12v battery

[MSAGRO]

I don’t know if this issue has been posted before, but with the advanced technology of Tesla why does the cars still have a 12 V battery?

It seems a bit pendantic to have a charging system adjunct that dates back to the 1960s… Is there anyway that Tesla could engineer a converter to replace the 12 V battery?

There is a lot of power sitting on the bottom of our Teslas, so why not just develop a converter to replace the antiquated 12v battery?

 

[N..8]

I don’t know if this issue has been posted before, but with the advanced technology of Tesla why does the cars still have a 12 V battery?

It seems a bit pendantic to have a charging system adjunct that dates back to the 1960s… Is there anyway that Tesla could engineer a converter to replace the 12 V battery?

There is a lot of power sitting on the bottom of our Teslas, so why not just develop a converter to replace the antiquated 12v battery?

I would say it would be how less efficient to make a 350/400v step down to 12v converter that would be in an always on state. Right now the 12v charger only comes online when the battery needs a top off. There is a lot of waste stepping down 350/400 volts but only for a few minutes. Not sure but I would venture in saying that the charger is putting out 20 - 60 amps into the 12v battery so the top of is quick.

 

[Tam]

...just develop a converter to replace the antiquated 12v battery...

Tesla did take up your advice and did not have a separate 12V battery for its initial Roadsters that are less than version 2.0.

Now, read whether it was a correct decision or not. Make sure to read the in-service from General Motors engineer to learn.

Lots of press covered Tesla's lack of a separate 12V battery at that time so Tesla gave in and changed its mind. It quit following your idea and started to have a separate 12V battery since Roadster version 2.0 and up until now (Model 3).

 

[Haxster]

I'm sure that Tesla considered using a supercapicitor instead of a fairly expensive 12V battery. I wonder why they chose not to. Anyone know?

 

[Tam]

...supercapicitor instead of a fairly expensive 12V battery...

Supercapacitor Information – Battery University

"The supercapacitor is often misunderstood; it is not a battery replacement to store long-term energy. If, for example, the charge and discharge times are more than 60 seconds, use a battery; if shorter, then the supercapacitor becomes economical."

 

[Haxster]

Supercapacitor Information – Battery University

"The supercapacitor is often misunderstood; it is not a battery replacement to store long-term energy. If, for example, the charge and discharge times are more than 60 seconds, use a battery; if shorter, then the supercapacitor becomes economical."

View attachment 269464

No surprises here.

With a constant source of regulated power from a high voltage step-down converter, this would seem to make a good 12V "energy buffer" (not an over-cycled battery) for the cars 12V loads. Likely more expensive, but it could eliminate the high warranty costs (and customer satisfaction issues) with 12V battery replacements. And no lead!

 

[Tam]

...Likely more expensive, but it could eliminate the high warranty costs (and customer satisfaction issues) with 12V battery replacements. And no lead!

1) High cost per watt
2) Low energy density: means more weight to get to an equivalent traditional battery energy.
3) More frequent recharging from the main pack (or as you suggested, constant step-down power consumption) which wears down the main pack quicker...

 

[N..8]

It would be a different idea for regen of power though. Might take the spikes out of power use from stop and go traffic. Not sure if it would worth the cost of it, maybe an add-on for the DL version cars.

 

[Haxster]

1) High cost per watt
2) Low energy density: means more weight to get to an equivalent traditional battery energy.
3) More frequent recharging from the main pack (or as you suggested, constant step-down power consumption) which wears down the main pack quicker...

1) High cost per watt
2) Low energy density: means more weight to get to an equivalent traditional battery energy.
3) More frequent recharging from the main pack (or as you suggested, constant step-down power consumption) which wears down the main pack quicker...

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I can't vouch for their data or what "Battery" technology they're comparing, but to address your bullet points:
1) Yes, the cost per watt is surely higher. But overall cost to Tesla with warranty costs figured in, it's TBD
2) At ~10% the energy density, a SuperCap of 1/10th the energy would be the same weight.
3) Since it can be charged MUCH faster and is good for way more cycles, this should balance out. The high voltage "re-charger" for the lead-acid battery could become a high current "burst charger" for the SC pack. I don't see how the main pack will be worn down any faster (other than somewhat higher self-discharge from the SCs).