STANLEY J309 Portable Power Station Jump Starter 600 Peak Amp Battery Booster, 3.1A USB Ports, Battery Clamps

I am not a mechanic only an engineering student but at my old student job we regularly jump started cars on campus (a few times a night). I've read either very good reviews or reviews where it just did not work. This thing works with my Toyota RAV4 but would I expect it to jump start a full size SUV or a large truck, well I haven't had the chance to try but I figure you would probably need something with higher current output. I've used it a few times when I was silly enough not to remember to make sure my lights were off and when my battery was starting to not hold charge like it used to (before I replaced it). Since there is one with 500A I am assuming if you have a car with higher current demands you should probably get that one or even higher. Another thing to point out is that sometimes if your battery is at that point where it is barely holding on, there's a good chance you need a real car that can sit there and rev up until you do get some current flowing. I've had a few jump starts where I had to rev the truck for 10 minutes. A simple jump start would not have worked especially if it was this jump starter and often times it would even die again when we took off the cables. Before you buy, you should check the specs on whatever you are planning on charging. There were a few times we had to jump start larger vehicles and we almost always had to push on the accelerator to give it more juice so I am assuming you would need something with a higher current output than this basic 300A.

Compact and comes in handy. When our power went out I was able to charge cell phones and Items with usb plugs.

I have one of these as a backup in a Honda Element that has a notoriously small battery for the size of the engine and the electrical loads that you might have when the engine isn't running. Look at the battery or say something about it in a critical manner and it will surely refuse to start after having powered the radio for 10 min.This keeps my wife from having to call me or the towing service when she forgets and accidentally leaves the headlights on for more than 10 minutes.The only criticism I have is that it is quite optimist to claim it has "600 Peak/300 Instant Amps" although I must admit I don't know what "instant amps" are. Must be marketing hyperbole.Anyway, it does the job for under $50 for which I am grateful.(P.S.: NEVER,EVER give anybody a jump from your car battery while your car is running. I know that's the way everybody does it (and it's great for mechanics who get to change your alternator for many $$$). Rarely do auto electrical systems have the rapid-response current-limiting protections to prevent the alternator from trying to supply all the current to start another car, so, the large diode/rectifiers in the alternator take the load and burn out. Use this thing if you are so overwhelmed by altruism. That's what I did, so, I don't have to say "No".)

Poor quality - not what I've come to expect from Stanley.Bought it to get my car going after the battery got run down from a light staying on a very long time. At first, it was totally useless because the car's battery was just too flat - it could not begin to jump-start the car, despite the booster being fully charged (on receipt, I plugged in for about 24h before trying to use it, as directed), though when connected, it did provide enough juice to wake the car up somewhat (big deal). Then I discovered that its internal from-wall-AC charger is safe to use to charge a second battery via the jumper clamps, so I used it as a charger for the car's battery (while disconnected from the car of course).Once the booster showed a full charge via its lights, I disconnected it from the car and set it aside, hooked the car back to its battery, and started it up under its own power. Just in case, I took the booster with me, which still read as fully charged at this point. When I got home, I brought it back in the house and plugged it in, as the instructions make it clear that it can be left plugged in indefinitely without harm.Everyone knows how car batteries are. Run one flat even once, or leave it sitting too long while even somewhat low, and it's trash. That said, I had no choice but to keep using it for a while until I could replace it.So, some time later, I used the booster again to try to straight-up jump-start the car, this time with the car's battery still having enough charge to run everything else except the starter (enough to click its relay, that's about it) - so it was just low, not flat. The booster just baaaaarely had enough juice to get the car going. I figure it should be good for a least one more start after that, especially since I was about to take a drive to the store, and run a couple other errands, so I took it with me, STILL showing a full charge. I came back out of the store after an hour or so, and again the car's battery had only enough charge to run everything in the car but the starter -- but I expected that, so out comes the booster. Nope, no good. Despite there clearly being at least some charge in the car's battery, and the booster showing an adequate charge, the two together were not enough to do more than give the engine half a turn. I had to get a real jump start from a friend.The irony of that trip? The very first thing did when I walked in the door was to head for the automotive department to look for a new car battery. No such luck though. Had to go to the local Autozone for a compatible one (due to the need for dual top-post and side-lug connections -- thanks GM! :-P ). While I was there, I had them check the charging system -- it tested good.When I returned home, I plugged the booster back in. It sat that way for perhaps a week, until I had to unplug and move it out of the way to do some routine vacuuming in that room. When I went to plug it back in half an hour later, It no longer showed a full charge - it self-discharged somewhat just sitting on the table, idle. Guess that explains why it didn't restart the car after I got done at the store.Um, guys, the whole point of a jump-starter/booster is to get the engine started when the car's battery is totally flat, to be able to do so at least a couple of times between recharges, and to hold a full charge for weeks on end. This one failed twice, barely worked once, and didn't hold a full charge after being unplugged for just half an hour.Bottom line: don't waste your money. Go to an auto parts store and talk to one of the associates there - get a brand they will stand behind.I'd get a refund on this unit if I could, but it took too long for the failure to become evident (I'm past the return window).

Great product. Perfect for small car (4cyl and small 6cyl). I bought one for my mother. It payed for itself within 1.5 months. She had to use it 3 times because of a loose connection on the battery. My wife has used hers numerous times to keep her phone charged. It keeps a charge for a long time also. I pulled it out of the car after about two months and it was still showing in the green. It also has a reverse polarity indicator and on and off switch. Great for the mother. She just hooks it up, checks the indicator, turns it on, then starts the car(Nissan Sentra). A friend of mine even used it to start his truck quite a few times till he could get it to the shop (Ford F150; unknown engine size). Son uses the light to read at night. Almost didn't get it back. Great for small to mid size cars/trucks/vans. Unit is quite durable also. Unit is not heavy either. My 66 yr old mother uses it and has not problems and feels much better knowing she doesn't have to worry about a dead battery and being stranded.