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New DPV - Dive Xtras

Discussion in 'Dive Propulsion Vehicles' started by cathal, Nov 14, 2019.

  1. Manatee Diver

    Manatee Diver Manta Ray

    # of Dives: None - Not Certified
    Location: Tampa Bay, FL
    You can also just make your own battery packs. Tool battery packs are almost always raw 18650 cells, wired together in a series. Bosch packs are so ubiquitous that I remember seeing kits to make your own on Alibaba.
  2. tbone1004

    tbone1004 Technical Instructor ScubaBoard Supporter

    # of Dives: I'm a Fish!
    Location: Greenville, South Carolina, United States
    obviously, but it's the BMS systems that are super critical....
  3. Manatee Diver

    Manatee Diver Manta Ray

    # of Dives: None - Not Certified
    Location: Tampa Bay, FL
    Nothing on those boards are unique, you just have the source the chips, which may take a couple of hours here in the US or five minutes in Shenzen.
  4. DA Aquamaster

    DA Aquamaster Directional Toast ScubaBoard Supporter

    # of Dives: 2,500 - 4,999
    Location: NC
    Here is what I know about the BlackTip straight from the mouth of Peter Link, the engineer who did most of the design work:

    1) Depth rating:

    The design depth is 300 meters (330 ft). It has however been tested to 600', at which it non catastrophically fail. What does that mean? It means the PVC tube collapses, but doesn't flood. And as the pressure is removed it will pop back into something similar to its previous shape. It'll be ruined and it won't take nearly the same pressure a second time, but it will protect the electronics inside. In any case if you can afford all the stuff to go deeper than 330', you can afford the 600' rated Piranha P1, P2 or P3.


    2) Batteries, performance and range:

    The Piranha P1, P2 and P3 were designed to the use ther 20 volt 5 Ah DeWalt battery, or compatible generics with the same 5 Ah rating. It's both a form factor and a buoyancy issue.

    The BlackTip can be run with any of the DeWalt DCB power tool batteries from 2 Ah to 12 Ah. Batteries smaller than 5 Ah don't make much sense, but you could install them and ballast the scooter to work with them.

    The 9 Ah and 12 Ah batteries have the same weight and form factor, so they are interchangeable without re-ballasting the scooter.

    The burn time with a pair of 12 Ah batteries will be about 40 minutes at maximum speed (around 210 fpm at 100% power), and 123 minutes at a cruise speed of 150 fpm (26% power). That's a range of about 8,400 feet at 100% power,/210 fpm, and an 18,450 foot range at 150 fpm. Drag is a square function and if you double the speed you quadruple the drag and the power required. 150 fpm is a good speed for planning purposes and it's still 3 times faster than the average cave diver's swim speed.

    The burn time with 9 Ah batteries will be around 93 minutes at 150 fpm (13,950 ft range).

    The burn time with a pair of 5 Ah batteries will be 50 minutes at 150 fpm (7,500 ft range ), but only about 15 minutes at 100% power (3,150 ft range).


    3) Battery options and costs:

    Currently the 12 Ah DeWalt batteries are running $199 each street price pretty much everywhere on line. So a pair of 12 Ah DeWalts and a DeWalt DCB-102 two bay charger ($99) will run you right at $500. I sourced them for a customer yesterday and billed her $498.

    The 9Ah DeWalt batteries will cost you $246 for a pair of them. and with a DCB-102 will cost you just under $350.

    The 9Ah Waitley batteries (DeWalt compatible) will run around $70 each on Amazon, and you can get a Pallwing clone of the DCB-102 for around $50 on Amazon. That gets you in the 93 minute run time and 13,000 foot range for under $200. That's probably the route I'll take with my demo BlackTip as I'd rather have the capacity of 3 sets of Waitley 9Ah batteries for about the same price as a single set of 12 Ah DeWalts.

    However, for recreational divers I'll probably recommend the 9 Ah DeWalt batteries as 3 years from now they'll still deliver about 90% of their capacity while the generics will be down around 70% capacity.

    For technical divers, using the BlackTip as a backup scooter, I'd recommend the 9 Ah or 12 Ah DeWalt, and if they plan to use it as a primary DPV, I'll recommend the 12 Ah DeWalt batteries.

    4) Buoyancy traits:

    Some of this is from Aaron Moser, who has done some testing for Dive Xtras. He indicates that with the 9Ah and 12Ah batteries it is just slightly tail low in trim. If you are ok with it being a pound or so negative, then you can get level trim. With the 5Ah or 6Ah batteries perfect trim is easy to achieve.

    I'm waiting to get my demo scooter to see exactly how it trims with 9Ah and 12 Ah batteries.

    4) Comparison with the Sub gravity Aquaprop:

    I've lost a lot of sales to recreational divers in the past who went with the Aquaprop due to the reduced cost compared to the P1 version of the Piranha ($2600 versus $4500), even though it had less than half the thrust.

    However, the BlackTip retails for $1,500 and as noted above with batteries and charger and shipping (about $60) you'll have a total of $1,760 to $2,060 invested depending on your battery and charger choices. An NiMh Aquaprop costs $1860 and the Lithium battery version costs $2600.

    Battery replacement a few years down the road will cost $800 for the NiMh powered Aquaprop and $1100 for the lithium powered Aquaprop. compared to $400 for 12 Ah DeWalt batteries and around $140 for 9 Ah generic batteries for the BlackTip. And obviously, you can afford a second set of batteries for a second dive for a BlackTip where that isn't really feasible for an Aquaprop.

    Performance wise the BlackTip has 57 pounds of thrust (continuous, 63 pounds in boost mode) compared to 31 for the Aquaprop and it has 8 speeds compared to 2 for the Aquaprop. The max speed for the Aquaprop is 164 fpm in second gear and 125 fpm in first gear.

    The BlackTip also has a battery monitor and a speed indicator as well as a very comfortable thumb operated trigger and shifter.

    The BlackTip weighs 24 pounds compared to 14 for the Aquaprop, but unlike the Aquaptop L, the BlackTip's batteries are TSA compliant. The TSA limit is 100 watts and normally that would be just 5 Ah for a 20 volt battery (5 amp hours times 20 volts = 100 watts). However, the 9Ah and 12 Ah flex volt batteries are in fact comprised of separate cells that are kept separate when the storage cover is in place so that each cell has less than 100 Watts total energy. So they can fly in your carry on. A small Pelican case is a great way to carry them.

    5) Comparison to the Piranha:

    The Piranha does have 10 pounds more thrust at 73 pounds, but that evidences itself only in the higher top speed - 268 fpm top speed for a single tank recreational diver, compared to 210 for the BlackTip. The BlackTip and P1 both weigh 24 pounds and both are travel friendly.

    The P1 is rated to 600' and the belt drive motor is a bit more efficient. The P1 delivers a 122 minute burn time at 150 fpm (19% power) using four 5 Ah batteries, while the BlackTip gives 123 minutes at 150 fpm (26% power) using two 12 Ah batteries.

    The above mentioned speeds and burn times are all based on the single tank Tahoe benchmark configuration. In the Tahoe technical configuration the P1 gives an 85 minute burn time at 150 fpm, pulling 32% power. The BlackTip will need the same additional power and will end up with the same shorter burn time around 85 minutes with the increased drag of a technical configuration.


    The BlackTip isn't expandable with additional battery modules like the Piranha, where you can double or triple the run time by adding 1 or 2 more battery modules. However, the BlackTip also actually costs less than just a Piranha Battery Module.

    Both the Piranha and the BlackTip have the X-prop, and with a single piece hub that securely holds the blades it is readily removable under water if you get a piece of line wrapped around the hub. (Note this is a Piranha in these pictures).



    The BlackTip uses an X Prop with a Polymer hub and a slightly shorter hub that makes it even easier to access the screw.


    In short, the BlackTip won't replace the P1 as it doesn't have quite as much capability. However it also costs only 1/3rd as much as a P1 even when the P1 is discounted 10%. I

    The BlackTip is being marketed as a recreational DPV, but it is still a 200 fpm capable DPV and it has the speed and range at 150 fpm (85 minutes and 12,750 ft) in a tech configuration to be very useful technical DPV in either a primary or tow behind back up capacity.

    The reality is that modern technical DPVs are placing technical and cave divers in a position where they can easily exceed the bailout requirements in the event of a DPV failure. 240, fpm, 200 fps or even 150 fpm will take you into a cave a lot faster than you can swim out and that has to be taken into consideration in planning reserve and bailout gas requirements.

    However, a $1500 BlackTip now gives a technical or cave DPV diver using a Piranha P2 or similar ranged DPV an affordable option for a back up DPV that will allow a rapid exit in the event of a primary DPV failure.
  5. DA Aquamaster

    DA Aquamaster Directional Toast ScubaBoard Supporter

    # of Dives: 2,500 - 4,999
    Location: NC
    Don Six is correct. DeWalt's 9 Ah and 12 Ah batteries are technically comprised of separate cells, each of which is less than 100 watts. The cells are physically separated with the storage cover attached and thus TSA legal.

    I worried about this when I started selling Dive Xtras scooters 3 years ago. However, there are several things that lead me not to worry:

    1) DeWalt has standardized this format for a long time, and there are a number of companies making generic batteries for existing tools, so if DeWalt changes format for some reason, batteries will still be out there.

    2) DeWalt does seem to be moving away from the 5 Ah format to some extent, pushing the smaller 3 Ah 4 Ah batteries as well as larger 6Ah and 8Ah batteries. The 6 Ah and 8 Ah batteries share the same form factor as do the 9 Ah and 12 Ah batteries.

    That would bode ill for the Piranha series, except for the fact that it's modular and worse case, you have to buy an adapter to switch to a different form factor battery. But that's worse case as there are a lot of tools out there that require the 5 Ah form factor and while it won't be front and center on the DeWalt battery display, I don't see DeWalt dropping it.

    3) Dive Xtras has been very accommodating in terms of the Cuda scooters, producing a conversion that allows the use of power tool batteries in the Cuda. It accommodates a pair of power tool batteries just like the BlackTip. It's an upgrade for Cuda users who are looking at a battery replacement and to go the PTB route.


    4) The BlackTip has been designed to be very format friendly. It will accommodate all of the DeWalt DCB series batteries and is intended to be used primarily with the 9 Ah or 12 Ah batteries, although they also publish numbers for the inexpensive 5 Ah batteries.

    5) As a non scuba example, I still own a pair of Bendix-King KX-99 hand held aviation radios. I can still get batteries for them from a number of vendors and a I can also get a case that allows the use of AA batteries. All of the options offer a lot more capacity than the original nicad pack it came with - about 7 times more capacity.

    Battery support for the Piranhas is not going away anytime soon.

    Currently, the price point on generics like the Waitley 9 Ah DeWalt compatible batteries (around $70 on Amazon) is the sweet spot as you can get a 90 minute run time at 150 fpm (in the TBM rec configuration) and around 60 minutes at 150 fpm in the TBM tech configuration. $190 will buy you a set of batteries plus a Pallwing clone of the DCB-102 charger (or spend $99 for the DeWalt branded charger), and $140 more will buy you a second set of batteries.

    That's hard to beat for bang for the buck, as even though it's well under the 12 Ah run times of 123 minutes and 85 minutes respectively for rec and tech configurations, a 9 Ah equipped BlackTip still a a lot faster than the 31 pound thrust Aquaprop. It's also faster than the 38 pound thrust, and 412 pound weight Suex 7, for less money, with comparable run time, and more run time if you install the 12 Ah batteries.

    The DeWalt 9 Ah batteries are currently selling for $124 each or $246 for two. If you worry about generic battery quality it's still a cost effective option.

    I should have my demo BlackTip and couple BlackTips for sale in stock in mid December. I plan on scheduling demo dives in cave country around Christmas and I'll also do a demo in eastern NC if you are in the area.
    Compressor and pauldw like this.
  6. runsongas

    runsongas Great White

    # of Dives: 500 - 999
    Location: California - Bay Area
    @DA Aquamaster

    wouldn't the 8Ah battery be a better choice than the 9Ah? slightly less capacity but it also adheres to the 160Wh IATA limit for non-US airlines
  7. DA Aquamaster

    DA Aquamaster Directional Toast ScubaBoard Supporter

    # of Dives: 2,500 - 4,999
    Location: NC
    It's certainly an option as you can ballast the BlackTip to be neutral with any of them.

    Technically, DeWalt uses separate cells in their larger 9 Ah and 12 Ah batteries to stay under the 100 watt limit used in the US. It should still work internationally, but I'd check first as I'm not sure how that fits with the "maximum of 2" wording.
  8. Texasguy

    Texasguy Solo Diver

    # of Dives: I just don't log dives
    Location: Fort Lauderdale, FL
    I am wondering about the trigger. How does it switch speeds, is it a soft zero to 60 or a jerky kind? Can you chose a speed with kind of a "light dimmer" where it evenly goes through min to max or is it like a physical selection of a number of speeds?

    What I did not like in UV26 was when you engage it, it gave a jerk. I think next versions had something like "venom" a speed controller.

    Not sure what this cheapo BlackTip has.
  9. DA Aquamaster

    DA Aquamaster Directional Toast ScubaBoard Supporter

    # of Dives: 2,500 - 4,999
    Location: NC
    The speeds are like those on the Piranha, in that they are separate, distinct speeds, not like a dimmer switch.

    Brushed motors have a softer start than brushless motors. The old Oceanic based motors had brushes and the start was what you got. The Oceanic based motors also varied a lot in terms of how they were wound and their resulting operating RPM (anywhere from 650 to 1000 rpm) and that had a direct effect on how hard the start felt.

    However, with the move to brushless motors where the motor ramped to full rpm almost instantly, it became common to have the speed control adjust the throttle ramp rate to make the start much smoother.

    In the Piranha the throttle ramp rate is adjustable, but comes from the factory set at "medium (16)". I have not been able to get actual numbers for the BlackTip but I'm told the throttle ramp rate is softer than the factory setting for the Piranha.
  10. Schwob

    Schwob Solo Diver

    # of Dives: 200 - 499
    Location: Illinois
    Presumably you may not know about that aspect for all generics, for those that you do know (which):
    Is that also true for the generic versions or for Dewalt only?

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