SunGuard SG-4 4.5 amp 12 volt Solar Charge Controller Regulator by Morningstar

I installed the SG-4 with a 50 watt solar panel on a motor home. This setup replaces a non-functional 7-watt panel that was supposed to keep the coach batteries charged. The controller is mounted behind the coach monitor panel and I connected it to the original solar charge wiring, which made the installation pretty easy. It is pretty much install and forget and it has worked perfectly for 2 years. The system has kept the two 6 volt house batteries and a 12 volt chassis battery fully charged while the RV has been in winter storage as long as two months unattended. It works as advertised and keeps the batteries healthy. It has internal circuitry (diodes I suppose) that keep the batteries from discharging back through the panels at night. Since it is only rated to 4.5 amps, you would not be able to use much more than 50 watts of panels with this controller. That means it is not suitable where you have to have a lot of energy to recharge batteries quickly. But for charge maintenance, this is perfect.

Received the item fast. Unfortunately it didn't work. We went to the Mfg website and looked at all the help files, followed all of their recommended procedures, and test procedures and nothing helped, it's just dead. My husband has a background in electrical, so he knows what he's doing. Returning it and ordering a different brand of controller. Hope that one works! SunGuard SG-4 4.5 amp 12 volt Solar Charge Controller Regulator by Morningstar

Returned the defective controller 2 months ago and am STILL waiting for my refund! Won't buy from this seller ever again. Just filed a claim with Amazon, maybe they can get me my money back.

Buy SunGuard SG-4 4.5 amp 12 volt Solar Charge Controller Regulator by Morningstar Now

I recently purchased this item to go with the Harbor Freight 45 Watt SunPanel kit as their controller leaves a lot to be desired. This unit is the ideal controller for this kit if you want your battery to be regulated properly.

Read Best Reviews of SunGuard SG-4 4.5 amp 12 volt Solar Charge Controller Regulator by Morningstar Here

I've had mine for over a year and it's just perfect for what it is. Vastly better charging than the dumb threshold on/off units. Temperature compensation is excellent. Albeit not MPPT, it really gets your batteries charged to their peak charge by floating the proper temperature-compensated voltage/amps to them. I.e., cold mornings you'll see like 14.6v, hot summer afternoons 14.2-ish.

How it works: When your battery needs charging, it directly connects your solar panel to your battery, so your solar panel voltage drops to battery voltage (below optimal, which is why MPPT is better). As the battery is charged, the voltage climbs to meet the target (say, 14.4v), it starts pulsing the current very rapidly to the battery to give it just the right amperage it needs to hold the target voltage. You'll see the solar panel voltage rise above battery voltage as this starts to happen. The target voltage is held and over time, the amperage taken from the panel decreases. Cool.

My application is my first dip into solar to maintain two big batteries in my Dodge diesel pickup that isn't driven often and is not located near an outlet. And when it is driven, the system only puts out 14.0 volts, not 14.4 like many other cars do, so while batteries certainly get a charge while driving, short drives can't replace all the energy taken on start-up. Compare that to say my 2008 GM which puts out 14.7v for the first 15 mins or so, then 14.4.

Even in the short winter days, a 10 watt panel is overkill, probably could have gotten by with a 5 watt panel. Again, my use is not "charging", it's "maintaining." I agree a 50W panel is about the max you can use on this, which is rated to be 4.5A at 12v (54 watts), or ~3.8A at 14V. That's still a pretty good charging rate for a single battery in applications where it is discharged.

I might put the solar panel in the interior (factory tint side windows block quite a bit) and see how it goes. Then again, I might bring the batteries to the basement for the winter and treat them to weeks of desulfating from my BatteryMinders.

I use a "Watts Up" on the solar side and battery side to monitor Whr, amps, volts, etc and a voltmeter on the batteries. Neat stuff!

Want SunGuard SG-4 4.5 amp 12 volt Solar Charge Controller Regulator by Morningstar Discount?

I bought this to replace a cheap controller that I use with a 15watt solar panel to keep a Jeep battery charged. The cheap controller just switched on and off and didn't have PMW to 3-stage charge the battery.

The good

It is ruggedly built with heavy duty wire in and out. It's in a heavy duty plastic shell that's filled with "potting compound" to make it water proof. The 4 wires come out through the potting compound. (They do warn you to install it so water doesn't collect in the open end of the shell.)

I hooked up a voltmeter and it's not contstantly turning on and off like the prior one. Now I'm getting a steady (in the short term) voltage based on the battery's state of charge.

The bad

There aren't any LEDs. You can't tell if it's working without a voltmeter and then you can only see one measurement at a time. (Volts in, volts out.)

There are cautions all over the instructions about not shorting out the solar power leads or it will ruin the controller. If you'll frequently be connecting/disconnecting the solar panels, install a short proof automotive connector that also prevents you from reversing the polarity.

Save 22% Off