Inverter (small)

[RockyinNM]

OK, so I'm on the grid, but have solar water well, and solar hot water, (evacuated tubes)-
So this is what I would like to do, the solar hot water runs when there's daylight--it has a .95 amp circulating pump that is 115v--I would like to install a 12v solar panel on roof, and feed it directly to a (small) inverter to run the 115v AC circ. pump. No batteries needed!
Any ideas on a inverter that can tie directly to the solar panel, and run the pump.
Thanks, Rocky in NM

[J.P.M.]

OK, so I'm on the grid, but have solar water well, and solar hot water, (evacuated tubes)-
So this is what I would like to do, the solar hot water runs when there's daylight--it has a .95 amp circulating pump that is 115v--I would like to install a 12v solar panel on roof, and feed it directly to a (small) inverter to run the 115v AC circ. pump. No batteries needed!
Any ideas on a inverter that can tie directly to the solar panel, and run the pump.
Thanks, Rocky in NM

Unless it's for a hobby kind of reason, I'd suggest keeping the pump for the solar hot water system on grid power. Less hassle.

[RockyinNM]

We have many outages in this area---1 to 3 @ month, lasting 2 to 7 hrs, it would be nice to make hot water, without firing up the generator.
Just trying to ck out my options.
thanks

[Sunking]

So this is what I would like to do, the solar hot water runs when there's daylight--it has a .95 amp circulating pump that is 115v--I would like to install a 12v solar panel on roof, and feed it directly to a (small) inverter to run the 115v AC circ. pump. No batteries needed!

Yes batteries are required. Very simple system design; 0.95 amps x 115 volt x 14 hours = 1.53 Kwh

That requires:

Panel Watts = 850 watts
12 volt Battery Capacity = 640 AH
MPPT Charge Controller = 65 Amps
Inverter = 200 watts.

Should not cost a penny more than $3200, with roughly a $1500 battery you replace every few years.

Have a nice day.

[J.P.M.]

We have many outages in this area---1 to 3 @ month, lasting 2 to 7 hrs, it would be nice to make hot water, without firing up the generator.
Just trying to ck out my options.
thanks

Understood. I lived in NM for a few yrs. Saw many thermosiphon batch heaters. PV pumping can work. 1st pumped DHW system I designed had DC pump and a small panel. Scrapped the pump & went to 120 V pump after about a yr. of fooling around. Maybe things are better now, but back in the day, a lot of such systems were sort of mickey mouse. Some approx. version of flow proportional to irradiance was a nice concept, but proved not worth the price in terms of initial price vs. hassle or potential lost production to me.

[SunEagle]

OK, so I'm on the grid, but have solar water well, and solar hot water, (evacuated tubes)-
So this is what I would like to do, the solar hot water runs when there's daylight--it has a .95 amp circulating pump that is 115v--I would like to install a 12v solar panel on roof, and feed it directly to a (small) inverter to run the 115v AC circ. pump. No batteries needed!
Any ideas on a inverter that can tie directly to the solar panel, and run the pump.
Thanks, Rocky in NM

Sorry. You really can't connect a pv panel directly to an inverter to run an AC load. You will need batteries and a charger or a special DC voltage pump that is run through a controller with a solar panel connected to it. Those are not cheap.

[organic farmer]

We have many outages in this area---1 to 3 @ month, lasting 2 to 7 hrs, it would be nice to make hot water, without firing up the generator.
Just trying to ck out my options.
thanks

Greetings, I live in Maine. I also have grid power, and the grid here is very much like you describe in your state.

[RockyinNM]

OK, I get it! Just thought I would ask--I know I (probably) could change circ. motor out to a 12v--would that allow me to go direct to solar panel??

[Wy_White_Wolf]

If you wish to run solar direct you need to forget the AC pump and go with one that is capable of running in that mode.

WWW

[bcroe]

What is the gph and head pressure required of the pump? I would elect to use a 12VDC pump connected to
a standby battery, which is kept at float voltage by an AC charger large enough to run the pump when it comes
on. So the battery would have a very long life, essentially in float all the time except for outages. The panels
really aren't the best approach to this solution. You might be able to use a battery already there, such as a
stored vehicle or gen set.

I have a 12VDC pump that runs on 4W, but only at no head. Bruce Roe

[PNPmacnab]

I'm curious as to what this system is, domestic water or hear? Is it a closed loop and under what conditions does it run, on a timer or thermostat or just all the time. If the sun is low level can it be off for a time?

[RockyinNM]

Yes, residential--36 evacuated tube, 120 gal.solar water heater, with 1500 watt. elec. back up. It is a closed loop drainback. It is run with a thermostat that has a 13 degree difference from the collector-from the tank temp. It has a small 115v ..95 amp circ.pump.
If it was just me here, it would supply all my hot water needs, but TW (the wife) draws a big bath every evening.