# My4Sons M4 backpack Sprayer Review



## TommyTester (Jul 3, 2018)

My Channel

*Unboxing*
[media]https://www.youtube.com/watch?v=IbqmEa36BhY[/media]

*Gallon Calibration*
[media]https://www.youtube.com/watch?v=EOQFaFp0wkA[/media]

*RUN TIME*
*Results until recharge needed:*
Measured 4 hours run time
Measured 108 gallons with a M4 T-Jet nozzle (Equivalent to 27 full refills)
Estimated 240K sq ft equivalent at 1K/minute 
= 5.5 acres

T-Jet operated at 0.45 GPM with sprayer at max PSI.

[media]https://www.youtube.com/watch?v=a32obMRRAio[/media]


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## Kicker (Apr 5, 2018)

I have the M4 Backpack Gold edition and I love it. I've been very impressed with everything about the unit aside from the sticker/decal that was placed on the tank to indicate how much fluid is in the tank.

I've used it around 4 times so far and had 0 problems since I first got it setup.

I honestly can't say anything bad about it..... yet.


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## TommyTester (Jul 3, 2018)

My Channel

*Variable Pressure Test*
[media]https://www.youtube.com/watch?v=jJZ-08Oahvw[/media]


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## TommyTester (Jul 3, 2018)

Just got in some TeeJet nozzles. They dropped right into the My4Sons M4 wands just like they do on the Chapin.


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## Kicker (Apr 5, 2018)

Tommy, I'm glad you tested the pressure coming from the tank. By my calculations (for my sprayer) i guestimated around 35-40 psi by the amount of time it took to discharge 1 gallon of water using teejet nozzles and referencing the teejet nozzle specs sheet.


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## TommyTester (Jul 3, 2018)

@Kicker .. I ran a series of tests yesterday on all the supplied nozzles, measuring PSI and GPM. As you can tell in the video above, the PSI meter is erratic due to the pulsations caused by the diaphragm pump. This makes taking a good PSI reading difficult. I'm replacing that meter with one filled with Glycerin oil LINK. The oil will dampen out the oscillations.

Although a fixed PSI sprayer is adequate for lawn work, having one with variable pressure opens up a lot of new uses, in addition to allowing use of other Ag nozzles.

In the graph below I show GPM vs. Knob position. Since the pressure knob is variable, I designated position 1 as the lowest setting, which points to "9 o'clock" as if it was a clock face. The knob rotates to MAX at the 6 o'clock position, making 10 positions. It turns out the PSI at each position is a function of the nozzle, not fixed, which makes sense.

I'd like to somewhat "characterize" each nozzle since there is no data on them out there currently. The GPM data will help people estimate when they may run out of ammo at various settings. I'll also be testing other nozzles.


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## TommyTester (Jul 3, 2018)

A look at the nozzles ....

My Channel

[media]https://www.youtube.com/watch?v=ulsYxsZ7cA8[/media]


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## Mozart (Jul 17, 2018)

Tommy, nice job testing the sprayer. I love the graphs as well as your thorough, scientific approach to testing.

Can I make one request? As you test this sprayer, at some point can you demonstrate how to achieve uniform application considering nozel height, walking speed and lane overlap? In particular I'm interested in seeing the ideal lane overlap (fan tip).

Thanks and keep up the great work!


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## TommyTester (Jul 3, 2018)

Mozart said:


> Tommy, nice job testing the sprayer. I love the graphs as well as your thorough, scientific approach to testing.
> 
> Can I make one request? As you test this sprayer, at some point can you demonstrate how to achieve uniform application considering nozel height, walking speed and lane overlap? In particular I'm interested in seeing the ideal lane overlap (fan tip).
> 
> Thanks and keep up the great work!


Of course. One step at a time. I built this jig today to test flat fan nozzle distribution uniformity at various heights, pressures, and GPM. From that data we can make informed decisions. :ugeek: <--- geeking out.


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## Levif (Jul 5, 2018)

Great in-depth review! I'll add my experience as I have really enjoyed this sprayer. I purchased it for work/personal use four months ago. I do ag/rights of way and aquatic spraying most sites are habitats along the river average 30-40gallons a day. The adjustable psi is king I could not use a fixed psi sprayer as I need to adapt to conditions. Battery/pump life have no decreased at least to a noticeable amount and despite being tossed around in the truck, boat and atv it has held up great.

Initially I was concerned about the plastic frame it's held but would still prefer metal. Straps are wide and comfortable but a waistband strap along with a better chest strap would be warmly welcomed. I don't understand why they used the sticker for gallons it isn't long for the world. Not a fan of the cap seal wish they went with rubber, it can fall out of the groove easily after awhile and if you tighten it down with it crossed you'll ruin it. Just some minor things overall it's a great sprayer


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## TommyTester (Jul 3, 2018)

Levif said:


> Initially I was concerned about the plastic frame it's held but would still prefer metal. Straps are wide and comfortable but a waistband strap along with a better chest strap would be warmly welcomed. I don't understand why they used the sticker for gallons it isn't long for the world. Not a fan of the cap seal wish they went with rubber, it can fall out of the groove easily after awhile and if you tighten it down with it crossed you'll ruin it. Just some minor things overall it's a great sprayer


I'll pass those comments on to the company. I might put 4 dabs of silicon between the lid and the gasket to see if that does the trick. What nozzle(s) do you use?


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## Levif (Jul 5, 2018)

TommyTester said:


> Levif said:
> 
> 
> > Initially I was concerned about the plastic frame it's held but would still prefer metal. Straps are wide and comfortable but a waistband strap along with a better chest strap would be warmly welcomed. I don't understand why they used the sticker for gallons it isn't long for the world. Not a fan of the cap seal wish they went with rubber, it can fall out of the groove easily after awhile and if you tighten it down with it crossed you'll ruin it. Just some minor things overall it's a great sprayer
> ...


That would be great, good idea on the seal. I use adjustable teejet conejets 5500 x6 to 18, turbo teejets, aixr, and xr never used the included wand and nozzles.


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## TommyTester (Jul 3, 2018)

Levif said:


> That would be great, good idea on the seal. I use adjustable teejet conejets 5500 x6 to 18, turbo teejets, aixr, and xr never used the included wand and nozzles.


I'd love to see a pic of the wand you use. Who makes it and why do you prefer it?


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## Levif (Jul 5, 2018)

TommyTester said:


> Levif said:
> 
> 
> > That would be great, good idea on the seal. I use adjustable teejet conejets 5500 x6 to 18, turbo teejets, aixr, and xr never used the included wand and nozzles.
> ...


It's a Teejet wand the company I work for provides them, dfw made a thread about it here https://thelawnforum.com/viewtopic.php?t=12

I prefer it for durability, hand feel and the trigger is crisp. I've broken more plastic ones then I can count and over time the trigger gets sticky on them (solo, chapin and sun)


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## TommyTester (Jul 3, 2018)

Levif said:


> It's a Teejet wand the company I work for provides them, dfw made a thread about it here https://thelawnforum.com/viewtopic.php?t=12
> 
> I prefer it for durability, hand feel and the trigger is crisp. I've broken more plastic ones then I can count and over time the trigger gets sticky on them (solo, chapin and sun)


OK, thanks.


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## TommyTester (Jul 3, 2018)

Nozzle test setup and "wet" run. :mrgreen:

A bit eye-opening!!

[media]https://www.youtube.com/watch?v=xAZOO8l2Omw[/media]


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## Kicker (Apr 5, 2018)

TommyTester said:


> Nozzle test setup and "wet" run. :mrgreen:
> 
> A bit eye-opening!!


Tommy, i'm not sure if you have any of the AIXR tee-jet nozzles, but i'd be curious to see the pattern in catch cups for that type of nozzle for systemic applications.


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## TommyTester (Jul 3, 2018)

Kicker said:


> Tommy, i'm not sure if you have any of the AIXR tee-jet nozzles, but i'd be curious to see the pattern in catch cups for that type of nozzle for systemic applications.


I have these 5 nozzles in house to test near-term:
1. Turbo T TT11002-VP
2. Turbo T TT11004-VP
3. XRC8006-VK
4. AIC11010-VS
5. Chapin Red Flat

I'll add an AIXR to my next buy. Any others? Anyone? Bueller?


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## Mozart (Jul 17, 2018)

Nice setup @TommyTester!

I am surprised to see a dip and rise at each end, I would have expected a standard normal distribution shape.

I wonder if the distribution you recorded is a function of the catch cup shape. There are two reasons I think this may be the case:

1. I would expect the middle of the application to be more narrow in depth (less dispersion) than the ends and the ends more misty (particles traveling a longer distance).

2. The angle at which the water droplets hit the cups may impact collection within the cups. The water droplets are not falling straight down, like rain. Maybe the particles are hitting the cup at the ridge and falling below.

Might get a different picture if your collection apparatus were more continuous with more depth (front to back). I attached a photo and suggestion at the end of this thread.

If the width of application is 42" while the fan tip is 21" off the ground that implies a 90 degree angled tip - is that what you were using?

A few more questions about the last graph in the you YouTube video:

What does the note "100% overlap" mean? Edge of current lane alingned with center of prior lane?

What is the x axis? Total width of 2 lanes combined?

What do the colored lines represent? Nozzle height, lane width, or something else?

Really cool test. Can't wait to see more!! :thumbsup:

Suggestion: just thinking out loud here but what about taking 96 cube ice cube trays (or something similar) and cutting them into 3x4 or 6x4 sections. Each section would replace a collection cup. Each tray would be placed immediately adjacent to the next so there would be no gaps. To measure volume of water, pickup a tray and dump it in a collection cup or other measuring cup and this would give you a good picture of how much product is applied in each band/ice cube tray section.

I wonder if 4 cubes deep would be enough to catch the mist at either end accurately? Six deep might be better. I understand if you don't feel the increase in accuracy warrants the increase in work but I do wonder if the end cups are impacted by the 2 considerations above.


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## Kicker (Apr 5, 2018)

Mozart said:


> Nice setup
> 
> I am surprised to see a dip and rise at each end, I would have expected a standard normal distribution shape.
> 
> I wonder if the distribution you recorded is a function of the catch cup shape. There are two reasons I think this may be the case:


I can confirm that is not the case. With both the provided flat fan tip and the XR 11004 TeeJet when I tested both tips there was a noticeable "dip and rise" in the patter from center to edge.

This was done using just water on my driveway.


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## TommyTester (Jul 3, 2018)

@Mozart ... The way the manufacturer's do it is to have a gutter every 2 inches and channel the entire volume of each gutter into catch cups. They test more that flats. I feel my method is adequate for our purposes as it catches most of the side-side spray and a good amount of the front-to-back spray being that the cups are 4.2" diameter. All we are trying to do is measure and understand the distribution profile so we can figure out the ideal overlap. Yes, 100% overlap means have the tip of your next row's spray reach the center of the last row. This is actually what is recommended for Ag nozzles >80 degrees. The one I tested above was measured at 90 degrees.


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## Mozart (Jul 17, 2018)

Thanks for the info, @TommyTester. Rows of gutters make a lot of sense. I agree your approach is adequate and I think I understand conceptually why there would be a normal distribution with an additional point mass at either end.

So the colored lines on the last graph represent various nozzle heights at 100% overlap?


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## Mozart (Jul 17, 2018)

@TommyTester

I like the idea of testing 100% overlap, and have a suggestion to normalize tests between nozzle heights. Hopefully I can explain well:

Simulate 3 lanes for each nozzle height and perform a 100% overlap. Only evaluate the middle lane at full width and normalize the graphs so that they show the same width and maximum rate in Excel.

For the middle lane you can also calculate an average volume and then a quality of fit against the observed data points. Ideally the average perfectly aligns with the observed values


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## TommyTester (Jul 3, 2018)

Mozart said:


> So the colored lines on the last graph represent various nozzle heights at 100% overlap?


No, the colored lines are inches of overlap using the cup diameter of 4.2 inches as the increment. I simply took the single nozzle data as if it was the first row sprayed, then simulated overlapping the pattern in an adjacent row; adding the values to obtain a mL value for the overlapped area, plotting it, and seeking the flattest result. The flattest result is the most uniform and establishes a value to use while calibrating and actually spraying.

The Ag people have long understood the need for significant spray overlap in order to achieve uniformity for fan nozzles, and with today's 110 degree nozzles they use 100% overlap on their booms (tips of the spray pattern must reach the center of the adjacent spray pattern). We need to do the same both when calibrating and while spraying.


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## TommyTester (Jul 3, 2018)

Mozart said:


> I like the idea of testing 100% overlap, and have a suggestion to normalize tests between nozzle heights.


I've only tested knee height so far. Although I set up the jig to test at various heights, I'm debating if that is worth my time. Knee height is a comfortable height and well understood.

Since my cup set-up is wide enough, I could run 30 seconds with an end cup being hit by the center of the spray, and then shift the cup rack and running another 30 seconds with the center of the spray hitting the "tip cup" from the first run. This would duplicate 2 rows with 100% overlap. I might even be able to shift it again to do a third row.


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## TommyTester (Jul 3, 2018)

Nozzle testing results of the supplied nozzles. PSI and GPM.

My Channel

[media]https://youtu.be/P1HU4IEfByM[/media]


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## TommyTester (Jul 3, 2018)

The M4 wand uses metric threads. TeeJet nozzles do drop into the M4 45-degree plastic elbow nozzle body, but to use the TeeJet Quick Caps you need to adapt.

I opted to use at the tip of the Stainless HD wand:
1. M14 x 1.5 Female to 1/4" NPT male adapter (Amazon)
2. 1/4" NPT female to 1/4" NPT male elbow (local)
3. QJ1/4T-NYB TeeJet Adapter 1/4" Female (Various Sources)
4. ... plus the TeeJet Quick Cap of your choice (Various sources)



Also, the battery indicator is simply slid into a slot in the lower body section and rattles a bit. I simply added some tubing over the slot guides and it is nice and sturdy now.


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