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The yesper yjs40 jump starter




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Every car driver must have the YESPER YJS40 jump starter in their car. This is the tool you buy never wanting to use, but to have when you need. People choose it because it is reliable and cost-efficient. Find all its advantages here!

4120 Peak Amps

All Gas Engines

24,000 mAh Battery Bank

12V Compatible

10L Diesel Engines

3 Mode LED Flashlight


Our Rating

Easy to Use
Value for the Money
Safety Features




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pros and cons of the YJS40


Great Value for the Money

Easy to use

Boosts most gas and diesel engines

Compact and portable design

Protective Case Included

Cigarette Lighter Adapter

Charge your smartphone and other gadgets

10 Protection Safety Layers including short circuit and reverse connection detection

Boost mode available

Embedded 3 Mode flashlight


Short Jumper cables

Long charge time

about this item and product specs

Why should you get a Yesper YJS40 jump starter? Discover all the features this jumper pack comes with and you’ll know why this is a must have in every car of your family.

Peak Amps


Gas Engines





3.37 lb

DC Output

Yes – 15V

Battery Bank

24,000 mAh



Operating Temperature

-4℉ to 140℉


12 Volts

Diesel Engines


USB Ports

2x Type A; 1x Type C


8.82 x 3.53 x 1.72 in

Boost Mode


Charge Time

4 hours

Safety Protections

10 layers including Spark-Proof & Wrong Connection Detection

12V CompatibleIt is compatible with motorcycles, cars, boats, lawnmowers, trucks, SUVs, minivans and pretty much everything that has a 12V battery.
4120AThis is more than enough to jump start pretty much every gasoline car.
60 Jump StartsDepending on the size and conditions of the engines, the Yesper Speed 4120 can give up to 60 jump starts from a single charge.
Works in temperatures from -4℉ to 140℉ It works in harsh temperatures.
24,000 mAh battery capacityCharge (several times) your smartphone and other gadgets via its USB ports.
All gas and up to 10L diesel enginesIt doesn’t matter if you drive an F150, a Silverado, or even a big 7.3L Diesel engine, you still have the power to jump start that vehicle.
10 Safety layersThe Yesper 4120A is spark proof (even if the clamps touch each other) and comes with reverse connection detection, and 8 additional protections to make jump starting your car a safe experience.
15V DC outputPower up small appliances like vacuum cleaners, tire inflators and more.
LED FlashlightA powerful LED flashlight with 3 different functions: Lamp, strobe and SOS.
IP65 RatedThis booster is water, dust, fire and shock resistant, and it is made of a sturdy and durable material for the wild life.

IS THE PRICE OF THE yjs 40 battery jump starter worth it?

With this booster you are getting a type of insurance. You are buying peace of mind for the road, and the best is this is only a one-time payment thing, so when seen from that perspective its price seems pretty fair.

For No products found. you get a very powerful jump starter that will probably be the only one you need in the next 10 years.

The Yesper YJS40 is among the top selling and most reliable jump starters because of the 4120 amps it can produce. Other brands sell comparable boosters at higher or lower prices, but with less features when compared to this one. Yesper truly delivers.

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the yesper yjs40 jump starter compared with similar items

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Advantages of owning the yesper yjs40 battery jump starter

Great PriceSimilar boosters are sold for more money and do not perform. The YSJ40 is the sure bet to get back on the road in seconds without having to break the bank account.
24000 mAh battery bankThis jump box comes with 2 USB type A ports and one of them is Q.C. 3.0 labeled, which means your phone charges faster. It also has a USB type C port that works as input for charging the booster but also as an output port to power up your USB-C compatible devices.
Compact DesignThe Yesper YSJ40 is small enough to fit anywhere in your car and pretty lightweight as well. Its dimensions are 8.82″D x 3.53″W x 1.72″H and it only weighs 3.37 lb.
Boost modeThis feature makes all the difference for this booster. The boost mode forces power to a car battery when is heavily discharged. Other boosters won’t detect a flat dead battery and would be useless.
Embedded LED flashlightThis lamp has 3 different functions to brighten your way in case you need it. Use it as a normal flashlight to see in the dark, or as a strobe or SOS signal to call for help.
Boosts all gas and most diesel engines in secondsWith the 4120 Amps the YJS40 produces, most cars get back to life in a matter of seconds. Use it in all gas and most diesel engines.
Easy to useJust plug the jumper cables of the booster to the terminals of the battery. then turn on your car and you are good to go. As simple as that.
DC Output portPower up other small appliances like vacuum cleaners, tire inflators, small compressors and more.
Does not require maintenanceThis booster is maintenance-free. You just need to charge it and store it. That is it.
Up to 60 jump starts from a single chargeYou may think that after jump starting a car the power of this unit would be depleted, but no. The Yesper YJS40 can give up to 60 jump starts on a single full charge before needing recharge.
Holds its power for monthsCharge this booster and its internal battery will hold its charge for more than 6 months. If you happen to need it, you know it will be ready for use.
Water, dust and shock resistantWater, dust and impacts can severely damage electronics. But the YJS 40 is protected against these thanks to its sturdy and durable construction.
10 safety protection layersJump starting a car should not be scary. This 4210A booster has safety protection technology embedded in its electronics to avoid the scary sparks that can harm you and your car.
Works in rough ambient temperaturesMany times batteries die not because you left a light on but because the freezing temperatures. This booster can operate in ambient temperatures of -4℉ to 140℉.
Compatible with multiple vehicle typesYou may think this only works with cars, but the truth is that if it has a 12V battery you can use this booster on it. Passenger cars, motorcycles, trucks, watercrafts, tractors, trailers, ATVs, UTVs, and snowmobiles can benefit from the use of this Yesper booster.

what is in the box of this jump starter?

This is what comes inside the box of the yjs40 battery jump starter

1Jump Starter
1Jumper Clamps
1USB A to USB C Cable
1Cigarette Lighter Adapter
1Carrying Case
1User Manual

Get the best accessories for your yjs40 yesper

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other benefits you get with this jump starter

Many people don’t know that jump starting a car with jumper cables can have a negative impact in the life and performance of the battery passing current.

When a person asks us if we can help to give them a boost, not all of us are aware of the damage we can do to our car, but since we want to do the right thing and be helpful, we do this without knowing the risks.

A booster like the YJS40 offers a safe, efficient, fast, secure, and easy way to help other people without having to put our cars in risk of an overcharge or something else.

Reviews of the Yesper 4120a jump starter

yesper yjs40
yesper YJS 40 jump starter review
People choose the YESPER YJS40 jump starter because it is reliable and cost-efficient. It features a compact design and comes with all you need to jump start your car if your battery dies.

Don’t let its small size fools you, since this compact booster has true power inside and can boost some big diesel trucks and pretty much all gas cars.

It also comes with plenty of power to charge and power up your small gadgets like smartphones and tablets.

Its DC output can power small vacuum cleaners, lamps, tire inflators, air compressors, and more, and it comes with the adapter of DC plug to cigarette lighter in case you need it, so no need to buy a spare one.

The 3 Mode flashlight is pretty often underestimated but this is a very handy tool, and it works as a lamp, SOS and strobe light, so you can ask for help or warn others about a potential situation on the road.

Its price is a true bargain when you consider all you get with it, and compare it to similar capacity boosters.

The Yesper YJS 40 even comes with its protection bag, which is strong and made of a hard material, and not just fabric.

The only real downside of this booster are the 5 hours it takes to recharge, yet that is expected given the 24,000 mAh battery capacity it has. Still, you can mitigate this by charging it on the go.

All in all, Yesper released a great product with the YJS40 and people are taking advantage of it, since they know other brands sell boosters with this amount of power and features for double or more the amount you pay for this one.
Easy to Use
Value for the Money
Safety Features
Easy to use
Boosts most gas and diesel engines
Compact and portable design
Charge your smartphone and other gadgets
Boost Mode Available
Embedded flashlight
Short Jumper cables
Long charge time

Our Rating

Check these reviews of the YJS40 so you see how simple is to use this booster. As you’ll see, there is nothing complex about using this jump starter to get your car back on the road in a matter of seconds. Even if you haven’t used a jump starter in the past, these videos will show how simple is to operate them.

other popular jump starters from YESPER

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OPINIONS from CURRENT owners of the yesper jump starter yjs40


I bought this after watching project farms test. I have it in my roadside kit. Unfortunately people just…


Wouldn’t even jump my 3.5 altima with a dead battery even with the boost function it would only get the dash lights to come…


This has got me out of a jam several times when my car battery died. Even though I have jumper cables there is not always someone there to let me jump off their car…

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the yjs40 is very easy to use

Using this jump starter is very simple. Check this video for a better illustration on how to use it, yet again, its operation is very simple and intuitive.

While using the Yesper jump starter YJS40 is very simple, I want to post here a few notes based on my experience to ensure you have a very efficient and effective jump start.

First of all, place your booster somewhere in your car near the battery since the cables are not that long. Make sure that no moving parts are close to the booster to avoid damaging it when your engine starts.

Identify the positive and negative terminals of your battery so you get the connection right. The red clamp goes to the positive and the black to the negative. The booster will lit the reverse connection LED in the jumper cables connector if the connection is not right.

Here is where it gets tricky. If the battery if heavily discharged, the booster won’t detect the battery and neither a reversed connection. At this point the next step is to click the boost button on the side of the jumper cables connector to force power through the battery.

The caveat here is that this boost mode deactivates all protection layers and safety technology of the jump starter. If the connection is reversed, you may damage something in your car.

All the boosters in the market with a force start, boost or manual override mode, do this. They deactivate their protections to force power through the battery.

By all means make sure the connection is right before using that boost mode.

After this just turn your engine on and you are good to go.

other things to consider before buying this jump starter

While the Yesper YJS40 model is a great jump starter, there are some things you may want to know before getting it.

  • Short jumper cables: While not a big deal, the length of the jumper cables is a bit short. This can make it complex to boost vehicles where the batteries are not easily accessible.
  • Long charge time: Consider about 5 hours to fully charge the unit from a 0% battery level. The good news is you can charge this while on the go in your car so it is always ready for use.


If you are looking for a powerful, reliable and cost effective jump starter that will be ready to help you when you need it, the Yesper YJS40 is a really smart way to go.

Not only the package comes with all you need to use it right out of the box, but you are getting yourself some peace of mind for a truly reasonable price.

People who bought this booster agree this was one of the best investments they have made and they are not shy about saying they will get a unit for each car of their family members.

You are seeing one of the best jump starters at the best price in the market here. What are you waiting to get yours and avoid a dead battery ruins your day? Get it at the best price here!

get the yesper SPEED 4120a car jump starter today

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▷ The Yesper YJS40 Jump Starter

The YESPER YJS40 Jump Starter gives up to ✅ 4120A to fire up all gas and up to 10L diesel engines. Click to get yours today!

Product Brand: Yesper

Product Currency: USD

Product Price: 129.99

Product In-Stock: InStock

Editor's Rating:


  • Great Value for the Money
  • Easy to use
  • Boosts most gas and diesel engines
  • Compact and portable design
  • Protective Case Included
  • Cigarette Lighter Adapter
  • Charge your smartphone and other gadgets
  • 10 Protection Safety Layers including short circuit and reverse connection detection
  • Boost mode available
  • Embedded 3 Mode flashlight


  • Short Jumper cables
  • Long charge time