Shouty Kilmer says hydrogen cars are the future.

[redpoint5]

Supercaps are fantastic for things like capturing regenerative braking energy. There might be a use in such an application.

I'm a big fan of supercaps and have replaced the battery in my motorcycle with 6-series caps, but there are severe limitations too. My bike can only sit for 3 days before the electronics drain the caps too far to start the engine.

Supercaps also introduce the problem of supplying the high-rate electricity needed to charge them in seconds to minutes. CCS chargers are already putting out something like 55 kW of energy, and that high rate still takes an hour to charge a vehicle. If we're going to charge faster than that, where are we going to get half a megawatt of energy, and how thick would the conducting wires need to be?

I think supercaps will serve useful functions in the future, but not as primary energy storage for a vehicle.

[RustyLugNut]

Originally Posted by redpoint5

Supercaps are fantastic for things like capturing regenerative braking energy. There might be a use in such an application.

I'm a big fan of supercaps and have replaced the battery in my motorcycle with 6-series caps, but there are severe limitations too. My bike can only sit for 3 days before the electronics drain the caps too far to start the engine.

Supercaps also introduce the problem of supplying the high-rate electricity needed to charge them in seconds to minutes. CCS chargers are already putting out something like 55 kW of energy, and that high rate still takes an hour to charge a vehicle. If we're going to charge faster than that, where are we going to get half a megawatt of energy, and how thick would the conducting wires need to be?

I think supercaps will serve useful functions in the future, but not as primary energy storage for a vehicle.

You highlighted some of them. Their ability to absorb and dispense large currents is notable. Using this ability allows us to apply them to niche applications.

A local San Diego company, Maxwell Technologies, has battery assist units that are connected in parallel to the batteries of large diesel units to aid in starting in extreme cold where batteries lose their abilities.

They were also tested in a UPS hybrid design where the capacitors could quickly and efficiently absorb the braking energy from the motor/generator for use when the vehicle needed to accelerate again.

[redpoint5]

I built a 5-series (3400F Maxwell caps) supercap bank to aid in starting my diesel truck. It was killing the 2 large Pb batteries, which are expensive to constantly replace. I intend to eliminate the large Pb batteries next time they die and replace them with a very small Pb battery and the supercap.

[RustyLugNut]

Originally Posted by redpoint5

I built a 5-series (3400F Maxwell caps) supercap bank to aid in starting my diesel truck. It was killing the 2 large Pb batteries, which are expensive to constantly replace. I intend to eliminate the large Pb batteries next time they die and replace them with a very small Pb battery and the supercap.

I would be very interested. I have two Dodge diesel trucks as well as a Freightliner diesel van. Batteries die on a constant basis out here in the heat of the desert.

[redpoint5]

Originally Posted by RustyLugNut

I would be very interested. I have two Dodge diesel trucks as well as a Freightliner diesel van. Batteries die on a constant basis out here in the heat of the desert.

It's a sore subject for me still...

My Dodge/Cummins batteries bit the dust, and my dad had been driving it. I told him to hold off buying batteries and that I would replace them with a supercap/battery, and I bought the parts.

He went out and spent a couple hundred on new batteries anyway rather than give me a week to replace them. He hasn't had a job in years, so it's not like he's flush with money. Just impulsive when it comes to spending, and he still relies on newspaper "sale" prices rather than the internet to actually find good deals on things.

I've got the supercap built, but it's not necessary since the truck has new batteries.

I'll see if the batteries can be repurposed for tractors or something and pick up where I left off, and document the build. Will be slow going because I have many projects, a 3 month old baby, and need to move to in the next couple months.

I've also got a Li-ion battery to test the virtual alt delete idea from the other thread, but haven't got around to that project yet either. I need to fix the infotainment/NAV issue first in my Acura.

[ProDigit]

I used a large capacitor on my car (a 2 to 3 Farad cap), because in Florida, car batteries generally last 2-3 years tops.
It definitely helped starting on a low charge.
However if the car stands still too long, those large caps do drain the battery.
Even small banks of caps do.
But if you drive it daily, I see no reason why not to install one of those 3 to 5 Farad caps they sell for audio equipment for like $25-40.
Generally 2-3 Farad is more than enough.

Strangely enough, my car didn't give me an indication anymore when the battery was needing replacement due to the cap. Perhaps it thought there was plenty of power left in the battery?

[redpoint5]

I don't think a 3-5 farad cap will do much for starting. My 6-series supercap in the motorcycle uses 400 Farad caps, which results in a series rating of 66 farads. It's barely adequate to start the motorcycle.

Certainly can't hurt though.

[ProDigit]

Not sure. Farad rating goes together with the rated voltage.
The higher the cap can handle voltage, the lower the farad rating.
I believe the 2-3 Farad cap I have, handles up to ~1000W of energy for 1 second,or at 13 v helps out the battery with about 76Amps. That's quite a bit!
It's also not meant to start the car with, but merely a helper to the battery. It proves a starter with greater initial energy, and charges up again after the starting process is done, and the alternator takes over.
The cap is also larger than any motorcycle battery.
About 4 of these fit in a large size car battery.
I'm sure the 400Farad ratings are a bit off, as a similar cap of 400 farad would be the size of an entire motorcycle.

[cRiPpLe_rOoStEr]

Originally Posted by seifrob

I cannot find any reference online, but in early 90's there was quite huge effort of using hydrogene in cars. Mercedes,iirc,

Those NECAR prototypes and the NEBUS
https://media.daimler.com/marsMediaS...nd-NEBUS.xhtml

[jcp123]

Heh, I just heard another automotive journalist put the smack down on Kilmer.

Frankly, I think hydrogen cars are just too impractical. Storing the hydrogen is a real issue. If you don't drive it regularly, it will run itself dry. Electricity, at least, is widely available compared to hydrogen and although not ideal, it's a lot more workable.