Using Ultra Capacitors to Replace Batteries

[Eeyore]

I have digital calipers that use a watch cell.
If it used an ultracap, I would never need to buy batteries.
I could charge the calipers in seconds

That's not very convenient is it, having to recharge it all the time ?

and it'll could run long enough
for me to make my measurements.

Another idea..
I brush my teeth for about 2 minutes. Maybe a charged ultracap could
last that long.

I suggest you work out the power budget for that. I'm very doubtful that it's
practical.

Graham

 

[Rich Grise]

One second ????

Sure, if your car is in good shape. Try it sometime. Just as you're
turning the key, say, "one thousand one," and see if it doesn't catch
before you're done.

Let us know the results. ;-)

Thanks!
Rich

 

[Rich Grise]

Two seconds sounds more like it to me.

How long does it take to say, "RRoww-VROOM!"? ;-)

Cheers!
Rich

 

[Eeyore]

Sure, if your car is in good shape. Try it sometime. Just as you're
turning the key, say, "one thousand one," and see if it doesn't catch
before you're done.

Let us know the results. ;-)

Some cars will 'catch' very fast (especially if they were only recently turned
off and they still use a carburettor) but my Saab seems to like a good couple of
cranks before it'll fire. It's so regular I suspect it's programmed into the ECU
actually.

Graham

 

[D from BC]

Some cars will 'catch' very fast (especially if they were only recently turned
off and they still use a carburettor) but my Saab seems to like a good couple of
cranks before it'll fire. It's so regular I suspect it's programmed into the ECU
actually.

Graham

At the very least I'm thinking the starter just needs to move any
pistons to the ignition part of the combustion cycle and the engine
begins to self-sustain.
Turn the key...the fuel injectors shoot...then a spark..and "vrooom".
D from BC

 

[Eeyore]

How long does it take to say, "RRoww-VROOM!"? ;-)

More like crank-crank-crank-Vroom in my case.

I like the idea that the cranking will build up some oil pressure before the
engine fires. It's done something like 165,000 miles and still uses almost no
oil.

Graham

 

[Spurious Response]

Some cars will 'catch' very fast (especially if they were only recently turned
off and they still use a carburettor)

That's baloney. If anything at all, carbureted engines have a delay as
the idle circuit is vacuum operated.

but my Saab seems to like a good couple of
cranks before it'll fire. It's so regular I suspect it's programmed into the ECU
actually.

TBI and injected engines, as nearly all are today, operate as:

If the key is on, the engine controller is on, and the injectors are
live. If the engine turns, the injectors fire at their appropriate index
locations.

There are NO injected engines that include a delay at startup for fuel
delivery. That is simply ludicrous.

 

[Spurious Response]

I like the idea that the cranking will build up some oil pressure before the
engine fires. It's done something like 165,000 miles and still uses almost no
oil.

Oil pressure does not build upon slow cranking. Oil pressure typically
comes up after the engine is running, and above a given rpm, like 600.
A starter cranking is like 80 rpm. This is related to the type of pump
used in most engines. Some modern engines MAY have a better oil pump
system, but not likely considering the cheap cost of the traditional
design that has been used for decades.

 

[Eeyore]

That's baloney. If anything at all, carbureted engines have a delay as
the idle circuit is vacuum operated.

Since when did a car with a carburettor have an 'idle circuit' ?

One reason carburetted cars can 'catch' fast is because there's still fuel lying
about in the intake system when it hasn't had time to evaporate.

With multipoint injection that simply doesn't happen.

Graham

 

[Eeyore]

Oil pressure does not build upon slow cranking.

Yes it does. Do you think the mechanical drive to the pump somehow doesn't work
when cranking ?

The damn oil pressure warning light goes out for heaven's sake.

Graham

 

[Eeyore]

Some modern engines MAY have a better oil pump
system, but not likely considering the cheap cost of the traditional
design that has been used for decades.

I said it's a SAAB. SAAB =/= cheap.

Graham

 

[Robert Adsett]

Wikipedia has an interesting energy density chart:
[ http://en.wikipedia.org/wiki/Energy_density ]

A few selected items from the list:

ENERGY DENSITY IN MJ/kg:
EEStor Ultracapacitor (claimed capacity).........1.0

Has anyone actually had a production or product sample from EEStor. I
hear about this "unbelievable" capacitor technology they "have", but I
am wondering at what stage of developement these guys really are in.

The last I heard they were remarking on the purity of the materials they
were producing.

Robert

 

[Robert Adsett]

Because maybe you're in the Arctic (where the cranking capacity of
your regular battery is drastically reduced), and your armored
personnel carrier needs to start *now* because you're under fire from
an enemy. The few thousand dollars for a booster cap will seem like a
real bargain.

There was (is?) a Russion company that was looking at using them for
just that purpose as supplement to or in cold enough areas as
replacement for standard starter batteries.

Robert

 

[Spurious Response]

Since when did a car with a carburettor have an 'idle circuit' ?

Hahahaha... You are caught in yet another techno-trap.

The idle circuit referred to in carburetor jargon, is that of small
passages that keep the car at the right idle rpm when the butterflies are
closed, which they are at idle (or nearly so).

Anyway, those passages are called idle circuits. It's like the trim on
an aircraft. A lot finer control.

Anyway, on a car, they drain out after the engine is turned off.

 

[Spurious Response]

Yes it does. Do you think the mechanical drive to the pump somehow doesn't work
when cranking ?

The clearances in the pump impeller teeth are made for higher rpm, and
at lower rpm the oil pressure is significantly lower right at the pump,
and subsequently throughout the oil circuits (yes, they too are called
circuits).

The damn oil pressure warning light goes out for heaven's sake.

Sure, the oil light goes out.

Do I need to tell you what that light is referred to as?

 

[krw]

Yes, that's probably the origin of it, predating radios and such like
(or maybe just the A battery on early portable radios).


Hmm.. if you just hook them across the battery (as in a non-electronic
toy) they're more like constant current with a constant load-- they'll
slow down (less back EMF) to deliver similar torque. So if junior is
running his toy truck up an incline, the constant current test should
be fairly close to the real operating conditions.

Makes sense that a constant load would demand a constant power (work
out ~ work in). Induction motors will attempt to maintain RPM with a
fixed load, so tend to be constant work, thus constant power in. If
a DC motor is forced to have a constant load (via PWM or load
regulation) it'll do the same.

I don't think you get the negative resistance characteristic showing
up that strongly except with electronic switching regulators.

And (quasi)synchronous AC motors.

 

[Eeyore]

Hahahaha... You are caught in yet another techno-trap.

No I'm not.

Stop talking nonsense.

Graham

 

[Spurious Response]

No I'm not.

Stop talking nonsense.

You're a snipTARD!

 

[Eeyore]

You're a snipTARD!

Problem ?

I've quoted you *exactly*.

Graham

 

[Vladimir Vassilevsky]

Robert Adsett wrote:

There was (is?) a Russion company that was looking at using them for
just that purpose as supplement to or in cold enough areas as
replacement for standard starter batteries.

I used to know russian company which manufactured the pseudo UPS for
computers in late 80x. They just rectified the 220V AC power to charge
the big bank of capacitors. The DC was applied directly to the input of
the computer power supply. Since it is SMPS, it doesn't matter if the
input is AC or DC. There was also a software included which shut down
the computer correctly while running on the capacitors.

There is a lot of nonsense always going on in USSR about the question of
the cold start of the car engine. The capacitors are no longer in
fashion because they freeze too. One of the latest brilliant ideas is to
warm up the battery by the electric heater running from the same
battery, and then crank the engine up.

But, the truth is all that you really need is a good battery, normal
engine and synthetic oil. If you don't have any of those components, you
will have problems. And the shamanism with capacitors and such is not
going to help much.


Vladimir Vassilevsky

DSP and Mixed Signal Design Consultant

http://www.abvolt.com