GOOLOO GT4000S Bounce Starter 4000 Amp Automotive Starter 100W Two-Manner Quick-Charging Moveable Automotive Battery Charger Booster Pack for 10L Diesel and 12L Gasoline Engines, SuperSafe Lithium Bounce Field for 12V Automobiles

My First Jump Pack – I Was Skeptical
I’ve been researching these compact jumper units for about a year, and they look pretty impressive – some better than others. But the price points – Oy vey! As sales went up the cost came down, Amazon offered this unit for 150 bucks. I jumped on it (pun intended). I was hopeful, but skeptical, this little box would deliver on the promise. But so far it appears to be everything the seller claims – and more. I’ve only had it for about a month and have yet to use it in an emergeny situation – but it seems capable.Was a little disappointed no hard case was included. However, the factory box it came in is built like a brick s***house. For long-term storage this container will work just fine. I’ll be keeping mine primarily in the door well of my truck, though. The unit with the cables was heavier than I expected, which I think is a good thing. The main case seems quite rugged and possibly waterproof as well. The display is excellent – very easy to read. A blessing for my tired old eyes. All functions are easy to access, and operation is quite intuitive. No one should have any trouble making it work. There are a couple things you need to know beforehand, so I’d suggest you [gasp!] parse the manual before going into combat. No worries – the instructions are short and sweet.My unit came 80% charged. This sounds about right for a Lithium Ion array (safety first). Tried the 5V USB port to charge it up – it worked, but it was waaay slow. Still, it’s nice to have that option in a pinch. But for fast charging, the included cigarette adaptor kicks butt (again, pun intended). As the photos show, I started at 80% when I plugged it into my truck (engine off). Charge rate showed 125 Watts – wow! Higher than Gooloo advertises. Charging really took off, and within 15 minutes was up to 90%. Another 10 minutes or so and it hit 99%. Not too shabby. at 99%, things slowed down quite a bit. That last 1% took about 12 minutes.Now for the real test – starting my truck with the battery disconnected. This is not recommended, except as a last resort. Some vehicle computers can go spastic doing this, and operating a running engine with the box connected can damage your alternator. BTW, this can also happen using standard jumper cables. I know my vehicle pretty well (2012 Chevy Colorado), and have previously tested the computer’s resilience by disabling the battery while running. But again, be careful. Many newer PCMs/ECMs are quite unforgiving. A word to the wise.The result: Started my cold engine (48 degrees ambient) in 2 seconds flat. Also fired up my yard tractor without the battery in 6 seconds. The tractor’s V-Twin engine is notoriously hard to start, even with a fully-charged battery. I’m looking forward to trying this on bigger engines, especially diesels, but for the time being this is all the testing I could do. The no-load potential of the Gooloo measured 16.2 Volts, which seems to be typical for these boxes according to the Project Farm guy and a few others. Doubtful that this voltage level will cause any problems with your computer or alternator.Only complaint I have is a minor one, nothing I can’t live with. The side input/output ports are grouped together and covered with a long, hinged rubber weathershield. Nothing wrong with that, except that when the jumper leads are plugged in the hinge stays open and all the ports are exposed to the elements. This could *potentially* allow moisture, rain, snow, beer, etc to infiltrate. Sure, in most cases this won’t be an issue, but for an otherwise well-engineered product this seems kinda cheesy. Maybe the next generation will address this.There you have it. So far, I haven’t unearthed a single major flaw in this device. Of course, durability can only be measured over time. Normally I wouldn’t award 5 stars to something still under warranty, but I’ll stick my neck out on this one. If it tanks, rest assured I’ll be back to let y’all know.

Compact and Powerful
Don’t be fooled by it’s small size compared to conventional jump boxes, this has more power than many four times it weight. Quick to charge, with the convenient screen showing percentage, it’s ready for multiple uses before needing recharge. Removable cables and it’s light weight make it easy to transport from vehicle to vehicle and into the house for charging.

Good, but I Prefer the GT4000A
I purchased the GT4000s, but ended up returning it, not because of a problem, but because Amazon lowered the price of the GT4000A to only $10 more than the GT4000s, and the GT4000A included the prewarmer tech which allows the unit to function in subzero weather by warming itself up before turning on.Both are good units, but for the slight increase in cost, the GT4000A makes more sense.

Great performance & Good number of starts & Easy to use.
12/2024: I had to finally use it in winter and the override / boost feature is a necessity if your battery is dead. It seems good at detecting a when to start discharge when crank is initiated and not just dumping everything into a dead battery. The Avapow wouldn’t consistently output since the battery voltage was too low. Gooloo FTW.Initial review: I tested it by performing 10s no fuel cranks with 15 minute cool downs. And this did 3x more starts and the engine cranked faster than a 4000A Avapow I also bought at the same time.

تمت تجربتها لأكثر من مرة على سيارة صديق ، كانت ممتازة واشتغلت السيارة بدون مشاكل ولم تسحب من بطارية الباور سوى ٥% في كل إشتراك وأراه معدل نزول جيد.