The best lawn tractor batteries, compared.
Top pick: Mountfield 118120002/1 20 Ah Best value: Withheld – Best value is withheld. The lowest shelf price is the same listing as the top pick, and one product does not carry both awards. The other two rows are dearer, for 20 Ah with no size, or for 3 Ah. Updated 23.10.2026.
A lawn tractor battery is the 12 V starter in a petrol ride-on or garden tractor. It is not an 18 V tool pack, and it is not the traction battery in an electric mower. In the UK you buy one when the machine turns slowly, clicks, or has sat through winter and will not start. You tell a suitable lawn tractor battery by voltage, the case in the tray, which end is positive, and the cranking figure, before chemistry. The usual garden case is a U1 group, near 195 mm by 130 mm by 183 mm. Measure the tray. U1 and U1R differ only by which end is positive. Do not cross the cables. Cold cranking is a short high current. Amp-hours are stored capacity. A few amp-hours with a high cranking figure are not a 30 Ah block. Sealed AGM and maintenance-free lead-acid suit the mower's charging circuit. A lighter lithium Group U1 belongs only inside the charge window the battery maker states. Those checks are in the [lawn tractor battery buying guide](/hub/lawn-and-garden-equipment/lawn-tractor-battery/sub/lawn-tractor-battery-buying-guide).
A lawn tractor battery is the 12 V starter in a petrol ride-on or garden tractor. It is not an 18 V tool pack, and it is not the traction battery in an electric mower.
11 products checked · 47 hrs invested · +16,840 readers
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Personal buying guide
Question 1 of 2
Where will the battery live?
The Mountfield row is part 118120002/1, a 12 V 20 Ah lead-acid battery at £72.59, with GGP as the manufacturer. The title names Mountfield 1228H, 1640H and 1740H, and the bullets add further Mountfield numbers plus Castelgarden, Lawn-king, Twin Cut and Alpina models. Across 26 amazon.co.uk ratings the line is 4.7, and the file holds five UK texts. Four of those say a Mountfield ride-on or garden tractor started after the swap. One owner says the original Mountfield battery had failed after six months and this replacement worked the first time. In the same set, one buyer found the top fixings did not match the housing and had to adjust the wiring, and that buyer would not order again without seeing the posts. Size, weight and cold cranking are absent from the capture, and none of the five texts says how many seasons the new battery then lasted. Buy it when your model is on the 118120002/1 list and you can compare the posts with the leads before you close the cover.
Pros
Cons
Best for: Your Mountfield, Castelgarden or Alpina model is on the 118120002/1 list and you will check the posts against the leads.
Less suitable: You want a printed case size and CCA, or a lighter lithium starter you can lift out each winter.
Specifications
Common questions
Which mowers does the listing name?
The title names Mountfield 1228H, 1640H, and 1740H, part 118120002/1. The bullets add further Mountfield numbers plus Castelgarden, Lawn-king, Twin Cut, and Alpina models.
Will the top fixings match the old battery?
The listing does not describe the terminal hardware. One of the five UK reviews says the top fixings differed from the housing and the wiring had to be adjusted.
What capacity and cranking does it state?
20 Ah and 12 V. Cold cranking amps, weight, and dimensions are not on the capture.
The Fulbat U1-32 / U1-12 is listed as a 12 V 32 Ah AGM at £59.72, with SAE posts, a stated weight of 6 kg, and model 550903. Across 273 amazon.co.uk ratings the line is 4.5, though in the first 50 texts saved with this ASIN only one is marked Reviewed in the United Kingdom, and that owner says it fitted and worked. The listing says the battery needs no acid handling and no maintenance, which is the sealed VRLA story for a ride-on tray if the case matches. A bullet prints 195 × 125 × 176 cm while the size line prints 19 × 13 × 18 cm, so you measure the tray rather than trust the centimetre unit on the long figure. Cold cranking is not on the page, so you cannot set it beside a Yuasa garden U1 that states 330 A to EN. One captured review says the posts were on the wrong side and the cables were crossed, which is a reason to check polarity before you tighten the clamps. It leads this set as a sealed 32 Ah AGM near a high-street U1 price, with the limit that most of the saved review texts are not from the UK.
Pros
Cons
Best for: You want a sealed 32 Ah AGM in a U1-size tray and you will check which end is positive before you bolt it down.
Less suitable: You need a printed CCA figure, a Mountfield part number, or a battery light enough to lift with one hand.
Specifications
Common questions
Does this Fulbat need acid before you fit it?
The listing says the SLA range needs no acid handling, no initial preparation, and no maintenance. It calls the design VRLA.
What size does the listing print?
The bullet prints 195 x 125 x 176 cm. The size line prints 19 x 13 x 18 cm. Those two strings are both on the capture. CCA is not stated.
Are the 273 reviews all from the UK?
The star line is 4.5 from 273 on amazon.co.uk. In the first 50 texts saved with this ASIN, one is marked Reviewed in the United Kingdom. That text says it fitted and worked.
The DOUKAS DKLU1 PRO is a Group U1 starter at £99.95, and the title states 12 V, 3 Ah and 450 CCA. Across nine amazon.co.uk reviews the line is 4.3, and all nine texts in the file are from the UK. Reviewers describe it as much lighter than the lead-acid block it replaced, and they say a ride-on or a generator turned over and started. The title and bullets say LiFePO4, while the specification table says Lithium Ion, and the page prints 1.25 kg, 1 kg and 3.3 lb without those three figures agreeing. A charger is not in the included line, and one review says you need a compatible charger sold separately. One reviewer says a safety cut-out needs frequent resets, and none of the nine texts covers a full winter, so the seller’s 2,500-cycle and 24-month standby lines stay claims. The 450 CCA figure has no test method on the listing, so it is not an EN figure you can place next to a Yuasa 330 A. It is the row for someone who lifts the battery out and will charge a lithium starter on the maker’s terms, rather than a 30 Ah store for a mower left on its own charging circuit.
Pros
Cons
Best for: You lift a Group U1 starter in and out, and you will buy a charger the lithium maker accepts.
Less suitable: You want 20–32 Ah of lead-acid on the mower’s existing charge circuit, or a car, UTV or v-twin the listing excludes.
Specifications
Common questions
Is a charger in the box?
The included line names one 12 V battery. It does not name a charger. One UK review says you need a compatible charger, and that the maker sells one separately.
What chemistry does the listing use?
The title and bullets say LiFePO4. The specification table says Lithium Ion. Voltage is 12 V, capacity 3 Ah, and the title states 450 CCA with no test method.
How heavy is it on the listing?
The table says battery weight 1.25 kg and item weight 1 kg. A bullet says 3.3 lb. Those three figures are all on the capture and they are not the same.
Three amazon.co.uk listings are scored, captured on 22 October 2026: Fulbat B0727YM4ML, Mountfield B06WV92XZL and DOUKAS B0GBSM1WB9. No lab test was run. A Yuasa garden U1 on a specialist page is a size reference. It is not a fourth row. Stars, review count, printed voltage and amp-hours, case or model list, terminal or a single weight, cranking only when a test method is named, and the price in this set make the score. Deductions use a captured review or a clash on the same listing. The working caps sum to 97. The weights below are that split scaled so they sum to 100. The top pick leads this set on those blocks. It is not a Which? Best Buy.
Amazon.co.uk stars
63%The star line times 12, up to 60 in the working score. A 4.5 becomes 54 before any deduction. The weight here is 63 so the blocks sum to 100. It is an amazon.co.uk figure, not a lab test.
Review count
15%200 or more reviews score 15. From 25 to 199 score 6. From 1 to 24 score 2. A larger pool carries more of the score than a higher average from a few ratings.
Voltage and amp-hours
4%Both printed on the listing scores 4. A lawn tractor battery in this category is a 12 V starter. Amp-hours are stored capacity, not cold cranking.
Case or model list
3%A group name, or a part number with named machines, scores 3. The tray and the model list are how you tell a U1 case from a named ride-on part.
Terminal or weight
3%SAE posts, or a single weight with no second weight that disagrees, scores 3. Two or three weights that do not match score 0.
Cranking with a test method
3%3 only if CCA is printed with a test method. A bare CCA, or a blank cell, scores 0. EN 50342-1 is a -18 °C test. A seller's figure without that method is not scored as cranking.
Price in this set
9%In the working score, £59.72 scores 9, £72.59 scores 5 and £99.95 scores 3. The weight here stays 9. Deductions for a crossed cable, mismatched fixings, a missing charger, a cut-out or a chemistry clash sit outside these weights.
Match the case, the positive post and the voltage before chemistry, then read cranking only if a test method is named. Three amazon.co.uk listings are on this page, captured on 22 October 2026. The scores use those listings and the review texts saved with them. They are not a laboratory test.
A lawn tractor battery in the UK is the 12 V starter in a petrol ride-on or garden tractor. It is not an 18 V tool pack and not the traction battery of an electric mower. Match voltage, the case in the tray, which end is positive, and cranking, and only then the chemistry. Price is last. Wrong posts waste the saving.
Amp-hours are stored capacity. Cold cranking is a short high current. 450 CCA beside 3 Ah is not a 30 Ah block. If no test method is named, the CCA is the seller's figure.
The cases match and the positive post does not. Layout 1 and layout 0 are the published pair. Crossing the cables to force a fit showed up in a captured review. Do not plan to do it.
Shop tubes take portable batteries, not vehicle batteries. A U1 lead-acid block goes to a council recycling centre or a battery retailer. Tape lithium terminals. Do not use a desulphation mode on lithium iron phosphate.
The usual UK garden group is U1. Yuasa's garden U1, which is a size reference and not a row here, is 12 V, 30 Ah at the 20-hour rate and 330 A to EN, about 195 mm by 130 mm by 183 mm. Types 895 and 896 are about 26 Ah and 250 A. Measure the tray. One listing prints 195 × 125 × 176 cm in a bullet and 19 × 13 × 18 cm on the size line. Do not read 195 cm as the case. U1 and U1R differ by which end is positive. Yuasa uses layout 1 and layout 0.
Cranking first, then amp-hours, then chemistry. EN 50342-1 is a -18 °C test. A stated 450 CCA on 3 Ah is not the same reservoir as 30 to 32 Ah. A blank cranking cell scores nothing here. Maintenance-free lead-acid, often calcium, can be supplied charged and still needs a storage charge. AGM is sealed, with no acid fill. Stay with AGM or maintenance-free lead-acid if you have not measured the stator. A lithium Group U1 is much lighter.
Three typical situations, each with a recommendation from this comparison.
You want another AGM or sealed lead-acid in a U1-size tray, and you will check which end is positive before you bolt it down. The Fulbat U1-32 / U1-12 is 12 V, 32 Ah, SAE posts, a stated 6 kg, at £59.72. Cold cranking is not on the listing. One captured text crossed the cables.
Your Mountfield, Castelgarden or Alpina model is on the 118120002/1 list, and you will compare the posts with the leads. The listing is 12 V, 20 Ah, at £72.59. Size, weight and CCA are not stated. One UK review had to alter the top fixings.
You will pay more for a lighter Group U1 starter and charge it on the battery maker's terms. The DOUKAS DKLU1 PRO is listed at £99.95. The title says 12 V, 3 Ah and 450 CCA, with no test method. No charger is named. Nine UK reviews do not cover a winter.
The top pick is the Fulbat U1-32 / U1-12. It scores 85 in this three-row set: 54 from 4.5 stars, 15 for 273 reviews, 4 for voltage and amp-hours, 3 for the U1 group name, 3 for SAE posts and 6 kg, and 9 for £59.72, minus 3 because one captured text crossed the cables. Cold cranking scores 0. It is not a lab result and not a Which? Best Buy. Best value is withheld. The lowest shelf price is the same listing, and one product does not carry both awards. The Mountfield part is £72.59 for 20 Ah with no size on the page. The DKLU1 PRO is £99.95 for 3 Ah. Neither is the value row.
Withheld
Best value is withheld. The lowest shelf price is the same listing as the top pick, and one product does not carry both awards. The other two rows are dearer, for 20 Ah with no size, or for 3 Ah.
Editorial
Peter F. is the editor for DIY & tools at productscompared.co.uk. Comparisons in this category are checked against amazon.co.uk listings, review evidence and public UK sources.
Guides on what to look for, how to use a product, and common mistakes.
Sources from the research digest. Listing prices, stars and review counts are the amazon.co.uk capture of 22 October 2026 for B0727YM4ML, B06WV92XZL and B0GBSM1WB9.
This page contains affiliate links. If you buy through them, we may earn a commission at no extra cost to you. The notes come from amazon.co.uk listings, review text and public UK sources, not from a lab test.
