I got a BlackTip when they very first came out. So, what is now called a BlackTip Travel. Later, I got a Tech tube and have both now. I pretty much only use the Tech tube these days.
I bought 2 brand new Dewalt 12 A-Hr batteries and a 4-bay Dewalt charger for it when I got the scooter. The batteries have only ever been used in my BlackTip, so always at the same time and always charged at the same time. I.e. they have identical usage history. I'll explain why that is relevant in a minute. I'm going to try and start with the good points.
I have never started a day with fully charged 12 A-Hr batteries and run them to exhaustion in one day. For dive days that are 2-tank boat charters, it gives plenty of burn time (if you buy the Dewalt 12s - if you go off-brand or use 9 A-Hr batteries, then that's a different story). Dive-X specs are pretty conservative on run-time with these batteries. They say 123 minutes at cruise speed, but I think it's at least 150 minutes and maybe more.
If you DO end up needing more run-time, Jona Silverstein makes a custom battery pack that is roughly double the capacity of a pair of Dewalt 12s and still (my understanding) allows the scooter to be neutral and trim.
I took my original BT/tube on a 250' dive on the E M Clark. At depth I noticed that the hull was starting to buckle in the middle. It never leaked or quit working. After, I took pictures and sent them to Dive-X. They promptly replaced the tube with a new one. The original tube had 3 reinforcing rings inside. The new Travel tube had 5 reinforcing rings. Were I to take it on another deep dive like that, I think I would have no problems at all. I have since taken it back on the same dive twice, with the Tech tube, with no problems at all.
I think it is a great scooter, very well suited for wreck dives. You don't generally need long burn time on wreck dives. I scooter around the Clark for 1/2 an hour and then scooter around during the drift deco for another 90 minutes and it has plenty of burntime to do all that. And, if it were to crap out during one of those dives, it really would not be a problem at all.
On the other hand, cave use is a bit different. Reliability is of more concern and run-time might also be of more concern.
Which brings me back to those Dewalt 12 A-Hr batteries and power tool batteries in general. The basic problem with them is that the scooter manufacturer has no control over the quality of those batteries. The BT Travel and Tech both use 2 batteries. And, they depend on those batteries having the same or very close voltage at all times. If the batteries develop a voltage imbalance, the scooter will shut off.
Dive-X has no control over the quality of the batteries and Dewalt has no QC specs that require their batteries to always have the same voltage as each other. There is nobody that takes responsibility for ensuring the batteries in your BlackTip (or CudaX, for that matter) will actually work reliably, including in tough conditions, in your scooter.
I have had my BT cut out on me on more than one occasion because I was working it hard and one battery pack dropped more in voltage than the other. The first time it happened, I was on deco, working against the current in the Saint Lawrence River, heading back to where my boat was anchored after diving the Jodrey. My scooter cut out and I was almost blown off the wall and out into the shipping channel. Fortunately, I was able to drop down and catch hold of a rock. After a minute or so, the scooter started working again. Presumably, after the batteries recovered a bit. But then it conked out on me several more times as I tried to get back to the boat. After the first time, though, I was ready for it and grabbed onto something on the wall/bottom and just held on until the scooter recovered and worked again for the next short blast.
So, any cave diver should just be aware of those possibilities. Ginnie and Little River have enough flow that trying to go in with a BlackTip may or may not work. If you get lucky and your batteries are good, then it could be fine. I have no idea if the BlackTip's thrust is enough to really work against the flow there, though. And, if it does crap out, the flow in those is high enough to easily turn around and ride the train out, towing the BlackTip.
The BlackTip is, IIRC, something like 45# of thrust, max. And, they even tell you that it will only run at max for a short time before thermal protection throttles it back to something less. In contrast, the Seacraft Future and Ghost are 75# of thrust. The Genesis is 90. I think the Sub-Gravity Reference RS is also around 75#. I think the Seacraft Go! is around 45 also, but will maintain that continuously.
Like I said, I really do not know how much thrust you need to work against the flow in Ginnie and Little River.
I absolutely would not trust a BlackTip on any cave dive that would require going against any flow to get out.
The BlackTip is the only game in town in the <$3000 department. The Seacraft Go! is just under $4K, I think. If you can even get one. But, if your buddy is going to take it in caves, and not willing to spend for a Genesis or Future, the Go! is probably a better choice. More expensive. But, also better for cave use. Batteries that are actually QC'ed by the scooter manufacturer is something that should not be undervalued!
