Best External Diesel Generator Fuel Tanks for Safe, Flexible Refueling
When you need reliable diesel power away from fixed fueling, an external fuel tank can extend run time and simplify maintenance. This guide highlights five selectable options that fit a range of generators and use cases. Best for portable field work, home backup, or remote jobsites, these tanks provide varied capacities, mounting styles, and features to suit different needs. Each choice is evaluated for compatibility, durability, and ease of use to help you pick the right external tank for your diesel generator setup.
| Product | Brand | Capacity | Notes |
|---|---|---|---|
| RDS Aluminum Auxiliary Fuel Tank – 20-Gallon | RDS MFG INC | 20 gallons | Vent-cap, dual withdrawal tubes; designed for exterior areas; not for gasoline |
| Bergs System HND1.2000IS | Bergs System | Unknown (integrated system) | Includes tank hose; single system |
| POWER PRODUCTS Universal 4 Gallon | POWER PRODUCTS | 4 gallons | Fits most open-frame 5-7KW diesel generators; compact |
| JJing Universal 7 Gallon | JJing | 7 gallons | Vent valve detail; includes mounting dimensions; large size options |
| EVIL ENERGY 19 Gallon Fuel Cell | EVIL ENERGY | 19 gallons | Aluminum with level sensor; compatible with various fuels |
RDS Aluminum Auxiliary Fuel Tank — 20-Gallon
The RDS 20-gallon auxiliary tank is designed for exterior placement with a vented fill cap and dual withdrawal tubes. One tube can serve as a diesel return line, expanding fueling flexibility for larger setups. Best for contractors or homeowners needing a rugged, weather-resistant add-on tank that can stay outside. A potential limitation is that it’s not intended for gasoline and requires careful labeling to prevent misfueling.
Who it’s best for: Portable job sites, cold-weather outdoor use, and users who need a simple external tank that supports a dedicated return line. Choose this if you want a robust, exterior-ready tank with built-in venting and dual outlets.
Why selected: It combines practical features (vented fill cap, dual withdrawal tubes) with exterior-ready construction, aligning well with diesel-only use and outdoor environments. The two withdrawal options can improve flow management for certain generator configurations.
Caution: Ensure you strictly use diesel. Avoid gasoline as designed usage explicitly notes it is not for gasoline applications.
Bergs System HND1.2000IS Tank
The Bergs HND1.2000IS is a compact, single-system solution described as including a tank hose and the Bergs single system. It’s well-suited for users who want a straightforward, integrated approach to diesel fueling with fewer components to manage. A potential limitation is that detailed capacity and compatibility specifics aren’t listed in the feature set, so confirm fit for your generator model before purchase.
Who it’s best for: Compact setups where ease-of-use and a ready-to-connect system are priorities. Choose this if you want a simpler kit without many extra pieces.
Why selected: It represents a convenient, system-integrated option that may reduce setup time and maintenance steps on smaller generator configurations.
Caution: Verify compatibility with your generator’s fuel inlet and hose sizing before ordering.
POWER PRODUCTS Universal 4 Gallon Diesel Tank
Designed to fit most open-frame 5-7KW diesel generators, this 4-gallon tank has dimensions of 18″ L x 13″ W x 5-1/4″ H and overall placement similar to a compact, stock-tank accessory. Best for lightweight, portable generator applications where space is at a premium. A limitation is the relatively small capacity, which may require refueling more often for higher-demand jobs.
Who it’s best for: Owners of mid-range open-frame diesel generators needing a compact, compatible auxiliary tank for shorter duration use.
Why selected: The universal fit and compact size make this a practical choice for many consumer and light-industrial diesel generators, offering a straightforward upgrade without bulk.
Caution: Check generator consumption and run time; this tank’s 4 gallons may require more frequent top-offs on high-demand loads.
JJing Universal 7 Gallon Tank (Honda/Predator Compatibility)
The 7-gallon JJing tank is marketed for compatibility with a broad range of generators, including Honda EC6500 and other popular models. It includes mounting dimension details (23.25″ length, 16.1″ width, 6.1″ height) and notes about the absence of a vent valve. This makes it a solid choice for systems that do not require vented operation, though it may not be ideal if vented fueling is essential for your setup.
Who it’s best for: Users needing a larger external tank without a vent valve, matching generators listed in the compatibility notes. Choose this if you’re prepared to manage venting separately or your system doesn’t require venting.
Why selected: It balances a larger capacity with a clear emphasis on dimensional fit, helping buyers avoid mismatches with mounting provisions.
Caution: If you require venting, this model is not suitable; verify whether vented tanks are required for your generator’s fueling system.
EVIL ENERGY 19 Gallon Fuel Cell
This aluminum fuel cell provides a larger capacity at 19 gallons and includes a built-in 3–90 ohm level sensor along with internal anti-slosh foam. The large capacity makes it suitable for extended run times or remote locations where frequent refueling is impractical. It’s noted as compatible with various fuels, but the feature set emphasizes diesel and related fuels rather than broad gasoline compatibility. A limitation is that the product is not described as vented, so consider venting needs for your installation.
Who it’s best for: Operators needing a high-capacity external tank with fuel level sensing for easier monitoring, especially in remote or long-running scenarios.
Why selected: The integration of a level sensor and anti-slosh design improves reliability in mobile or rough-use environments where constant fuel monitoring is beneficial.
Buying Guide: Key Purchase Considerations
What capacity fits my needs?
Assess your generator’s runtime goals and fuel consumption. Higher gallon capacities reduce refueling frequency but add bulk and weight. Balance capacity with space and transportability for your application.
Do I need a vented fuel tank?
Vent valves prevent pressure buildup and fuel lock, important for certain installations and fuels. If your system requires venting, avoid tanks without vents or plan an alternate venting solution.
What mounting and dimensions matter?
Compare hole-to-hole measurements and overall dimensions against your generator’s fuel inlet location and mounting space. Choose tanks with compatible mounting patterns to avoid fit issues.
Is a built-in fuel gauge or level sensor important?
A built-in level sensor helps you monitor remaining fuel without manual checks. For long deployments, this feature enhances planning and reduces unexpected outages.
What materials and durability are necessary?
An aluminum or high-density polyethylene (HDPE) tank can withstand outdoor exposure differently. Consider weather conditions, UV exposure, and the risk of corrosion in your environment.
What are the potential limitations to watch?
Some products may lack vent valves, have non-standard mounting, or imply compatibility with a broad range of generators without explicit fit confirmation. Always verify your specific generator model’s fuel inlet size, mounting holes, and venting needs before purchase.
FAQ
- What is the main purpose of an external diesel tank for a generator? It extends run time between refueling and provides a dedicated, portable fuel source for off-grid or worksite applications.
- Do all external tanks require venting? Not all do; some tanks omit vent valves. If your setup relies on venting, select a model that includes a vent valve or plan an alternative vent solution.
- Can external tanks be used with gasoline engines? These diesel-focused tanks are typically designed for diesel fuel. Do not use them with gasoline unless explicitly stated by the manufacturer.
- How do I avoid sizing errors when buying? Carefully compare mounting dimensions, capacity, and inlet/outlet configurations against your generator’s specifications and mounting hardware.
- Is a fuel level sensor worth it? Yes for longer deployments; it helps prevent unexpected outages by showing fuel levels in real time.
- What safety considerations apply? Ensure proper labeling to prevent misfueling, secure mounting to withstand movement, and use appropriate venting and filtration when required.