How about using a capaciator to increase battery capacity?

[Cobb]

Found this 63 farad one on ebay listed at 125 volts. 63 Farad 125V Ultracapacitor Supercapacitor Module NEW | eBay The seller said he think about letting me hook it in parallel to the ima battery.

At the least, maybe we can charge it using a few diodes and an extension cord?

[retepsnikrep]

Hooking it in parallel with the main battery will look impressive but that's about all.

It's a nice unit and cheap but stores only a small amount of power. Someone good with maths can gives us a few figures in Ah over a limited working voltage range.

To actually get the full but relatively small amount of capacity/power in and out you need a special two way DC-DC converter in between the supercap and the Insight battery that will allow you to drain it down to 0V and charge it back up again.

If you just connect it in parallel with the main battery and only cycle it between say 125 and 100V or whatever the working range is for an I2 battery then you will get only a small amount of power. It will however help to smooth the demand on the I2 battery a little bit.

Safety is an issue with those units.

1) I doubt it's fused in any way.
2) It can deliver huge currents in an instant through you or anything else you short it with including spanners, screwdrivers etc.
3) It will have to be charged via a limiting resistor or CC supply upto exactly the same voltage as the ima battery before you finally connect them together if you want to try the parallel pack idea or the current inrush into that pack will be enormous and blow fuses or weld the connections.
4) It will need it's own proper DC rated fuse depending on where you connect it into the IMA setup. It will need to be permanently connected to the cells like siamese twins.
5) I don't know what the maximum voltage is for the I2 system but it must not be over 130v (preferably 125V) when regening down a steep hill when full or you will destroy the unit. I don't know how supercaps fail in an overvoltage scenario but it might be spectacular.

[samwichse]

1f = 1 amp/sec/v.

So this unit has 63 * (125/2) = 3938 amp/sec capacity or 1.1 ah at an average voltage of 62.5.

Sort of.

That's assuming you have some kind of dc/dc that can take an imput of near 0v to 125v and feed the more constant output the I2 will need at its battery. Say you hooked it up directly parallel to the I2's pack (I believe about 96v resting?), then you would be looking at basically using the capacity within the range of 85-120v, or only a small fraction of the unit's capacity.

[2Slow4u]

I developed ultracapacitor packs in a previous life using the maxwell caps, as its been stated before this is not a quick and dirty drop in replacement. Ultracapacitors are not childs play and I would highly advise against them for your insight.

[3-Wheeler]

Originally Posted by Cobb

Found this 63 farad one on ebay listed at 125 volts. 63 Farad 125V Ultracapacitor Supercapacitor Module NEW | eBay The seller said he think about letting me hook it in parallel to the ima battery.

At the least, maybe we can charge it using a few diodes and an extension cord?

I think it really makes a difference on what the capacitor is being used for.

For example, the battery has *capacity* but is not really good receiving or discharging more than 1C.

If you drive the car and regen slowly into the battery, then there is no advantage in using capacitors.

On the other hand, if you are racing the car and need to stomp on the brakes and recover that energy, then there is no way the battery can capture that effectively, and the capacitor could help.

So the question becomes, "How do you drive the car?"

Jim.

[Cobb]

It was just an idea. I may have my car sold to a co worker in a few days and it would be a moot point altogether.