Question Fathom Dive Systems has their own version of a Genesis Warp Core?

[stuartv]

I just saw this Magnus for sale on FB. What really got my attention was the battery pack for it that looks like a ... looks very similar to the Genesis Warp Core battery pack.

And then I found a post from Fathom on FB from 2021 announcing these new battery replacements for Magnus and some other scooters.

I don't see them now on the Fathom website.

Is this a thing (still)? Is this style of battery available for any other brands of scooters (besides Silent/Subsea and Logic Genesis)?

 

[mr_v]

@stuartv, yes, they did. I don't believe they manufacture the core any longer. However, there are a few scooters with the core for sale. Here is one (re-post from Cave Diver):

Magnus DPV

Silent Submersion Magnus DPV Fathom Dive Systems 840WH battery pack with user replaceable cells. 3 speed trigger system. Currently set up for fresh water and has only seen fresh water since I?ve owned it. Great condition and works like a dream, I mostly used this as my tow scooter and just...

www.cavediver.net

@MattK911 may have more info.

 

[stuartv]

@stuartv, yes, they did. I don't believe they manufacture the core any longer. However, there are a few scooters with the core for sale. Here is one (re-post from Cave Diver):

Magnus DPV

Silent Submersion Magnus DPV Fathom Dive Systems 840WH battery pack with user replaceable cells. 3 speed trigger system. Currently set up for fresh water and has only seen fresh water since I?ve owned it. Great condition and works like a dream, I mostly used this as my tow scooter and just...

www.cavediver.net

Yes, I believe that's the scooter where I got the picture (but on FB).

 

[grantmac]

Not very energy dense getting only 850wh in a scooter that big.
There are a few options for weld-less battery building but all are rather expensive.

 

[Jona Silverstein]

The user replaceable cell model is something thats used to easily get around FAA regs on flying with batteries. While they still need to be UN38.3 certified to fly with cells in them, if all the cells are removed before transport, then no cert is required.

Fathom made these for a bit but they stopped making them due to various reasons.

We have looked into making aircraft friendly batteries for a while. Similar to the Seacraft Sticks as we feel those are the best option for flying with batteries. What we have looked at was a "one size fits most" option that would be able to be used in. Sierra, Cuda, Minnus, Viper, Magnus, Tusa. But its at the bottom of the priority list these days.

PTB is a great option and would be better if the battery technology was similar to Makita that actually uses a balance connector on their chargers.

 

[stuartv]

Maybe PTBs *could* be a great option. But, the way they work in my BlackTip makes them a really poor option, for ME.

There is literally NO Quality Control performed on the Dewalt PTBs to certify them for use in the way that they are used in a BlackTip.

Which means that, when your BlackTip cuts out on you at the time you need it most, because the PTBs have a voltage imbalance between them, not only are you kinda screwed in the water, you have no recourse when you get out of the water. Dewalt has no responsibility to make it right and ensure your PTBs have identical discharge curves. And neither does Dive-Xtras. They both walk away with clean hands, leaving you with a scooter that could cut out at any time, but most likely when you are really running it hard - i.e. when you most likely need it the most.

PTBs are fine for scooters that are used in benign environments where you are never far from an easy exit. But, I am very much over using them on dives where having the scooter cut out could result in a very significant risk to the diver. Fool me once...

Yes, any scooter can die at any time and we have to be prepared for that. Nevertheless, just as I would not start a dive with a regulator hose with a bulge in it, I would not do a "serious" dive with a scooter with PTBs. I may be prepared and able to handle it if the hose ruptures or the scooter dies, but it makes no sense (to ME) to take on that risk knowingly. Start with good regulator hoses and a scooter that is properly maintained, has a known-sufficient amount of charge, and has actual QC done for its battery design and the way it's used.

 

[stuartv]

I don't know how the PTB Piranha and Cuda X work.

Do the ones with 4 x PTBs have some extra "something" that mitigates the problem of battery imbalance? Or does having 4 batteries just make it all the more likely to have your scooter shut down due to a voltage imbalance?

 

[grantmac]

A PTB system based on 60v which runs the flexvolt PTBs in 60v mode and parallel in the DPV would offer a more failsafe system.

Just based on my experience with other batteries.

 

[Whitrzac]

I don't know how the PTB Piranha and Cuda X work.

Do the ones with 4 x PTBs have some extra "something" that mitigates the problem of battery imbalance? Or does having 4 batteries just make it all the more likely to have your scooter shut down due to a voltage imbalance?

The cuda and Sierra ptb conversions don't monitor for imbalance.
I'm 90% sure the the piranha one doesn't ether.

 

[Jona Silverstein]

A PTB system based on 60v which runs the flexvolt PTBs in 60v mode and parallel in the DPV would offer a more failsafe system.

Just based on my experience with other batteries.

Ive had several guys talk to me about this and it honestly is the best possible option for running the PTB route.

For those not familiar the "FlexVolt" system can be ran either in a 5s3p yielding 12Ah @ 18v or a 15s1p yielding 4Ah @ 54v. The energy capacity is the same but it allows for a higher voltage through the system which increases efficiency and reduces the current load on the wiring.

At the time when DX came out with this option there wasn't a suitable VESC that supported more than 12s and was CHEAP. Now we do have these options and we see them quite frequently in the OneWheel and esk8 space. so its something that could come in the future but not today.

Not to mention the failsafe tech we could put in it would be similar to the power distribution boards we had built for the "Portable Underwater Space Habitat." (Thats a mouthful) These allow us to put several packs in of various SOC and it would do a few things,
A. not nuke batteries if you have one thats dead and one thats fully charged.
B. Sort them by SOC, as you draw power it would pull from the topmost battery first, then once it reached the SOC of the second pack, it would put them in parallel, and so on. This meant that you could take a 8Ah, a 2Ah, a 5Ah, and a 10Ah pack and it would still perform flawlessly. It does mean that whatever pack you use would have to be able to support the max draw of the unit by itself but we usually opt for matching batteries and matching SOC.

The cuda and Sierra ptb conversions don't monitor for imbalance.
I'm 90% sure the the piranha one doesn't ether.

The piranha has circuitry that shows you that all of them are charged but does not have balance measurement, that is done on the vesc side with a voltage divider.


Personally I dont feel that DeWalt is right in having the proper transport clearance as they are not physically isolated. only electrically. I dont know how they managed to pull that one off. (or who they managed to pay off) I think that thus far the only DPV manufacturers who have batteries that meet the regulations and pass the sniff test would be Seacraft and ScubaJet.

The Warp Core is an awesome tool and it has its own place, personally I do not like end users having the ability to mess with individual pieces of their own life support... But hey thats just me.