So my saga of Li-Ion booster packs continues and I've not yet decided whether or not I will keep this one or not. I gave it a pretty hard first test. Please understand my use for these is not typical use for how they were designed. My debacle with these jump packs started years ago with a NOCO GB30. At first I thought it was the greatest thing since sliced bread until I actually had to use it to start a boat with a diesel that had glow plugs and a deeply depleted 8D battery. Click, click.... After a few attempts to start customers boats, who'd killed their banks, stuck bilge switches, forgot and left battery switch on, etc. I finally melted the solder right off the printed circuit board of the GB30. Dead.... I then read about the new improved GB40. I bought one. On the first use it too failed to start the boat. This one was well within the return period so it went back. I then tried about 4 more various Chinese made Li-Ion jump packs, all claiming more Ah capacity, all with dismal results, and all were returned. These things are marketed as the be all end all of jump starting but what they fail to tell you is just how small the internal battery really is. On the GB30 & GB40 it was roughly 2Ah.. Guess what happens when you connect a 2Ah Li-Ion battery to a 200Ah+ bank that's sitting at 6V and then needs 15 seconds of a 30A-60A glow on top of cranking..... It really does not take much to suck the capacity right out of it before you can even hit the key... Click, click.... I guess I am a glutton for punishment because I once again bought into the "convenience factor", I really do need one for me and the guys as lugging those heavy AGM jump packs is just not fun. I want to like them and have given them multiple tries.. I purchased this massive NOCO GB150 Li-Ion jump pack last week. When I say massive, I mean it. This is a Balmar 6-Series 150A alternator next to it!! Because it's winter, and I am not jumping too many boats, I purposely discharged the 12V battery on my wife's antique Mercedes 240D to 6.54V and attempted to start the car. This car is a 2.4L 4 cylinder diesel and the GB150 claims it will start 10L engines easily. Her car also has glow plugs and arguably needs a bit of cranking, sometimes two or three rounds when cold (diesels don't like cold), to get going. Guess what....??? The car did not start before I wiped out the GB150. The cars battery is now re-charging and the $400.00 NOCO may get boxed up and returned. Why NOCO would only stick 8Ah of capacity in this HUGE booster is beyond me. When I called tech support I was told many guys with diesels buy two of them... Ah, okay that's about $750.00 !!!!! This thing should easily fit 25+ Ah of Li-Ion cells. I will say this, the new GB150 is quite well built and is now using 200C (392F) 4AWG silicone wire. Silicone wire of this quality is expensive! I know, because I use it when building custom alternators...... It needs that type of wire to deliver the kind of impulse current that it can. While my test above was very abusive it is not to say these things won't start cars or trucks with smaller banks and no glow plugs. My use case, as a marine electrician, is clearly much more abusive on these things than the general population. I understand why they get mostly glowing reviews and that is because most are not expecting what I am from them. The optimal way to use these is to jump the smallest battery on-board eg: the "start battery", not the large house bank. We also work on power boats where the start batteries are often also house or very large 8D's. I don't want to have to physically disconnect batteries, not very easy on some boats, just to do the jump. These days I see a lot of folks deciding to forego a reserve/start bank in favor of a Li-Ion jump pack. After my trials and tribulations I would urge strong caution on this. Many boaters fail to recognize that a reserve/start battery is also reserve house power.. It should be thought of not just for emergency starting but also to run the entire boat should the house bank malfunction or short internally. There are members of this forum a house bank catastrophic failure has happened to... Just be forewarned that a Li-Ion jump pack may not always work and certainly does not have the capacity to run/power the boat in an emergency.. There is not a lot of Ah capacity in these things and some times not enough to be connected to a large depleted bank, then do glow, then start the motor before that capacity is wiped out. Even this massive one, with 8Ah, could not start my wife's 2.4L Mercedes, in winter, with the small starting battery at 6.5V.