Tesla home battery pack and DPV battery pack Technology

[kwinter]

I'm lost, how and when did you get thrown anywhere?

Is your nickname "Wookie"?

Tobin

I think he's referring to my Kaiser comment. Damn, Tobin, you're getting slow.

 

[cool_hardware52]

I think he's referring to my Kaiser comment. Damn, Tobin, you're getting slow.

Thanks. You are probably spot on. Long day in the salt mine…..

Tobin

 

[KaizerWilhelm]

I am. Apparently the quote function didn't work as I expected...

 

[Akoni]

I'd be happy with DPV batteries at about current pricing if they were less finicky, longer lived and actually gave the user more information about their 'health'. A 5 year lifespan where you then need to repopulate the pack with new cells at the manufacturer level is pretty tough to swallow on a dollar per use scale. However, if the pack was built so that they were end-user serviceable, that might be an improvement. Unfortunately, cells age differently even when they were properly matched initially and with the built in BMC's not really providing the user with cell specific information, it's a bit of a dice roll. As improved technical level DPV's allow greater ranges/runtimes, they start to cross start the line into 'life critical gear' territory especially when combined with rebreathers. It's imperative that scooters start providing real information to divers during use and when charging, ie. more than just an LED.

 

[cool_hardware52]

I'd be happy with DPV batteries at about current pricing if they were less finicky, longer lived and actually gave the user more information about their 'health'. A 5 year lifespan where you then need to repopulate the pack with new cells at the manufacturer level is pretty tough to swallow on a dollar per use scale. However, if the pack was built so that they were end-user serviceable, that might be an improvement. Unfortunately, cells age differently even when they were properly matched initially and with the built in BMC's not really providing the user with cell specific information, it's a bit of a dice roll. As improved technical level DPV's allow greater ranges/runtimes, they start to cross start the line into 'life critical gear' territory especially when combined with rebreathers. It's imperative that scooters start providing real information to divers during use and when charging, ie. more than just an LED.

Add a data logger, example Eagle Tree. ~$100-150. Done.

Tobin

 

[Akoni]

Add a data logger, example Eagle Tree. ~$100-150. Done.

Tobin

An EagleTree or similar will not tell you about the condition of individual cells. You can test the individual O2 cells in your rebreather yet you can't really tell much about the condition of individual cells in your scooter pack. Basically, you have to blindly trust the BMC...no es bueno.

 

[cool_hardware52]

An EagleTree or similar will not tell you about the condition of individual cells. You can test the individual O2 cells in your rebreather yet you can't really tell much about the condition of individual cells in your scooter pack. Basically, you have to blindly trust the BMC...no es bueno.

1) Not exactly true. A data logger can reveal if individual cells are failing vs an entire pack that is wearing out

2) Given that it is *extremely* poor practice to replace individual cells, as they will *never* be matched to the remaining cells how *exactly* does knowing "cell #3" is failing help the user?

The reality is data logging will provide the user with good information regarding the capacity of the pack, the % of capacity used on any given dive, important for planning, and will provide some advance notice of pending failures.


Tobin

 

[Akoni]

Adding a $100 hobby grade component to a $5-8k scooter that may impact diver safety is not exactly an elegant solution. Not that what the EagleTree logger does is rocket science but it's not what I would consider a tested component when you buy one. Additionally, you need to disassemble your scooter to view the information. I look forward to Jon's solution as it seems a step in the right direction.

As for knowing in advance that a cell is on the way out, even if the pack continues to charge and balance, may make your dive planning more conservative. How is that a bad thing? It is a pity that cells have to be changed en masse when just one cell has gone TU but that is the nature of Li batteries.

So while data logging IS a good thing, no one offers it!

 

[Jack Hammer]

... Additionally, you need to disassemble your scooter to view the information.

I'm missing the difficulty in this. You have to disable most scooters to charge the battery anyway. Plenty of people have used watts up meters in their scooters without issue. Data logging is nothing new. [emoji2]

 

[Akoni]

I'm missing the difficulty in this. You have to disable most scooters to charge the battery anyway. Plenty of people have used watts up meters in their scooters without issue. Data logging is nothing new. [emoji2]

I don't think anyone stated that data logging is 'new'. Yet, no manufacturer offers it.

Not all scooters need to be disassembled to charge, not all scooters need to be disassembled to the point where you would intercept the motor feeds for a logger in order to charge them. I don't have to count tire revolutions and use a dipstick in my fuel tank to get basic information about my trucks fuel status and mileage.