Replace your car battery with capacitors!

[redpoint5]

If a LiFePO4 needs to be jumped, then it's probably already toast. I've killed a 4.2 Ah battery just in the time it took to measure various electrical loads with the engine off; probably 15 minutes of testing. I would only recommend a 4.2 Ah battery for vehicles with very modest electrical requirements and parasitic drains, such as a motorcycle. 20 mA is a common parasitic drain (car off and parked), and that would give about 1 week of standby time and not leave enough charge left to start the vehicle.

I consider 20 Ah to be minimum for most vehicles. This would allow engine off coasting, listening to the radio with the car off, or parking the vehicle for several weeks.

[oldtamiyaphile]

Originally Posted by redpoint5

If a LiFePO4 needs to be jumped, then it's probably already toast.

Yeah, I know that. I was thinking from an OEM perspective, if they started fitting LiFe at some point someone would try jump starting one. AFAIK only the 911 GT3 RS is available with a LiFe option.

My first attempt in the Fiat died as two weeks of standby draw killed the battery. New cars have pretty crazy standby currents, closer to 50mah from memory.

So far so good running 14.4Ah in the Proton though, even with extensive EOC, but I'm certainly mindful of keeping an eye in it. It's an almost daily driver which helps. With so little capacity and such good charge efficiency, the alt seems really effective at keeping the battery 100% full.

The plan was an alt delete and 400W of solar panels, but enough LiFe to store that current could be expensive. I may well still have to go to a deep cycle Pb. Or just stick with the alt, LiFe, and a smaller solar panel.

A 10% gain is amazing, same as what Darrin reported with a full alt delete. I'm not sure how much might still be on the table with a full delete.

[teoman]

%10 is fairly amazing.

I wonder how that would change if you are really using the electrical stuff in the car. Obviously it will go up. Ut will that %10 efficiency still be maintained?

[oldtamiyaphile]

This car does a lot of short trips. That's why I think I'm getting this almost indecent gain.

With a Pb, every time you park for 10 mins, it's like someone is sucking 2A out of your battery. When you start again, the alt then works hard to replace that 2A (at very low efficiency), only for you to stop again and all that hard work evaporates.

EOC probably has the same effect.

If you drive steady on the highway, you might get different results.

[teoman]

Originally Posted by oldtamiyaphile

I mean if the LiFe is the one being jump started. The low internal resistance should mean the Pb delivers current well in excess of the LiFe's charge rating.

I don't doubt the amazing tech in these small batteries. 7.6Ah is quite enough to start a small car. I just feel safer with a bit more reserve. I also felt that the 30A charge rating of a single pack might be too close for comfort. 60A should be fine with the stock 75A alt.

I think it would be wise to bolt on a charger like the imax or charging harness with diodes and resistors not to kill the lithium battery. Also if it nees a jump start i think that the battery is already dead.

[RedDevil]

Originally Posted by Isaac Zackary

... just imagine one of these days a 300 mile range Tesla that charges in 5 minutes.

Old post, I know, but:
https://techcrunch.com/2019/02/04/te...eries-a-boost/

Tesla has acquired energy storage company Maxwell Technologies in an all-stock deal valued at $218 million, a deal aimed at helping the electric automaker improve its batteries and lower costs as more competitors enter the market.

The offer will value each of Maxwell’s 45.9 million shares at $4.75. The merger is expected to close in the second quarter of 2019.

That dream may well come true sooner than later...
Or at least slightly less untrue.

The secret sauce is Maxwell’s dry electrode technology, which is used to make the ultracapacitors. The company says this dry electrode technology, which can be applied to batteries of varying chemistries, boosts performance and is more cost-effective than the more commonly used wet electrode technology.

Tesla CEO Elon Musk is a fan of uItracapacitors and has long viewed the technology as the possible path to a breakthrough in battery performance. He even tweeted back in 2013 that he was going to do his PhD at Stanford on ultracapacitors.

At least we can have a "Tesla" powerbank.

[redpoint5]

That's exciting news; thanks RD. I hope at least Tesla is able to sell those supercaps at lower price points. $350 for 5 of the highest capacity ones is a bit steep.

[teoman]

The ones form china that ecky bought seem to be a reasonnable price.

[hayden55]

Seems like solid state batteries are just around the corner now. Never really thought of a dry capacitor as a solid state battery until this came up.

"The company claims that its newly developed lithium-ion ultracapacitors boast the advantages of capacitors—high energy density, quick charge and discharge, and low degradation—but also larger storage capacities, comparable to that of a battery. At a commercialized, EV-ready scale, this technology could decrease charge times, have a longer service life than a traditional lithium-ion battery, resist overheating during heavy charge or discharge, and be capable of greater energy output."

[redpoint5]

Originally Posted by hayden55

Seems like solid state batteries are just around the corner now. Never really thought of a dry capacitor as a solid state battery until this came up.

"The company claims that its newly developed lithium-ion ultracapacitors boast the advantages of capacitors—high energy density, quick charge and discharge, and low degradation—but also larger storage capacities, comparable to that of a battery. At a commercialized, EV-ready scale, this technology could decrease charge times, have a longer service life than a traditional lithium-ion battery, resist overheating during heavy charge or discharge, and be capable of greater energy output."

What makes you think it's just around the corner? I've seen no evidence of this, and AllDarc's battery expert has gone all dark.

It hasn't been explained how something can simultaneously utilize static storage and chemical storage. Those are 2 vastly different techniques of storing energy.

Nothing has been demonstrated that excites me yet.