I have read quite a bit on PV systems and am just beginning to understand some basic concepts. I read the post on this forum regarding the ease of installation of the pool heating panels.

I am wondering if converting my pool filter pump to a DC motor and PV panel energy source might be a good first project and am asking for any info that might help me. I think Solar Guppy has some experience in that area. What do you think?

I've learned a few things,

DC motors, unlike AC motors have brushes that phyically wear with use. Where a AC motor might go for 5-10 years without maintanace a DC motor running 10-12 hour every day might only make it one year. I my case it lasted 7 months

There needs to be sometype of controller to limit the amps going into the motor. I had 1500 watts of PV directly connected to a 3/4 HP motor. when the motor failed it was due to the wires connecting to the brushes had overheated and failed. One could use much less PV but then "normal" performance as compared to a AC motor will only be for an hour or two per-day, with the 2X of PV to HP rating I was getting very good pool filtering performance

Also if one has solar thermal as I do, you need the additional PV to keep the motor running close to peak many hours for the thermal panels to work properly.

For now, its just simpler to run the panels into a Grid-Tie inverter which gives me 6-8kWh day and run the AC pump according number of hours

I've thought about modifing a Charge Controller to deal with the needed regulation but for now I have a full plate of things to do

It seems that things are never as simple as one would think them to be. That does make sense to me. I guess I will just have to start thinking of a grid tie system and do it incrementally with the first phase being enough pv generating capability to run a few things such as the pool pump. Seems the key might be rewiring some circuits in the house to put a couple of items, the pool pump for example, on a circuit to the inverter.

With gridtie there is no need to rewire anything. Power is consumed onsite by something or the meter runs backwards, providng you have the proper meter and an interconnection agreement with your electric provider

I just keep track of what the solar generates in kWhr's and run the pump for the equvilant time.

If your looking to save dollars, Solar PV is not the way to go here in Florida. Your much better off reducing the runtime on the pump and making sure you have a high efficiency AC pump. Most pumps are also oversize BIG TIME.

A 1/2 hp motor without solar thermal will run a pool just fine, I use 3/4 due to the 20ft of head for the thermal. Keep in mind, if you change the HP of your pump, you have to change the impeller, otherwise you'll just run your smaller pump harder as the RPM dictates the amount of work required. Bigger HP motors have bigger impellers (I learned this the hard way )

In summary, install a smaller pump/impeller, make sure you have the pump on the timer, I currently run for 5 hours per day, in a 1-3-1 run periods (9am-10am,11am-2pm,6pm-7pm all other times its off)

Why the 1-3-1 periods instead of a continuous 5 hours around the middle of the day?

Better at cleaning the the bugs out of the water after the afternoon storms (rainy season), same for the morning and the pool is a screened but knats seem to get thru especailly with rain!.

Wow. That is the most carefully planned pool filter cycle I have ever heard of. I am running mine about 6 hours starting around 9 am.