Rubicon Solar Power Experience (1 Viewer)

[Cruiserdrew]

There have been a number of threads about solar power, battery charging and refrigerator power use so I thought I would post up my experience since I finally bought a folding panel this year, and used it extensively at the recent Rubithon event. At this year's event, I sat for 4 days at the mid point (Buck Island Lake) and then 3 days in Rubicon springs. This provided a chance to test if a 100 watt panel could keep up with my fridge, and keep the batteries charged.

Equipment:
Renogy 100 watt folding solar panel
Moringstar SunSaver 10 Charge controller
Costco Marine/Starting 100 amp-hour battery x2 - One isolated to start, the other for house loads
Engel MT45 refrigerator vintage 2003
Blue Sea SI-ACR 120 amp charging relay (0.175 amp draw when closed, ie "on"))

Weather:
Sunny-ideal power production conditions
Daytime 90F+
Nighttime 65F
Parked in full sun, but no direct sun on the fridge-all windows and tailgate open

Results:
Average Fridge daily power consumption: 11 amp-hours to 16 amp-hours (2.7 amps when running)
(in fairness not measured every day, only 3 of the days but this was the range)
Battery resting voltage 12.8 volts
Average House Battery voltage at dawn just before sun rise: 12.5 volts
9am-3pm Panel output - 5.7 amps (moved every 2 hours or so to face the sun)
Would make measurable power from 7am-5pm from 2 amps up to 5.7 amps
Generally by 11am the house battery was fully charged to 13volts-
-this would close the charging relay and top the engine battery too
The rest of the day, the batteries would float at 13.4 volts

Comments:
The Engel is much more efficient than I would have thought
I did not measure run times to get duty cycle but it's around 1:10 at night
During the day, the panel supplied all the power when the fridge was running
Batteries remained fully charged all day after hitting full charge each morning
Having a power meter is very helpful to see how much current is flowing and the power consumption of various loads.

So a 100watt panel can easily keep up with a standard 12volt refrigerator with room to spare. It was very helpful to have a permanently mounted dual voltmeter to monitor battery voltage and thus state of charge. Very happy with this set-up and frankly surprised at how well it kept up with the fridge and kept the batteries at 100%. This was a test run for a Baja trip and everything looks good to go.

There was some discussion in another thread if the MorningStar controllers would float the batteries-it does. You can watch the voltage step up to 14.4 for the absorb phase and drop to 13.4 to "float". @TrickyT wanted to post up data and this is what I got in real world conditions. Many thinks to him and @george_tlc for pushing me in this direction.


And one other thing-once parked at each spot, I did not restart the truck until I left, so the panel was supplying 100% of all power used.

 

[Cruiserdrew]

Here's the power plant in operation.

 

[JMJA]

Where did you purchase all your equipment?

 

[Cruiserdrew]

Where did you purchase all your equipment?

Amazon!
Good price on the panel and charge controller.

 

[george_tlc]

Hi Andrew, sounds like you have a good setup and some real world experience and success.

In oz my 80W panel pushes a solid 5A if not more into my batteries while in full sun. I've seen up to 6A while the panel is cool, the battery needs topping up, the sun is full pelt, though I do have an MPPT charge controller so that tends to do a little better. A decent cable length lets you move the panel out where the sun can hit it most of the day and still have the vehicle in a more shaded area. I have the charge controller at the vehicle end of the longer cable so that any voltage drop occurs on the longer 'unregulated' run and the charge controller can compensate. I just have a few feet of cable from the charge controller to the battery. Anderson SB50 connectors to mate everything together. Then you can have an couple of cables to mate together as extension cords.

Certainly anything in the 5A range will do just fine with a modern fridge, engel, arb. Keep the fridge in shade and provide airflow around it so that it can shed heat while running and your good to go 24/7.

It's great to be able to make camp, set things up and not have to worry about battery condition over several days use even in hot weather. Given that most evenings the temps will drop, the fridge will cycle less and battery AH use drops. Up comes the sun and heat, but then the panel is topping up the battery and as you found it only takes a few hours and then the panel more than keeps up with the daytime demand. Plenty of extra power to charge other gadgets etc.

Much better than a noisy/smelly generator that needs to be topped up etc.

cheers,
george.

 

[Cruiserdrew]

Thanks George. I do nearly the same. Charge controller next to the battery, 10ga wiring out to the panel. I'm running a PMN controller which is a bit less efficient but at these low power levels it isn't much. When I go to 2 panels, I'll wire in series to decrease the voltage losses and use an MPPT controller. The best I saw into the battery (power meter between the controller and the battery) was 5.9 amps, but usually it read 5.7 amps, then dropping off as the batteries neared full.

I also have all the wiring terminated in Anderson powerpoles. Makes for a very flexible and modular set up, and TrickyT and I were mix and matching components while trying to trouble shoot his system. It turns out this was a major advantage-to get every one in the group to agree on the same connectors.

My main 25 foot cord is a 10 gauge extension cord where I'm just not using the ground wire. I also have a couple of 10 foot extensions, so I can mix and match to get the shortest possible run. Then a couple of short jumpers to run from the charge controller to the battery.

On previous similar trips, the last day I'm always worried about my battery state of charge. It's usually marginal by then. I was very impressed at the panel's ability to keep up with the fridge, 2m radio and occasional HT charging. And on the last day-batteries were fully charged taking the worry out of start up.

One last thing I should mention-the Morningstar controllers are very well made and have an excellent reputation. Just be aware that if the temp sensor on the front of the controller is damaged, the controller will default to off and will not function.

 

[TrickyT]

Thanks George. I do nearly the same. Charge controller next to the battery, 10ga wiring out to the panel. I'm running a PMN controller which is a bit less efficient but at these low power levels it isn't much. When I go to 2 panels, I'll wire in series to decrease the voltage losses and use an MPPT controller. The best I saw into the battery (power meter between the controller and the battery) was 5.9 amps, but usually it read 5.7 amps, then dropping off as the batteries neared full.

I also have all the wiring terminated in Anderson powerpoles. Makes for a very flexible and modular set up, and TrickyT and I were mix and matching components while trying to trouble shoot his system. It turns out this was a major advantage-to get every one in the group to agree on the same connectors.

My main 25 foot cord is a 10 gauge extension cord where I'm just not using the ground wire. I also have a couple of 10 foot extensions, so I can mix and match to get the shortest possible run. Then a couple of short jumpers to run from the charge controller to the battery.

On previous similar trips, the last day I'm always worried about my battery state of charge. It's usually marginal by then. I was very impressed at the panel's ability to keep up with the fridge, 2m radio and occasional HT charging. And on the last day-batteries were fully charged taking the worry out of start up.

One last thing I should mention-the Morningstar controllers are very well made and have an excellent reputation. Just be aware that if the temp sensor on the front of the controller is damaged, the controller will default to off and will not function.

2x on the Anderson Powerpoles. Been using these for nearly 10 yrs now and really like 'em a lot. And 2x on the inexpensive but well-engineered Morningstar SunSaver and SunGuard series PMN PWM (pulse width modulation) charge controllers. The performed very well with our simple solar setups. The interchangeability of all the various components that @Cruiserdrew and I have made it easy to pin down a problem with my setup to a defective solar panel. I sent my PowerFilm 60W foldable panel back to the manufacturer on Friday at their request because they said the type of problem I was having was highly unusual and they want to diagnosis the cause. The other indispensable component to our setups is a plug-in watt meter, also equipped with Anderson Powerpoles. I posted a pic of mine in another thread and will dig that up and provide a link, but these inexpensive meters allow you to monitor voltage, current, instantaneous wattage, watt-hours, amp-hours, and time since startup. If you are into quantitative data, then for ~$30 you can't go wrong.

EDIT: Here's the post about the watt meter: https://forum.ih8mud.com/threads/he...r-my-solar-install.801072/page-2#post-9332633

 

[surfpig]

Amazon!
Good price on the panel and charge controller.

Andy, just curious, why not the charge controller that comes with the solar panels?

My trigger finger is getting pretty itchy for this setup...

 

[Cruiserdrew]

I wanted a better/more robust charge controller.
Mixed reviews on the one from Renogy.
I got to mess with one of these on the Rubicon trip. The programming is a bit confusing, but the controller worked fine in the end.

Morningstar seemed more of a pro option and still not that expensive.

 

[TrickyT]

Also, at least with some Renogy models, isn't the charge controller mounted on the back of the solar panel? You're much better off having the controller be near the battery because 1) any voltage loss in the wiring between the panel and the controller will be accounted for and the battery will see the full output from the controller, and 2) most good charger controllers are temperature compensated and should be located in the same/similar thermal environment as the battery to work properly.

 

[Cruiserdrew]

Tom brings up the 2 compelling arguments for divorcing the charge controller from the panel.

Run the higher voltage in from the panel and experience less voltage loss to the batteries.

And, have the controller with it's temp compensator in the same environment as the batteries.

And Nial if you are following this-If I were doing this again, I'd buy the panel with the controller, cut it out and stick it in my glove box as a spare, and run the Morningstar like I am now. I think the price difference is only $25 or $30.

I am thinking of a new set up for my Baja FJ62. 150 watt panel on the roof rack and George's MPPT controller into the battery. It should net me close to 10 amps and maybe a bit more. Even 4 hours of sun would more than replace any power use. The down side is the 150 watt panel is very large and does not fold. The folding panels are very easy to store in the back of a wagon. I may just get another 100 watt folding panel.

 

[surfpig]

You're totally right about the controller. I had it set up near the battery with my makeshift 45w setup. Which never really worked...

 

[e9999]

Nice to read about your positive experience, Andy. 100W nominal should indeed be enough under most sunny conditions for a fridge and a bit extra. Did you do any test to see if there is a significant shading effect with those panels? I was perusing Youtube and saw somebody showing a rather unexpectedly large power drop with minimal shading on that system. Seemed odd but I suppose possible depending on the wiring. I thought that was no longer a problem but...

George, seems like the monolithic SB50s are way overkill for this. Have you looked at the interlocking 30A Powerpoles? Should be plenty strong enough and much cheaper. And the standard for Ham equipment now apparently.


Damn, got to get off my butt and finally build myself a decent system too.... That self-contained portable system is indeed attractive as far as ease of use, and especially for reorientation needs. If a bit costly. (And it looks like they are now including a controller with some data recording capabilities, if still PWM, which is nice.) OTOH, it is also easily stealable when you're not around, that's less attractive. Is there an easy way to secure it reasonably well?

 

[george_tlc]

I like the SB50 since I use them for all my larger 12V stuff, including a cordless drill (which is now 12V corded), spare 12V compressor etc. The powerpoles are nice for a lot of areas (I use them for lots of interior 12V stuff - charging cables for radios, LED lighting that runs from 12V etc., but the SB50 are big, tough and handle larger gauge wires easier. Just my preference for 'exterior' wiring.

Real shade (trees etc) will affect panels quite a bit, cloud cover on the other hand has to be pretty thick before it makes a big difference.

Folding panels for 12V (18V typical open circuit) are wired in parallel, so even if one panel is somewhat shaded, the other panel will still run full output.

cheers,
george.

 

[Cruiserdrew]

@e9999 Like all panels, they are very affected by focal shading. For instance, holding your hand in front of 1/2 of the panel would cut almost all the output from that side of the panel. Cloud cover less so. A good example-I was measuring output in my driveway when a cloud came in and obscured the sun.. Output dropped from 5.9 to roughly 4. Not bad, but not full output either. Tree cover is a different story, and any tree shade would pretty much kill the panels output.

SO it's good practice to have a heavy gauge long wire to reach out to the panel in full sun, and keep the wire runs from the controller to the battery short. My set up has a 25 foot 10ga main wiring and 2 10 foot sections I can add if I need to reach out further. There is a limit to this due to voltage losses but it seems manageable out to about 40 feet-I've tested that set up. With series wired panels at higher voltage, the relative voltage losses would be less, but then you'd need an MPPT controller to take advantage of it.

Regarding the connectors-I used the standard 45 amp small powerpoles. They work extremely well with this set up. The plastic connectors for 15-30-45 amps are all the same, but only the 45 amp size inserts will fit 10 gauge wire.

 

[e9999]

Yes, what I meant by shading effect is when a small area of the panel is shaded by a discrete object (like a tree branch) and the overall output drops by (much?) more than the ratio of shaded to unshaded panel surface area. That was a problem with some earlier panels at least I believe. (Perhaps related was when one bad cell would zero out the whole panel output but you'd think it is easy to wire around that issue.)
So if you say that just a hand shadow would kill the whole 50W panel's output, that suggests it still is a problem with that system. I thought they had figured that one out. I guess not.

Yes those smaller powerpoles are great. Do you know if you could in principle connect a 15A, say, and a 45A together with adequate contact or are the metal tongues incompatible even though the housing is the same?

 

[Cruiserdrew]

Yes those smaller powerpoles are great. Do you know if you could in principle connect a 15A, say, and a 45A together with adequate contact or are the metal tongues incompatible even though the housing is the same?

Yes-you can connect these together no problem. The actual contact part is the same, only the wire crimp area is different.

 

[TrickyT]

The 15/30/45A powerpoles are especially nice for their interconnection capability, but in practice 10 AWG is the largest wire size you can use. Anything larger and the insulation is too large to fit the housing, and even then you've got to make a perfect crimp and struggle a bit to insert the contacts into the housing. That's where the SBB50 excels as they work with 6, 8 and 10 gauge wire. Also the SBB50's are tough as nails. I'm sure I could drive my 80 over one and not have it break. In the end, for me, it came down to interconnectivity. I can't begin to count all the stuff I have that's terminated with the 15/30/45A powerpoles: batteries, lights, radios, meters, solar panels, charge controllers, battery chargers, extension cables, distribution blocks... It makes connecting stuff up a snap. And, as noted in post #7 above, if you've got buddies with similar setups you can swap stuff around which makes for easy-peasy troubleshooting at the component level. Powerpoles definitely get 5 stars from me.

 

[e9999]

The one size up from the 15-45, the PP75, can go to 6AWG and 120A I believe, and still has the separate housings.

 

[TrickyT]

The one size up from the 15-45, the PP75, can go to 6AWG and 120A I believe, and still has the separate housings.

But the PP75 can't directly connect to the 15/30/45A powerpoles, so who cares? Might as well jump to the 50/120/175A monolithic housings. Like I said, interconnectivity of the smaller housings are their major advantage.