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Plug & Pylon

Head to head

MUSTART vs J+ Booster 2

Same 40 amps, same Level 2 speed. What you are really choosing between is a certification you can verify and a rugged body, against a display and a delay timer.

By Sawyer V. · Published September 10, 2026

A hand holding an EV charging connector
Illustrative photo, not either of the units compared.

How this page is funded: we earn a commission if you buy through our Amazon links, at no extra cost to you. It does not change what we recommend, and we say plainly when the honest answer is to buy nothing. Full disclosure.

When two chargers deliver the same current, the comparison becomes about everything around the current. Here that means one question that matters a great deal and two that are genuinely nice to have.

The two units

Ranked for a first home charger. Every row jumps to the full write-up below.

#ProductBest forMax outputPrice
1MUSTART Level 2 portable chargerBudget portable. J1772, 25 ft cable.Budget portable40 A9.6 kWCheck price on Amazon#ad how we are funded
2J+ Booster 2The best portable overall. J1772, 25 ft cable.The best portable overall40 A9.6 kWCheck price on Amazon#ad how we are funded

The specifications, side by side

Published specifications
MUSTART portableJ+ Booster 2
Maximum output40 A / 9.6 kW40 A / 9.6 kW
Current settings15, 25 or 40 A (version-dependent)6 to 40 A in eight steps
DisplayLCD: current, voltage, power, statusNot a feature
Delay timer1 to 10 hoursNot a feature
Cable25 ft21 ft or 25 ft
BodyIndoor and outdoor use, per manufacturerIP67, drive-over resistant
CertificationCould not be verified from published sourcesETL certified to UL standards
Warranty2 yearsManufacturer limited warranty

The question that matters: certification

A portable charger carries 40 amps continuously for hours, often on unfamiliar outlets. A genuine listing from a recognized laboratory is the one specification on this whole purchase with no acceptable trade-off. The J+ Booster 2 publishes ETL certification to UL standards. For the MUSTART, we could not find a listing stated on the pages available to us.

That is not an accusation that it lacks one -- it is a statement of what we could and could not check. The practical instruction is simple: confirm the MUSTART's current listing with the seller before you buy. If you cannot, buy the unit whose listing you can see. How to read certification wording.

The nice-to-haves: display and timer

The MUSTART's LCD shows current, voltage and power. On an unfamiliar circuit that is genuinely useful -- a voltage reading tells you whether the supply is coping. Its delay timer lets you plug in at dinner and start charging at midnight without an app or a car that schedules itself.

Both units in full

Full specifications and the case against each.

1. Budget portable

MUSTART Level 2 portable charger

MUSTART · J1772 · 40 A / 9.6 kW · 25 ft cable

A 40 A portable with an LCD display, adjustable current and a delay timer, at the budget end of the category. The display is genuinely useful on a unit with no app.

What is good

  • 40 A from a portable, the same speed as many wall units on a NEMA 14-50
  • LCD display shows current, voltage and power without needing an app
  • Built-in delay timer for off-peak charging with no phone involved
  • Adjustable current, so it works on smaller circuits too

What is not

  • Two-year warranty, shorter than the three-year category standard
  • We could not verify a specific safety listing from published sources -- confirm before buying
  • No app or connectivity of any kind
Published specifications for the MUSTART Level 2 portable charger
Maximum output40 A / 9.6 kW at 240 V
Adjustable15, 25 or 40 A, depending on version
ConnectorSAE J1772
Cable25 ft
PlugNEMA 14-50
DisplayLCD showing current, voltage, power and status
Delay timer1 to 10 hours
Warranty2 years

Skip this if: Skip it if you need a documented safety listing you can verify -- see the note below before buying.

Specifications above are the manufacturer’s published figures. Source: MUSTART. We have not tested this unit — see how we pick.

Check price on Amazon#ad how we are funded

2. The best portable overall

J+ Booster 2

J+ Americas · J1772 · 40 A / 9.6 kW · 25 ft cable

A 40 A portable in a military-grade aluminum body, ETL certified to UL standards and IP67 rated, weighing 2.2 lb without cables. The portable that behaves like a wall unit.

What is good

  • 40 A, matching many wall-mounted units
  • Eight amperage settings from 6 A to 40 A, so it fits almost any outlet
  • Adapters for a wide range of outlets, including NEMA TT-30 for campgrounds
  • IP67 and drive-over resistant, which portables usually are not
  • 2.2 lb without cables, so it genuinely travels

What is not

  • Costs more than most portables, and more than some wall units
  • Every extra outlet adapter is a separate purchase
  • Still a portable, so it is not rated for permanent outdoor mounting
Published specifications for the J+ Booster 2
Maximum output40 A / 9.6 kW at 240 V
Adjustable6, 8, 12, 16, 20, 24, 32 or 40 A
Power range1.4 kW to 9.6 kW
ConnectorSAE J1772
Cable21 ft or 25 ft, depending on version
Adapters includedNEMA 14-50 and 5-15
Further adapters available5-20, 6-15, 6-20, 6-50, TT-30
Weight2.2 lb without cables; 7 lb with cables and adapters
BodyMilitary-grade aluminum, drive-over resistant to 6,600 lb wheel loads
RatingIP67 waterproof and dustproof
CertificationETL certified to UL standards

Skip this if: Skip it if you only ever charge in one place. A hardwired wall unit is cheaper for a fixed installation.

Specifications above are the manufacturer’s published figures. Source: J+ Americas. We have not tested this unit — see how we pick.

Check price on Amazon#ad how we are funded

The verdict

If you can confirm the MUSTART's safety listing and you value the display and timer, it is a reasonable buy at the lower tier. If you cannot confirm it, or the charger will travel and take knocks, buy the J+ Booster 2. The full portable roundup has the rest of the field.

FAQ

Questions people actually ask

Is the MUSTART as good as the J+ Booster 2?
They charge at the same 40 A. The J+ Booster 2 publishes ETL certification to UL standards, IP67 and drive-over resistance; the MUSTART adds a display and delay timer, but we could not verify its safety listing from published sources.
Is the MUSTART EV charger UL listed?
We could not confirm a listing from the published sources available to us. Check the current listing with the seller before buying.
Does the J+ Booster 2 have a timer?
Not built into the unit. Scheduling can be set in most cars instead. The MUSTART has a built-in 1-to-10-hour delay timer.

Sources

Where these numbers come from

  1. MUSTART Level 2 EV charger, 40 A, NEMA 14-50, 25 ft — MUSTARTPublished output, display, delay timer and warranty. Certification not stated on the pages we could access.
  2. Portable Level 2 EV charger 40A (UL) -- J+ Booster 2 — J+ AmericasCurrent settings, adapters, weight, IP rating and certification.

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