We get a lot of phone calls, email inquiries, Facebook posts and blog comments related to jump starter health. After “Where can I go to buy your products?,” it is probably the question most frequently asked of us. Sometimes, the question is very specific, relating to a jump starting situation or use case that makes it quite unique. Most of the time, though, these questions fall within several common areas of concern. So, we thought we’d address them in a blog post in the hopes that we can help dispel any misbegotten notions and arm you with the information you need to get the most out of your jump starter investment.


How often should I charge my unit?

This one comes up a lot. If you are a high volume user, you have likely found your rhythm, but we’ll address those use cases as well as less frequent use case. We’d love you to charge the unit after each use, but we know that may not be realistic in all situations. So, if you are running a mobile service operation or other non-stationary function, we strongly suggest charging overnight whenever the unit has been used to jump or serve as a power supply. Putting the unit on a charger at 7 p.m. should bring it to full charge before the next work day begins. For occasional users, we suggest charging after each use and every 90 days when the unit has not been used. Keeping your unit at or near full charge is the number one predictor of unit longevity, so give it a charge.

Note: We offer recharge alerts to help you to remember to recharge every 90 days. If you haven’t done so already, you can sign up for these by clicking here.

I received my recharge alert and went to charge my unit, but the light was green. Does that mean I shouldn’t charge it?

No. We still suggest charging the unit for 4-6 hours. Although the charger may not turn on if the unit is fully charged, if it is slightly below full charge yet high enough to trigger the green light, doing so will bring the unit back to a full, beneficial charge.

Similar, but different than the above. When I purchased my jump starter, the manual and carton said to charge it for 24 hours upon initial purchase, but when I went to do so, the light was green.

First, this confuses a lot of people. It is important to understand that some units go from manufacturing to the final user very quickly and others move more slowly. So, we ask all purchasers to charge their unit upon purchase, since we can’t be sure which ones really require the charge. But, like the above answer, we encourage all purchasers, even those that get a green light to charge for 4-6 hours upon purchase.

Is it OK to leave the unit connected to AC power continuously?

For current generation units, the answer is yes, absolutely. For older units, the answers is more, “it depends.” For Booster PAC and Truck PAC models, yes you can do this regardless of vintage. Same is true for all vintages of JNC770, JNCAIR, JNC950 and JNC1224 models. For JNC4000 and JNC660 models, if you have LEDs showing CHARGING and CHARGED on the face, you can remain connected to AC indefinitely. For JNC300XL models, if you have a BC icon on the bottom label, you can as well. Otherwise, charge overnight and then remove the unit from the charger.

Can I leave my jump starter in the car during the winter? After all, the manual states that the ideal storage temperature is 70˚F.

The easy answer is yes. Like your vehicle battery, the unit should perform well until it encounters extreme temperatures. Our general rule of thumb is if the unit is going to see temperatures below -20˚F, you might want to consider bringing it in overnight. Also, during extended extreme cold stretches, we recommend charging every 30 days vs the normal 90 day charging interval. When bringing the unit in to charge in extreme temps, allow it to warm up for 30 minutes or so prior to charging. The battery will take the charge more readily if you do so.

What if I haven’t used or charged the unit for 2 years? Why isn’t it working?

Like your vehicle battery, if a jump starter is allowed to sit for a very long time without activity, its battery’s internal chemistry will begin to deteriorate. Eventually, its ability to accept a charge is compromised and the battery is rendered useless. Just as you’d never expect to start a vehicle that sat in the driveway for 2 years without replacing the battery first, the same is true for a jump starter.

What about lithium units? I have read that they can go a year without needing a charge?

Lithium jump starters are not too different from the other lithium battery driven devices in your life, whether it be a phone, tablet or other item. You wouldn’t expect to be able to put your phone in a drawer for a year and come back and use it as if you last touched it yesterday. Same is true for lithium jump starters. Like our lead acid units, we recommend charging them every 90 days when not in use, daily if used regularly.

My jump starter included a DC charging cord. Should I use that or the AC charging method?

The DC charging method, using the supplied cord, should be used only in those times when the AC charging method isn’t viable. For example, you do not have access to an AC outlet, but need to recharge the unit. In those times where it is necessary to use the DC method, there are a few things to remember. The first is that the DC power port on your jump starter is a direct feed to the internal battery, so care must be taken not to overcharge the jump starter. Frequently monitor the voltmeter and watch its progress. Once your reach 13.0-13.2VDC state of charge, you should disconnect. Second, it is important to remember that the output of your vehicle’s power port is quite high in comparison to the output of your AC charging system. That means that the unit could be recharged very quickly using the DC charging method. So, please don’t connect in this fashion and check back an hour later. It might be too late.

I think I lost my wall charger. I found one that fits, can I use it?

No matter the type of jump starter you own (lead acid, lithium, ultracapacitor, other), it is really important to use only the wall charger specifically designed to match the needs of your unit. Each wall charger model could potentially output a different voltage and amperage. All batteries are sensitive to overvoltage conditions and they should be avoided at all times. When in doubt, check with us. We’ll confirm that you have the right one, or we’ll help you get what you need.

We hope you find this helpful. Our jump starters typically last a good length of time, but remembering the above answers/tips will help you get the maximum life from your unit. And remember to sign up for recharge alerts if you haven’t done so already.









9 thoughts on “Q&A Related to Jump Starter Health”

  1. Well I have another question I have a JNC660 if I need to move a vehicle that has no battery in it can I use the JNC in place of the battery for a short period.

    1. Paul – Yes. It can be done. That said, we recommend that you keep it to very short exposures. This would apply to our lead acid models only. Thanks, Jim from Clore Automotive

  2. Excellent summary, gut one more Q. Without other equipment (voltmeter et al) how charged can the jump started battery become? Will it need to be fully charged on another charger?

    1. Charles – Assuming that the vehicle’s alternator is functioning properly, once you start the vehicle with the jump starter, the battery should be recharged relatively quickly. We would suggest driving the vehicle for 10-15 minutes and it should be enough to get the battery back to a near-full charge condition. Another alternative, as you suggest, is to connect a charger like our PRO-LOGIX PL2320 and run a full charge cycle. This would be the best option. Thanks, Jim from Clore Automotive

  3. I have the JNC660. Can I jump the battery by using the male to male adapter to the 12v outlet instead of popping the hood and using the cables? I have seen this done with other brands. Thanks,Joe

    1. Joseph – In many cases, you can bring the depleted battery up in this manner (assuming the power port is live while the vehicle is turned off), but it will be slow and may be ineffectual, depending on how low the vehicle battery was when you started. For sure, the fastest and most effective way to use the product is by direct connection to the battery and a grounding point. Thanks, Jim from Clore Automotive

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