light weight battery replacement (super caps)

[Wiggys.shop]

What do you use for a light battery for your street car? I was playing with some super capacitors and was thinking about running them on my 2275.

https://youtu.be/aLI2PmrwrLk

[ps2375]

Why the need for a light weight battery in a street car? A race car, yes, but street car? I suppose you can recharge them from a jumper box or maybe cables.

[Wiggys.shop]

It was just an idea I was playing with I had the capacitors for a different project. They just charged directly off the alternator. I kind of like the idea of a battery under 10 pounds that's rated to last 10 years.

[ps2375]

I understand the light weight and life cycle benefits, but for the price(I did a quick search), for the cost of (what I found) you can buy a new battery for the same or less and have much more reserve power. And with a properly maintained charging system, the battery should last about 5 years before having to worry about it. I can see all the benefits, weight and life cycle, as big advantages in a race car/toy, but in a street vehicle not so much.

I watched a couple of your vids, very interesting. Do the ckt bds regulate charging and anything else?

[Wiggys.shop]

I ended up using 6 caps to get the voltage rating higher for the alternator output. The circuit boards just help keep the caps balanced.

[FJCamper]

Gentlemen,

For racing, except in extreme cases where overall weight reduction matters, stock heavy batteries are your first choice because you are relocating them to shift chassis weight. A 40-lb lead acid battery in the nose of a Ghia where the horns used to be really helps the front to rear weight ratio.

"High performance" batteries such as Optima save some overall weight, are made for mounting in odd places (sideways, for example), and embody the competition look. WE have an Optima yellow sponsorship battery in the Blitzwagen and an Optima Red in the Historic Sportscar Racing Ghia. HSR people are all about prestige and beauty or we'd be using a DieHard in the Ghia. We have fancy relocated battery terminals in the front luggage compartment because our Optima Red is mostly hidden under our FIA fuel cell.

A big reason to need a full-size battery is for sprint cars that run without charging systems, to save weight. It also takes HP to turn an alternator. If you run with your B+ and Exciter wires disconnected from your alternator, you'll get a 5 HP boost, on average. And you'll be running on your battery.

We air-cooled road racing guys can't just toss the alternator because it's contains the bearings and shaft for the fan, and it take power to turn the fan. You can disassemble the alternator and cut out the coil windings to lighten the assembly.

I'm not implying we give up on innovation. We all love that and probably wouldn't be in this sport without it. My point is, if you are competing, and are trying to win, don't innovate yourself out of the race.

FJC

[Bruce2]

It also takes HP to turn an alternator. If you run with your B+ and Exciter wires disconnected from your alternator, you'll get a 5 HP boost, on average.

Not nearly that much.
If you were on the track during a daytime race, your electrical load isn't much. Ignition, engine management, fan(s), gauges.... What does that draw? 20 amps? That would be just over 1/3hp. By the time you add the inefficiency of the drive belt and the losses in the alternator, it might be robbing a half hp from your crankshaft.
Otherwise, every race car in the world would have a momentary switch on the steering wheel so the driver could cut the charging while exiting a corner.

The cooling fan is another story. Dyno tests show 10-15hp at 6k rpm. If you want the edge on your competition, install some kind of clutch arrangement on the drive so you can stop the fan while you try to pass that guy you've been following for several laps.