Question Blacktip 12 AH Batteries ?

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

OP
ermaclob

ermaclob

Contributor
Messages
523
Reaction score
92
Location
Miami Dade County, Florida
# of dives
200 - 499
Any one got advise on how to properly trim out the scooter with the 12ah packs for salt water. Does the weight in noise cone that it come with need to be reduced? what about the trim weight in the middle? :confused:🤔 i have the tech tube.
 

macado

Contributor
Scuba Instructor
Divemaster
Messages
1,432
Reaction score
1,037
Location
Salem, MA (north of Boston) in the summer.
# of dives
1000 - 2499
The one annoying thing about the Blacktips that I've noticed are that no two are weighted the exactly same. You will probably need to tweak things a little bit to your liking. I would just check to see how it trims out as stock first and also check the weighting on the nose cone.

Two DeWalt (9Ah / 12Ah) batteries weigh around ~1460 grams each. (~2920 grams total)

The salt water plate inside the body should stay in the tech tube. You only need to remove it if you're diving fresh water. My nose cone is weighted to be around ~2635grams. I've seen them weighted anywhere from ~2625-2690 grams You can use a food or postage scale to help check this. Keep in mind anything you add to the body needs to be accounted for including a medium bolt snap on the nose.

I personally prefer my scooter to be slightly buoyant / neutral at depth since I find negative scooters annoying. There is some minor amount of o-ring compression that occurs at the tail and nose section. This means that if your scooter is just a hair positive on the surface it will likely be neutral or even slightly negative at depth as the o-ring seals compress.
247100106_1869259383246593_571741078621121468_n.jpg
 

Jona Silverstein

Registered
Messages
66
Reaction score
50
Location
Lake Havasu City AZ
# of dives
1000 - 2499
Any one got advise on how to properly trim out the scooter with the 12ah packs for salt water. Does the weight in noise cone that it come with need to be reduced? what about the trim weight in the middle? :confused:🤔 i have the tech tube.
They should come trim and neutral from DX for the 9ah and the 12ah batteries so you shouldn't have to change much unless you start adding things then you really need to start tweaking.
 

Ulfhedinn

-Skill Collector-
ScubaBoard Supporter
Messages
1,277
Reaction score
321
Location
Southern California
All this battery madness has me excitedly waiting for @Jona Silverstein batteries so I can get this scoot in the water.
 

stuartv

Seeking the Light
ScubaBoard Supporter
Scuba Instructor
Divemaster
Messages
10,237
Reaction score
6,162
Location
Lexington, SC
# of dives
500 - 999
I had a DPV student last week with a new BT Tech. He used my DeWalt 12s for class. We took his Saltwater plate out, as we were in a fresh water lake.

His BT was negative in the water. After the first dive, we took out one of the weight plates. His came with 2 identical looking weight plates plus a bunch of lead shot under them in the nose.

With 1 plate removed, it was positive. Seemingly, about as positive as it had been negative with both plates in.

I don’t know if that is all down to manufacturing tolerances, or if somebody at the factory effed up. But, I would figure on having to spend some time screwing with it, to get it “right” before taking it on a dive where its performance is important.

Once you get it neutral in fresh water, with DeWalt 9 or 12s in and the saltwater plate out, then going to salt water should just need the salt water plate put in, to get it neutral. You’ll have to experiment with the position into which you install the saltwater plate to get the trim just right.
 

stuartv

Seeking the Light
ScubaBoard Supporter
Scuba Instructor
Divemaster
Messages
10,237
Reaction score
6,162
Location
Lexington, SC
# of dives
500 - 999
The one annoying thing about the Blacktips that I've noticed are that no two are weighted the exactly same. You will probably need to tweak things a little bit to your liking. I would just check to see how it trims out as stock first and also check the weighting on the nose cone.

Two DeWalt (9Ah / 12Ah) batteries weigh around ~1460 grams each. (~2920 grams total)

The salt water plate inside the body should stay in the tech tube. You only need to remove it if you're diving fresh water. My nose cone is weighted to be around ~2635grams. I've seen them weighted anywhere from ~2625-2690 grams You can use a food or postage scale to help check this. Keep in mind anything you add to the body needs to be accounted for including a medium bolt snap on the nose.

I personally prefer my scooter to be slightly buoyant / neutral at depth since I find negative scooters annoying. There is some minor amount of o-ring compression that occurs at the tail and nose section. This means that if your scooter is just a hair positive on the surface it will likely be neutral or even slightly negative at depth as the o-ring seals compress.
247100106_1869259383246593_571741078621121468_n.jpg
I’ve seen that chart before, but I’m not sure I trust it.

My Travel came with 2 weight plates - a thick one and a thin one. It is neutral in fresh water with DeWalt 12s and no weight plates or lead shot. If I left both weight plates in, as the table says, it would be very negative. In salt water, I add the thin weight plate and enough stick-on tire weights to total 260 grams. The thin plate by itself is not enough and the thick plate by itself is too much.
 

macado

Contributor
Scuba Instructor
Divemaster
Messages
1,432
Reaction score
1,037
Location
Salem, MA (north of Boston) in the summer.
# of dives
1000 - 2499
The last 6 Blacktip Techs I have encountered were negative from the factory requiring shot weight to be removed from the nose cone and some of the tire weights affixed to the tail section of body to be removed in order to get the scooter to properly trim.

Perhaps it's just a bad coincidence but I stand by my statement that they are not always "trim and neutral" from the factory and may require a little bit of tweaking.

I'm testing a new one tomorrow and I suspect it will also be negative but we're leaving it stock as an experiment to see.
 

Whitrzac

Contributor
Messages
290
Reaction score
189
Location
WI
I had a DPV student last week with a new BT Tech. He used my DeWalt 12s for class. We took his Saltwater plate out, as we were in a fresh water lake.

His BT was negative in the water. After the first dive, we took out one of the weight plates. His came with 2 identical looking weight plates plus a bunch of lead shot under them in the nose.

With 1 plate removed, it was positive. Seemingly, about as positive as it had been negative with both plates in.

I don’t know if that is all down to manufacturing tolerances, or if somebody at the factory effed up. But, I would figure on having to spend some time screwing with it, to get it “right” before taking it on a dive where its performance is important.

Once you get it neutral in fresh water, with DeWalt 9 or 12s in and the saltwater plate out, then going to salt water should just need the salt water plate put in, to get it neutral. You’ll have to experiment with the position into which you install the saltwater plate to get the trim just right.

Check the tail side of teh tube for sticky weights too... Someone at the factory thought the heavy end of the tube needed more weight
 

macado

Contributor
Scuba Instructor
Divemaster
Messages
1,432
Reaction score
1,037
Location
Salem, MA (north of Boston) in the summer.
# of dives
1000 - 2499
The other brand new Blacktip I tested today was also very negative in the freshwater with saltwater plate removed and 12Ah batteries. That makes the last 7 Blacktips I've seen not really weighted properly.

I measured the nose cone at 2691 grams plus a **** load of tire weights in the tail section
 

stuartv

Seeking the Light
ScubaBoard Supporter
Scuba Instructor
Divemaster
Messages
10,237
Reaction score
6,162
Location
Lexington, SC
# of dives
500 - 999
What a coincidence! I weighed my Tech nose just now and it came out to 2691 also. LOL

Mine has a paracord leash and big boltsnap on it.

I don't think my Tech tube has any tire weights in it, as it was purchased when the original Tech tubes were offered to the original BlackTip purchasers.

With the nose at 2691g (and, I think, no tire weights in the tube) and DeWalt 12Ah batteries, mine is still just a little bit negative at depth, in fresh water.

I am going to take some of the shot out, to get it down to the recommended 2623g. That's just over 2 oz. See how that does.

2021-11-16 13.53.09.jpg
 
https://www.shearwater.com/products/peregrine/

Top Bottom