Car Battery Jump starter FAQs

best jump starter faq

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1. What are the things I should look for in a car jump starter?

The cranking amp ratingdepending on the size of the engine of your vehicle(s) but usually the higher the better.

Voltagemost of the car batteries are 12V but commercial trucks, RVs and machinery can have up to 24V. Check your battery for the voltage.

Cable lengthagain, depending on the size of the car and the size of the car battery jump starter. With small jump starters, the cable length is usually between 10 and 12″ – just to reach both terminals easily but with bigger car jump starters you might want to have longer leads (around 60″) to ensure comfortable and safe operation.

Reverse-polarity protection – a handy feature for those unsure which cable goes to which car battery terminal – if you get it wrong, the jump starter will indicate and won’t let you damage your car.


Based on your needs you might want to check whether the jump starter has an integrated flashlight, USB ports, 12V outlet or a compressor which might save you in other situations.


2. Some articles are saying I have to look for CCA and CA but most of the product descriptions are talking only Peak amps. How and where can I find more details about these?

Some manufacturers don’t make it easy for customers – we are continuously expanding the product descriptions but if you are particularly interested in a certain jump starter but can’t find this information here on jumpstarter.io, please email us at [email protected] and we will find out.


3. We have a small car (4 cylinders), 2 sedans (6 and 8 cylinders) and a commercial vehicle what would be the best option, should I buy jump starters for different cars?

It depends – if you have a commercial truck (which generally needs over 500 cranking amps to jump start), any jump starter that covers this will also start your other vehicles. Another aspect to consider is portability – even the strongest jump starter is useless if it’s sitting in the garage because it’s too heavy or big, while you are stranded in “the other” vehicle so you might also want to get one of the smaller jump starters that fit in the glovebox. You might want to check out our list of best car battery jump starters here


4. I see battery packs, power sources and then jump starters in the market. Which one is best? What is the difference? Do the battery packs and power sources work the same way i.e. just connecting the jumper cables to the dead battery should work?

Battery packs and power sources are mostly just different names for the same thing – jump starters. You can find the list of best jump starters or best portable jump starters on our website. 


5. I have read in one of the articles that not all jump starters are able to start a battery which is completely flat. how do I ensure that the jump starter I am buying will be able to jump-start even flat batteries?

It is absolutely true that not all jump starters are capable of starting a vehicle with a battery that is completely dead as the power will flow into the dead battery AND to the starter motor, that is why it is harder to start a car with a battery that is completely dead – the dead battery will simply absorb more of the power. This is another reason to get the jump starter that has the highest cold cranking amp rating, this gives it the best possibility of starting the vehicle with a dead battery.


6. What cautions I should take when using a car battery jump starter?

Read the manual first to make sure you follow the recommended way of using that particular model/type of the battery jumper. As a rule of thumb, when using the car battery jump starter, connect the positive lead first, then the negative lead. Make sure you are connecting correct leads to the corresponding terminals ( “+” and “-” signs and/or colors – red cable is usually “+” and black “-“) Some more advanced units have an on/off switch. These are better because the cables can be connected and then the switch turned on. This prevents sparking when connecting the cables. You can also refer to our article with tips for using a jump starter


7. If the label on my battery reads 550 CCA does that mean the battery will produce 550 Amps of current or it requires a jump starter with 550 CCA to jump-start the vehicle if the battery goes flat?

A high CCA battery rating is especially important for starting in cold weather. Generally, you do not need a battery jumper box with the same rating as the battery. A lower rating is usually acceptable.


8. In my commercial vehicle, I have 2 batteries. Which battery should I use to jump-start the vehicle?

The two batteries are interconnected so it does not matter that much which one you use. When jump-starting the car, just connect to either battery. Again, CCA can be lower than the sum of the batteries. In case both of your car batteries are completely flat, you might want to try to disconnect one as completely flat batteries do make it more difficult for jump starters to work, especially in cold weather. You can read more about it in our Peak amps vs cranking amps article.


9. If I am buying a car battery jump starter that can jump-start the largest of my vehicles, does that mean I need to buy one that has some sort of overload limiter to prevent damage the batteries of the other, smaller cars?

During the start, the vehicle will only pull as much power as needed from the jump starter battery. There is zero chance of the jumper box overloading and damaging the vehicle’s electrical systems so don’t worry.

10. How to recognize one that can jump-start even dead battery and a jump starter which can NOT jump start a vehicle with a dead battery?

The higher the Cold-cranking amps rating, the better the chance of actually starting a vehicle with a dead battery. A car jump starter with 500 cold-cranking amps should be able to start just about any vehicle with a dead battery.

11. What is reverse polarity indicator and do I need it?

Reverse polarity indicator helps you to avoid connecting the cables the other way round to the battery terminals by letting you know if you have done so. This will give you the opportunity to correct the connections before attempting to start the vehicle. 

12. What car and other automotive accessories can a car battery jump starter power?

Car battery jumper boxes are amazing in their versatility. Ability to charge your phone/iPad via the integrated USB ports is a standard, some jump starters offer even more than one. Some jump starters, especially the larger ones, offer 12V connections so you can charge/power anything that is using the standard 12V plug but also 9V sockets that can charge laptops, etc.