Solar advice for my hot tub

I would like to charge my hot tub using solar. It is a basic inflatable that uses 120 volt but I don’t have electrical in my desired placement. Can I do solar for this hot tub for $400 or under? I would use it regularly but not necessary to have an over abundance of energy in the non-summer months. I live in Southern California. I have no experience with solar.

Hot tub Specs from the manual:
110-120 AC, 60Hz,
Single Phase 12A at 68degrees F, 20 C
6.5A for massage blower
11.3A for heat element
0.7A for water pump

I would appreciate any advice. Thanks!

Jeffkg1 said:

I would like to charge my hot tub using solar. It is a basic inflatable that uses 120 volt but I don’t have electrical in my desired placement. Can I do solar for this hot tub for $400 or under? I would use it regularly but not necessary to have an over abundance of energy in the non-summer months. I live in Southern California. I have no experience with solar.

Hot tub Specs from the manual:
110-120 AC, 60Hz,
Single Phase 12A at 68degrees F, 20 C
6.5A for massage blower
11.3A for heat element
0.7A for water pump

I would appreciate any advice. Thanks!

Click to expand...

Nope. Not even close.

11.3A * 120V = 1320W
a 6.5A massage blower is an electric motor (pump), so it may need as much as 30A to start (30A * 120V = 3600W).

Sounds like this thing needs a 20A circuit too, not just 15A.

Your inverter alone will cost more than $400.
You'll need batteries unless you only plan to use during peak solar... which isn't the optimal time to use a hot tub, and you'll need on the order of at least 1000W of solar to get a couple hours of daily use assuming you don't lose much heat from the water. 1000W of solar will take at least three to four days to heat water from 68°F to 105°F.

Electric heat and electric motors are about as bad as it gets for off-grid demand.

Wow! Thank you for this detailed and very helpful response. You’ve made my decision so easy now. This is what these forums are for and I greatly appreciate your time. Cheers!

While sunshine eggo is not wrong, let me offer an alternative scenario. A couple of years ago, a neighbor offered up two solar thermal panels. Not evacuated tube, just the copper pipes with fins in a box with glass. I got them home and amazingly they didn't leak. A year before, we bought a 350gal rubbermaid stock tank for a summertime kids play pool. Two and two came together and I plumbed the two panels in parallel, and used an old mag drive submersible pump from my saltwater aquarium days. With just a sheet of greenhouse film on top of the water in the tank, no insulation whatsoever, and by plugging in the pump in the morning and unplugging after work, the vast majority of days outside of winter require stirring the tank a bit at 9pm to cool off the water. The hottest I ever got it to was 125degF. I like starting at 107 with a dip to 103 once you've sat with the cover off for half an hour. With some insulation and active control, all of this would be more convenient. It depends on how much you want to think about it and put in some work each day. Perhaps you could find some craigslist panels and some scrap insulation? I have been super impressed with what these ancient panels can do. A small pump is essential. Skip the thermosiphon stuff.

You can run the system of the grid. In addition, just connect a heater to some solar panels directly (or through a switch or solid state relay) and the heater in the hot tub to pre-heat the water. There are many ways to do it, you can even put a coil of regular wiring in the pool if you don't care about aesthetics. Just calculate how big a heater would a good fit for your solar panels (you can use higher Wattage heaters on lower voltage at a reduced capacity, they don't need to be DC) and make sure all the electricity connections are REALLY watertight and safe! Every Watt you get from solar to heat the water is a Watt you don't need to get from the grid.

Lots of articles on-line with possible options on how to do it, including this forum.

Likely not going to find the pv to do it dc direct for $400.... maybe a whole old stack from a decomissioned syestem from craigslist or the like? Anyway, the op will have to put in some work, likely both initially and ongoing, to have soaking water after the sun goes down. You can get ghetto, just unplug everything before getting in....

Being in so cal helps them in the solar thermal department.... considerably.