Portable solar kits

finnski1 said:
Anyone use a portable solar kit for their RV's. Am looking for a simple one to keep my RV 12 V battery topped off.
Am considering this one which gets pretty good reviews and is reasonably priced.
https://www.amazon.com/Renogy-RNG-KIT-STCS100D-SP-Monocrystalline-Controller-100W-Waterproof/dp/B01NADR1CI/ref=sr_1_13?crid=13MOOJT36ZXJM&keywords=renogy&qid=1646154995&sprefix=renogy%2Caps%2C80&sr=8-13
Welcome any input.
Click to expand...

We have solar on the roof, but I am considering adding solar on the side. They work well for topping off the batteries. 100W pointed right at the sun and not in the shade works better than 200W on my roof that is flat and might be shaded. So solar on the ground is a great option. I fixed that by putting 1200W of solar on my roof but that is a lot more complex.

That Renogy kit is fine. If you have a Costco close by, they sometimes have good kits. Harbor Freight also sells really cheap kits. They seem to all be made by the same company so it comes down to durability of the solar panels more than electronics.
 
I just looked at it. Renogy is a good brand.

You can save a bit of money to buy separately a PV panel and a charge controller, but it may not be as portable.

Be careful someone will not walk off with it. I read a story of an RV'er who got his Honda generator walking off, despite being chained to his bumper. What is scary is that this happened while he was inside his RV.

Obviously, the generator was not running at the time, else he would hear it stopping or the engine getting less and less loud as it walked away. :)
 
corn18 said:
We have solar on the roof, but I am considering adding solar on the side. They work well for topping off the batteries. 100W pointed right at the sun and not in the shade works better than 200W on my roof that is flat and might be shaded. So solar on the ground is a great option. I fixed that by putting 1200W of solar on my roof but that is a lot more complex.

That Renogy kit is fine. If you have a Costco close by, they sometimes have good kits. Harbor Freight also sells really cheap kits. They seem to all be made by the same company so it comes down to durability of the solar panels more than electronics.
Click to expand...


Yeah I like the idea of pointing it to the sun when I want rather than fixed to the roof which might not even be oriented very well for solar gain in any one campsite. Seems more practical and efficient.
 
NW-Bound said:
I just looked at it. Renogy is a good brand.

You can save a bit of money to buy separately a PV panel and a charge controller, but it may not be as portable.

Be careful someone will not walk off with it. I read a story of an RV'er who got his Honda generator walking off, despite being chained to his bumper. What is scary is that this happened while he was inside his RV.

Obviously, the generator was not running at the time, else he would hear it stopping or the engine getting less and less loud as it walked away. :)
Click to expand...
Yes I've read many positive reviews about the Renogy product. I can see theft as a problem but I will have to deal with that as I would rather have this suitcase, ground mounted option so that I can aim it directly at the sun for more efficiency.
 
NW-Bound said:
.........You can save a bit of money to buy separately a PV panel and a charge controller, but it may not be as portable.
........
Click to expand...

Yes, you pay quite a premium for the "suitcase". For $125 you can buy a solar panel and controller. It is pretty easy to make a PVC stand to orient the panel. Add some wire and you are good to go.

For my Casita travel trailer, I have panels on the roof and a portable panel that plugs into the same controller for when I'm parked in the shade. It is the best of both worlds for me.
 
travelover said:
Yes, you pay quite a premium for the "suitcase". For $125 you can buy a solar panel and controller. It is pretty easy to make a PVC stand to orient the panel. Add some wire and you are good to go.

For my Casita travel trailer, I have panels on the roof and a portable panel that plugs into the same controller for when I'm parked in the shade. It is the best of both worlds for me.
Click to expand...
Yeah I will look at individual components and make my own "kit". You guys have convinced me.
I did not want it permanently mounted on the roof just because I wanted more flexibility in use. Also these would be on an A frame pop up (ALiner) and many campground sites are not always conducive to the right orientation for the sun. Would rather just aim them with my own kick stand arrangement.
 
The components that travelover recommends look inexpensive and should work.

Be aware that although the panel says it's 12V, its optimal operating voltage is 20.4V at a current of 4.91A. The controller is an inexpensive PWM, not a more expensive MPPT design.

Driving into a battery at 13V or so which is less than the optimal voltage of the panel, the controller will deliver a bit more current, perhaps about 5A max for a power delivery of 65W instead of the 100W that the panel is capable of.

You can get a more expensive MPPT controller or just get a 2nd panel. This controller can do 10A, and should be able to handle two panels.
 
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NW-Bound said:
The components that travelover recommends look inexpensive and should work..........
Click to expand...
For a small camper, this is an optimal "bang for the buck" system. Certainly one can go with a MPPT controller, lithium battery, etc but I've found for my off grid camping needs it works great as long as one upgrades to LED lighting and does not try to run a bunch of appliances off an inverter.
 
It depends on what you use the 12V for.

For my motorhome, I run a 2-kW inverter, and power a microwave. If I have excess juice, I can also run the water heater for a short time.

I will bring an induction burner for the next trip.

Definitely do LED lighting. Incandescent bulbs are obscenely power-hungry.
 
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travelover said:
Be careful with this controller. I have the exact same one in my camper and I foolishly disconnected the battery while in bright sunshine (190 watts solar on roof) and it smoked the controller.
Click to expand...

Sorry to hear that.
I have the same controller. Thanks for the warning.
I never remember the shutdown sequence, I have to read the manual every year when I shut it down.
 
NW-Bound said:
The components that travelover recommends look inexpensive and should work.

Be aware that although the panel says it's 12V, its optimal operating voltage is 20.4V at a current of 4.91A. The controller is an inexpensive PWM, not a more expensive MPPT design.

Driving into a battery at 13V or so which is less than the optimal voltage of the panel, the controller will deliver a bit more current, perhaps about 5A max for a power delivery of 65W instead of the 100W that the panel is capable of.

You can get a more expensive MPPT controller or just get a 2nd panel. This controller can do 10A, and should be able to handle two panels.
Click to expand...
Looks like a comparable MPPT controller is about $80 more. Can I approach the 100 watt panel rating with this method and thus save some time when charging the 12 v batteries? I will probably bump up to a 20 or 30amp version as well just in case I add more panel capacity.
 
If you don't mind the modest additional cost, an MPPT controller really squeezes the most out of a panel.

For non-electronic types, an MPPT controller is a DC-DC converter, which automatically varies its duty cycle to look for an operating point that maximizes the current flow to the battery. With the above Renogy PV panel, an MPPT controller will squeeze out more than 5A going into the battery. The load that it presents to the PV panel will be close to the 20V that the latter is optimal at. The current from the PV panel will be a function of the solar intensity.

It should be noted that PV panel ratings are measured at the standard 1 kW/sq.m. solar irradiation, and at a panel temperature of 25C (77F). Needless to say, real-life conditions are usually worse than the above, sometimes a lot worse. For example, I clocked my PV panel temperature as high as 170F in the summer. Mucho degradation in power output at that temperature!
 
To use an MPPT controller, you want the panel to put out a significantly higher voltage than the battery. The MPPT controller acts as a voltage adapter between the panel and the battery. It tunes itself to maximize the current flowing to the battery. Its operating point varies with the panel and the battery voltages, and of course is transparent to the user.

I used several different MPPT controllers in my home system, and they all work well. They are of the residential type however. These Outback and Midnite controllers cost me more than $700-800 each.

The small ones that I have had good luck with is the MakeSkyBlue controller. It exists in different versions of 30A/40A/50A/60A.

I have a 60A job still going for the 4th year now. The only problem I have with it is that the cooling fan is a cheap sleeve bearing job instead of a ball bearing fan. I had to oil it after 3 years. The thing runs throughout the daylight hours in these years, so YMMV.
 
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I forget to warn people that there are many phony charge controllers out there advertised as MPPT, while they are simply PWM type.

If you see a too-good-to-be-true "MPPT" controller that sells for $40, you should know that it is not true. It still works, but as a PWM type and not MPPT. Some people simply do not know the difference, and are still happy that it works.
 
NW-Bound said:
I forget to warn people that there are many phony charge controllers out there advertised as MPPT, while they are simply PWM type.

If you see a too-good-to-be-true "MPPT" controller that sells for $40, you should know that it is not true. It still works, but as a PWM type and not MPPT. Some people simply do not know the difference, and are still happy that it works.
Click to expand...
I've decided to get the MPPT version, 30 amp so that I can add up to (3) more 100 watt panels if desired.

https://www.homedepot.com/p/Renogy-...justable-LCD-Display-RNG-CTRL-RVR30/308729490
and I'll start with (1) 100 watt panel.
https://www.homedepot.com/p/Renogy-...ar-Panel-Compact-Design-RNG-100D-SS/307642178
and a few adapter cables. Will make my own pivoting stand.


Buying at Home Depot for 2 reasons:
A) have a $250 gift card to use up.:)
B) Easy to return if necessary to my local store.
It turns out the price is almost identical to Amazon anyway.
 
While I don't have personal experience with the above controller, Renogy is a good brand and you are likely not going to be disappointed.

For people messing around with solar power and generally DC wiring, a clamp-on DC ammeter is a necessity. The DC current has to be measured with a Hall-effect sensor. Old AC ammeters use an inductive coil which will not measure DC currents.

My clamp-on DC ammeter is indispensable!
 
NW-Bound said:
While I don't have personal experience with the above controller, Renogy is a good brand and you are likely not going to be disappointed.

For people messing around with solar power and generally DC wiring, a clamp-on DC ammeter is a necessity. The DC current has to be measured with a Hall-effect sensor. Old AC ammeters use an inductive coil which will not measure DC currents.

My clamp-on DC ammeter is indispensable!
Click to expand...
I got one from seeing YouTuber Hobotech use this one.

https://www.amazon.com/KAIWEETS-Mul...apacitance/dp/B07Z398YWF?ref_=ast_sto_dp&th=1
 
finnski1 said:
I've decided to get the MPPT version, 30 amp so that I can add up to (3) more 100 watt panels if desired.
.........
Click to expand...
As long as you have your wallet out, a great addition is a smart shunt that will give you amps in/out of the battery, volts and battery charge level. The bluetooth ones are neat as you just mount it in series with the negative battery terminal and run a small + lead to power it. Your phone serves as the screen.
 
spencnor said:
I got one from seeing YouTuber Hobotech use this one.

https://www.amazon.com/KAIWEETS-Mul...apacitance/dp/B07Z398YWF?ref_=ast_sto_dp&th=1
Click to expand...


Isn't technology wonderful? These DC ammeters used to be unobtainable at any price. Now, they are so cheap.


travelover said:
As long as you have your wallet out, a great addition is a smart shunt that will give you amps in/out of the battery, volts and battery charge level. The bluetooth ones are neat as you just mount it in series with the negative battery terminal and run a small + lead to power it. Your phone serves as the screen.
Click to expand...


Oooh... Victron hardware is about the best that money can buy.

If I wanted to blow the dough, I would buy all Victron hardware. :)
 
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