Liters Not Amps product guide
GOOLOO GP4000 4000A 12V Jump Starter
Larger gas and diesel engines, plus 12V accessory power
The GP4000 is a 4000-amp pack that GOOLOO rates for all gas engines and diesels up to 10 litres, with a 150-watt 12V output and a cigarette-lighter adapter. Its manual limits you to three consecutive starts two minutes apart and asks for a 30-minute cool-down before recharging.
Listing checked . Confirm the model, included parts and availability before ordering.
Published specifications
- Manual: GP4000 (Epower-137B), 4000 A peak, 800 A starting current
- Manual: capacity given as 74Wh/5000mAh on GOOLOO's site, 99.2Wh on the listing copy
- Manual: max 3 consecutive starts, 2 minutes apart; cool 30 min before recharging
- Manual: full charge 6-8 hours at 5V/3A; wall charger not included
- Manual: operate -20°C to 60°C; charge only at -10°C to 45°C; recharge every 3 months
- Manual: 18-month warranty, original purchaser with receipt or order ID
Fit and limits
Strengths
- Smart cable reads out connection, reverse polarity and low voltage on one light
- 15V/10A DC output and a cigarette-lighter adapter for running 12V accessories
- GOOLOO publishes a full text manual, a troubleshooting guide and clear usage limits
Caveats
- Three published battery capacities for one model: 74Wh, 99.2Wh and 24000 mAh
- Only three consecutive starts, and no recharging for 30 minutes afterwards
- The manual lists yachts as supported and then forbids use on boats
A 4000-amp pack with a 12V accessory socket built in
GOOLOO's manual titles this the GP4000 Jump Starter, Titan Series, and gives its model number as Epower-137B. Peak current is 4000 amps, and the manual's specification table separately lists a starting current of 800 A. The claim on both the listing and the manual's highlights is that it starts all gasoline engines and diesel engines up to 10.0 litres.
What sets it apart from a plain booster is the output side. Besides two USB-A outputs — one a quick-charge port — and a Type-C in-and-out port, it has a 15V/10A DC output described as 12 to 16.8 volts at 150 watts maximum through a 5.5 by 2.1 mm barrel socket, plus a cigarette-lighter socket adapter in the box for running 12V accessories. The manual warns that a short circuit or a load above 150 watts on that port shuts the unit off, and that you must clear the fault and recharge to reset it.
The manual's package table lists the host, an EVA box, a USB-A to Type-C cable, a USB-C to USB-C cable, the cigarette lighter socket adapter and the user manual; the revision attached to the listing lists a Smart Jumper Cable in place of the USB-C to USB-C cable. Both the listing and the manual state that a wall charger is not included.
Three different battery capacities are published for this one model
This is the clearest example of why you should read the paperwork rather than the bullet points. GOOLOO's manual as published on its own manuals index gives the capacity as 74Wh/5000mAh at 14.8 volts. The revision of the same GP4000 manual attached to the Amazon listing gives the capacity as 99.2Wh. Amazon's details table says 24000 milliamp hours.
Those cannot all be right, and the difference is not trivial — it is the number that determines how many starts and how much phone charging you actually get. The two manual revisions differ elsewhere too: the site copy lists quick charge as 5V/3A, 9V/2A, 12V/1.5A, while the listing copy says 5V/2.4A, 9V/2A, 12V/1.5A, and the listing copy adds a second starting-current line reading 800A for 3 seconds and 500A for 5 seconds.
We are not going to pick one. Check the label on the unit you receive against whichever manual comes in the box. Both revisions do agree on the physical figures: 228 by 99.5 by 38 mm and 820 grams, a lifetime of more than 1000 cycles, and a full charge in 6 to 8 hours at 5V/3A. Amazon's table lists 3.94 pounds, which is well above 820 grams and looks like packaged weight.
Three consecutive starts, two minutes apart, then thirty minutes off
Warning 27 in the manual is the duty rule: do not start the product more than three consecutive times, because this may cause it to overheat and damage the product, and if you need multiple attempts, wait two minutes between each one. That is a tighter limit than several competing packs advertise, and it is written as a damage warning rather than a suggestion.
Warning 17 adds the other half: do not recharge the product immediately after using it to start a vehicle — cool it down for 30 minutes before charging. Warning 8 says not to use the unit to start a vehicle while its internal battery is charging, and the FAQ confirms it cannot charge other devices while starting a vehicle, though it can charge devices while it is itself being charged.
Before you start, the manual says the unit must be over 50 percent charged, which is two bars on the indicator, and warning 15 repeats that you should only use it to start a vehicle when the indicator shows more than two bars. If it has not been used in more than two months, the manual says to charge it first. Warning 16 says to remove the unit from the battery once the engine has started rather than leaving it connected.
What the clamp light means, and when to press BOOST
The smart jumper cable does the diagnosis. The manual's sequence is to plug the blue connector fully into the unit with the clamp indicator off, then red to positive and black to negative, then read the light. Solid green means the connection is correct and you can crank. Solid red means the terminals are reversed and must be reconnected until green is solid.
A flashing green light means the vehicle battery voltage is too low: press BOOST, wait for solid green, and complete the jump start within 30 seconds. No light at all may mean the battery is completely damaged; the manual gives the same instruction — check the connections, press BOOST, and finish within 30 seconds once green is solid. Warning 14 says specifically not to press BOOST with the clamps connected in reverse.
Warning 11 is a small detail with an expensive consequence: make sure the blue plug of the jumper cable is fully seated in its socket, because otherwise the plug could melt. Warning 12 notes that dirty or corroded battery terminals reduce the unit's output power, and the troubleshooting guide's pre-flight checklist asks you to confirm the terminals are not loose, dirty or heavily oxidised. Both GOOLOO and the listing describe ten built-in types of protection under the SUPERSAFE name, but neither document we read lists what those ten are, so we cannot name them, and neither states whether any of them change when BOOST is pressed.
The manual contradicts itself on boats
The product highlights page says the GP4000 works with 12V vehicles, motorcycles, pickup trucks, RVs, tractors, trucks, cargo vans, ATVs, snowmobiles, yachts and many more, and the Amazon bullet repeats yachts in the same list. Warning 5 in the same manual says the unit is for 12V vehicles only, may not be suitable for other vehicles, and that it is forbidden to use for other machines such as aircraft and boats.
Those two statements are in the same document and they do not agree. If you were buying this for a boat, that contradiction is the thing to resolve with GOOLOO before purchase, not something for us to smooth over.
The rest of the warning list is conventional and worth following: do not use it in place of a vehicle battery or as a battery charger, do not connect the two clamps together, do not use it if a cable, clamp or cord is damaged or the unit is overheated, swollen or leaking, keep it dry, keep it out of explosive atmospheres, do not modify or disassemble it, and keep it away from children.
Temperature, the three-month recharge, and an 18-month warranty
The specification table gives an operating temperature of -20°C to 60°C, or -4°F to 140°F. The FAQ explains what is at stake above that: this is a lithium-polymer battery, and above 60°C the internal construction of the cells will be damaged and the pack may swell and become unsafe, so the manual tells you not to leave the device in a vehicle parked in hot weather for long periods. Warning 23 repeats not to store it where the temperature may exceed 60°C, and warning 24 sets a narrower charging window: charge only at an ambient temperature between -10 and 45°C, or 14 to 113°F.
On keeping it ready, GOOLOO is more specific than most. Warning 10 says not to let the unit over-discharge and that it is best to recharge it every three months, and FAQ Q10 gives the same three-month answer. The Amazon bullet says every two to three months, and the starting instructions say to charge first if it has sat unused for more than two months. Treat three months as the outside limit. The unit powers itself off after 30 seconds with no load, and the FAQ notes it cannot charge devices drawing under 200 mA — phones and accessories with very low draw will trigger that same 30-second shutoff.
The warranty section promises to replace a unit defective through manufacturing issues with a new one within 18 months, alongside 18 months of online after-sales service and a 30-day money-back window through Amazon. It is valid on presentation of the original receipt or order ID by the original purchaser, does not cover normal wear and tear, physical abuse, improper installation, misuse, or modification or repair by unauthorised third parties, and all claims are limited to repair or replacement at GOOLOO's sole discretion. Amazon's details field also says 18 months. Keep the receipt, and check the seller and condition of the offer you select.
Check the current listing
Confirm the model, included parts and availability before ordering.
Primary sources
- GOOLOO GP4000 user manual, English section (maker manuals index copy)
- GOOLOO product manuals index listing the GP4000 manual
- GP4000 manual revision attached to the listing, with a different specification table
- GOOLOO GP4000 jump starter troubleshooting guide, updated June 16, 2026
Primary sources checked .
Compare with
- NOCO Boost GB20 500A 12V Lithium Jump Starter
Gas engines up to 4.0 litres, motorcycles and powersport
- NOCO Boost GB40 1000A 12V Lithium Jump Starter
Gas engines to 6.0L and diesels to 3.0L on 12V lead-acid
- NOCO Boost X GBX75 2500A 12V Lithium Jump Starter
Gas engines to 8.5L and diesels to 6.5L on 12V lead-acid
- GOOLOO A3 3000A Jump Starter with Air Compressor
One glovebox tool for a flat battery and a soft tire
Side-by-side pages, this model next to: NOCO Boost GB20 500A 12V Lithium Jump Starter, NOCO Boost GB40 1000A 12V Lithium Jump Starter, NOCO Boost X GBX75 2500A 12V Lithium Jump Starter, GOOLOO A3 3000A Jump Starter with Air Compressor.