FlyHi 800A 18000mAh Portable Car Jump Starter(Up to 6.5L Gas, 5.2L Diesel Engine) 12V Emergency Battery Booster Pack with Built-in Smart Protection, Phone Power Bank(Quick Charge) with LED Flashlight

I initially gave this battery jumper a good review based on it's features. However, I finally had to use it and I couldn't be more disappointed. Rather than update my previous review, I'll review it again based on how it actually worked or, rather, how it didn't work.The temperatures dropped to the high 30s and when I went to put my motorcycle up for the winter the battery barely cranked the engine. I thought this gave me an opportunity to finally try this out for the main purpose it's intended. It was fully (100%) charged. I hooked it up and it did ----- absolutely nothing. I tried repeatedly because jumper batteries, like all batteries, put out more voltage and amps when warmed up and they warm up a bit with each try. Still no luck at all. That's really all I can say about this. It simply doesn't work. It's passed the return period so I'm stuck with it. It may be OK for charging smart phones but I don't need it for that so maybe I'll use it for a doorstop.A couple other things. The cables are aluminum. They are not copper. I believe some reviewers said they're copper if I remember correctly. If so, they are wrong.An odd thing about the owner's manual is that it tells you NOT to use the Boost button. Here's a quote from tne manual: "Normally, please don't press BOOST button when the jump starter is connected to car battery." (The grammatical errors are as they are wrtten in the manual.) There is no explanation about why you shouldn't press the boost button or when you should use it. I assume there are situations where you should use it because why would it have a Boost feature if you are never supposed to use it. But, as far as I can tell, you have to press the boost button to jump a battery. In fact, after you hook it up to the battery your going to jump and turn the jump battery on, in a couple seconds a message comes up telling you to press the Boost button!Keep in mind that it failed miserably when trying go jump a motorcycle battery so the jump battery - at least mine - could never jump a car, SUV, or truck battery, let alone a diesel engine as is claimed by the manufacturer.Tonight I was watching YouTube videos and, coincidentally, an comparison of various jump start batteries popped up by the extremely informative YouTube channel called Project Farm. (If you haven't checked it out, you should. The guy who has the channel does outstanding comparisons of all kinds of products.) Anyway, the video that popped up was a comparison of various brands of jump start batteries. The FlyHi jump start battery was not among the ones he tested but I learned that some of these simply don't work but some work quite well. This FlyHi battery obviously doesn't work. However, two of the jump start batteries he tested worked really well and I'm going to buy one of them. Maybe I'll just give this FlyHi battery to someone who may have a use for it to charge small devices.

First of all, the product works fine, I have jumped started two different Sienna vans for a few times, works well in that regard. The problem is the capacity is not 1800mAh as claimed, I tested out by charging a Nexus 6, it can only fully charge the phone 4 times, each full charge will reduce the jumper battery by 25%, so the capacity is no more than 3220*4=12,880 mAh, each time I waited for the phone battery completely drained and shut off, so the phone was being charged while it was off, make sure the phone is not burning power while it is charging, which would affect the accuracy of the calculation. The phone is a few years old, so the battery might not even hold the full 3220 mAh capacity, which means the 12,880 mAh calculation result is the best case scenario, could less than that.The other minor issue is the flashlight is not very bright.

Came with 76% charge. Comes with plenty of accessories needed to use this unit. Was able to test this on my car with an old weak battery, started right up. Only negative thing is doesn't have usb charging, have to use included 12v charger.

This little thing is powerful! It takes 5.5 hours to charge, but once charged it’s supposed to jump start 25 times. I used it to jump a friend’s 65 Mustang about 5 times (starts easy) and the indicator showed 98% battery left. It will jump start my 2006 Mustang Supercharged just fine too. Great investment! With 800A peak and 400A continuous this is no lightweight.Update: months later with no use it still shows 92%full battery!

Only used it a few times so far on my 5.4L V8 truck and it's started it up every time. Has a nice bright light that flashes as well. Comes well packed in a fairly big carrying case. Won't fit in your pocket but it is portable enough to keep in the car. I like the battery percentage indicator which displays on the little screen. Bought this on sale and so far it has done what I've needed it to do. Clips that come with it are a little short but not too big a deal. For someone who won't use it very often and just needs something in an emergency instead of lugging around a big jump starter, I would recommend buying this; especially when it's on sale.

The unit comes with a nice case and adapters. Had been stored for over a month and still at 100% charge. Have a 72 chev truck and batters was almost dead and the FlyHi started it with no problem and had 97% left, and it took 3 tries to start the truck. Outstanding unit.

Tried to charge it after 6 months and the battery will not go beyond 60%.

Looks good, seems well built, haven't had the opportunity to try it out yet - hence the four stars. I will update after I've worked with it a few times...