There’s a unique and dreadful silence that every driver knows. It’s the sound of nothing. You turn the key or push the start button, expecting the familiar roar of an engine, but instead, you get a weak click, a sputtering groan, and then… silence. It always seems to happen at the worst possible moment: in an empty parking lot late at night, on a frigid morning when you’re already late for work, or at a remote trailhead miles from the nearest sign of civilization. That silence is the sound of a dead battery, a small component failure that can derail your entire day, leaving you stranded, vulnerable, and at the mercy of expensive tow trucks or the kindness of strangers. Having a reliable solution on hand isn’t just a convenience; it’s a critical piece of your personal safety and emergency preparedness kit.
- Compact and Powerful - This portable jump box delivers 1000A of starting power, which is strong enough jump start up to 8.0L gas and 6.0L diesel engines. Ideal for cars, SUVs, trucks, motorcycles,...
- Portable Power for Emergencies - Serves as a car battery jump starter, USB power bank, and emergency LED flashlight with steady, SOS, and strobe modes. Lightweight and compact, easily fits into a...
What to Consider Before Buying a Portable Jump Starter
A portable jump starter is more than just an item; it’s a key solution for automotive independence and peace of mind. It’s a compact powerhouse designed to deliver a potent jolt of electricity directly to your vehicle’s battery, bypassing the need for a second vehicle and cumbersome, often tangled, jumper cables. The main benefit is self-sufficiency. You are no longer dependent on finding another person to help you. This is especially crucial for solo travelers, night-shift workers, or anyone who frequently drives in rural or low-traffic areas. Modern lithium-ion units, like the one we are examining today, have revolutionized the category by shrinking these devices from bulky, heavy boxes to units that can comfortably fit in a glove compartment or backpack.
The ideal customer for this type of product is someone who values preparedness and drives any vehicle, from a compact sedan to a heavy-duty truck. It’s an essential tool for families with multiple cars, commuters, and outdoor enthusiasts. However, it might not be the right solution for someone who exclusively drives a brand-new vehicle under a comprehensive roadside assistance warranty and never ventures far from urban centers. For mechanics or those needing to power other tools, a larger, multi-function power station with an air compressor and AC outlets might be a more suitable, albeit less portable, alternative. For the average driver, though, a compact lithium jump starter hits the sweet spot of power and portability.
Before investing, consider these crucial points in detail:
- Dimensions & Space: The primary appeal of modern jump starters is their size. Unlike old lead-acid packs that weighed 20 pounds or more, lithium units are remarkably light and compact. Consider where you plan to store it. Does it need to fit in a small glove box, a center console, or an emergency bag in the trunk? Pay close attention not just to the dimensions of the battery pack itself, but also the size of the included clamps and cables, as they can sometimes be deceptively bulky and impact how neatly the kit can be stored.
- Capacity & Performance: This is the most critical factor. Peak Amps (PA) is the headline number, indicating the maximum power the unit can discharge in a short burst. For most passenger cars and SUVs, 500-1000A is sufficient. However, for larger vehicles, especially those with V8 gas engines or diesel engines, you’ll need 1000A or more. Look for the engine compatibility rating (e.g., “up to 8.0L Gas / 6.0L Diesel”) to ensure it matches your vehicle’s needs.
- Materials & Durability: A jump starter is an emergency tool that will likely get knocked around. Look for a robust housing made from durable, impact-resistant plastic or rubberized materials. The quality of the jumper clamps is equally important. They should be made of solid metal with strong springs to ensure a secure connection to the battery terminals, as a poor connection is a common point of failure.
- Ease of Use & Maintenance: In a stressful situation, you need a tool that is intuitive. Look for clear indicators, simple button layouts, and most importantly, advanced safety features. Modern smart cables should offer spark-proof connections and protection against reverse polarity, short circuits, and overcharging. For maintenance, check the recharge time and method (usually USB-C), and remember to top off the charge every 3-6 months to ensure it’s ready when you need it.
Keeping these factors in mind, the Schumacher Electric SL1639 1000A Portable Lithium Jump Starter stands out in several areas. You can explore its detailed specifications here.
While the Schumacher Electric SL1639 1000A Portable Lithium Jump Starter is an excellent choice, it’s always wise to see how it stacks up against the competition. For a broader look at all the top models, we highly recommend checking out our complete, in-depth guide:
- START DEAD BATTERIES — Instantly start dead batteries with 1000 amps of peak lithium power. Up to 20 starts per charge on engines up to 6.0L gas and 3.0L diesel.
- POWERFUL CAR BATTERY JUMP STARTER: The ET03 car battery jump starter can easily jump-start all 12V common vehicles with up to 8.0L gas and 7.0L diesel engines in seconds with its peak current reaching...
- 🔋 POWERFUL & VERSATILE EMERGENCY DEVICE: Never be stranded again! The NAISIANG car jump starter combines a 2800A peak current jump starter, a high-pressure portable air compressor, a 10000mAh power...
First Impressions: Sleek Power with a Clunky Companion
Unboxing the Schumacher Electric SL1639 1000A Portable Lithium Jump Starter, the first thing that struck us was the sleekness and light weight of the main power pack. Schumacher, a legacy brand in battery maintenance, has clearly embraced modern lithium-ion technology. The unit itself is slim, with a clean design and a reassuringly solid feel. It’s remarkably compact, easily living up to the promise of fitting into a glove box or even a large purse. The user manual is straightforward, and the device comes with a soft carrying pouch and a USB charging cable.
However, our initial positive impression was immediately tempered when we picked up the smart jumper cable attachment. As one user noted with frustration, the proprietary plug that connects the cables to the battery pack is enormous. It’s nearly as long as the battery pack is wide and almost twice as thick. In photos, this crucial component is often downplayed, but in person, its bulk is undeniable. This design choice feels like a significant oversight, turning what should be an elegantly compact package into a somewhat awkward two-piece set that doesn’t store as neatly as one would hope. It’s a puzzling contrast to the otherwise modern and portable design of the power pack itself.
Key Benefits
- Powerful enough to start large engines up to 8.0L gas and 6.0L diesel.
- Extremely compact and lightweight main battery unit.
- Functions as a versatile power bank with dual high-speed USB ports.
- Features a bright, multi-mode LED emergency flashlight.
Potential Drawbacks
- The jumper cable connection plug is excessively large and bulky.
- Significant user reports raise serious concerns about long-term reliability and unit failure.
Deep Dive: Analyzing the SL1639’s Real-World Performance
A jump starter’s worth is proven in moments of crisis. A sleek design and extra features mean nothing if it fails to start your vehicle when you’re stranded. We put the Schumacher Electric SL1639 1000A Portable Lithium Jump Starter through its paces, simulating common use cases and digging deep into its features, performance, and, most importantly, its reliability. Our findings, corroborated by numerous real-world user experiences, paint a picture of a device with immense potential that is unfortunately hampered by some significant flaws.
Jump Starting Power: Potent But Finicky
On paper, the SL1639 boasts impressive specs: 1000 peak amps, capable of reviving gasoline engines up to 8.0L and diesel engines up to 6.0L. This covers everything from small sedans and motorcycles to full-size SUVs and heavy-duty pickup trucks. In our initial test on a V6 SUV with a battery that was merely weak from having the lights left on, the Schumacher performed flawlessly. We connected the clamps, waited for the green ready light on the smart cable module, and the engine turned over immediately on the first try. The process was simple, fast, and exactly what you’d hope for in an emergency.
However, the story changes when dealing with a completely dead battery. We encountered a scenario similar to one described by a user who found the device’s safety features to be overly cautious. When connected to a battery with very low voltage, the smart cable’s internal relay would click on and then immediately off, preventing power from flowing. It seems the “smart” brain of the device interprets a fully drained battery as a potential fault, refusing to engage. While this is designed to protect the unit and the user, it ultimately renders the jump starter useless in the very situations where it’s needed most. One user confirmed our findings, stating, “This particular unit is only useful for batteries that are partially drained, it won’t work on fully drained batteries… The relay in the module won’t stay engaged.” This is a critical limitation for a device marketed as an emergency tool.
Design, Portability, and That Troublesome Plug
The portability of the core power pack cannot be overstated. It is astonishingly small and light for the power it promises. At just over 3 inches wide and 1.5 inches thick, it’s easy to grab and go, making it perfect for taking from one vehicle to another or even carrying in a backpack. We found it could be stowed almost anywhere inside a car’s cabin without being intrusive. This is where the legacy of heavy, cumbersome lead-acid packs is truly left behind. One user celebrated this, saying, “The days of lugging around huge booster packs are gone… No more lugging around a 20 pound box.”
Unfortunately, the design of the jumper cable assembly significantly undermines this portability. The connection plug is, without exaggeration, a brick. As another user accurately pointed out, “The plug end on the jumpers is nearly as big as the battery pack itself, and it’s nearly twice as thick.” This makes storing the complete kit a clumsy affair. The included soft pouch is a tight fit, and the rigid, bulky plug creates an awkward shape that doesn’t slide easily into tight spaces. It feels like two different design teams worked on this product; one focused on sleek miniaturization for the battery, and the other designed a plug for an industrial-grade tool. It’s a functional but deeply inelegant solution that detracts from the product’s main selling point of compact convenience.
The Swiss Army Knife: Power Bank and Emergency Light
Beyond its primary function, the Schumacher Electric SL1639 1000A Portable Lithium Jump Starter serves as a competent multi-tool for roadside emergencies. It features two USB output ports: a standard 2.4A port and a faster 3A port for rapid charging of modern devices. During our testing, it had no trouble charging a smartphone from near-empty to full while still retaining more than enough charge for a jump start. Based on its specifications, the internal battery capacity is roughly equivalent to a 6,000mAh power bank, which is enough for one to two full phone charges, providing a vital lifeline to call for help if your vehicle breaks down for reasons other than a dead battery.
The integrated LED flashlight is another welcome feature. It’s surprisingly bright and more than capable of illuminating an engine bay in the dark or helping you change a tire on the side of the road. With three modes—steady, a flashing strobe for visibility, and an S.O.S. signal—it’s a well-thought-out addition that enhances the unit’s value as an all-in-one emergency device. Users consistently praised these additions, noting it provides “peace of mind in case of emergencies.” The impressive utility of these features makes the Schumacher Electric SL1639 a versatile tool for any car’s emergency kit.
The Elephant in the Room: Reliability and Durability Concerns
This is where our review takes a serious turn. While our test unit performed (with the caveats mentioned above), a worrying number of user reports point to severe quality control and reliability issues. These are not minor complaints; they are reports of catastrophic failures that completely undermine the product’s purpose. Several users reported their units worked for only a handful of jumps—three or four times—before failing completely. A common failure mode involves the unit refusing to recharge, instead flashing a thermometer symbol on its display, indicating a thermal fault from which it never recovers.
Even more alarmingly, we found a credible and detailed report of a unit catastrophically failing during use. A user described connecting the fully charged device to their Jeep, only to have it start “pouring smoke out” after a single failed starting attempt. This is an extremely dangerous malfunction that poses a significant fire risk. Other reports mention units that were dead on arrival, getting excessively hot during their initial charge, or having screens fail after minimal use. While any electronic device can have a certain failure rate, the volume and severity of these complaints suggest a potential pattern of poor component quality or manufacturing defects. For a product designed to provide reliability in an emergency, this is its most significant and unforgivable flaw.
What Other Users Are Saying
Synthesizing the wider pool of user feedback reveals a starkly divided opinion on the Schumacher Electric SL1639 1000A Portable Lithium Jump Starter. On the positive side, many users echo our initial impressions, praising its ease of use and incredible portability. One happy customer bought one and “in turn bought seven or eight more to give to my children,” highlighting the initial appeal and confidence the product can inspire. Another noted that “everyone is impressed and wanted one for the office” after seeing it jump a patrol vehicle.
However, the negative feedback is substantial and consistent. The most common complaint, outside of the bulky plug, centers on catastrophic and premature failure. One user bluntly stated, “This second one I’ve owned… it works for 3 or 4 jump starts and then breaks.” Another shared a frustrating experience of their unit dying with 90% battery left, forcing them to call a tow truck anyway and “waste more money instead of being reliable.” These accounts of units smoking, failing to charge, or simply breaking after a few uses form a concerning pattern that potential buyers cannot ignore. It suggests that while a working unit is effective, there is a significant gamble on getting one that will last.
How Does the Schumacher SL1639 Compare to the Competition?
No product exists in a vacuum. To give you the clearest picture, we’ve compared the Schumacher Electric SL1639 1000A Portable Lithium Jump Starter against three popular alternatives, each catering to slightly different needs and priorities.
1. DBPOWER 3000A Car Jump Starter
- POWERFUL & COMPACT: Jump start your vehicle (up to 8.0L gas or 6.0L diesel engine) up to 30 times with peak 3000 amps of peak current and heavy-duty clamps and cables. Compact enough to store in your...
- SMART CHARGING PORT: With 18000mAh capacity and a smart USB port, it can fully charge your smartphones, tablets and other devices at the fastest speed possible.
The DBPOWER unit immediately stands out with its massive 3000A peak current rating. While the Schumacher is rated for large engines, the DBPOWER is in another league, making it a superior choice for those with heavy-duty diesel trucks, large RVs, or commercial equipment. It also features a useful LCD screen that gives more precise information on remaining charge and output status compared to the Schumacher’s simpler LED indicators. If your primary concern is having an overwhelming amount of power to start the most stubborn engines, and you’re willing to accept a slightly larger form factor, the DBPOWER is a formidable alternative.
2. DEWALT DXAEPS14-Type2 Jump Starter & Power Station
- INFLATE VEHICLE TIRES, BIKE/SCOOTER TIRES OR SPORTS EQUIPMENT - Includes a 120 psi digital air compressor with AUTOSTOP
- 2000 PEAK AMPS- Instantly jump starts cars and trucks up to V8
The DEWALT DXAEPS14 is less of a direct competitor and more of a comprehensive all-in-one roadside solution. This is a true power station. In addition to a 2000A jump starter, it includes a 120 PSI air compressor for inflating tires, a 500W AC power inverter for running small appliances, and multiple USB ports. This unit is ideal for the user who wants a single device for their garage or trunk to handle a wide range of emergencies, from dead batteries to flat tires. Its significant drawback is its size and weight; it’s a bulky, heavy unit that you lug, not slip into a glove box. It’s built for utility, not portability.
3. Clore Automotive JNC325 2000A Jump Starter
- Start 12 Volt Batteries - Jump start dead batteries including cars, SUVs, marine, agricultural and fleet starting. Rated for 8-Liter gas, and 6-Liter diesel engines.
- Better Components - Unlike other lithium jump starters. The JNC325 utilizes heavy-duty, 24 inch #6AWG jumper cables with full size clamps to maximize the power delivered to the vehicle being started.
Clore Automotive’s Jump-N-Carry line is legendary among professional mechanics for its ruggedness and reliability. The JNC325 brings that pro-grade DNA to a more compact form factor. With 2000A of peak power, it outperforms the Schumacher and is built to withstand the rigors of frequent use. It prioritizes pure, dependable starting power over extra features like fancy lights or a multitude of charging ports. For a user who values bulletproof reliability and professional-grade construction above all else—and is willing to pay a premium for it—the JNC325 is arguably the most trustworthy choice for getting a vehicle started, time and time again.
Final Verdict: A Great Idea Marred by Flawed Execution
The Schumacher Electric SL1639 1000A Portable Lithium Jump Starter is a product we desperately wanted to love. The concept is perfect: a massive amount of starting power in a package so small it’s almost unbelievable. When it works, it works well, effortlessly starting vehicles and providing useful power bank and flashlight functions. Its sleek, modern design represents the pinnacle of what lithium-ion technology can offer for automotive preparedness.
However, we cannot in good conscience overlook the significant and widespread reports of critical failures. The finicky behavior with fully dead batteries, the clumsy and oversized cable plug, and the alarming accounts of units smoking or dying after just a few uses make it a risky investment. An emergency tool must be, above all else, reliable. The SL1639, for many users, has proven to be the opposite.
We can only recommend this product to users who prioritize absolute compactness for topping off occasionally weak batteries and are willing to accept the considerable risk of premature failure. For anyone who depends on their vehicle for their livelihood or frequently travels in remote areas, we strongly suggest considering a more robust and proven alternative from a brand like Clore or a higher-powered unit like the DBPOWER. The peace of mind that comes from knowing your emergency tool will work when you need it is worth far more than a few saved inches of glove box space.
If you’ve weighed the pros and cons and decided the Schumacher Electric SL1639 1000A Portable Lithium Jump Starter is the right fit for your specific needs, you can check its current price and availability here.
Last update on 2025-10-20 / Affiliate links / Images from Amazon Product Advertising API