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Use ultracapacitors to extend lifespan, improve performance for many solar-dependent applications

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billhartman77
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re: Use ultracapacitors to extend lifespan, improve performance for many solar-dependent applications
billhartman77   4/20/2011 10:48:55 PM
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Hi Weglobal, (with apologies from the marketing guy to EE's out there) The EnerPak supplied load is peak powered through ultra low power MCU controlled ultracaps. The energy source is energy harvesting/regen braking, etc. that is conditioned and charges the ultracaps. These ultracaps shift to series when charge is available to rapidly/efficiently/low stress recharge the secondary storage. When primary source is not sufficient, the secondary recharges the ultracaps. We use a secondary lithium battery but could use other battery types. Our first systems have been in a wireless sensor network trial for over two years with zero down time and well over 120,000 charge/discharge cycles per EnerPak. There is lots out there now on the potential benefits of hybrid parallel ultracap plus battery systems in terms of longer overall battery life. We are seeing significantly longer battery life, higher battery performance, much better low temp battery performance, and expect the system to perform well over 1 million cycles. Hope that helps

weglobal
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re: Use ultracapacitors to extend lifespan, improve performance for many solar-dependent applications
weglobal   3/14/2011 4:53:37 PM
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Hi billhartman77, could you please explain how did you combine the bat and the supercap ? I am designing a circuit to supply a voltage to a LED driver which works from 0.8V to 5.5 V. My idea is to have a SLA 2.0V 2500mA in such way that would charge two 220F 2.3V in parallel (supercap) , so when they are charged the battery will be disconnected and they will run until 0.85V , once that happens battery will turn on again charging the caps and still running the circuit. I believe doing that it will increase the battery like. What do you think. Thanks

billhartman77
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re: Use ultracapacitors to extend lifespan, improve performance for many solar-dependent applications
billhartman77   2/3/2011 5:35:38 PM
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The network is outdoors harvesting solar light, although would work with indoor lighting, thermoelectric, etc. In this field trial, it is a question of cost and volume. The EnerPak as a set of discrete components is still smaller than two AA batteries and can easily be much smaller as an ASIC. The solar cells are about 2 x 3 inches and could probably be sized smaller. Clearly if size and space for a large secondary battery and solar conversion cabinets are not an issue, an EnerPak system would not make sense.

Simpleton
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re: Use ultracapacitors to extend lifespan, improve performance for many solar-dependent applications
Simpleton   1/28/2011 11:24:34 AM
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Bill, Out of curiosity wanted to know is the wireless mesh sensor network is deployed indoor and harvesting ambient light or outdoor where exposure to sunlight is not an issue.

Simpleton
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re: Use ultracapacitors to extend lifespan, improve performance for many solar-dependent applications
Simpleton   1/28/2011 11:18:27 AM
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Ultra cap can replace the conventional rechargeable coin batteries as long as the availability of source of energy is guaranteed. A simple example is the low power sensor network having low transmit duty cycle and sleep current. Depending on the max voltage dip allowed; the cap size can be selected.

billhartman77
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re: Use ultracapacitors to extend lifespan, improve performance for many solar-dependent applications
billhartman77   1/20/2011 6:33:27 PM
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Hope I don't sound like an ad, but I am working on new applications for the TPL EnerPak circuit, which uses an ultra low power MCU to control solar and other energy harvesting input to power the load through an ultracap, to use the ultracap to charge a li-ion battery for backup, and to have the li-ion battery charge the ultracap when solar/other-EH is insufficient. Current version is 2.75-3.3 volts with an app-specific ultracap/battery combo, but all can be tailored. We've completed a two-year trial powering a wireless mesh sensor network. While hearing a lot about new ultracap and new secondary li-ion apps, we have not seen anything like the EnerPak approach. The benefits of combining ultracaps with secondary batteries are the power and energy density tradeoffs one expects. The benefits from the charging scheme of the secondary li-ion are more of the harvested energy captured, faster battery response time, and much longer life of the battery/ultracap combo--We are at over 100,000 real-world cycles on each of the trial EnerPaks. The original targeted app is ultra low power wireless networks, but we expect the scheme to scale to other apps. Love to have comments pro and con on the scheme and where it might be of benefit. Thanks

weglobal
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re: Use ultracapacitors to extend lifespan, improve performance for many solar-dependent applications
weglobal   1/20/2011 2:29:43 PM
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I did a project in 2008 using Boostcap Maxwell ultracapacitor, in that case I used a 2.7V 1200Farads cap.. The idea was to feed 12 10mA led using a LED driver that could still work at 0.7V, it did work but compared to 3.6V 2500mA NI-MH battery that I ended up using, the ultracapacitor was way to expansive and to archive the same hours output, the size of the ultracapacitor was 3 time the battery. I wonder if there is anything better at this time. Thanks

prabhakar_deosthali
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re: Use ultracapacitors to extend lifespan, improve performance for many solar-dependent applications
prabhakar_deosthali   1/18/2011 12:51:01 PM
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As per my knowledge the ultra capacitors are superior to batteries almost in all respects such as charge holding duration, charge release rate, recharge time, life time. Their only shortcoming as of today is their capacity. With new materials like Graphene , this shortcoming is also expected to be overcome in the coming years

Sanjib.A
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re: Use ultracapacitors to extend lifespan, improve performance for many solar-dependent applications
Sanjib.A   1/17/2011 5:29:36 PM
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Apart from LED lighting application using solar power, are there any other applications which the ultra-capacitors fit into? How are these ultra-capacitors be as effective as the batteries in holding the charge for longer duration?

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