The best jump starters for lawn mowers and tractors

Almost everyone shopping for this buys too much tool. A jump starter rated for a diesel pickup will start a mower, but you are carrying and paying for current the mower will never draw — and the oversized pack is no faster, no safer and no more likely to work on the day.

Quick picks

Tap any row to jump to the full write-up. Scoring criteria are published in full on our methodology page.

#	Product	Best for	Our read	Price
1	NOCO Boost Sport GB20 Best overall for mowers and garden tractors	Motorcycles, ATVs and small engines	500 A and 2.1 lb — correctly sized, not oversized	Check price on Amazon→ #ad Affiliate link · We show no price here; Amazon shows the current one
2	NOCO Boost Plus GB40 Best if the same pack must also start the car	Most cars and small SUVs	One pack for the mower and the driveway	Check price on Amazon→ #ad Affiliate link · We show no price here; Amazon shows the current one
3	NOCO GENIUS2 Best fix for the root cause	Motorcycles, ATVs and lawn equipment	2 A up to 40 Ah — built for U1 batteries	Check price on Amazon→ #ad Affiliate link · We show no price here; Amazon shows the current one
4	Battery Tender Plus 12V 1.25A Best for the mower that sits all winter	Long-term storage on a car battery	1.25 A storage maintainer, 10-year warranty	Check price on Amazon→ #ad Affiliate link · We show no price here; Amazon shows the current one

The reason the small pack wins is the size of the battery it is reviving. John Deere's own lawn-and-garden battery, the TY25221B, is a 12-volt U1 BCI battery rated at 30 amp-hours and 350 cold cranking amps — and Deere lists it as the fitment for well over two hundred machines, from Z-series zero-turn mowers to the 100-series lawn tractors.

Put that next to a car battery and the gap is obvious. An OPTIMA YellowTop D34/78, a normal passenger-vehicle AGM, is rated at 50 amp-hours, and the RedTop 34/78 at 800 cold cranking amps. A mower battery is roughly two-thirds the capacity and under half the cranking current of the one in your driveway.

A jump starter does not push its full rating into a battery. The engine draws what it draws, and the pack supplies it. A 3,000-amp pack on a mower delivers exactly the same current as a 500-amp pack would — it is simply heavier, bulkier and holding reserve you will not use.

Where a bigger pack genuinely helps is margin: a cold morning, an aging battery, several attempts in a row. A mower does not get used on the coldest morning of the year, which removes most of that argument. What size jump starter do I need works through the sizing logic in full, and peak amps versus cranking amps explains why the big number on the box is not the number that starts your engine.

A car battery that goes flat usually has a cause worth chasing: a parasitic drain, a failing alternator, an aging cell. A mower battery that goes flat usually has a much duller cause — the machine sat in a shed from October to April with nothing connected to it, and a small lead-acid battery left to self-discharge through a winter does not come back the same.

That is why two of the four picks here are chargers rather than packs. A jump starter gets you through one morning. A maintainer means there is no morning to get through. If you are buying once, buy both — they cost less together than most of the oversized packs people reach for.

Pick the charger by amp-hours, not by vehicle. The NOCO GENIUS2 is a 2-amp charger rated for batteries up to 40 amp-hours, which brackets a 30 Ah U1 battery almost exactly. NOCO's own GENIUS5 product page names lawn mowers, tractors and ATVs among its uses too, but at 5 amps and up to 120 Ah it is sized for a car — and NOCO's own guidance for the GENIUS2 is that small batteries want small current. What amp battery charger do I need covers the sizing rule.

1. 1Read the label on the battery, not the brochure. It will give the group size, the amp-hours and usually the cold cranking amps. That is the number both the pack and the charger have to match.
2. 2Check the battery is the problem. A mower that clicks, or does nothing with the key, may have a dead battery, a bad safety switch or a failed solenoid — small engines use several interlocks and any one of them stops the starter. A cheap multimeter reads resting voltage in ten seconds.
3. 3Check where the battery lives. On most riding mowers it sits under the seat, and the terminals can be awkward to reach with full-size clamps. A compact pack with a slim clamp body is easier to work with than a big one.
4. 4Decide whether the machine is stored. If it sits over winter, the maintainer is not optional — it is the thing that stops this repeating every spring.

1. Best overall for mowers and garden tractors

NOCO Boost Sport GB20

NOCO · Best for motorcycles, atvs and small engines

The smallest pack in the range and the right one for powersports: 500 peak amps, 2.1 lb, and a gas rating that stops at 4.0 liters — which is all a bike or a quad ever asks for.

Published specifications

Peak amps

500 A source

Internal battery

24 Wh lithium-ion source

Gas engine rating

Up to 4.0 liters source

Diesel engine rating

Not recommended source

Weight

2.1 lb (0.95 kg) source

Water resistance

IP65 source

Flashlight

100 lumens source

Warranty

1-year hassle-free source

What works

• +2.1 lb — light enough to live under a motorcycle seat or in an ATV storage box, which is the whole point
• +500 peak amps is correctly sized for powersports batteries rather than wildly over them
• +Same IP65 enclosure and reverse-polarity protection as the larger packs
• +24 Wh, so it flies in carry-on baggage like the rest of the range

What does not

• −The 4.0 L gas ceiling rules out most cars, so it is not a do-everything pack
• −NOCO states diesel is not recommended at all for this model — read that as a hard limit
• −Small reserve, so cold-weather attempts eat into it quickly

Skip it if

Do not buy it as your car's pack as well. NOCO's own rating stops at 4.0 L gas and says not recommended for diesel, and a bike pack asked to start a car is exactly the wrong economy.

Check price on Amazon→

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Raw specifications: NOCO’s own page for the NOCO Boost Sport GB20.

2. Best if the same pack must also start the car

NOCO Boost Plus GB40

NOCO · Best for most cars and small suvs

The default answer for a four- or six-cylinder car: 1,000 peak amps, 24 watt-hours, and light enough that it actually stays in the trunk.

Published specifications

Peak amps

1,000 A source

Internal battery

24 Wh lithium-ion source

Gas engine rating

Up to 6.0 liters source

Diesel engine rating

Up to 3.0 liters source

Weight

2.45 lb (1.11 kg) source

Water resistance

IP65 source

Flashlight

100 lumens source

Warranty

1-year hassle-free source

What works

• +24 Wh sits far under the 100 Wh carry-on threshold, so flying with it needs no airline approval
• +2.45 lb and pocketable — the size that decides whether a tool is still in the trunk six months later
• +IP65 enclosure, so a wet shoulder in the rain is not a problem
• +Reverse-polarity protection means a backwards clamp does not spark

What does not

• −1,000 peak amps runs out of headroom above a 6.0 L gas engine
• −The 3.0 L diesel ceiling rules out most modern diesel pickups
• −24 Wh is a small reserve — it is a jump starter, not a power bank substitute

Skip it if

Not the one to buy if you drive a diesel pickup or a big V8. You would be at the edge of its rating on a cold morning, which is exactly when you want margin.

Check price on Amazon→

#ad Affiliate link · We show no price here; Amazon shows the current one

Raw specifications: NOCO’s own page for the NOCO Boost Plus GB40.

3. Best fix for the root cause

NOCO GENIUS2

NOCO · Best for motorcycles, atvs and lawn equipment

A 2-amp maintainer for the small batteries a car charger would cook: motorcycles, ATVs, mowers and anything that sits for months.

Published specifications

Charging current

2 A DC source

Capacity range

Up to 40 Ah source

Operating temperature

-4 to 104 °F (-20 to 40 °C) source

Weight

1.1 lb (0.5 kg) source

Warranty

3-year limited source

What works

• +2 A is the right order of magnitude for a 10-20 Ah powersports battery
• +Safe to leave connected through a whole off-season
• +Light and small enough to live on a shelf beside the bike

What does not

• −The 40 Ah ceiling makes it a maintainer for a car battery, not a recovery charger
• −Recharging a flat car battery at 2 A takes most of a weekend

Skip it if

Not the charger to buy if your actual problem is a flat car battery you need back tonight. That is a 5 A or 10 A job.

Check price on Amazon→

#ad Affiliate link · We show no price here; Amazon shows the current one

Raw specifications: NOCO’s own page for the NOCO GENIUS2.

4. Best for the mower that sits all winter

Battery Tender Plus 12V 1.25A

Battery Tender · Best for long-term storage on a car battery

The storage-maintainer benchmark: 1.25 amps, automotive batteries up to 80 Ah, a four-step program and a 10-year warranty behind it.

Published specifications

Charging current

1.25 A at 12 V source

Battery capacity

Automotive batteries up to 80 Ah source

Chemistries

12 V lead-acid, flooded, AGM and gel cell source

Warranty

10-year source

What works

• +A 10-year warranty is the longest in this category by a wide margin
• +1.25 A is low enough to leave connected through a winter without heat build-up
• +Covers flooded, AGM and gel without a chemistry switch to get wrong

What does not

• −1.25 A is a maintainer current — it will not revive a deeply flat battery quickly
• −The 80 Ah ceiling rules out large truck and deep-cycle batteries
• −No 6 V mode on the standard Plus; that is a different model in the line

Skip it if

Not the unit for recovering a flat battery on a deadline. Buy it for the car that sits, not the car that stranded you this morning.

Check price on Amazon→

#ad Affiliate link · We show no price here; Amazon shows the current one

Raw specifications: Battery Tender’s own page for the Battery Tender Plus 12V 1.25A.