No gadget is fancy enough to make greasing machinery a pleasurable pastime, but a battery-powered dispensing gun can go some way to easing operator ire.

Many will argue they’re purely a frivolity but, having put them through a harvest’s worth of abuse, we can attest that they save considerable time.

Chiefly, with just one finger required to work the pump, the other hand is free to hold the pipe securely in place, ensuring a good connection.

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This means fewer failed attempts at getting grease to go where it should and puts an end to awkwardly propping a manual gun to allow single-handed operation.

But how do you know if the grease is going in? It’s true that battery guns don’t have the feel of a manual one, but users soon tune in to the sound the pump makes when it’s working as it should.

Added to that, if these machines are used on a seized nipple, there’s usually a telltale change of pitch from the motor and it’s relatively easy to see the pressure building up in the dispensing pipe.

There’s clearly a price premium to pay, but for those already invested in a cordless battery system, the bare tools are relatively affordable – particularly when shopping online.

Like all cordless equipment, the lack of compatibility between manufacturers’ batteries means buyers generally get locked into running one brand.

However, if you like the look of a model from a rival manufacturer then cheap aftermarket adapters are available to convert them; not that we can vouch for their quality.

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Winner

Milwaukee M18 GG-0

• Battery system 18V, 5Ah
• Max working pressure 690bar
• Flow rate 74g/min
• Weight 4.4kg with 5Ah battery, 3.7kg bare
• Hose length 1,200mm

Thanks to keen trade show deals and a monster portfolio of powerful cordless tools, Milwaukee machines have proliferated across UK farms.

As a result, thousands of people will already be geared up with the firm’s batteries, making the M18 grease gun surprisingly affordable.

The bare tool is sold through several respectable online retailers for £120.

Paired with a 5Ah Redlithium-ion powerpack, it should be good for 20 or more tubes per charge, and it has plenty of poke to deliver them.

But best of all is the accuracy of the trigger, allowing operators to pump the perfect amount of gunk into sealed bearings.

This level of precision renders one of the M18’s standard features redundant: a roller wheel that sets a limit on lube output per trigger pull, ranging from the equivalent of one manual gun pump to infinite.

More useful are the series of markings on the plunger rod that show the quantity of grease left in the barrel, which none of the other tools offer.

There’s also a trigger lock to avoid inadvertent discharge, a largely pointless integrated LED light and hose clips down one side that are obstructed by the protective coil and therefore not overly helpful.

Some people may be perturbed by the M18’s size and weight, but it’s far less bulky than the Makita and has a long hose that means it can be rested a fair way from the target nipple.

Online prices (cheapest at SGS)

• Bare tool £120.82
• Battery £48.29 (5Ah)
• Charger £20.54

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Sparex S170527

• Battery system 12V, 2Ah (built-in)
• Max working pressure 550bar
• Flow rate 87g/min
• Weight 2.5kg (with integrated battery)
• Hose length 750mm

Exeter-based spare parts specialist Sparex recently added the unlovingly titled S170527 to its range.

Unlike the other models featured here, its 2Ah battery is built into the gun body.

So, rather than whipping it off and slotting it into a charger, it has a USB Type-C port that means it can be plugged into a socket just like a smartphone.

There are two supposed upshots to this setup.

For one, there’s no need to buy spare batteries and a charging dock.

And, second, it can be energised via a USB plug or cigarette lighter in the tractor cab.

Except neither are necessarily beneficial: the lack of charging paraphernalia doesn’t make it significantly cheaper than the alternatives, and not everyone will want a mucky gun slung down the side of their seat.

Plus, once it has run out of puff – there’s no battery life display – it can’t be brought back to life with a quick swapsie.

Instead, there’s no option but to wait for it to charge (90min from flat), or sheepishly reach for the manual gun to finish the job.

Once full, it should manage about six 400g cartridges.

But it does win on size; it’s the smallest, lightest, and takes very little effort to carry.

And it’s best employed on relatively lightweight jobs as, like the Sealey, it lacks the power to push grease through resistant nipples before getting hot and giving up.

These shortcomings are tolerable in the main but, at £168, it’s hard to justify over most of the others, particularly given the build quality.

Open slots across the main body accumulate muck and dirt and the diddy rubber bung that covers the charging port is unattached and guaranteed to get lost.

Retail price

• Tool including integrated battery £168 

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Milwaukee M12 GG

• Battery system 12V lithium-ion, 4Ah
• Max working pressure 562bar
• Flow rate 74g/min
• Weight 3.4kg with 4Ah battery, 3kg bare
• Hose length 895mm

Compact proportions and minimal weight make Milwaukee’s M12 GG far easier to handle than its beefy 18V sibling.

Payoffs are the fact that it goes without a dial for adjusting output, or a trigger lock, and it can’t dispense grease at such a high pressure.

However, the force it produces is ample for most tasks and the flow rate is same 74g/min as the 18V model. 

That said, we found that we did need to hold the trigger for longer in order for it to deliver the same quantity of grease.

Helpfully, the pump makes an audible pulsing sound during use which makes is relatively easy to count how much grease is going in.

The battery might be small, but it gives enough run time to dispense several cartridges.

The cells can be replenished using standard Milwaukee chargers, which generally have slots for both 18V and 12V batteries.

Four legs provide a sturdy base for it to sit on and its construction is reassuringly high quality.

Online prices (cheapest at Power Tool World)

• Bare tool £83.32
• Battery £33.29 (4Ah)
• Charger £20.54

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Sealey CPG18V

• Battery system Supplied with 18V 2Ah lithium-ion battery and mains charger
• Max working pressure 550bar
• Flow rate 100g/min
• Weight 2.8kg with 2Ah battery, 2.4kg bare
• Hose length 620mm

Sealey offers the cheapest package as far as gun, battery and charger goes. Its look and feel matches its price tag.

However, that’s not necessarily bad news – the thin plastic makes it pleasantly lightweight and, when faced with an hour’s worth of morning greasing, this factor alone made it popular among the test team.

It’s also well balanced and comfortable to hold, and comes with a trigger lock and LDC battery life indicator.

The comparatively short hose (620mm) wasn’t a problem and, when not in use, it makes the gun neater to store than the others.

However, the modestly sized 2Ah battery managed little more than five grease cartridges between charges, which is well down on most of the competition.

And online reviews are far from vintage, with the charger and battery coming in for particular stick.

Online prices (cheapest at Toolden)

• Tool including 18V battery and charger £126.47

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Makita DGP180Z

• Battery system 18V, 5Ah
• Max working pressure 690bar
• Flow rate Slow speed mode 142g/min, auto speed 284g/min
• Weight 5.3kg with 5Ah battery, 4.7kg bare
• Hose length 1,220mm

Makita’s cordless grease gun is a beast.

It’s almost a kilogram heavier than the Milwaukee M18 – enough to warrant the company including a shoulder strap in the box.

It has an “auto speed” mode that will jettison up to 284g/min from a 400g tube, should you have a need for it.

And the big numbers continue in other departments: the snaking 1.2m-long hose is handy but not the easiest to store neatly

The bare tool comes in at £172, making it the most expensive by some margin. Adding a battery and charger will take that figure to near £250.

But those meaty prices are at least reflected in the quality of the tool.

It feels reassuringly solid and such is its power that the whole thing wiggles as it churns out the contents of the barrel.

The choice of two discharge rates might be beneficial.

We found no reason to switch from “slow”, as it allows for more accurate control than the splurging “auto” mode, but the latter might prove handy for bunging barrow loads of grease into an old set of Cambridge rolls.

Other than the size, the only thing we’d change is the blister button switch for the largely futile LED light, which can be accidentally turned on and left to cane the battery.

Online prices (cheapest at UK Planet Tools)

• Bare tool £171.66
• Battery £52.46 (5Ah)
• Charger £18

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Ryobi 18V ONE

• Battery system 18V, 4Ah
• Max working pressure 690bar
• Flow rate 210g/min
• Weight 4kg with 4Ah battery, 3.3kg bare
• Hose length 750mm

They might share the same parent company (Techtronic Industries), but while Milwaukee caters for the needs of the professional user, Ryobi is aimed more at the homeowner.

Build quality and features are a little lower as a result, but the firm’s 18V ONE grease gun was still a decent performer in our tests.

Unlike most brands that place the motor and pump above the grease cartridge, Ryobi has staggered them. 

This makes it an ungainly beast that’s unstable when placed on the ground. Yet when it’s picked up, it’s surprisingly well balanced and not too heavy.

Flow rate and pressure compare favourably with many of the higher-spec models here and it’s relatively easy to judge when each pump of grease is delivered.

The hose is a little on the short side, but it comes with a trigger lock to prevent accidental discharge and an LED light to provide some illumination.

Battery life shouldn’t be a concern as Ryobi claims it can deliver 23 tubes of grease to one charge of a 4Ah battery.

However, the lack of keen online deals makes it look pricey compared to some better-specced rivals.

Online prices (cheapest at B&Q)

• Bare tool £137.50 
• Battery price £60
• Charger price £34

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Kielder KWT-555

• Battery system 18V, 4Ah
• Max working pressure 690bar
• Flow rate 280g/min
• Weight 4.3kg with 4Ah battery, 3.6kg bare
• Hose length 765mm

Hailing from Sheffield, Kielder power tools are aimed at serious mechanics that don’t want to pay the prices commanded by top-flight brands.

The 18V KWT-555 grease gun doesn’t disappoint on pressure and flow, but the concession for the lower price is slightly cheaper build quality. 

Threads on the barrel could be hard to get started at times, the hose is a little short, and the light-grey plastics soon look grubby. But features are up there with the priciest models.

There’s a light, trigger lock, hose clamp on both sides of the body and a speed dial that adjusts how fast the pump spins in five stages.

The slower speeds are fine for most situations, with the fastest only required for delivering particularly high volumes.

The pulsing of the pump also helps users judge how much grease is being dispensed.

When fitted with an 18V, 4Ah battery, Kielder claims 24 grease cartridges can be dispensed to a charge.

These packs have a three-stage light to show how much life is left in them.

Online prices (cheapest at Machine Mart)

• Bare tool £84.99
• Battery price £50
• Charger price £16.60

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FW verdict

All seven models performed well over the course of our harvest test, and even the small 2Ah batteries have enough juice to churn through an ample six cartridges between charges.

What will really split these guns is longevity. While some buyers of the “budget” brands have bemoaned battery problems, the likes of Milwaukee and Makita employ time-proven technology that is already well tested in the unforgiving world of farm workshops.

These are also more solidly built, come with longer hoses and, surprisingly, don’t necessarily work out to be more expensive.

We’ve given Milwaukee’s M18 the win, though the bulkier Makita doesn’t fall far short – both offer accurate, powerful grease delivery in a package that should stand up to agricultural abuse.