I am considering a solar setup on my Toyhauler. We do 3-6 day trips at least once and usually twice a month year round. We do not have a TV or large stereo in the trailer. We do charge our cell phones, cameras and 2 way radios off the battery and the laptop with a 300 watt inverter or the generator. I have a 225 amp hour battery bank and cannot increase the size due to space and weight. I am not trying to totally eliminate generator use just trying to reduce it and also keep the batteries up in storage and have the batteries recharge in storage rather than having to recharge them before I take the trailer back to storage. In a nutshell I want something that will charge the batteries while I am out playing so I don't have to run the generator as much when I am back at camp. I am looking at a 200 watt array with room to go to 300 watts if necessary and need some input on charge controllers. On the fence about a remote panel, once the solar system is up and working I don't think that it is that big a deal to open the outside compartment and see what the battery voltage is when the sun does down to determine if I need to run the generator for a while.
The Rogue MPT 3024 is a possibility. I like the ability to set the charge set points on the unit without having to buy a seperate panel. A concern I have is that the users manual states that it could shut down if the ambient temperature exceeds 104 degrees F and the heatsink exceeds 185 degrees F and then the unit has to be manually restarted-not good if this happens in storage. I camp in the desert in the summer and I store the trailer where the ambient temp exceeds 100 degrees almost daily during the summer. Can any users of the Rogue unit confirm that the thermal shutdown is a concern? One drawback of the Rogue controller is that if I want to measure amperage use and battery capacity I have to buy a separate device like a Trimetric. For a short duration boondocker like myself is it really necessary to monitor this information? Couldn't I just look at the charge cycle before the sun goes down (bulk, absorbtion,float)or the battery voltage on the controller after the sungoes down to get an idea of state of charge? I do like that this controller monitors the charging voltage at the battery and not at the controller pretty much making my .50% Vdrop a 0% voltage drop. Price on this unit without a remote display is $325.
I am also considering the Blue Sky Energy 2512iX with the IPN Pro-Remote so I can set the voltage set points (not possible without the IPN Pro Remote). This set up can use a shunt so I could monitor everything that a Trimetric does. This controller cannot sense voltage at the battery. Downside is I have to get the IPN Pro Remote (which adds $200 dollars to the package) to set the charging voltage set points, the up side is I only need to buy a shunt to accurately measure state of charge and amp hour usage to know exactly how long I have to run the generator for to bring the batteries up to 90% SOC or better. Price on this system (controller, shunt, temp sensor IPN Pro Remote) is $530.
The question is for a user like myself how many bells and whistles do I need? I don't want to buy more than I need.
If you have a tri-metric, then the gauge is not really required, you have the meter to monitor the battery state of charge, and nothing else is required, unless you might want to see that 21 amps are going in at this moment. But I think you will be more interested in riding than watching a meter.
If I only had $500 to spend, I would rather spend it on a 100 watt solar panel than a fancy controller.
Check with these people. Ask about the simple controller, and a solar panel that is 18 - 21 volts output. Like the 195 watt 19 volt panel they where selling a couple months ago for $263. A couple of those, and a couple of $65 controllers rated at 12 amps will get the job done for much less money.
Yet use care when selecting panels at this site, most are 24 volt nominal and would require MPPT controllers to transform the 30+ volts to 13.5 to charge the battery bank.
They only list a few 18 - 21 volt panels on their website, and they are difficult to find among the 38 - 42 volt panels and some in the 60+ volt range.
I would not recommend a panel larger than 200 watts on a RV because of space. My 120 watt panels are large enough that finding real estate up on the roof was difficult. They will not fit between a 14" vent centered on the RV and the sidewall.
I made solar panel mounts from 6" long 2" angle aluminum from Home Depot. 3 holes 3/16" on the roof side with #10 screws into the roof with lots of rubber roof sealant, and 1- 5/16" hole into the panel with a 1/4-20 bolt into the panel with a nutsert pop riveted into the panel frame. Tamper resistant stainless steel bolt finished the mount.
I ran #10 direct burial wire down the refrigerator vent, one line for the pair of 45 watt panels and 75W panel, another line for the pair of 120 watt panels. Yes a little light on the wire size, but it does work, considering it is only a 15' wire run.
I have a solar boost 50 controller, not many MPPT controllers to pick from in 1999. It has not had a problem controlling about 22 amps so far. At least you will not need to invest $3,000 into your solar and inverter system, like I have in mine! Prices have come way down.
If you can find panels that are nominally 18 volts, then consider the tristar NON mppt 45 amp unit.
I consider a temperature sensor an essential item. It is not included in the Blue Sky Unit--but is in the Rogue. I believe the Rogue has the Blue Sky beaten, hands down.
I don't think you need to do a bunch of monitoring. Although I would want the flexability to choose your own charging profile so it will work during storage and while in use.
I don't have all these controllers to compare. I do have the Morningstar MPPT 60. You may only need the 45 or even the non-MPPT 45 version. I really like the ability to have a very short absorbtion voltage period while in storage and automatically extend the absorbtion voltage period while in use. You set the trigger voltage and the extended period as you see fit.
I use a netbook computer to make the programming changes. It will log information if you want to retrieve it later or you can monitor real time with the computer. Otherwise I opted for no display and once programmed I intend to pretty much not manage or monitor anything through the controller. I have a voltmeter in the trailer to show the general battery status.
Controller has both voltage sense if needed and temperature compensation.
If you are close to, Norco CA 92860, you can get good prices on panels and controllers at http://www.solarblvd.com/ and save the shipping.
I bought my stuff here.
* This post was
edited 04/16/12 09:12am by smkettner *
You definitely don't need all the bells and whistles. A basic MPPT controller with temperature sensor is adequate. In addition, all solar needs an amp meter. The amp meter is your feedback that the system is functioning correctly - that shade isn't a problem, or the panel is dirty, or whatever. I bought a volt-amp combo panel meter at ebay for ~$35 (including shunt).
I've been using the SB 2512iX without the IPN for 5 years. Haven't had any problems. These days, the biggest drawback for this unit is its low max voltage. Five years ago 12V panels were the norm. Now higher voltage panels are cheaper. The 2512 can only be used with 12V panels.
Remote voltage sense is nice, but it's not a must have item. I would rather spend the money on a fatter cable (between controller and battery) than have remote sense.
It's good that the Rogue has thermal protection. But not that great if it requires manual control to restart it. In your case, I would point a 12V fan at the controller. Add a thermal switch inline with the fan power so that it turns on when temperature is greater than 100F.
The SS series is designed for outdoors and has a WIDE temp tolerance that would be ideal for desert heat. It has a built in temp compensation and should be kept in the same environment as the batteries. It is epoxy encapsulated and safe to install around batteries.
I use one of these with a 130W panel.
I also have a MS TS-45 PWM as recommended by pianotuna above and it is a good choice if you plan to expand.
The panels I am going to use are rated at 22 volts open circuit and 18.5 volts at max power point. Research shows that I only benefit from MPPT in bulk mode. I think that I will buy a non-MPPT Morningstar TS45 and use the money saved to buy another solar panel.
That is $2 a watt right there. $3.20 a watt if mounting kit included.
With three in series you are over the max voltage for Rogue so you are looking at parallel or just two panels for series.
3 panels $600, Rogue $325 = $925
Consider some larger 24v panels 235w 24v $235 x2 $470 Tristar MPPT 45 $426
This gets you 470w for the price of 300w. + series connection for superior performance and easier wiring.
Of course if you don't have the space there are smaller panels for $1.35 per watt, maybe less.
* This post was
edited 04/24/12 11:39pm by smkettner *
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