Homemade Load Bank

[dav5]

I have 2 "milk house heaters" that I assume are similar to garage heaters. They are 4500W each. I hooked them up plus a couple of 1500 W baseboard heaters. My 803A was quite happy with that amount of load.

 

[csmitty]

Digging up an old thread here, but I'm looking to put together something similar soon. Having an 802 though the common 5400W elements are a bit much for stepping up the load. I was looking at the 3000W elements but those are $20-30 more typically. I was thinking of taking the 5400W elements and basically removing half the wire. Effectively cutting it down to the 2700W range. I haven't looked at one to see how the wire is connected to the plug but just brainstorming a bit and thought I'd see what folks thought. It would cut down on cost and allow me to step up the loads gentler on a 802.

 

[csheath]

Digging up an old thread here, but I'm looking to put together something similar soon. Having an 802 though the common 5400W elements are a bit much for stepping up the load. I was looking at the 3000W elements but those are $20-30 more typically. I was thinking of taking the 5400W elements and basically removing half the wire. Effectively cutting it down to the 2700W range. I haven't looked at one to see how the wire is connected to the plug but just brainstorming a bit and thought I'd see what folks thought. It would cut down on cost and allow me to step up the loads gentler on a 802.

Taking out half the wire would increase the load. Connecting two 5400 watt elements in seris decreases the load. That is what I did on one of my circuits.

They are currently showing out of stock but look at the Heater Deal thread. Buying one of those would be the way to go IMO. They also make a 7500 watt version. Other sellers have them listed for a little higher price so shop around or keep checking to see if Rural King gets them back in stock.

 

[csmitty]

Taking out half the wire would increase the load. Connecting two 5400 watt elements in seris decreases the load. That is what I did on one of my circuits.

They are currently showing out of stock but look at the Heater Deal thread. Buying one of those would be the way to go IMO. They also make a 7500 watt version. Other sellers have them listed for a little higher price so shop around or keep checking to see if Rural King gets them back in stock.

Yea thats a good point. It was early and didn't feel like doing math. I had seen those heaters and it would be a good option if they were in stock. Would save some time anyways and be multi purpose. Guess I'll just suck it up and get the 3000W units. Two of those should be good and I can add a small 120V space heater if I need to.

 

[csheath]

In hindsight I don't see any reason to under or over load a unit. My monthly test consists of visual inspection of components and fluid levels followed by warming the engine up then running for a couple hours with two of the 5400 watt elements turned on. After the run I look everything over again and top up the fuel tank.

For an 802 you will probably do just as well to build a mini unit with one 5400 watt element and let r rip.

 

[csmitty]

In hindsight I don't see any reason to under or over load a unit. My monthly test consists of visual inspection of components and fluid levels followed by warming the engine up then running for a couple hours with two of the 5400 watt elements turned on. After the run I look everything over again and top up the fuel tank.

For an 802 you will probably do just as well to build a mini unit with one 5400 watt element and let r rip.

I would like to take it to 6250W from time to time since they are pretty underrated at 5KW. My idea to take it up there in a few steps is just for diagnosing any issues. Currently mine will trip out before hitting 100% (hot water heater) Does just fine with lighter loads though. Probably need to clean the AC connection switch but regardless if I dumped the 5400Ws on it right now it would probably trip. In the future with it cleaned up I'm sure it wouldn't have a problem and could add a small load if deemed necessary. The $70 heater would be perfect. Not as fun to make but time is a at a premium as well right now.

I haven't even started mine since the hurricane in Sept.

 

[Farmitall]

Just ordered two of these: https://partsmoito.com/products/dryer-heating-element-for-kitchenaid-keys750jt1-dryer

They will be mounted in a metal box with a ten inch Rotron 240v fan to cool them...much like the OP's design.

I've had the fans for ages from my "dumpster diving" days. They were mounted in small cryogenic refrigeration units. The fans will also run on 120v, they just turn slower.

I think dryer elements are the way to go for a load bank, quick and easy and pretty cheap.

Thanks for the design ideas OP!!

 

[jcollings]

Digging up an old thread here, but I'm looking to put together something similar soon. Having an 802 though the common 5400W elements are a bit much for stepping up the load. I was looking at the 3000W elements but those are $20-30 more typically. I was thinking of taking the 5400W elements and basically removing half the wire. Effectively cutting it down to the 2700W range. I haven't looked at one to see how the wire is connected to the plug but just brainstorming a bit and thought I'd see what folks thought. It would cut down on cost and allow me to step up the loads gentler on a 802.

I searched several and the only ones I found that had a specification were 5400 watts. 5400W / 240V = 22.5A. 240V / 22.5A = 10.66 ohms. You can connect two elements in series to cut that in half. I checked one of these and it read 10.? ohms. Didn't pay it a lot of attention. Two of them in series were right at 20 ohms even.

There may be elements out there that have different values but I figured loading my 10KW generator to 13.5KW should be sufficient for testing. It runs with no effort with two of the 5400W elements turned on and reads over 100% on my load meter. My unit's voltage drops as I load it and I am going to study that but I think it's a natural phenomenon on all generators when running near capacity. I'm not sure what effect the cooling of the elements has on the current draw, if any, but it seems it would have to lower it some if you keep them cooler. The ohms law calculations don't seem to match my real world measurements but I am also using an inaccurate HF ammeter. I checked the ammeter against a Fluke and it was about 3.5 amps low on a 480V 3 phase boiler with 30KW in elements. 3 phase has a different formula but amps is amps when you are reading two meters side by side on the same leg. With two 5400W elements turned on I was reading 35.4 amps. Adding the 3.5 amp difference and calculating the voltage drop still does not come up to the calculated load.

All that said I am trying not to over think it. I suspect if my voltage drops to 230V and 58 hertz my house will survive or I will learn another expensive lesson in life.

I used your design in some way,Thanks!

 

[4Rider]

csheath,
nice howto building DIY load bank! Thank you for sharing! Going similar route myself. I have used old stove for load bank for my MEP-803A. Not satisfied completely as stove's thermostats constantly switch elements on and off, thus not providing the constant load I need for exercising . So I decided on buying four oven heat elements ($10.32 each) which are rated @ 3400W 240V each and install them in metal box with fan to dissipate the heat. Planning on adding service panel with 4 circuit breakers for switching on/off. My math is a follows. 3400W/240V=14.66A for each element, for total of ~56A (13600W) if using all four elements in parallel or ~44A (10200W) for 3 elements in parallel. Also want to be able to keep the generator load between 50%-75% when power goes off. Typically my house only use 2000W-3000W or less during night, but occasionally I want to use cloths dryer or stove/oven with ability to manually add/remove loads with the DIY load bank. What are your thoughts? Thank you!

 

[NormB]

I was going to post pictures, which I’ll get around to.

I bought a power distribution box, made a 50 foot extension cord (6/4 rubber cable), another 30amp ext cord (coleman, premade/commercial) then made a 30 amp splitter so I could run TWO 4800 watt heaters. One I’d bought a year ago to load the 802a, it was pricey, around $99 delivered.

Recently ran my new (to me) 803a with one heater, and two water tank heaters (5500 and 1500 watt) plus a hair dryer and small 1500 watt space heater (added up to about 12kw). Ran flawlessly for about a half hour, just long enough for the water in a 20 gallon garbage can to come to a boil.

Then I found a deal on the jungle website two weeks ago for another heater: https://smile.amazon.com/gp/product/B002SG7EWG/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

Got it “used” (never out of box, just returned for some reason), delivered, for $31 and change/tax.

I coulda bought a dedicated load bank, but for me, this is more practical, as the idea of the PDU/ext cord and splitter is, if we get another ice storm and lose power for a day (or five - the record here, but 24-28hrs isn’t unusual), I can fire up the genset, get the splitter on the main floor, heat that floor and the basement (where the water pipes are), burn firewood in the firebox, keep the house nice and toasty warm while running some lights, toaster, microwave, coffee make, refrigerator. Not all at once, of course.

If I need to load test/decarbonize the gensets, I can put enough load onto it/them to suit.

Many ways to skin a cat.

 

[155mm]

csheath,

can you scribble me a schematic for this? What did you use for switches for the different load? Did you only run single ph?

I have a 30kw load, but I need a 60kw for a MEP006A, so building one is cheaper that buying, or even renting a load tester that large.

 

[Light in the Dark]

I would start your build with these 155mm: https://www.alpinehomeair.com/viewproduct.cfm?productid=453068826

Meant for air handling systems. Surely you can fabricate up an appropriate tunnel to mount 3 of these into with a real high cfm fan at one end (and a critter guard at the other). Thats what I would do at least.

Runs at 240 single too!

 

[Light in the Dark]

So as its already got a breaker wired in standard, you could simply wire back to a panel with more breakers of the same size, and make a redundant switch. This would allow for centralized control. I would probably do that just for safety sake, due to the amperage being drawn.

 

[csheath]

csheath,

can you scribble me a schematic for this? What did you use for switches for the different load? Did you only run single ph?

I have a 30kw load, but I need a 60kw for a MEP006A, so building one is cheaper that buying, or even renting a load tester that large.

I don't think my model would be a good one to follow for your application. You should research further to fabricate a suitable 3 phase load bank.

For switching I used a 100 amp load panel with 6 120v spaces. That gave me 3, 240 volt single phase circuits. I just use the breakers to switch the circuits.

 

[155mm]

I don't think my model would be a good one to follow for your application. You should research further to fabricate a suitable 3 phase load bank.

For switching I used a 100 amp load panel with 6 120v spaces. That gave me 3, 240 volt single phase circuits. I just use the breakers to switch the circuits.

I was more curious about how you switched the load on/off, cb's would do it just fine.

I will probably go with a 3ph heat unit like LitD suggested, I have an old 200amp distribution box to use as switching, unless the heaters come with cb's.

https://iwae.com/shop/20kw-goodman-...r-handlers-package-units-3-phase-ha10917.html

 

[Light in the Dark]

3ph for this is even better! I didn't look too hard earlier, but glad you found something.

 

[155mm]

you gave me the better idea to look for, thats worth something

 

[jcollings]

I would look for a old ac air handler. Modify with the 3 20k heat strips each on separate breaker. Use the blower, remove the coil. I have seen a libby load bank on ebay awhile back for 900.
Almost pick it up. But it was more k than I needed.

you gave me the better idea to look for, thats worth something

Sent from my SAMSUNG-SGH-I317 using Tapatalk

 

[csheath]

I was more curious about how you switched the load on/off, cb's would do it just fine.

I will probably go with a 3ph heat unit like LitD suggested, I have an old 200amp distribution box to use as switching, unless the heaters come with cb's.

https://iwae.com/shop/20kw-goodman-...r-handlers-package-units-3-phase-ha10917.html

That unit says it includes the limit switches and circuit breakers. You might can eliminate the use of a load panel and just connect the line leads directly to the generator. The problem with doing it that way is having the wiring connections exposed. It may be possible to relocate the breakers that come on the unit and mount them in a project box or something for switching.

If you build a single tube that all three will fit in that will make one hellofaheater! Will need a good 3 phase fan to go with it.

research 3 times and build once.

 

[ZiggyO]

csheath,

can you scribble me a schematic for this? What did you use for switches for the different load? Did you only run single ph?

I have a 30kw load, but I need a 60kw for a MEP006A, so building one is cheaper that buying, or even renting a load tester that large.

I have an Essex electro engineers A698 60kw load bank available...... pm for details

Z