Mighty Mule FM600 FM150 Battery - 12 Volt - 7.0 Amp Hr.
The RB500 is a 12 volt, 7 amp-hour sealed replacement battery used in select Mighty Mule, GTO, and Linear PRO automatic gate opener systems. It is commonly cross-searched with Mighty Mule FM150 because both references are tied to the small 12V 7Ah gate opener battery used in many older control boxes.
The battery is the heart of many low-voltage gate operators. The AC transformer or solar panel charges the battery, and the battery supplies the current needed to run the motor. When the battery weakens, the gate may click, stall, move slowly, reverse unexpectedly, or fail after only a few cycles.
Correct battery selection matters because not every Mighty Mule operator uses this compact 7Ah battery. Several newer or larger systems require an automotive or lawn tractor battery, or an external battery enclosure. Always match the existing battery size, terminal type, and operator manual.
Compatible With
This part is commonly associated with the following Mighty Mule, GTO, and Linear PRO applications. Always match the part number, operator model, and parts diagram before ordering because older and newer generations may use similar-looking parts.
- Select Mighty Mule gate openers designed for the FM150 / RB500 12V 7Ah battery
- Commonly associated with FM402, FM500, FM502, MM560, MM562, MM-SL1000B, MM-SL2000B, and MM-LPS13 applications where specified
- Select GTO/PRO and Linear PRO operators that use the same 12V 7Ah sealed battery format
- Gate opener control boxes sized for the small sealed lead-acid 12V 7Ah battery
- Not for models that require an automotive or lawn tractor style battery unless used in an approved battery enclosure setup
Features and Specifications
| Manufacturer | Linear / Mighty Mule / GTO |
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| Product Type | Sealed gate opener battery |
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| Part Number | RB500 |
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| Related Battery Reference | FM150 |
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| Voltage | 12 VDC |
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| Battery Type | Sealed lead-acid style replacement battery |
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| Capacity | 7 amp-hour |
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| Application | Battery backup / primary DC power source for compatible gate operators |
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| Notes | Match size, terminals, and operator battery requirements |
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Also Known As / Related Part Numbers
- RB500
- FM150
- LIN-RB500
- Mighty Mule FM150
- Mighty Mule RB500
- 12V 7Ah gate opener battery
- 12 volt 7 amp-hour battery
- GTO PRO RB500
Technician Note
A new battery can fail quickly if the transformer, solar panel, charge circuit, or wiring is not working. If the old battery is repeatedly dead, test the charging source before assuming the battery is the only problem.
Before Ordering
- Match the existing battery voltage and amp-hour rating.
- Confirm the operator accepts the compact 12V 7Ah battery format.
- Check terminal style and battery compartment clearance.
- Inspect charging voltage from the transformer or solar input.
- Do not install this in operators that require a larger automotive or lawn tractor battery unless the manual allows it.
Professional Advisory
Batteries should be replaced with power safely disconnected and polarity observed. If the battery wires are damaged, overheated, or corroded, have the system inspected before continued use.
Product Questions and Answers
Is RB500 the same battery as FM150?
RB500 is commonly associated with the FM150 12 volt 7Ah replacement battery reference. Match the original battery label and operator manual before ordering.
Will this fit every Mighty Mule opener?
No. Some Mighty Mule operators use a larger automotive or lawn tractor battery instead of a compact 7Ah sealed battery.
What symptoms point to a weak gate opener battery?
Slow gate travel, clicking, short run time after power loss, low battery alarms, or stalling under load can point to a weak battery or charging issue.
Can a new battery fix a gate that will not charge?
Not by itself. If the transformer, solar panel, charge wiring, or control board charge circuit is bad, the new battery may discharge again.
What voltage is this battery?
This is a 12 volt DC battery with a 7 amp-hour capacity.
