Solar controller for Shurflo off-grid sap pump

[DMF]

Just got some access to a property to tap and I will need to have a solar pump set-up. I am not all that familiar with solar set-ups so I'm still learning. What is the difference between MPPT and PWM and which style do I really need?

Thanks!

[NhShaun]

It depends a lot on the panels and battery you will be using as well as the power consumption required for your pump/s. Are you planning on using just one shurlo for vac and no transfer pump too?

[DMF]

I think I can get my collection tank close enough to the road to use my gas powered pump to transfer to the truck, so just one shurflo pump just for vacuum. I was looking at this solar starter kit on Amazon : Amazon.com : Renogy 100 Watt 12 Volt Solar Panel Starter Kit with 100W Monocrystalline Solar Panel + 30A PWM Charge Controller + Adaptor Kit + Tray Cables + Mounting Z Brackets for RV Boats Trailer Off-Grid System : Patio, Lawn & Garden and it has the option for both types of controllers....?

[maple flats]

For a small solar set up, to just run one 12V diaphragm pump you will be better off using a PWM controller. PWM is pulse width modulation, they are far lower cost and very adequet for that use. If the pump calls for 12V at 3 or 4 amps, just get a 12V deep cycle battery, to run the pump and a 60-100 Watt panel with a PWM controller to maintain the battery, it will work fine. Keep in mind that the solar panel needs sun exposure, place it where it will in fact get enough sun. Also you might want a second deep cycle battery to swap out if you have a period with too little sun, or too much snow on the panel. Battery, don't get a LiFePo4 battery for this use, they can't be charged at sub freezing temps. You are likely best off using a FLA (flooded lead acid) or an AGM (absorbed glass mat) or a Gel battery. The first choice requires checking electrolite levels about every 2 weeks in this type of use, and refilling as needed with distilled water, the other 2 don't need anything except maintaining clean contact with the wiring connections, but the cost more to buy.
If you were to use an MPPT (maximum power point tracking) controller, you would need a larger solar panel and maybe larger battery, they consume power 24/7, a PWM only uses power when it's controlling the solar output into the battery.
My history, I bought 16 LiFePo4 batteries each was 3.3A and 200 WH (watt hour) wired in series. For use in my largew solar system in my sugarhouse. When new they cost $2500+ total. I then added a 65 watt heating pad and a full 1" insulation foam enclosure to maintain battery temperature plus a BMS (battery management system) which was susposed to shut the charge off at 34F so the batteries would not be charged below that temperature. Long story short, the BMS failed and the $2500+ battery bank was ruined, they could not be charged ever again, despite several attempts at various voltages and amperages. They were junk. I have now replaced them with AGM batteries.
My solar is actually two part, First I have 4800 watts of solar on one charge controller strictly grid tied. The second part is 1480 watts solar on a 60A charge controller, tied to a 6048 inverter and the back up batteries, that portion is strictly off grid however it could also be grid tied and was at one point. The 6048 inverter is a 6000 watt continuous power/12,000 watt surge inverter, tied to a 48V battery bank.
The reason it is not grid tied is because of the extremely risky situation the world is now in. In case of an EMP (electro magnetic pulse) or any real issues with the grid, my equipment would be ruined, having it isolated, I'd still have my own power, up to the ability of the batteries and the inverter. If I was real certain that would happen, I'd have 400 AH batteries instead of 200AH, for more backup.
You also need to realize, 12V power needs heavier gauge wire than higher voltages. That's why the main cables on your car battery are so heavy, it's also why the grid transports power long distances at very high voltages, then transforms it to medium high voltages to go from sub stations, and again transformers to feed 240V/120V to your home. The extreme high voltages allow the pwer to flow with less loss than a lower voltage could do.
On 12V the wire must be heavy or the loss in voltage is lost as heat. Now, on your system even for a little 12V diaphragm pump, keep the 12V wiring heavy and short. It's far lower cost to move air (or vacuum) or sap in correctly sized piping than to use long wires for the distance.

[mainebackswoodssyrup]

We added 200 watt panels to our 100 watt setups this year and charging/battery swapping was much improved. Recommend at least 200w of panels, 300w is better.

[DMF]

For a small solar set up, to just run one 12V diaphragm pump you will be better off using a PWM controller. PWM is pulse width modulation, they are far lower cost and very adequet for that use. If the pump calls for 12V at 3 or 4 amps, just get a 12V deep cycle battery, to run the pump and a 60-100 Watt panel with a PWM controller to maintain the battery, it will work fine. Keep in mind that the solar panel needs sun exposure, place it where it will in fact get enough sun. Also you might want a second deep cycle battery to swap out if you have a period with too little sun, or too much snow on the panel. Battery, don't get a LiFePo4 battery for this use, they can't be charged at sub freezing temps. You are likely best off using a FLA (flooded lead acid) or an AGM (absorbed glass mat) or a Gel battery. The first choice requires checking electrolite levels about every 2 weeks in this type of use, and refilling as needed with distilled water, the other 2 don't need anything except maintaining clean contact with the wiring connections, but the cost more to buy.


Thanks for the help Dave! The property has a clearing on it that has southern exposure so I think my panel would get the most light possible. I have 10 gage wire if I need to move the panel further away from the tank than I plan.

So would the link I provided above work to get me going? For batteries, is something like this what I need: https://www.amazon.com/WEIZE-Battery-Trolling-Overland-Applications/dp/B0BGKHQQTP/ref=sr_1_4?crid=15KTF96WKEW5K&dib=eyJ2IjoiMSJ9.gRLA6jVnKMgaSFtb6I51Q08kQhJZ6cqLh eHkxCFY0GFDOnCxzJbwWAmq8wzUKRCIttgDsbVBv2ZgfyM_K8Q r5BgSvybjcC4qiQoTkkeOlgx4DY-2wrgiGxD84u3GcAYZoHNx5tDFS64geGJHmnxSKF_fYVSleUEbY PqYjihlkziN-wke-pucviO2sHP4a7Z-G_ALUH-GlXD_CgY_mrD95t2rSBhcWYRMSyvYa3OWzGI.Q5TeKmioy37YY LNSgtkLj6pEFKuBX-UgRkRRPOJvDNA&dib_tag=se&keywords=deep%2Bcycle%2Bagm%2Bbattery%2Bfor%2Bsola r&qid=1713182254&sprefix=deep%2Bcycle%2Bagm%2Bbattery%2Bfor%2Bsolar %2Caps%2C127&sr=8-4&th=1

Thanks again for all the help!