Replace your car battery with capacitors!

[jakobnev]

Are they so expensive you have to sell a kidney for one?

[teoman]

It took me a while but i Figured the joke before i saw your response

No idea where they can be purchased from.

[redpoint5]

Ah, that photo of my setup is now in the Acura.

LiFePO4 battery is in the glovebox, and the ultracaps are sitting where the battery used to be.

I've got 2x 10 gauge cables going to the glove box. One has an XT60 connector and the other an XT90.

Originally Posted by teoman

Seems they have better caps now. 3.0V 3400F

https://www.maxwell.com/images/docum..._datasheet.pdf


A pack at 15V would be 680F

I have a 5s pack of those 3v 3400 farad caps. It did cost an arm and a leg, something like $220.

It couldn't quite start my diesel truck, but then I only briefly tested and may need lower resistance connections.

I need to pull those off my shelf and see what I can do with them.

I've got 400 farad Eaton Ultracaps in my motorcycle, so those extra 50 farads might make the difference. Your engine is twice mine too.

[teoman]

And it is a power hungry thing, all sorts of servos and lights come on. Even the steering lock is battery powered.

[redpoint5]

I'd suggest running a LiFePO4 as long as the battery won't drop below freezing temperatures when in operation.

There's some inexpensive ones on Amazon these days;

https://www.amazon.com/dp/B07X5G2FFW...lig_dp_it&th=1

[teoman]

Whoow, the price has dropped a lot.

[redpoint5]

Turns out I have the 2.85v version of BCAP3400. My 5s setup is then only rated to 14.25v if I achieve perfect balance. I read in the datasheet that a 0.1v tolerance is acceptable, so that gives me up to 14.75v for perfectly balanced caps. Wish I had those 3v ones! I don't see the higher capacity Maxwells anywhere now that Tesla owns them. Insert conspiracy theories that Tesla is soaking up all supply here.

Those smaller wires incorporate my LED balance circuitry.


I'm sure I could eliminate the battery altogether in my Acura with this thing. Only question would be how long I could let it sit without draining it too much, or how long I can leave the dome lights on.

[redpoint5]

Doing a little testing with my BCAP3400 5s Ultracaps.

Charging from 4.8v to 13.8v (9v delta) took 16 Wh.
Discharging from 14v to 7v (7v delta) consumed 13 Wh

I'd say there's about 10 Wh useful between 13.5v down to 8v. That's 600 watts (0.8 horsepower) for 1 minute, or 3,600 watts for 10 seconds.

Hoping I don't accidentally weld something or send a pool of molten copper through the floor.

[Bicycle Bob]

https://newatlas.com/energy/skeleton...urved-graphene

Lithium batteries with capacitor electrodes.

[Tahoe_Hybrid]

Originally Posted by teoman

Seems they have better caps now. 3.0V 3400F

https://www.maxwell.com/images/docum..._datasheet.pdf


A pack at 15V would be 680F

the best consumer one on the market is XS power 2.85 @ 3150F @ 65 $ maxwell equivalent would be way higher in price even for a used one



you can get 1260F@ 14.25v for $850 from xs power it's in a battery shaped container(so you can find the group you need)

Eaton offered 500F at 16.2 for $650

or 1500F at 12v-16.2v rated for $1300 (spend your stimulus check on that)