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Your Questions Answered, 2023 Edition


It has been quite some time since we did an article focused on the most common questions we receive via phone, email and blog comments, so we thought it was time to take a swing through the mailbag in the hopes that it just might address a concern that you could have. Here we go!

Q1:  How often do I need to charge my jump starter?

We strongly advise charging your jump starter, whether lead acid or lithium, every 90 days. This is the number one determinant of jump starter longevity, due to the fact that batteries (all batteries) really like to be charged and really don’t like to sit for any length of time in a discharged state. We even provide a free quarterly reminder email to charge your jump starter ­– you can sign up here – that’s how much we want you to charge it on a regular basis. During periods of extreme cold, we recommend charging more frequently, such as monthly. Charge early and charge often – make sure your jump starter is ready to answer the call when you need it the most.

Q2a:  What if I go to recharge my unit after 90 days of non-use, but it says it’s already fully charged?

Q2b:  What if I’ve used the unit a few times, but it says it’s still fully charged?

This is another very common question. Our jump starter batteries are very powerful and, in many cases, are relatively unaffected by a normal starting cycle on an otherwise healthy vehicle. So, it isn’t unusual for the jump starter to remain in a very high state of charge even after several uses. It also isn’t unusual for our units, after 90 days of non-use, to still show full when the battery status is checked. That said, regularly charging your jump starter is still beneficial, even if its state of charge is high. We suggest putting the unit on charge in the evening and letting it charge overnight. This will ensure the battery has been exercised and that it is truly at full charge (which is higher than the voltage level required to show the unit is charged enough when you check the status).

Q3:  Can I leave my jump starter plugged into AC power indefinitely?

There was a time when this was a complicated question to answer, but it really isn’t any more. Unless your jump starter is 10 or more years old, you can plug your Booster PAC or Jump-N-Carry into an AC outlet and leave it connected indefinitely without adverse consequences. We switched over the last of our units to fully automatic charging around ten years ago (some have had it for much longer). If in doubt about your unit’s age, the quick shorthand is that Booster PAC units have had automatic charging (almost) forever and any Jump-N-Carry with a circled BC symbol on the rear label has automatic charging.


Q4:  Can I leave my jump starter in the car during periods of extreme heat or extreme cold?

Our manuals indicate that the ideal storage temperature for your jump starter is 70˚F, which is absolutely true. This causes quite a lot of confusion. We realize it is not realistic to keep your jump starter in a 70˚ environment throughout the year. Long term exposure to very hot or very cold temperature will affect your jump starter’s longevity just like your car’s battery. A few simple steps can help to mitigate the impact, though. Charge your jump starter more often during periods of extreme weather if it is not stored indoors. Also, try to stabilize the unit’s temperature prior to charging – if you bring it in to charge, let it sit for an hour and then charge it. Also, when it is going to be extremely cold overnight (-15˚ to -30˚), bring the jump starter inside rather than leaving it in your trunk, especially if you have an important event you need to get to the next day. These steps will really help you get a longer life from your jump starter.

Q5:  Can I use my jump starter to charge my dead vehicle battery?

The answer to this one is complex, but the easy answer is “not really.” Yes, if you connect your fully charged jump starter to your dead car battery, over time, the batteries will equalize. So, your dead battery’s state of charge will rise. But, rise enough to power your vehicle? Maybe, but not likely. The better answer is 1.) jump start the vehicle and let your vehicle’s alternator charge the battery – that’s the job of the alternator, or 2.) attach a quality battery charger, like our PRO-LOGIX PL2310, to your vehicle’s battery and charge it right. Of course, there could be bigger issues that caused the dead battery in the first place, such as a defective alternator, but essentially, the answer is no, trying to “charge” your battery with your jump starter isn’t particularly effective.


Q6:  Can I use my Booster PAC or JNC jump starter to jump a lithium vehicle starting battery?

Absolutely. A jump starter essentially provides auxiliary power to your vehicle’s starting battery, as if you installed a second (or backup) battery in the vehicle. As long as your voltages match (12V vehicle – 12V jump starter, etc.), and you follow all safety precautions and use the proper connection procedure (read the manual), it should be no problem at all. This includes always connecting your jump starter’s negative to the vehicle ground, not the battery’s negative post.

Q7:  Why are you guys always harping on about connecting the negative lead to vehicle ground?

While it is often easier and faster to connect your leads to the two battery terminals, without a doubt you should connect the negative lead to a chassis ground or an engine ground (whether jump starting or charging). The most important reason for this is that batteries can be very dangerous, particularly so when they expel hydrogen gas due to excessive cranking or other causes, which is a normal occurrence. If you connect the positive lead to the ungrounded battery post and then the negative lead to a chassis ground away from the battery, if a spark should occur, it is much less likely to contact the expelled hydrogen gas. There is a reason that UL standards require us to write our manuals citing this connection sequence – because it is a best practice.

A newer reason is that the charging system in your vehicle is a lot smarter today than it was 20 years ago. On many late model vehicles, there is a sensor in the positive battery cable or on a busbar connected to the battery positive terminal. This sensor monitors power going to the battery and, if you connect both clamps (from your jump starter or your battery charger) to the battery terminals, you are bypassing this sensor, which will result in your smart vehicle power management system getting very confused, which is a bad thing.

Q8:  Related to Q6, but different – Can I use my battery charger to charge lithium vehicle batteries?

When this question dealt with jump starters, we said, “Sure… go ahead!” Isn’t it the same here? The answer is a definitive no, it’s not the same. The way a battery charger supplies power to a battery is very different than how a jump starter supplies power to a battery. Where a jump starter simply augments that battery it is connected to, a battery charger is pumping energy into a battery. When charging lithium vehicle batteries, it is important that the energy from the charger is specifically calibrated to meet the power requirements of a lithium battery. Lithium batteries, in general, are very sensitive to over-voltage conditions, so you have to be sure, when you are charging them, that you are using a charger that dials in the voltage exactly how they want it. Only use a charger that is specifically designed for charging the type of lithium battery you are servicing. Our PRO-LOGIX PL2112 and PL2140 models feature charging modes optimized for charging the LiFePO4 lithium starting batteries found in most vehicle applications in North America.


Q9:  Can PRO-LOGIX and CHARGE IT! Battery Chargers charge a totally dead battery?

Quick answer is yes. Now for the detail. On almost all smart chargers, including our chargers, a minimum voltage must be present in the battery to activate the internal electronics and enable the charger’s polarity protection feature to sense the polarity of the battery it is connected to. If the battery’s voltage is extremely low or at zero volts, the charger essentially can’t see it. But, if you have a battery that is below the threshold, our chargers can still charge it. First, confirm that your connections are correct (very important) and that you have good surface contact at each of the connections. After confirming those things, hold down the charger’s START/CHARGE button for 3 seconds to force the charger to commence charging. Once the battery’s voltage rises above the threshold, all of the charger’s advanced safety features will turn back on.

4520 Battery Charger

Q10:  Will changing the clamp on my product void the warranty?

Yes. Our limited warranty specifically states that products that are abused, misused or modified are no longer eligible for warranty. There are many reasons for this, but they all come down to safety. Modifying the clamp on one of our products adds inherent safety risk, which is why it is not allowed.

We hope that this has been helpful to you and maybe answered a lingering question that you didn’t have time to ask directly. Do you have any other questions we could answer for you? We would love to hear about it in the comments below.

19 Responses

    1. Al – Thanks for your question. This should not be an issue. That said, when I have a battery (of any type) on extended charge, in a situation such as you describe, I tend to take it off the charger for one week per month, just to give the battery a break and also allow it to self-discharge a little before charging again. Thanks again, Jim from Clore Automotive

  1. Clore products are good, we are using in my work jnc660 and 770 r they are great, i work in one of the world’s largest car dealer- group 1 automotive.
    My question is do you have spare parts to this jumpstarter? The parts that i am looking is a metal connection at the end of the cable that is attached to the clamp because of the twist snd turns it was broken, auto supplies don’t have it, please inform me if you have it.
    Thank you!
    Alarcon alipio

  2. This is very helpful! Question though, I assume the Q&As are applicable to a variety of Units including my 5000? I want to print and keep with unit. Is my assumption correct? I want to know b4 I print, please.

    Much thanks.


    1. Loren – Thanks for your question. For sure, the topics related to jump starters would apply to your ES5000, as with any other jump starter. Thanks, Jim from Clore Automotive

    1. Philip – Thanks for your question. It sounds like you battery has reached the end of its useful life. You could either install a new battery or purchase a whole new unit. These are the two best options. Thanks, Jim from CLore Automotive

  3. I got rid of my heavy 12/24 jumper and bought Noco GB70 booster and does it need charge more often than the full size packs?

    1. I would check it every 45 to 60 days and make sure it is fully charged. I don’t have a NOCO but I have a few similar battery boosters, I always check to them every 45 days as I went to use it once after 90 or 120 days and it was about dead and wouldn’t start the vehicle I was working on…

    2. Oliver – Since we do not manufactuire it, I think it’s best to check with Noco. That said, I’d charge it every 90 days, at least. Thanks, Jim from Clore Automotive

  4. After charging my 660 for ~24 hours the yellow light was still lit. But, when I unplugged it, the green light came on. And then turned off. Did I do something wrong. Usually, the green light comes on when it is fully charged.

    1. Ken – Thanks for your comment. Sometimes, the battery wants to sit just below the threshold to turn the light green. In these cases, what you’ll see if that if you unplug it and check the status, it’s green. Or, if you unlug it and plug it back it, it’s greeen. The threshold to get to green while in a continuous charging situation (plugged in an the light was yellow and I let it run through it charging cycle) is slightly higher than that of the other two situations. We’d suggest checking the state of charge on the meter. If you at or above 12.8V, your unit is fully charged. Thanks again, Jim from Clore Automotive

  5. I successfully used my JNC 550A to inflate a flat car tire. However, it was very loud. Was I operating it correctly?

    1. Myles – Thanks for your question. Honestly, the compressor in the JNC550A can, at times, be a little loud (for example, vs the compressor in the JNCAIR). That said, you likely did nothing wrong and, if it properly filled you tires, is likely working as intended. Thanks, Jim from Clore Automotive

  6. Good Morning, I use you JNC660 frequently far away from AC power and need to charge it using my vehicle and the automotive power cord. Can you tell me how to know when charging is complete?

    1. Chad – Thanks for your question. I would say that, when charging via the Male-Male cord from a running vehicle, to monitor the state of charge of the unit via the gauge every 10 minutes. Once the state of charge reaches ~12.9-13V, stop charging. I hope this helps. Thanks, Jim from Clore Automotive

  7. Hello Clore Automotive,
    Are your JNCxxx 12-volt Lithium Jump Starters Underwriter’s Laboratories rated?
    Best regards,

    1. James – Thanks for your question. Yes. Our JNC325 and JNC345 models are certified to comply with the UL2743 safety standard for lithium jump starters. Thank you, Jim from Clore Automotive

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