Using a generator + 220v plug to send out 220V (to TEST out hot tubs)

jiuchessu

Well-known member
Jun 19, 2020
76
Los Angeles
Hello,

As a mover, I come across hot tubs. Some are from the 80s and can't be resold even if they work or have had repairs done (pump is good, heater is good, control panel is good etc). Some are taken directly to the landfill. Some are removed, and are from the late 90s, early 2000's and people are willing to buy them for the prices that I sell them for ($250, $500 gets them out of here same day sometimes). I get about 1 hot tub per month so it's not a big business for me, but a few extra hundred dollars a month is awesome. I only sell them if I see them working before I remove them. However, sometimes people don't want to refill them and test them out, especially if they are paying for "junk removal". Since I don't have an office, I bring them home (i can hold one maybe to tubs if needed).

This means that I don't want someone coming back to my house after being sold a non working tub that was advertised as working. So I trash the ones that I can't see working.

Another problem is that I rent this house. There is no 220/240v set up. I personally have a 120v spa because of this. Don't want to bother the landlord and I'm happy with it.

I would like to do the following. Test out every hot tub that I come across.
Here is what I'm setting up.
A few water holding barrels that can fill the largest 8x8 tub (more or less) so that I can use my waterpump to transfer the water from those tanks to the tub and once I finish my test, send the water back into those barrels. The goal is to conserve water and reuse that water a few times.

Can I use a generator for this? If so, how many Watts, Apms should the generator have?
Can I use the 220v cables coming out of the spa's (most of the time they have us take that as well) and wire it to something like this:
https://www.amazon.com/Mophorn-Gene...9Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

and then use that plug to plug it to a generator like this

I'm hoping that I can even salvage parts from old tubs (sometimes they have been upgraded and are newer than the tub) and sell them once I figure out hot to test them as well.
 

Andrew_D

Well-known member
May 8, 2020
59
Manitoba, Canada
In theory, yes. The cord you linked has 4 wires, which is good as this gives you all the lines needed for any testing (line1, line2, neutral, ground). No reason why a generator won't work. Just keep in mind that the generator needs to be sized large enough. Loads like motors (ie pumps) usually need a generator sizes 1.5 - 2 times bigger than the motor. A 3hp pump would be 18-20 amps, so if the biggest pump is 240V, 20A you would need at least 240V x 40A = 10KW generator.

Another idea, instead of water barrels would be an IBC. 250gal is a very common size, although there are other sizes available also.

Andrew
 
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jiuchessu

Well-known member
Jun 19, 2020
76
Los Angeles
In theory, yes. The cord you linked has 4 wires, which is good as this gives you all the lines needed for any testing (line1, line2, neutral, ground). No reason why a generator won't work. Just keep in mind that the generator needs to be sized large enough. Loads like motors (ie pumps) usually need a generator sizes 1.5 - 2 times bigger than the motor. A 3hp pump would be 18-20 amps, so if the biggest pump is 240V, 20A you would need at least 240V x 40A = 10KW generator.

Another idea, instead of water barrels would be an IBC. 250gal is a very common size, although there are other sizes available also.

Andrew
I've seen pumps that show 5.5hp. Not sure if that is the max since I never actually paid attention to the specs. This is where it gets a bit confusing. If a 220/240 pump is 3hp vs another pump thats also 220/240v but 6hp for example, will it take more amps as well?

I would like to get a generator that will be able to handle all 220/240v hot tubs so that I avoid having to buy a more powerful one late.
Do you think a generator pumping out 10KW can handle all tubs?

Also, Thanks for the IBC info. It looks like I can use a pallet jack (luckily i own one) to maneuver it around if needed (though I would rather use a hose), but it's good to have a moving option.
 

jiuchessu

Well-known member
Jun 19, 2020
76
Los Angeles
In theory, yes. The cord you linked has 4 wires, which is good as this gives you all the lines needed for any testing (line1, line2, neutral, ground). No reason why a generator won't work. Just keep in mind that the generator needs to be sized large enough. Loads like motors (ie pumps) usually need a generator sizes 1.5 - 2 times bigger than the motor. A 3hp pump would be 18-20 amps, so if the biggest pump is 240V, 20A you would need at least 240V x 40A = 10KW generator.

Another idea, instead of water barrels would be an IBC. 250gal is a very common size, although there are other sizes available also.

Andrew
Also, for what im doing would you recommend a gas powered generator or Electric? It would be nice to be able to just leave it plugged to the house whenever I need to reload it vs buying some kind of fuel/gas/propane.

However, I just starting looking into this so i know close to nothing about either one. I don't know which of the two are generally less expensive, more reliable, etc.. Sorry to ask you this much, but you seem to know about generators and hot tubs
 

1Sammy

In The Industry
Jul 20, 2017
380
Windsor, Ontario. Canada
The motor is not the only thing to look at, the heater will take a lot of amps also depending on the size and there are many. Never seen an electric generator :(.. For a fraction of the cost of a huge genny you can tap off a 220V plug from your main panel and can remove it if / when you ever move.
 

jiuchessu

Well-known member
Jun 19, 2020
76
Los Angeles
The motor is not the only thing to look at, the heater will take a lot of amps also depending on the size and there are many. Never seen an electric generator :(.. For a fraction of the cost of a huge genny you can tap off a 220V plug from your main panel and can remove it if / when you ever move.
I see. Ok so no electric generator no problem. Our landlords are not the easiest people to get along with, I really dont want to mess with the box, I can already picture the wife yelling at her husband about it, even though he had nothing to do with it. What is a safe bet when it comes to amps? I know im spending a bit on a generator, but I plan to make the money back within the first 2-4 hot tub sales so im ok with that. I just want to make sure that I know how many amps, watts I need to look out for when finding a generator
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
6,904
Central California
There are 220V extension cords available. Isn't there a 220V outlet somewhere in the house? Behind your dryer? In a laundry room or garage where the laundry hookups are? Those should be 30 amps. No laundry hookups? Are there any 220V breakers in the box? If so, what are they labeled for?
 

jiuchessu

Well-known member
Jun 19, 2020
76
Los Angeles
There are 220V extension cords available. Isn't there a 220V outlet somewhere in the house? Behind your dryer? In a laundry room or garage where the laundry hookups are? Those should be 30 amps. No laundry hookups? Are there any 220V breakers in the box? If so, what are they labeled for?
we dont have 220v plug ins. In CA its very rare. I used to move appliances for years, I maybe saw 20 houses with 220v hookups. Dryers are gas powered here. Washers are regular 120v. We would need to hire an electrician to install a 220v set up coming from the box
 

Dirk

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TFP Guide
Nov 12, 2017
6,904
Central California
we dont have 220v plug ins. In CA its very rare. I used to move appliances for years, I maybe saw 20 houses with 220v hookups. Dryers are gas powered here. Washers are regular 120v. We would need to hire an electrician to install a 220v set up coming from the box
Interesting. They've been in every house I've owned so I just assumed they were common. Bummer. OK, back to your regularly scheduled programming...
 

Andrew_D

Well-known member
May 8, 2020
59
Manitoba, Canada
Yes, 240V 6HP will draw approximately twice the amps vs 240V, 3HP. Depends on motor efficiency, but approximately 2X.

I have no idea what size generator you would need. I don't have a hot tub, so have no idea what the draw is for them.

No idea what an electric generator is. Seems counter-intuitive...... plug it in to the house, to generate electricity, to use at the house?

Gas or diesel generators are what you are after.

Andrew
 

jiuchessu

Well-known member
Jun 19, 2020
76
Los Angeles
Yes, 240V 6HP will draw approximately twice the amps vs 240V, 3HP. Depends on motor efficiency, but approximately 2X.

I have no idea what size generator you would need. I don't have a hot tub, so have no idea what the draw is for them.

No idea what an electric generator is. Seems counter-intuitive...... plug it in to the house, to generate electricity, to use at the house?

Gas or diesel generators are what you are after.

Andrew
What "draw" categories are there? Volts seems to be the easiest. I search 240v generator and I get a list. But the rest is what gets confusing.

If say I find out that the maximum amp to be pulled is 40amps, would i be ok with a 40amp generator? Or would I need to get a 50 to be safe? Other than amps, is there anything else like "watts"? that are a factor?

I thought about the electric generator since we have these jump starters for cars that are able to be charged overnight with a regular 120v. But battery powered was just a bonus, not really a big deal.

I guess finding out the max amp output of a hot tub is the next step
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
6,904
Central California
@Andrew_D answered that earlier. He wrote "A 3hp pump would be 18-20 amps, so if the biggest pump is 240V, 20A you would need at least 240V x 40A = 10KW generator." Watts = Volts x Amps. 240 x 20 = 4800, 4800 * 2 = 9600. Andrew rounded that up to 10000, or 10K, so 10KW. KW = kilowatts. So you'd need a 10 kilowatt generator. But as someone else pointed out, some tubs have heaters, or other electronics I suppose, so it's not always going to be about just the motor's HP.

And just to keep your lingo straight: hot tubs don't output amps, they draw amps. So, yes, you need to determine how many amps the largest tub you'd want to work with will draw, then go 1.5 to 2 times bigger (according to Andrew).

A quickie google of "how many amps do standalone hottubs draw" comes back with breaker requirements of 30A, 40A, 50A and even 60A, depending on model. That doesn't mean that bad boy is going to use all 60 amps to fire up, but that the manufacturer recommends a breaker of that size to properly protect the tub and your wiring. The actual amp draw will be some amount less. Not sure where that number would be available other than from the manufacturer or perhaps the tub's documentation, which you can probably find online if you have brand names and/or model numbers.

What does a 30KW generator look like? o_O
(240 x 60 x 2 = 28800)

Here's a 20KW, only $5K. Runs on natural gas. May be better to figure out a way to schmooze your landlord...
49LX82_AS01.jpeg
I'm going to guess you can fire up a tub for a few minutes with a much smaller unit, but I'm also going to guess you're going to be into four figures, even if it's low four-figures.
 
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Brett S

Well-known member
Mar 15, 2019
709
Orlando
What "draw" categories are there? Volts seems to be the easiest. I search 240v generator and I get a list. But the rest is what gets confusing.

If say I find out that the maximum amp to be pulled is 40amps, would i be ok with a 40amp generator? Or would I need to get a 50 to be safe? Other than amps, is there anything else like "watts"? that are a factor?

I thought about the electric generator since we have these jump starters for cars that are able to be charged overnight with a regular 120v. But battery powered was just a bonus, not really a big deal.

I guess finding out the max amp output of a hot tub is the next step
Generators are usually rated in watts, rather than amps. However watts = volts times amps. So if you want a generator that can supply 50 amps at 240 volts, then you need a 12000 watt generator. That is going to be a pretty sizable generator. It’s going to be big, heavy, and expensive.

Unfortunately with hot tubs you’ve got two things working against you. The large pump can draw a lot of power and the heater can also draw a lot of power. And together it can add up to a massive amount of power.

An “electric generator” isn’t really a thing. But what I think you’re referring to are things like the goal zero yeti power station. It’s basically a bunch of batteries that can provide power when you’re away from an outlet. But again, the amount of power you need for a hot tub makes something like that prohibitively expensive. The largest goal zero yeti costs $3000 and can provide 1500 watts of power. As I said above, you need something that can provide nearly 10 times that much power. If you wanted to do this with batteries you would probably need to spend well north of $10,000 and frankly I’m not even sure that anyone makes a portable battery operated power station that can provide that much power.

The other thing that worries me a little is that you seem to be jumping into this without a lot of knowledge. Now don’t get me wrong, I certainly don’t expect you or anyone else to know everything and you have to start at zero when you learn something new. There’s no problem with not knowing something, and reaching out and asking for help and doing research is great.

However, if you have little knowledge and get a term wrong no one gets hurt. You learn the new term and don’t make the same mistake in the future. But 240V of electricity, especially with the huge power draw of these hot tubs is downright dangerous. It can kill you or anyone around you. And adding water to the mix just makes it even more dangerous. If you don’t know what you’re doing when you try to wire the hot tub to your generator and you make a mistake it could easily be enough to send you to the hospital or even kill you.

I appreciate what you are doing here and not only can you make a little extra money on the side, but you’re helping to promote reuse and keeping huge things out of landfills and I’m all for that. But unfortunately with the fact that you’ll need a very large generator due to the huge power draw... and the fact that this could actually kill you if something goes wrong, I’m not sure that this is something that you should be pursuing.
 
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Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
6,904
Central California
Maybe modify your business model? You stated you normally junk tubs you can't see working, due to the fact that the owner doesn't want to fill the tub. So you modify your service. You charge x amount for a tub that works, and y amount for one that doesn't, or can't be demonstrated as working. The delta between those two prices might entice the owner to fill the tub for you. Or reveal that the owner already knows it doesn't work and is just trying to hide that fact. Then you test on site before you move it. Eliminate the whole testing/storing at home aspect and stay out of the tub-wiring business all together.

@Brett S and I both cautioned you about the size of the generator you're going to need, but he brought up a much more important issue. Hot-wiring 240V hot tubs is not like plugging in your 120V model...
 
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cowboycasey

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Jul 3, 2013
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Fletcher, OK
I have a whole house generator that is 20K, it can run my 1hp pool pump, 2 2hp hot tub pumps and a 6000 watt heater (my hot tub took a 60 amp breaker) along with my house.. all those pulled about 13 kw...

A 10 kw Generator should run 95 % of all hot tubs out there... You may be able to find a generator rebuild company and buy a used light generator, they are right around the 9 to 10kw size.. they are going to sell between $2,000 to $4,000 depending on quality, type and size... A diesel gen is better and gas is cheaper but your going to have a hard time finding a used gas gen as they normally die a horrible death and can't be repaired...
 

Andrew_D

Well-known member
May 8, 2020
59
Manitoba, Canada
Again, since I know little about hot tubs and what type of safeties or interlocks are in there, can you use a smaller generator and test each piece seperately? If it has a 1/2 hp motor (3A) for circulation and a 1 hp motor for jets (5A) and a 5KW heater (20A), you wouldn't need to run all ~30A at the same time. I mean, you don't need to set it up and have a soak and a beer in it!! But maybe the heater is wired so that it won't run without pump flow, I have no idea......

Andrew
 

Andrew_D

Well-known member
May 8, 2020
59
Manitoba, Canada
Another option: I have no idea if you live in a large city, small town, or acreage. But, if you have a larger property, do you have a tractor for yard maintenance? One that has a rear PTO? Pull type, or 3 point hitch mount, generators are often cheaper than ones that have an engine to run them...

Andrew
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
6,904
Central California
Just to reiterate (my favorite thing!): we're talkin' $250... that's to disconnect the thing (wiring and plumbing), drag it home, wire it up, fill it, test it, then empty it. If it works, then you gotta go through the trouble of finding a buyer and dealing with all that, if not ya gotta haul it to the dump? Sounds like we're talkin' doing that for a year or three, at least, for "free," to pay for the generator to make all that happen? And that's if they all actually work?!?

Sorry, just not seein' it. I think you've already got the working model. If it works on site, you resell it. If not, dump it. Incentivize the owner somehow to let you fill it onsite. Either by discounting your rate if it works, or flat out refusing to serve them if you don't get to fill it. Make that a condition of your haul-away service. You offer the guy a $50 discount if the thing is running when you get there, I'll bet you get plenty of takers. The ones that don't bite know their tub doesn't run...

If you were doing one of these a day, and most of them worked, and you could get $500-1000 for them, then you've maybe got a plan. Otherwise... sounds like a lot of trouble. And we're all about being Trouble Free, aren't we?! ;)
 
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