charge hybrid battery uing portable solar charger?

picard

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Is it possible to charge the hybrid car battery using the portable solar charger plug into lighter socket? The solar charger would be left laying on the dashboard. Can this method of charging work while the car is traveling during sunny day? /ubbthreads/images/graemlins/confused.gif
 

BB

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Re: charge hybrid battery uing portable solar char

Not really--Those dash-board chargers are only ~5 watts...

You would need a 100 hours of bright sun (5-6 hours a day?) just to send the average EV a bit over 1 mile (if I recall my numbers correctly at ~400-500 watt*hrs for an average EV per mile).

A single "large" panel from www.bp.com are 175 watts in full sun--even a full day's worth of sun from one panel would send you around 2 miles.

-Bill

(fix watt/hrs to watt*hrs...).
 

gadget_lover

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Re: charge hybrid battery uing portable solar char

Picard, the answer is.... sorta.


The hybrid battery packs are all high voltage (around 300) and hold a fair amount of energy (2000 watt hours or so). The dashboard solar charger puts out a watt, maybe two, at only 12 volts. That means the charger has to sit in direct sunlight for about 2000 hours to gather enough energy to charge my Prius battery. It also would need some sort of inverter to bring the voltage up to the battery pack voltage.

If you figure that you only get 4-8 hours a day of highest quality sunshine, it becomes apparent that under the best of conditions, it would take a year to charge.


Bump that solar cell up to several hundred watts and you have a different beast that could make a difference.
 

picard

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Re: charge hybrid battery uing portable solar char

Brunton produce 24 & 30 watt solar chargers. It should charge more quickly than average 1watt charger.
 

mattheww50

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Re: charge hybrid battery uing portable solar char

First of all the capacity of hybrid battery is pretty small. 700-800 watt hours, not 2 kilowatt hours.

An electric car it is not. The Honda Civic is 144 volts, and 6 Amp hours IIRC, the Prius is a more voltage (277V IIRC), but fewer AH. The purpose of the battery pack and motor in the hybrid is primarily to recover the energy normally converted to heat in braking, and to allow the car to move when hit the gas, even if the engine has been shut off. You'd be lucky to get 4 miles on pure battery. So while you can add solar cells, and they could put a fair bit of charge into batteries in a typical work day, the total energy stored in the battery pack is really of very limited usefulness.

By comparison the battery capacity in the Electric Rav4 is about 28Kilowatts, roughly 35x the energy storage in the hybrid battery.

If you want 2 Kilowatt hours in NiMh cells, you are looking at tripling the weight of the battery pack,and tripling the size. Hybrids are attractive in part because you don't need a great deal of weight or space for the battery pack. On the Honda Civic Hybrid, think 120 C size NiMh's and you will have the right idea.
 

evan9162

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Re: charge hybrid battery uing portable solar char

According to john1701a, the current Prius battery pack is 201V nominal, 6.6Ah, for 1.3kWh.
 

gadget_lover

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Re: charge hybrid battery uing portable solar char

And the "Clasic" prius (1999 - 2003) was 277v at 6.6 ah for 1801 ah. I rounded it off to 7 ah, since it did not really matter to teh discussion. Like all NiMH batteries, the voltage is not really 1.2v per cell when freshly charged, so some documents list it at 300 volt (Nominal 277).


But all that aside, the question proposed by Picard has has some practicality. Here's why I take that stance.

The typical non-commuter uses their car for short trips, running to the store, school or post office as needed. A small pure BEV with a 20 mile range could handle 90% of these tasks without any problems. It's that last 10% that require a larger battery pack for more range. Solar may be a way to extend that range, but it's notoriously unreliable.

But if you use a solar charged hybrid, you have a sweet little city car. The solar cell can top off the batteries when it can, even when parked at the grocery store. The hybrid can supplement it when it needs to on coudy days or when you have to make several extra trips to the hardware store.

There are, of course lots of little "gotcha's" involved, but it's not a bad idea.

Daniel
 
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