What battery size does the John Deere L120 use?
The John Deere L120 uses one 12-volt BCI Group U1 lawn and garden battery. The original John Deere battery part is TY23017, listed as a 12V, BCI U1, 165 CCA battery. For replacement, a 12V Group U1 battery with higher CCA is usually the better owner choice if it fits correctly.
John Deere L120 Battery Size: Group U1
The John Deere L120 takes one 12V BCI Group U1 battery. The original TY23017 battery is 165 CCA, while many owners choose a stronger modern U1 replacement with higher CCA.
Higher-CCA U1 battery, commonly around 300 CCA, if it fits correctly
Battery Type
Flooded lead-acid or AGM lawn tractor battery
Best simple answer: buy one 12V BCI Group U1 lawn tractor battery. The original TY23017 spec is 165 CCA, but a stronger higher-CCA U1 replacement is usually a smarter buy.
Best Replacement Battery for a John Deere L120
The correct replacement size for the John Deere L120 is a 12V Group U1 lawn and garden battery. The original Deere TY23017 battery is listed at 165 CCA, but many modern U1 mower batteries are available with higher cranking power. For easier starting, especially on older mowers, a higher-CCA U1 battery is the better pick.
Replacement Check
What to Look For
Group size
BCI Group U1
Voltage
12V only
CCA
165 CCA minimum original-style spec; higher CCA is better for starting
Terminal layout
Match the old battery so the positive and negative cables reach safely
Physical fit
Must fit the battery tray and clamp down properly
Owner tip: if two U1 batteries both fit, choose the one with more CCA. It gives the starter more cranking power and usually handles sitting unused better.
What Battery Should You Buy for a John Deere L120?
Best Choice
One 12V Group U1 battery with higher CCA than the original 165 CCA spec, as long as it fits correctly.
Acceptable
A direct TY23017-style 12V U1 replacement rated around 165 CCA.
Avoid
Wrong-size batteries, wrong terminal layout, loose fitment, or anything that is not 12 volts.
Blunt verdict: the cheapest low-CCA U1 battery may work, but a stronger U1 battery is the better buy if you want reliable starting.
Charging issue, parasitic drain, bad connection, or mower sitting too long
Fast check: before replacing parts, clean the terminals, tighten the cables, charge the battery fully, and confirm the battery is the correct 12V Group U1 size.
John Deere L120 Battery Replacement Tips
Tip
Reason
Take a photo before removing the old battery
Helps you reconnect positive and negative correctly
Match the terminal layout
Prevents cable stretch, bad routing, and polarity mistakes
Clean the cable ends
Corrosion can make a good battery act weak
Secure the battery
A loose battery can damage terminals and wiring
Use a maintainer if it sits
Lawn tractor batteries go flat when unused for long periods
John Deere L120 Battery Questions
What battery size does a John Deere L120 take?
The John Deere L120 takes one 12V BCI Group U1 lawn and garden battery.
What is the John Deere L120 battery part number?
The original John Deere battery part listed for the L120 is TY23017.
How many CCA is the John Deere L120 battery?
The TY23017 battery is listed as 165 CCA.
Can I use a higher CCA battery in a John Deere L120?
Yes. A higher-CCA 12V Group U1 battery is fine if it fits the tray, clamps securely, and has the correct terminal layout.
How many batteries does a John Deere L120 have?
The John Deere L120 uses one battery.
Can I use a car battery in a John Deere L120?
No. Use a proper 12V Group U1 lawn and garden battery.
Why does my John Deere L120 click but not start?
The usual causes are a weak battery, loose cable, dirty terminal, poor ground, or starter solenoid issue.
John Deere L120 Battery Size Summary
Battery size: BCI Group U1.
Voltage: 12 volts.
Number of batteries: 1.
Original John Deere part: TY23017.
Original CCA: 165 CCA.
Best replacement move: use a 12V Group U1 battery with strong CCA, correct terminals, and secure fitment.
Last checked: John Deere L120 battery part number, BCI Group U1 size, 12V voltage, and TY23017 165 CCA spec verified against John Deere quick-reference and parts catalog listings.
