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No—not to produce heat or ignite. The Big Buddy uses propane for heat and piezo ignition. Batteries are only needed to run the fan on models that have one: Mr. Heater’s US owner’s manual specifies four D-cell batteries for fan operation. Some current MH18B configurations have no fan, so check the exact unit before buying batteries.
What batteries do—and do not—power
The MH18B is a propane radiant heater. Propane supplies the heat, while the manufacturer lists piezo ignition; neither function depends on batteries. Batteries power the fan on fan-equipped models, according to the Mr. Heater US owner’s manual.
Which batteries does the fan use?
The US manual specifies four D-cell batteries for fan operation. If your unit has a fan and you want to use it, install four D cells as directed in the manual. If the fan is absent, batteries have no fan function to power.
Can you run the fan without batteries?
Yes. The manual says the fan can also be powered by Mr. Heater adapter F276127. It specifies 6V DC, up to 800mA, with positive-tip polarity. Mr. Heater lists the F276127 AC power adapter for Big Buddy heaters. Use the specified adapter rather than assuming another power supply is compatible.
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- Product Specifications : Power adapter Input: AC100V-240V 50/60Hz. Output: DC 6V 800mA. Plug size: 3*6.5*4cm/2.56*1.57*1.18in. Net weight: about 76g
- Extended Power Cord : The heater accessories comes with an extended 5.84ft power cord, giving you the freedom to move and place the heater anywhere you want. No more limitations due to wire length
- Safe to Use : The heater adapter is equipped with overvoltage/ overcurrent/ short circuit/ over-temperature protection system to ensure stable output voltage and frequency during charging. Fanless and quiet,high quality, safe
- Compatible Equipment : Suitable for Mr. Heater Big Buddy Heater MH18B and Tough Buddy Heater models, such as MRH-MH18B, MRHMH18B. Also suitable for Big Buddy Mr. Heater F274800, F274830, F274865 and F276127. Not applicable to Mr. Heater MH9B, MH12B series
- Warm Tips : Please check the plug type, power consumption (must not exceed the maximum output of the adapter), and polarity of the device before ordering, otherwise it may cause problems or damage the device
| Fan power option | What it requires | When it makes sense |
|---|---|---|
| Four D-cell batteries | Four D cells, per the US owner’s manual | You have a fan-equipped unit and want to run its fan without relying on household power. |
| F276127 AC adapter | Mr. Heater F276127; manual specification is 6V DC, up to 800mA, positive-tip polarity | You have a fan-equipped unit and an appropriate household power source nearby. |
| No fan power | Neither batteries nor adapter | You do not want to run the fan, or your MH18B configuration has no fan. Propane heat and piezo ignition do not depend on fan power. |
Check whether your Big Buddy has a fan
Mr. Heater’s current Big Buddy product listing says the fan has been removed on some MH18B models. That means battery advice depends on the actual configuration, not just the model name. Inspect your heater and consult its manual before purchasing batteries or an adapter.
Check the instructions for your market
Use the manual and product labeling for the exact regional version. The US manual describes the MH18B as an unvented gas-fired portable heater, while Mr. Heater’s Massachusetts/Canada MH18B listing labels that version for outdoor use only. Do not generalize indoor-use guidance across regional versions; follow the applicable instructions and local requirements. The US manual also warns not to leave the heater unattended while burning.
Rank #2
- Uses household electricity
- Powers products requiring 6VDC and up to 800mA current
- Mr. Heater AC Power Adapter
- MH 6V AC POWER ADAPTER
- Recommended Uses For Product: Power Big Buddy or Tough Buddy Heater
Other specifications are separate from the battery question
Mr. Heater’s 2023 catalog lists 4,000, 9,000 and 18,000 BTU ratings, with approximate runtimes of 11 hours on low, 4.8 hours on medium and 2.8 hours on high when using two 1 lb propane cylinders. These are manufacturer catalog specifications, not independently measured results; they do not change what batteries are for.
Quick Recap
Best Value
- Heats up to 450 square feet
- Low, Medium, and High heat settings: 4,000 / 9,000 / 18,000 BTU
- Heats up to 216 hrs. on two 20lb Propane tanks with optional hose (low setting)
- Big Buddy dual heating system combines radiant heat comfort with convection heat air flow
- Built-in high powered fan
Rank #4
- Exclusively engineered for use with the Mr. Heater Portable Buddy Heater, Model MH9BX. Compatible only with single-tile Buddy units manufactured after 2009. This fan accessory is not approved for use on any other heating appliance. Do not install or operate on models MH18B, MH12HB, MH12B, DXH12B, MH4B, or MH4BC.
- Self-Powered Air Circulation: Uses thermoelectric technology to convert heater-generated heat directly into fan power.
- No Batteries Required: Operates entirely without batteries or external power sources for maximum convenience.
- Easy Compatibility: Specifically designed to fit all MH9BX Mr. Heater Portable Buddy Heaters.
- Improved Heating Efficiency: Quietly distributes warm air, enhancing comfort and warmth in any space.
Rank #3
- Compatibility - Powers the built-in fan to distribute heat evenly; Works with Mr. Heater Big Buddy Heater MH18B and Tough Buddy Heater models such as MRH-MH18B, MRHMH18B, Big Buddy Propane Heater, Mr. Heater F274800, F274830, F274865, Replaces F276127. Does NOT work with Mr. Heater MH9B, MH12B Series
- UL Listed - UL listed, surge protection, short circuit protection, safety ensured
- Input Voltage - AC 100V - 240V; Output Voltage: 6V 800mA
- Long 5.75 FT (1.75m ) Power Cord – gives you some room to move and position the heater
- If you have any questions, please let us know, and we will do our best to answer them in a timely and helpful manner
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
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