GOOLOO 4000 Amp Jump Starter GT4000S Car Starter 100W Two-Way Fast-Charging Portable Car Battery Charger Jumper Starter for 12L Gas and 10L Diesel Engines, SuperSafe Jump Box for 12V Vehicles

I needed to replace my tired booster pack so i first watched the Project Farm review. My favorite from the PF review was "last year's model" of gooloo.Looking into the specs and the fact i live in a northern latitude where it's typically 0F or -18c when i need it, i picked this model that has an internal heater to warm the battery for jump starting in winter!The other big improvement with this model vs. others is how crazy fast it charges! At 125w, unless I've drained the battery dead using to run my air compressor or computer, it will be topped off with 15 minutes drive.I bought it when my main car battery was failing but it was under warranty and it took a couple weeks to get the store to understand the battery was shot even though it would pass the cold crank test because they would charge it immediately before testing!Anyhow i needed to use it daily for a couple weeks and then I've used a dozen times helping others. It's beyond powerful, i won't bother trying to find a different brand.The display is comically large but it's beautiful!Customer service is top tier! They stand by their product and are very responsive, reason alone to buy gooloo.They have a bunch of models you don't need to get the very best one especially if you have a small car and live in a warm climate.We were having temps of -10f or -23c when i bought mine and that was factored into why i bought the high end model.This unit is very well made, crazy solid construction, and you can sense the quality from the heft.

I purchased this after a friend used a similar one to jump my dead battery and I realized how much more useful these can be than jumper cables. In doing my research I watched a few "Project Farm" videos on YouTube and this particular brand was highly rated. I've since had occasion to use it a few times and it has worked flawlessly. The quick charge feature is desirable in my opinion and it is very well made and sturdy. I like the large, bright display and the well made clamps. Even jumping a large V8 engine using the boost feature, you should get 6+ starts before recharging. For the price and convenience, it's a great value.

There is a version of this device that will pre-heat the device in extremely cold weather. Make sure that's what you get if you're in very cold places!This one does NOT have the heater and being in a car overnight in the 20s or below means it needs to warm up to about 50 before it will deliver full charge. Trying to jump with it before it warms up can damage the thing or it simply won't do anything at all.But, cold weather issues aside... it's a very good performer, jumps most anything the first time without any problems, even batteries that are so dead they won't even register as a circuit when the box is hooked up (digital display does not turn on to indicate it's detected a battery).For occasional use one will be good - just charge it up once very month or two (it'll loose less than 10% a month while in storage). If you use them daily like I do you'll want two or more. While very good they are very, very sensitive to overvoltage and will drop into safe mode very, very quickly and it takes upwards of 10 minutes before it'll reset itself.And they discharge relatively swiftly... 7 'dead' cars or 10 'weak' cars, at most, before they're below 20% charge where it'll begin to struggle.Type-C charger means it'll recharge *FAST* - about 90 minutes from 0 to 100% at a wall outlet with a decent outlet charger (20v min). 2+hrs with a standard car utility outlet (5v).

It it work very goodAnd easy to use

I got this product over a year ago and kept it in my van. I've been able to use it once and loan it out twice and it works great!Most recently I went to use it again as my van is a diesel and the cold ran out the battery. When I went to use it, though, the battery had died, and it couldn't charge up. I contacted Fiona in customer service on December 16th, and after sending her a video showing that it wasn't charging properly, as of today, the 19th, I already have a working replacement. Not only was Fiona extremely easy to work with, she was very kind, responsive, and replaced my battery under the 18-month warranty. I am so glad to have purchased this and for the amazing team at Gooloo!

I’ve only tried it on a dead semi truck that still had dash lights on when I turn the key. It did not have the power to turn the crank a single time. The unit was fully charged. It drained down to 70 as soon as I turned the key but it wasn’t enough to start. I’ll keep looking for something that will work. It does in fact have fast charging capabilities. Im getting 39w in my car and 106w in my home using Anker 140w charger.

Works great, easy to use, had been very handy