# Solar Car Prototype



## izzy0855 (Sep 30, 2008)

Hello everyone,

This is a prototype of our first solar powered battery-car. There are 10 cells that charge at 4 volts each at a rating of .50 mills, times that by 10 = 40V @ 500 milliamps. We added a small voltage regulator which brings down the 40 volts to 24 volt to charge the 18V 2000millimap AA Nimh battery-pack underneath the solar cells. In our next design there will be two battery-packs underneath the solar cells that will be able to alternate between charging and discharging, so while your operating your train the other pack is being charged. Not sure on the cost just yet, but we should have this available by the end of April.











Rick Isard
Cordless Renovations, LLC


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## izzy0855 (Sep 30, 2008)

Just to add... 

Each solar cell is rated at 4 volts per cell x 10 = 40 volts in series. Wire each cell in parallel at 50 milliamps x 10 = 500 milliamps or solder five cells in series at 20 volts then another five cells in parallel = 250 amps. I'm going to add two additional cells per side = 24 volts @ 300 mills, so while one set of cells are charging one battery pack the other battery is running your engine. The problem with this prototype is just that, there's still kinks in the design and in the concept so that's why I thought I would put this prototype out there and see what you guys think? Please keep your thoughts coming! 

Thanks Greg, 
Rick Isard 
Cordless Renovations, LLC


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## Del Tapparo (Jan 4, 2008)

Interesting concept. I had the same notion some years ago. What are your test results so far? How long can you run one of your diesels on the same set of batteries? Seems like overall, the charge rate is going to have to exceed the demand rate, or you are still back to the battery charger. A lot of variables going on here. It could work for some folks.


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## izzy0855 (Sep 30, 2008)

Del, 

This first design has only one 18v 2000mah AA Nimh battery-pack, but in the second design there will be two. First trial was with a center cab diesel pulling 6 cars for about a half hour, but with our flat layout we should get around 1.5 to 2 hours of runtime while the second battery is charging. That's my idea. I can get 24 volts per side but your right, to gain more milliamps the voltage will need to increase. On the second design I may put in a digital display so you can dial down the voltage from the regulator, it's kind a the same concept we had with our CR-2 smart charger. I'm going to try to stay away from a PCB onboard charger, but we're still in the design stage. 

Rick Isard 
Cordless Renovations, LLC


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## Del Tapparo (Jan 4, 2008)

Posted By izzy0855 on 01 Apr 2011 07:44 PM 
... we should get around 1.5 to 2 hours of runtime while the second battery is charging. ....

Yes, I can do that with a 2200mah battery as well, no solar required. Have you proven the solar will actually charge the battery, and at what rate? Then is that rate sufficient to run your train all day long and still have a fully charged battery pack at the end of the day? 


I would assume the goal is never having to charge the batteries offline? Or perhaps just extend the run time? So you will need to get at least more run time from this setup, than you would with the two batteries you are hauling around. 

Pessimistic me, but why not take the same solar panels ( or even bigger and better) off the train, aim them at the optimum direction for max charge rate, and charge the batteries offline? Then simply swap batteries when needed. You always seem to be focused on hauling around a battery charger on the train. You asked for input.


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## Totalwrecker (Feb 26, 2009)

April 1st..... hmmmmm


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## izzy0855 (Sep 30, 2008)

Yes, the solar cells charge the battery at 24v @ approximately 250 - 300 mills. I won't know until we do some more tests with an additional battery on the runtime, but that's the goal is to charge one battery while your running your train with the other. Somewhere in this mix both batteries will be dead at the same time because of the charge rate from the solar cells being less than a bench charger. 

Del, all of our systems are designed with an on board charging system, that's just the way we started and we think it's the easiest and cheapiest way to offer a complete system to the customer. I looked at an offline solar charging panel but the voltage of those panels increase with size, unless you wire two 12V panels in series. It just seems to big and too bulky to carry around. 

Rick Isard 
Cordless Renovations, LLC


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## FRedner (Mar 20, 2011)

Rick, with 10 cells at 4 volts and 50 milliamperes each, I cannot understand how you have 250 of charging current. 

In series, you have a maximum of 40 volts and 50 milliamperes (enough voltage but very low charging rate) 

In parallel, you have a maximum of 4 volts and 500 milliamperes of current (not enough voltage to charge anything) 

You don't get 10 times the voltage AND current in series... 

I would guess you would want at least 1/4 amp charging, (and this is all maximum, optimal, which actually cannot be without the cells flat and high noon). 

This would take probably 10 in series, and then 5 groups of 10 in parallel, that's 50 cells.... or 5 cars total. 

Of course, maybe you are just testing us or pulling our legs a bit in fun... I see you posted on April 1 


FR


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## izzy0855 (Sep 30, 2008)

No this was not meant as a April fouls joke, still in the design and testing stage. 

Rick Isard 
Cordless Renovations, LLC


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## East Broad Top (Dec 29, 2007)

Hmm, probably not the best solution for a subway.  

Later, 

K


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## izzy0855 (Sep 30, 2008)

Not sure what the subway comment means? 

Greg, I do have two 12V 1.67 amp hour cells that I think would fit on a 53' box-car, I'll test those out later this week and see what happens? 

Rick Isard 
Cordless Renovations, LLC


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## East Broad Top (Dec 29, 2007)

Subway = underground = no sun = solar panels don't do any good. It was meant as a joke. 

Having said that, I'm still trying to figure out the "why" of such a car beyond proof of concept (which is in its own right a perfectly reasonable "why," and catalyst for a great many discoveries.) But for commercial application, how many modelers are going to want to put solar cells on the roof of their box cars or B-units? To my thinking, the goal of a battery car (if you're going to use one) is for it to blend in with the rest of the train, not stick out like a sore thumb. I'm playing with solar arrays for charging the batteries that light my buildings at night right now, and my biggest stumbling block right now has nothing to do with the technology--it's been working well for me all winter--it's how to disguise the solar farm so it gets maximum exposure to the sun, but is hidden from view when I look at the garden. Good on you if you can make it work, but I tend to agree with Del. A better application would be a solar charging station where you plug your drained batteries to charge after you've swapped them for fresh ones. _That's_ something I'd be interested as a customer. Take something like your CR-2 charger, power it from a solar array on top of a shed, and you've got a zero carbon footprint railroad. (You could even charge the AA or AAA cells that power your remote transmitters!) 

Later, 

K


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