Ultracapacitors

[Circlotron]

This thing turned up in my letter box today. Got it off Ebay -> http://www.ebay.com.au/itm/Ultracapacit ... 1a01d2440b Put it in a plastic lunch box and connected it across the battery. What it does is help the battery to stay at full voltage for the first few seconds of cranking instead of, as it normally would, dip down to about 10 volts. Some guys with smaller engines ditch the battery completely as just use the capacitors, but if you leave the lights on it will discharge in about 1 minute. What the big deal about them is they can deliver absolutely mental amounts of current for a few moments without the voltage dropping much. Bigger ones are used on some hybrid cars to absorb braking energy and feed it back into the electric motor when you take off again.

Anyway, I fitted it up and instead of the old 304 taking several turns to fire up (LPG) it only took about 1/2 a turn (cranked almost twice as fast as before). That was with the engine hot. Tomorrow morning when it is cold I'll try it without priming the gas. It can be a hassle to start if you don't do it just exactly right. I'm the only one that can start it. Should help the battery to last longer too. Cost about $150 delivered but should last pretty much forever.

[Holden202T]

nothing like a high powered lunch box

its an interesting way to get more cold cranking amps

[VL400]

Nice!! Can you data log it when cranking or still early 160baud bin? Would be interested to see a with and without capacitor when cranking, sounds like it makes a huge difference.

Have been following a few using cap banks and a smaller battery. Good weight saving.

[Circlotron]

Haven't got any data logging facilities set up unfortunately. One thing I did notice though is that now as soon as it fires it actually revs up to where the IAC tells it too. Big ends rattle louder and the fan belt squeals for a few seconds. Never did that before.

[Circlotron]

So, this morning was 11 deg C. Cranked over lots better than normal but (because I didn't prime it first) fired for a moment then died. Stupid LPG setup! Primed then started normally. Tomorrow will prime as usual then crank and see how we go.

One thing I noticed is that if you switch of then re-start straight away, same as if the engine stalled for example, then because the caps are at still at full 14 volts the engine cranks soooper good. Instant start. Weeeeeee!

[Tazzi]

Ahhhh!! This is perfect for the old mans porsche 944. That has significant voltage drop during crank. It actually affects the dual relay used in them for the fuel pump causing it to switch off/on when it should remain on.

Guess I know what hes getting for an early present haha.

[Charlescrown]

I have been looking at these for some time now and wonder how it would work as a battery eliminator?

[Jayme]

wow 58 farad is insane.... sure puts my 1 farad cap to shame that I used to run for the car amplifier... way smaller too !

[vlad01]

I have been looking at these for some time now and wonder how it would work as a battery eliminator?

Funny how this thread popped up, I literally came to that idea on sunday and started looking for super caps for the same purpose.

Looking at 100F 2.7v caps so I can give it a go in my cheap 21 LED torch. So sick of buying new AAA batteries all of the time and only get useful light from the first 1/3 of the battery's charge before the LED fall below threshold. Caps I can just wire direct and make a quick charge on a PSU.

And i can have some fun melting stuff with the caps too, maybe make a spot welder

Maybe 10 in parallel, mmmm 1000 farad

[Jayme]

did a bit of research on the subject... 1 farad is 1 amp second per volt... so 58 farads of this unit at 12v can deliver 696 amps for one second. but I doubt those pissy wires would be pushing 700amps through them, so in a real situation it would be boosting it by maybe 100ish amps which would mean the unit would last for 6 seconds. either way, more then enough charge to help in this situation, but not enough to run batteryless unless race car