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

[stuartv]

So, what does the voltage imbalance monitoring in the BlackTip actually do?

And by that, I'm not asking how it works. I'm asking what "bad thing" is it protecting me from by shutting down if the pack voltages get out of balance?

I thought it was protecting me from a situation where one pack draws down on voltage way below the other pack, but the combined voltage is still high enough that the scooter keeps running. In that case, the lower battery could be permanently damaged and maybe even be at risk for leaking and causing a fire.

But, I posted something to that effect somewhere (FB? I think?) and was shut down and told that is wrong.

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.

Based on the answer to my question above, regarding risk to the end user from a voltage imbalance, what does that mean regarding the Piranha?

And what about the Cuda X?

Does the way they deal with pack voltage mean they are not at risk for whatever problem the BlackTip is?

Does it mean they are at a higher risk, because they don't measure the voltage balance?

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.

You didn't mention Genesis. You're saying they don't meet the regs?

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.

Uh oh. Are you also going to start manufacturing regulators...?

 

[Jona Silverstein]

So, what does the voltage imbalance monitoring in the BlackTip actually do?

There is a voltage divider circuit between the 2 packs which brings down the voltage of one pack down to something that the ADC can actually read. In the firmware theres a setting to adjust what this resistance value actually is (no one should mess with this)

The VESC now "Knows" what the voltage of one pack is and can determine what the other pack voltage is because it knows what the total voltage it is being fed with. It's a very simple way of doing it that requires only 2 resistors. In our 20Ah pack we build the same circuit so it can be a drop in replacement that requires no changes in the FW.

I think the "imbalance voltage" is set far too tight for the batteries they are using. Every pack is different. Personally I would have had it coded so that its not measuring the imbalance because it doesn't matter, I would calculate the voltages of each pack, then determine which one is lower and give a battery capacity readout from the lowest measured battery, and cutout when the lowest battery reaches say 3v/cell. This would alleviate 90% of the issues you mentioned above.

And what about the Cuda X?

The Cuda X has the same circuitry. Its just the PTB retrofit kits and the piranha that dont have it.


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Don't get me wrong, the genesis is an awesome piece of kit and I would love to have one. Everyone has their own respectable opinions on the way things can and should be done, But I have seen far too many divers throw mountains of money at problems because they could afford a couple extra braincells. And even though Jon has a pretty airtight manual on how to assemble and service the warp core, there will always be someone that just wings it and does it wrong.

 

[grantmac]

I don't own a warp core, but based on the manual you can't really assemble it wrong in a way that would fail in the water.

Also the genesis tail unit uses physical relays instead of software cut-offs for a lot of critical system. It's simple and incredibly robust.
Without that set of relays I'm unsure I'd want a warp core style battery.

 

[Whitrzac]

I don't own a warp core, but based on the manual you can't really assemble it wrong in a way that would fail in the water.

Also the genesis tail unit uses physical relays instead of software cut-offs for a lot of critical system. It's simple and incredibly robust.
Without that set of relays I'm unsure I'd want a warp core style battery.

Never ever underestimate the stupidity of people.

 

[stuartv]

There is a voltage divider circuit between the 2 packs which brings down the voltage of one pack down to something that the ADC can actually read. In the firmware theres a setting to adjust what this resistance value actually is (no one should mess with this)

The VESC now "Knows" what the voltage of one pack is and can determine what the other pack voltage is because it knows what the total voltage it is being fed with. It's a very simple way of doing it that requires only 2 resistors. In our 20Ah pack we build the same circuit so it can be a drop in replacement that requires no changes in the FW.

I think the "imbalance voltage" is set far too tight for the batteries they are using. Every pack is different. Personally I would have had it coded so that its not measuring the imbalance because it doesn't matter, I would calculate the voltages of each pack, then determine which one is lower and give a battery capacity readout from the lowest measured battery, and cutout when the lowest battery reaches say 3v/cell. This would alleviate 90% of the issues you mentioned above.


The Cuda X has the same circuitry. Its just the PTB retrofit kits and the piranha that dont have it.

Thank you for explaining all that.

I'm still left looking for confirmation on what the actual problem is that I'm being protected from by this voltage imbalance monitoring. Was I correct earlier in my summation of what could happen without the cutoff for a voltage imbalance? Potential for permanent damage to a PTB, and possibly worse?

And, in the Cuda X with 4 PTBs, does having 4 of them make it even more likely to have it cut out due to a voltage imbalance?

 

[Whitrzac]

I belive the initial worry was someone putting in a full batt and dead or half batt at the same time,

 

[stuartv]

I belive the initial worry was someone putting in a full batt and dead or half batt at the same time,

Okay, but that still doesn't tell me what the consequences are for not having that protection.

I mean, I *think* I am correct in what I posted regarding the potential consequences. I'm just looking for explicit confirmation or correction.

 

[Jona Silverstein]

I'm still left looking for confirmation on what the actual problem is that I'm being protected from by this voltage imbalance monitoring. Was I correct earlier in my summation of what could happen without the cutoff for a voltage imbalance? Potential for permanent damage to a PTB, and possibly worse?

And, in the Cuda X with 4 PTBs, does having 4 of them make it even more likely to have it cut out due to a voltage imbalance?

PTB have no internal circuitry to prevent them from being over discharged. Its always up to the tool to depict when the battery is too low for use. In a real world situation, so long as your packs aren't wildly off and you aren't burning your packs down to zero, disabling the imbalance feature wont hurt.

Disable it, run the scoot until you have 1 bar left and when you get back out of the water, measure the voltage on each pack and see how far off they are. They may be closer than you think.

For the Cuda X Exploration and the BT Exploration then both run a 2s2p config of the PTBs. In theory you have an added redundancy if one of the packs starts to fall short so the other one can hold it up a little longer but the same problem could present itself.

 

[Jona Silverstein]

The worst that will happen is you drop a pack too low and the charger wont recognize it, then you would need to "jump" the pack enough for the charger to play nice. these cells are rated for over discharge and in order to be certified must past the test with "No Fire, No Explosion" This isn't LiPo stuff anymore, you can abuse this stuff and they will keep trucking so long as you aren't dead-shorting the entire pack or flooding it.

And I do know for a fact that DeWalt can warranty some pretty dumb stuff. Divers may do some dumb things but contractors are worse!

 

[Jon Nellis]

Don't get me wrong, the genesis is an awesome piece of kit and I would love to have one. Everyone has their own respectable opinions on the way things can and should be done, But I have seen far too many divers throw mountains of money at problems because they could afford a couple extra braincells. And even though Jon has a pretty airtight manual on how to assemble and service the warp core, there will always be someone that just wings it and does it wrong.

No piece of technical equipment is completely immune to "user inattention" (...I'm being nice) and having the equipment "professionally serviced" is no guarantee either. The only time's I've had regulator problems is either brand new out of the box or after having them "professionally serviced," which is why I now maintain my own regs.

There are two trains of thought.
1. Make it non-user serviceable, as some manufacturers do with their shaft seals, prop bearings or batteries that can't ship via air from their overseas country of manufacture (not to mention most regulators, computers, lights, etc.) ...or

2. Embrace the Right to Repair and let the user fix any issues they are comfortable repairing. If they are not comfortable or lack the experience in doing a repair, then they can choose to hire someone to do it for them.

Is there a possibility of a user "winging it"? Yes, but they do so at their own expense and it is generally obvious before they ever get into water or very soon after, not 300ft deep and/or a mile back in a cave. There is no reason to penalize the majority of users who are perfectly competent enough to perform their own maintenance. Ask Stuart, he did a full cell change on a 18 layer Warp Core and later did a conversion down to 9 layers, all before understanding what #S#P meant. Then we had another user overseas "wing it" and installed a bunch of cells backwards. Since every cell in the Warp Core is individually fused, all he did was blow some fuses, which he ordered locally and had someone resolder, before successfully reassembling the Warp Core the second time around (after actually reading the manual.)

The Genesis 3.0 includes more serviceable design elements vs previous models, (beside just the Warp Core) so users around the world can service them locally, if they have the necessary skills and experience to do so.

Regarding the original topic, yes, Fathom copied the Warp Core design to some degree, but the most important difference is the cell holders we use. I had to re-engineer the contacts for more clamping force on standard flat top 18650 cells, since the normal cell holders available from the manufacturer are designed for protected cells that are slightly longer and don't make the best contact with the flat top cells over time. Logic Dive Gear is the only one in the world with these higher contact pressure cell holders, since we own the tooling to make them.

Cheers,
Jon