My4Sons M4 Battery Powered Backpack Sprayer Review (2020)

After expanding my old yard an extra 8,000 ft.2– totaling ~17,000 ft.2 I had to ditch the manual backpack sprayer and upgrade to a more suitable battery powered sprayer. I knew I also wanted to make the transition from a granular schedule, to one that included more liquids. For many reasons – particularly cost – liquid applications were the way to go… for the most part.

After spending nearly a full New England season with a $25 backpack sprayer from Harbor Freight, I went all-in on a My4Sons M4 sprayer. I researched other – including King and Chapin – but decided to pull the trigger (literally) on the M4. A bit more expensive than the others, but many factors came into my decision. Here’s what I think of the My4Sons M4 battery powered backpack sprayer.

If there was one thing that made me 100% happy with my purchase of the M4, was the customer support. There are hardly any cons with this tank of a machine. Even those negatives – which there are and did arise – were instantly rectified by Lance and company. Let’s get those out of the way.


I put “cons” in quotes – think of them as air quotes – because there’s nothing Lance won’t do to make sure you’re 100% happy. Having a smaller, family-run business essentially offer their ‘no questions asked’ approach to customer service makes it all worth the while – and the $189 price tag. 

I had issues with the flex tip – shown in the short 4s video below. I emailed the company and the sent a replacement out that following Monday. This is a huge benefit from buying from a smaller family-owned and operated company.

I also couldn’t figure out the switches. The main on/off switch and 10-60 psi on/off knob was initially confusing. But in short, the latest M4 model is a parallel unit and wired to allow both switches to turn the unit ON. To use the silver rotary psi variable flow switch, the main red on/off switch must be OFF. Otherwise the red switch turned ON keeps power at 100%.

And just like the flex tip I thought I may have had issues with the battery life and the sound(s) of the machine. When charging the M4 battery, it is good to go once the charger light is green. And the silver rotary psi switch makes more noise when it’s on the low setting – this is normal. However I was delighted to know that Lance would gladly ship a new replacement rotary switch in case I felt mine was noisier than usual. 

More on customer service below…


First off, you will definitely want to watch their quick start videos on their website before you start going all-in with the sprayer. There’s tons of amazing content about their tips and attachments, and this blog won’t do any justice. There’s a slew of tips from sharp streams and dual heads, to gentle showers and mists. Check out the links below.

When I received this product I was pretty excited. I took a picture and threw it up on Instagram with some hashtags. The company caught wind and sent me a message, thanking me for purchasing their product, and offered to send me a 15 foot adjustable wand – which I happily obliged. I received it, completely free of charge the following week.


This has an extremely strong, durable and flexible Viton hose. No kinks and no clogging. I put this through the ringer with powdered fertilizers, granular humic acids, and liquid concentrates. Never clogged on me once.

This comes with adjustable brass and plastic wands. The brass wand has good extension and makes for comfort when walking and spraying a large area. I had no issues with leaks either one. For everyday fertilization, the brass one is recommended.

This sprayer also came with a bunch of nozzles and tips. Everything from sharp streams to super fine mists. As mentioned, I had issues with the flex tip leaking, but that was rectified.

There is a super easy slide in/out Durable Li-Ion battery. It’s a heavy battery with great life. The charger is also great. Once the light turns from red to green, it’s fully charged. And you don’t have to worry about damaging the battery if you leave this plugged in overnight. 

There is a volt meter on the front of the backpack sprayer, too, to indicate the level of remaining power in the battery. A red and green light means the battery is good which takes the guess work out of it. 

Large 4.5 gallon tank with clear, large calibrations markings on the outside. The filter inside the tank can be accessed and removed easily. The mouth is extra wide, making for less spilling when trying to fill the sprayer. The sure wide mouth also has a water tight lid seal, so if it tips over or even upside down, nothing will leak or spill.

Triple-thick shoulder straps are very thick and extremely comfortable. This is probably my most favorite feature. Even though this unit is on the heavier side – 14 lbs. – the over-the-shoulder straps make it feel much lighter. The straps are easily adjustable, too. And finally, on the side there is a wand pocket to store the extra wand, and additional pockets to keep the extra tips and nozzles all in one place.

This is definitely on the pricier side compared to other backpack sprayers. But this is a solid machine, back by an awesome family-owned company. I have no buyers remorse whatsoever, and highly recommend this M4 backpack sprayer.

Buy the M4 on Amazon or directly though the M4S website


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