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Portable solar setup

whoaru99

whoaru99

Epic Member
I've recently acquired two 200W Renogy "solar suitcases". Each one has its own 20A PWM solar/charge controller.

The idea is use these in a portable setup with 12V, 210Ah LiFePO4 battery and 12V > 120V inverter, and thought I could simply parallel both panels to one of the charge controller inputs. But Renogy's info says not to do that.

Renogy says with these particular controllers it's OK to series connect the 200W panels to one controller for a 24V system, but parallel the 200W panels to one controller for a 12V system is not OK.

Anyone know if it would be OK to parallel the controller outputs to the battery rather than parallel the panels to controller input?

I understand a higher capacity MPPT controller would be better in more than one way but that's down the road for now.
 
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I am experimenting with solar panels, charge controllers, and batteries. I have put two 260W panels in parallel into one 100A controller charging 3 12v 100ah batteries for several months. No ill effects been observed. I have diodes on hand to wire OR the panels output if I find it necessary. The diodes can serve panel isolation and protection.
 
I’ve had good results getting panels and batteries for mixed residential and commercial installs through Fotovoltaika - dodavatel a velkoobchod Raylyst Solar since they cover most of Europe and keep stock from major brands. What helped me most was their technical support and partner training, which made planning larger setups way smoother. If you’re juggling different project sizes, their logistics service takes a lot of stress off your plate.
 
I have a small solar powered water pump to use for a fountain. I don't know the output of the panel but even a passing cloud drops the pump output to near zero. I bought a solar charge controller a while back and I'm thinking of getting a rechargeable battery and linking the two. I think a relatively small battery would be enough to keep the pump going through partly cloudy days. Maybe even a slightly higher capacity battery for longer run times if the solar panel could charge the battery and run the pump at the same time. I'd also need some sort of enclosure to protect the battery and controller from the weather.
 
RickeyM said:
I have a small solar powered water pump to use for a fountain. I don't know the output of the panel but even a passing cloud drops the pump output to near zero. I bought a solar charge controller a while back and I'm thinking of getting a rechargeable battery and linking the two. I think a relatively small battery would be enough to keep the pump going through partly cloudy days. Maybe even a slightly higher capacity battery for longer run times if the solar panel could charge the battery and run the pump at the same time. I'd also need some sort of enclosure to protect the battery and controller from the weather.
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Probably just the quality of the panel. The one built in to the top of the camper we bought last will still charge the battery on a cloudy day, of course not at the same rate as a sunny day.
 
RickeyM said:
I have a small solar powered water pump to use for a fountain. I don't know the output of the panel but even a passing cloud drops the pump output to near zero. I bought a solar charge controller a while back and I'm thinking of getting a rechargeable battery and linking the two. I think a relatively small battery would be enough to keep the pump going through partly cloudy days. Maybe even a slightly higher capacity battery for longer run times if the solar panel could charge the battery and run the pump at the same time. I'd also need some sort of enclosure to protect the battery and controller from the weather.
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Yeah, panel output will drop pretty much for any reason the amount of sunlight goes down.

Have not done a lot of charting/graphing with mine (pretty close to none, actually) but I'd presume the less "cushion" capacity the panels have vs. load/demand then closer you are to the situation you see.

The keys are understanding the power requirement, panel output, and the average "solar" available where it's set up.

Ultimately any size battery eventually goes dead if the panel can't produce enough power over time vs load over time to keep sufficient charge in the battery.
 
This particular charge controller is rated for 10 amps and work with 12 or 24 volt input. I can add another panel to either increase the wattage or double the voltage to the controller. Figuring a 5 or 6 watt draw from the pump a 15 ah battery would keep things flowing 25-30 hours continually. With the fountain operating just during the daylight hours it should keep going even on partially cloudy days. The question is would the original panel charge the battery when needed and still power the fountain pump. Keeping the battery no larger than necessary will make it easier to keep it charged with the current solar panel.
 
Maybe you know, but the charge controller rating is only the max it can handle for output.

It still requires knowing the solar panel capability to ascertain available input, which translates to available output.

IOW just because the charge controller output could max out at 120W (12V x 10A), if the solar panel(s) can only put out 20W (or whatever) you can't get more than that out of the charge controller, and more like maybe 90% of input just for rough estimating.

5-6W for a fountain water pump seems low, but maybe I'm envisioning a different sort of fountain than it actually is?

What you have described is a load at the same time the panel has output, but no extra time for recovery. The panel needs enough to run the load and some surplus to keep the battery up at the same time because the panels are not putting out anything at night when the pump isn't running.

The panel output rating is key to see if this can maintain or gain or still net loss.
 
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whoaru99 said:
Maybe you know, but the charge controller rating is only the max it can handle for output.

It still requires knowing the solar panel capability to ascertain available input, which translates to available output.

IOW just because the charge controller output could max out at 120W (12V x 10A), if the solar panel(s) can only put out 20W (or whatever) you can't get more than that out of the charge controller, and more like maybe 90% of input just for rough estimating.

5-6W for a fountain water pump seems low, but maybe I'm envisioning a different sort of fountain than it actually is?

What you have described is a load at the same time the panel has output, but no extra time for recovery. The panel needs enough to run the load and some surplus to keep the battery up at the same time because the panels are not putting out anything at night when the pump isn't running.

The panel output rating is key to see if this can maintain or gain or still net loss.
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All points already taken into consideration. An amp meter will show the panel output. I already know the panel puts out around 19v unloaded. Another way to gauge the panel output is to insert a small "power station" I have between the solar panel and the pump. The battery level indicator will either drop or maintain.
 
RickeyM said:
All points already taken into consideration. An amp meter will show the panel output. I already know the panel puts out around 19v unloaded. Another way to gauge the panel output is to insert a small "power station" I have between the solar panel and the pump. The battery level indicator will either drop or maintain.
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Several years back I bought a small solar panel to use as a maintainer for a car at a location without power that was driven infrequently. The panel has 23V open circuit but is only 5W output. Panel area is 0.9 sq ft.

It worked as a maintainer because it only had to offset like 30mA of parasitic draw on the battery.
 
I've started to get interested in solar backup solutions and have just started to follow this thread on AK. I have had a rooftop system for a few years but my 'bank' of kwh runs out about January each year (right when we are using the most power and have the least sun). Getting extra panels right now is not cost effective. I have been researching getting a solar generator and panels, power it up each day and plug in a couple of appliances overnight. I have found that plug-in micro inverters (balcony systems) are now becoming available in the US although they have been in Europe and Australia for years. I got a couple of free used 300 watt rooftop panels and an AP systems EZ1 micro-inverter (supports two 400 watt panels) a couple of weeks ago and have since been experimenting with them. Right now the panels are just leaning against the fence but I plan to make a mount where the angle can be changed as the sun gets higher. Still following solar generator pricing waiting for a deal that I can't refuse.

Does anyone else have experience with these Balcony Systems or recommendations for mounting solutions?
 
This is the first Fountain experiment with the solar powered water pump. A flower pot, a pot saucer and the pump.. The solar panel of this system is just enough to keep the pump going and even passing clouds will stop the pump. Adding a battery will keep the pump going during voltage sags from the panel but the current (no pun intended) panel probably won't run the pump and charge a battery at the same time. I've got my eye on a 35W 24V solar panel that should do the job. That should be enough to power the pump and charger a small battery. Both my power station and my charge controller can handle a 24V input while giving a 12V output the pump can use. In the long run, a battery and charge controller would probably be better for continuous (daytime) operation. I could even up the ante by adding a second battery connected in series for a 24V panel, 24V battery storage outputting 12V to the pump.

 
Phase 1 of the solar with a battery backup fountain experiment. Extension power cords to place the solar panel in a sunny spot aquired. Solar panel (10-1/4" x 13-1/4") mounted on a South facing wall connected to a small solar power station by the aformentions cables. The panel is charging the power station but the output is unknown. The internal battery is about 15aH. I have a small USB powered fan plugged into the power station for a load. The spot where the panel is hung gets direct sunlight for a couple more hours so we'll see how it goes.
 
Is the panel angled according to your location (latitude)? Helps to optimize output.

For example, a year 'round average number for where I am is ~34 degrees up from horizontal. There are online calculators to use your location for getting the angle(s).

Some change the angle a two or more times per year, e.g. lower angle in summer, higher angle winter.
 
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Interesting thread, thanks for starting it.

We were talking about portable panels yesterday. As a possible was to slow down the electric meter.
My wife saw some news about availability, there was also a quote from Eversource that their meters are not equipped to handle the back feed and will actually charge you for the power you generate. Hmmmm...it's either sour grapes or they designed it that way on purpose.

I wouldn't mind a temporary set up to power my inflatable hot tub all summer.
 
Working up another LiFePo4 battery pack, this time using some B grade cells I bought a while back.

This one will be a 12V 305AH battery. If it goes well I'll end up with two of them.

Very preliminary stage of just eyeballing up fit, space, etc to see if this group 27 battery case will work. The cells fit no problem but still need to fit cables and a BMS in there. I think the BMS may fit in the battery box cover, but will see.

The quasi bummer is today I could buy a premade 12V 305AH battery from a decent source for possibly less than I'll have in this one as most of the cost was sunk in the cells a year or more ago.
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Is anyone considering 24/36/48 volt systems instead of the more common 12V? My little charge controller can handle up to a 24V panel array and 12v or 24v battery, but 24V battery and 24v @ 10 amps from panel(s) is probably overkill for my little bubbly fountain project.
 
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