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Plug Power Selects Maxwell Ultracaps for GenDrive Fuel Cell-Based Power Packs for Lift Trucks

Plug Power Inc., a developer of hydrogen fuel cell-based power systems for electric lift trucks, has selected Maxwell Technologies’ BOOSTCAP ultracapacitors to enhance performance and energy management in its line of GenDrive power units.

Plug Power has placed a purchase order for MC2600 2,600-farad ultracapacitor cells to be delivered during the third and fourth quarters.

Ultracapacitors’ burst power capabilities for lifting, as well as regenerative braking for energy recuperation and longer operating life make them an ideal complement to hydrogen fuel cells in this application.

—Andy Marsh, Plug Power’s president and CEO



I'm getting 2600*0.5*2.7^2 = 9477 J or 2.63 Wh. That doesn't seem like a lot of energy, but I suppose it only has to store enough for a single instance of braking.



Also recuperate from descending load,power managment(stores oversupply)and boost reducing fuel cell size and speeding operation.

Henry Gibson

Ultracaps have to be used if LiIon cells are not used because it would not match the leading edge publicity requirement of having the latest technology if they used NiMH technology that is well proven by Toyota.

The CISIRO ultracap built into lead cells is too mundane when some people believe that ultracaps store more energy than lithium batteries.

The EFFPOWER bipolar battery would be more cost effective if it were on the market, and even if they will not use Firefly's negative foam plate technology. Positive carbon foams may never make it to the lead battery market, but negative and positive carbon foams should be tried out for bipolar nickel-cadmium large batteries where the oxidation voltages are lower.

It is a total engineering mistake to use Ultracapacitors alone in this application as it wastes the fuel cell's ability to produce constant energy, but fuel cells are very expensive for peak short power bursts.

Ultracaps may have some use in parallel with any battery type but they have too low of energy capacity to get the most out of a constant flow of electricity from a fuel cell.

The prior energy calculation is correct for one cell, and it indicates a good comparison point with NiMH cells or even ordinary alkaline cells. There are some eight amp hour D cell size NiMh cell in a local store, there seem to be 16 amp hour units being made as well. This single 8 amp hour cell stores at least 8*60*60*1.2=34560wattseconds or joules of energy or the equivalent of more than 1314 ultracap cells because ultracaps are not used down to zero volts. Three quarters of the energy in ultracaps is already gone at half voltage.

Ultracaps require complex circuitry to protect each cell from over voltage and to deliver power into a motor circuit, and this complexity could be used instead for a simple electric flywheel system.

Ultimately the lift trucks would be better served with a hydraulic-air reservoir and INNAS or other hydraulic technology with a plain simple electric motor hydraulic pump run off the fuel cell.

Even more cost effective would be to use Firefly's Oasis batteries and plug in the units for recharging or trade battery packs. The six pack yellow top batteries at the local auto parts shop are adequate as well.

If you have the money for a fuel cell, you can go much lower cost and lower maintenance with swapable special ZEBRA battery packs. Single standard ZEBRA cells weigh less than a kilogram and contain about 100 watt-hours of energy or enough for a half mile or more of travel in a modern car. Multiple standard ZEBRA packs have both enough power and enough energy for any electric car, but higher power ZEBRA cells can and have been made.

The high power claims of ultracaps are misleading to many people who are only familiar with high power engines that also provide the power for many minutes or hours.

Whilst ultra-capacitors have their uses, there are places where the space used by them is better used by other technology of more energy or at least the space and also money should be split with higher energy technology. ..HG..

Zaphod Beeblebrox

Golly, just my luck to follow one of Henry's essays :)

If you made it this far:

When will they start pulling funding from the fuel cell hydrogen boondoggle? Hurry up and burn through your cash.

A reasonably sized Li-ion battery pack can deliver sufficient power for most applications. Some good enough chemistries from Toshiba, Ener1, Altair and others. Ultracaps with ultra low energy density are very niche.


These fuel cell products replace Pb Acid batteries that are between 510 - 1300 A-hr, no lithium supplier could supply such a battery that would make sense to a fleet vehicle user such as Wal-Mart.

Even if a Li-Ion battery could be produced cheap enough, it doesn't eliminate the charging infrastructure or the time to charge the battery, in which case the customer might as well just stick with the incumbent technology.

A fuel cell solution allows the customer to replace it's hundred plus chargers with a single or double point refueling system so the vehicles can refuel in less than a minute as opposed to the 4 - 8 hours it takes to charge a battery. Most of these customers run 24 hours a which means they need multiple batteries.


These fuel cell "products" are supposed to replace battery powered fork lifts? A hydrogen refuelling station is supposed to replace "chargers" (i.e. sockets in a wall)? Well I'll believe it when Wal-Mart places a PO. So far, all we've seen is demonstration project after demonstration project, funded by the fuel cell suppliers (with some support from US and Canadian governments).



As long as low-cost, low temp electrolyzing is on the table - H2 will be also.

I think I knew a Beeblebrox from Betelgeuse (600-LY Orion) - any relation?

Jack Willard

Are any on you aware of an activated carbon electrode developed by Reticle Inc.? It has 10-20 times the capacity as Maxwell's 3000F Cap. Maxwell's has around 5 F/g, including the cap housing, etc. (It weighs just ovey one pound) A Reticle cap would have 50-100 F/g and uses the same activated carbon precursor as Maxwell does. There was a paper presented by a Dr. Carl Nesbitt at the Boston CleanTech symposium last spring. I think it was titled "Reticle Carbon for Ultracpacitors. Any comments?

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