GOOLOO GT4000 4000A 12V Portable Car Jump Starter with 100W Fast Charging & -40℉ Pre-Heating Tech - SuperSafe Battery Booster Pack for 10L Diesel & 12L Gas Engines (Includes Jumper Cables) - Perfect for Emergency Roadside Assistance, Winter Travel & Vehicle Maintenance

I had wanted this particular product for quite some time, so much so that I placed it in my Amazon Cart under Your Items, Saved for Later. Finally, it went on sale and a very good discount was offered. I saw the discount and immediately placed an order.This product is one of the best jump starters available of the market (not including those designed and produced for use in business operations). It has a very large electrical capacity (4000 Amps) and can also serve as a very large power bank for recharging other devices, if desired.This product is very well made, has a large LCD screen for delivering status information, and it conforms to the latest charging protocols, which in my case, meant that the product was capable of charging extremely fast. Perhaps best of all, this product is capable of operating in very cold temperatures thanks to its “Pre-heating Technology.” While lithium-ion batteries have a lot of incredibly useful properties, they do not function well when they are cold. The colder the temperature, the lower their performance. That is why EVs perform so poorly in cold weather and have such diminished range. The GT4000 jump starter has the ability to warm the lithium-ion polymer battery contained within the product so that its performance returns to near normal. The product’s Amazon page states, “pre-heating technology ensures reliable starts in extreme cold as low as -40°F.” Interestingly enough -40°F is the same as -40°C. This technology enhancement ensures that the product will operate properly in virtually all environmental conditions.As requested in the User Manual, the first thing I did was to fully charge the product. I used my new GaN-based charger and added a new USB-C Analyzer into the charging circuit. I was amazed to see that this product was capable of actually charging at 20-volts and 80-watts. While the new GaN-based charger is marked as a 100-watt charger, it seems that it was not capable of fully meeting its labelled specification as both my USB-C Analyzer and the GT4000 reported that only 80-watts was actually seen. In any event, the GT4000 charged very fast and the GaN-based charger actually got warm for the first time ever.The manufacturer, GOOLOO, states that the GT4000 has ten built-in protection technologies to ensure safe and protected operation of the device. The protections include:○ Over-Charge Protection○ Over-Current Protection○ Short-Circuit Protection○ Reverse-Polarity Protection○ AI Software Protection○ High and Low Temperature Protection○ Spark-Proof Protection○ Over-Voltage Protection○ Over-Load Protection○ Reverse-Charge ProtectionThe GT4000 also has a built-in LED light that actually works and works very well. The light is very bright and would be a great help trying to get a car started on a dark and stormy night. The light has two flashing modes that I personally do not understand the need for. The electrical connection ports for the device are covered with a well-fitting silicone rubber cover to keep out dust, dirt, and water. The ports on the device include a USB-C port for charging the GT4000 and providing the ability for the GT4000 to charge other devices. This port conforms with the Power Delivery (PD) charging protocol and is capable of providing up to 100 watts (max) of power (PD100). The first USB-A port (USB1) supports the Quick Charge (QC) protocol, specifically QC3.0 and is capable of supplying 18 watts (max). The second USB-A port (USB2) provides [email protected] for a total of 12 watts (max) power provided. The GT4000 also has a DC output port and an adapter is provided that allows the connection of those devices that use a 12VDC plug like that used with a 12VDC power port or cigarette lighter. Finally, the last port is the connection for the battery jumper cables. The jumper cables included with the GT4000 are a set of robust clamps, sturdy cables (wires), and the connector to interface directly with the GT4000. The GT4000 jumper cables do not use a large plastic box on the end of the cable assembly like many other jump starter products. All of the needed electronics are placed inside the GT4000 product’s case.The GT4000 is supplied with a USB-C to USB-C cable, a USB-A to USB-C cable, a car charger adapter to charge the GT4000, a 12VDC output adapter, the jumper cables with clamps, and a very well written User Manual. All of these items are supplied in a very nice, sectioned and padded box for the storage of the product. That said, I purchased the GOOLOO Jump Starter case for storing the product.I wanted this product for a long time and I was finally able to purchase one at a very good price. It is a quality product and I am very happy with the product. It is everything that I expected and I believe that it will serve me well for a long time to come.