Need guidance on existing 9V Solar Water Fountain add-ons

lanew2021

New Member
Hi experts. I am new to this forum, so I beg your indulgence.

I have a 9V solar panel driving a 6V pump for a solar water fountain. This simple set-up works just fine.

What I want to do is add a battery to it along with a charge controller so that I can have the pump run when there is no sunlight.

While I understand the basic principles, I do not understand how to size the charge controller and the battery properly. I would love it if I could get some guidance on this.

Furthermore, the single panel is fixed pointing southwards, so there are certain times of the day when the panel receives marginal light from the sun. I was wondering if I could add two more 9V panels (in parallel), with the two additional panels angled eastwards and westwards - the idea being that I would get sufficient sunlight throughout the day to power the pump. Is this a feasible idea or should I just stick with a charge controller/battery configuration?

Appreciate the feedback and guidance.

Regards,

Lane
 

snoobler

Solar Honey Badger
Welcome to the forum.

I don't have a direct solution.

The main issue is the voltage. 6V batteries are fairly common, but I'm not aware of any 6V solar charge controllers. For me, the logical solution would be to get a 12V SCC, 12V battery and a DC-DC converter for the 12-6V step down, but this would negate the use of your 9V panels unless they were put in series.
 

lanew2021

New Member
Ah, this is great! So, a Walmart SCC + a 6V battery should do it?

Any thoughts on my second question - re: adding a couple of 9V panels in parallel, but pointing eastwards and westwards? Thinking that would allow me to get sunlight throughout the day, and be sufficient to power the pump and charge the battery...

Thanks for the great advice! Appreciate it greatly.
 

snoobler

Solar Honey Badger
Looks like that should do it.

What is the power consumption of the pump?

What is the 9V panel rating in Watts?
 

snoobler

Solar Honey Badger
Well, then we have to assume the pump is less than 3.5W since the panel likely never puts out that much, but it's hard to be certain what the actual usage is.

Assuming 3W, 24hr, that's 3W * 24hr = 72Wh

72Wh/6V = 12Ah. You'll want twice that to keep from destroying the battery, so 24Ah.

6V 24Ah battery for each 24 hours of operation.

Since you now have a battery, it's more important that you get as much charging as possible per day rather than spreading it out through the day.

3.5W / 6V = 0.6A, so that charge controller can handle 8 of those panels.

I'd start with three facing due south tilted for your latitude. If the battery is dipping to below 12.1V in the morning before charging starts, add panels one at a time until it stays above 12.1V.
 

lanew2021

New Member
@snoobler: Thanks for the analysis! What you suggest makes sense, so I will get a couple more of those panels (Do I need to put them is series or in parallel?).
 

snoobler

Solar Honey Badger
Parallel due to the restrictions on the charge controller. It's PWM, so it needs panel voltage appropriate for the battery.

Specifications:
Waterproof IP67
Rated Voltage:DC 6V/12V
Max input VOC: 11V(6V) / 22V(12V)
Max Current:5A
Power of solar panels: 30W (5A,6V)/60W (5A,12v)
Max Solar input voltage: 22V
Float:13.8V
Charge reconnect: 6.5V (6V) / 13V (12V)
Discharge stop: 5.6V(6V) / 11.2V(12V)
Discharge reconnect: 6.3V(6V) / 12.6V(12V)
Working Temp:-10- +40degree;
Weight:33g
 

lanew2021

New Member
@Forbisher: I haven't purchased the other two panels yet. The first one I got came as a kit so I paid about USD 30 for the panel, the submersible pump and a 16-ft length of wire.

The panel is in a plastic frame with a screw-in barrel-type connector (not sure how to describe this type of connector precisely!). The wire came with the ends equipped with screw-in watertight connector on one end, the other directly attached to the pump. I bought that from a company called Silicon Solar (it came with a SCC and a battery, but I could never get the contraption to work and they refunded me for the SCC/battery.
 

lanew2021

New Member
Parallel due to the restrictions on the charge controller. It's PWM, so it needs panel voltage appropriate for the battery.

Specifications:
Waterproof IP67
Rated Voltage:DC 6V/12V
Max input VOC: 11V(6V) / 22V(12V)
Max Current:5A
Power of solar panels: 30W (5A,6V)/60W (5A,12v)
Max Solar input voltage: 22V
Float:13.8V
Charge reconnect: 6.5V (6V) / 13V (12V)
Discharge stop: 5.6V(6V) / 11.2V(12V)
Discharge reconnect: 6.3V(6V) / 12.6V(12V)
Working Temp:-10- +40degree;
Weight:33g

Hi @snoobler:

Been thinking a bit more about your guidance. The highest AH battery I found is 6V 12AH. So I would need to get two of those batteries and put them in parallel to get 6V 24AH (otherwise I risk burning out the pump?)?

Thanks!
 

lanew2021

New Member
Well, then we have to assume the pump is less than 3.5W since the panel likely never puts out that much, but it's hard to be certain what the actual usage is.

Assuming 3W, 24hr, that's 3W * 24hr = 72Wh

72Wh/6V = 12Ah. You'll want twice that to keep from destroying the battery, so 24Ah.

6V 24Ah battery for each 24 hours of operation.

Since you now have a battery, it's more important that you get as much charging as possible per day rather than spreading it out through the day.

3.5W / 6V = 0.6A, so that charge controller can handle 8 of those panels.

I'd start with three facing due south tilted for your latitude. If the battery is dipping to below 12.1V in the morning before charging starts, add panels one at a time until it stays above 12.1V.
You mention battery dipping below 12.1V... The battery voltage requirement is 6V. Can you clarify? Thanks.
 

lanew2021

New Member
Sorry. Had 12V on the brain. 50% for a 6V battery would be about 6.05V.
Thanks for the clarification, @snoobler.

I take it that a single 6V battery will do the trick. The one I am looking at is "Power-Sonic Rechargeable Sealed Lead Acid Battery PS-6100 6V 12.0 AH @ 20-hr. 6V 11.5 AH @ 10-hr" (found on Amazon).
 

lanew2021

New Member
Hello folks.

Wanted to give you an update on my little project.

I purchased the following:

- 6V 12AH battery from Amazon (Power-Sonic Rechargeable Sealed Lead Acid Battery PS-6100 6V 12.0 AH @ 20-hr. 6V 11.5 AH @ 10-hr)
- 5A Waterproof Solar Charge Controller 6V 12V Auto from Amazon)
- BUD Industries CU-3285 Plastic Style A Utility Box, 8-1/4" Length x 5-9/64" Width x 3-7/64" Height also from Amazon

Total cost for these three items: under $50 (the utility box was kind of pricier than I expected!)

As I mentioned earlier, I already had a solar panel and a pump from a kit I had purchased last year.

The original kit contained a 2-lead wire with a screw-in waterproof connector (barrel-type) on each end - one for the pump side and one for the solar panel side. I cut the wire at an appropriate point so that I could hook up the charge controller and battery. The wiring was simple - from the pump to the charge controller load connection, from the solar panel to the controller's panel connection, and the battery from the controller's battery connection.

The instructions for the charge controller required that the battery be connected first and let the controller stabilize. Next connect the solar panel and let the controller sync up. Finally connect the pump.

I used the utility box to house the battery and the charge controller - drilled a couple of holes on the bottom for the wires (from the pump and the panel).

I have to double-check the power consumed by the pump, but I seem to have no issues running the pump continuously for 24 hours (so I assume the pump is operating at 0.5A roughly).

Right now, the panel and pump wires are twist-connected to the controller inside the utility box. Ideally I would like to install two waterproof screw-in connectors so I can easily attach/remove the pump and panel wires from the utility box. HOWEVER, I am having trouble figuring out the most appropriate such connectors (because they need to be affixed to the side of the utility box). Any suggestions as to the what kind to get would be greatly appreciated.

Regards,

Lane
 

gnappi

Solar Enthusiast
I have a few 12 volt pumps and a number of LED "mood" lighting systems in my yard and considering the wide availability of 12 volt stuff and relative low expense I wonder why you're struggling with cobbling together a 6 volt system?

As far as connectors go, why "screw" type? Have you looked at SAE connectors? They come in flush mount as well as inline and are water resistant.
 

lanew2021

New Member
HI @gnappi - Only reason for the 6V system is that originally I was missing a battery and a charge controller. But I see your point that a 12V system might work better, and it seems like all I need do is get a larger solar panel and a larger battery. Am I correct?

Also, I am just learning about all this stuff, so rather than buying an entire kit, it seemed more useful to me to cobble something together.

Re: the screw-in connectors, guess anything that flush-mount that I could affix to the bottom of the box I am using would work. Any suggestions would be gratefully welcomed.
 
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