacitor across the panel's power could solve this problem since it would charge from the 12 volt panel and could supply the tiny pulse of greater current needed by the charge pump. Perhaps I'll try this soon and add a comment in that regard.Cheers! Please do something good for someone with the power these solar panels and controllers provide.

Just what I needed to complete my solar setup. Fast shipping to boot!

I contacted PowerFilm about a design flaw (or improvement they could make) and they agreed but I see nothing has changed. Note that there are no LED's not this. There is nothing to tell you if it is working or not. They should at least have an LED that turns RED when it is getting juice from the solar panel and Green when it is sending that juice to the battery (maybe no LED light if battery is fully charged) - so you know it's working. Even if you put a meter on the output to check the voltage/current coming out - the meter won't display anything. Apparently there's a circuit that detects if the battery is lower than X condition and if so, it then sends the juice across. Using a VOM meter on the output isn't enough to trigger the flow. As such, there is no way to know if this is working or not; act of faith. PowerFilm people said I could attach it to an undercharged battery and leave the system (solar panel+regulator+battery) set up for a few hours and "see" if the battery had more charge. It should be easier than spending a couple hour out in the field to learn if something is working or not. It gets 3 stars because it does do what it is supposed to do - regulate the voltage to the battery it is charging; an important job. But it looses two stars because there is no simple way to verify if it is actually working or not.

Perfect with my solar pannel

Too bad. The powerfilm solar panel is good. Need something that works with it. Would not recommend. Waiting for powerfilm to come up with alternative.