Backyard Aquaponics
A place to discuss aquaponics

So casual to just drop in that you want to build an electric car

How far along are you with it?

I think he's unwound the extension cord...

Took a quick look through the thread and could not see it anywhere. What ebay regulator did you end up with? Some claim to be a MPPT but really are not.
You can tell pretty quickly the panel should be sitting at Vmp which is generally around 17-19v for a "12v" panel.

Check for shading at different times as well. Just a small shadow can cause a big drop in output.

Just took a look at Lungy's thread quickly. He didn't have the battery fused at the terminal which I would recommend. Also aluminum insulation being conductive/thin could "spray" sparks if somehow a wire touched it.

The 120w panel not enough current to cause it to combust if the battery shorted and there was only 1 battery shown.

From the small setup/battery shown in the picture I saw I would be leaning towards as an assisted fire. He suggested that might have occurred.

The one I've got was stuck to the back of this item:
http://www.ebay.com.au/itm/120W-FOLDING ... 2202wt_979

From the flashing I'm pretty sure it's a PWM module, not mppt.


And I think that the problem with charge is shadow as you suggest, the nearby fence and plants were casting shadows across the panel at some parts of the day. I've moved the panel to help with this.

We just bought a new car to replace our gashog SUV. It was a great truck that would move 8 people but only got about 16 mpg. This fall my son goes to school 25 miles away. There and back twice a day (100 miles!) was going to get real expensive. I considered a Focus Electric-plugging in at night and middday wouldn't be a problem, but it cost $39,000. There is a federal tax-credit program worth about $7500, but we being a single income 2 kid family don't pay enough taxes for a credit program to pay off. Instead we got a regular Focus for half the cost and get over 40 mpg(we live rural and most of our driving is 55 mph highways).
Anyhow, in among all the research of electric cars I had considered building an electric car. The tech is out there and to modify a regular car to electric will run about $8,000 for an AC motor and controller (AC allows for regenerative braking), batteries (using lead-acid or nicads for the initial build and seeing if LiFePo4 or something better comes down in price in 3-5 years when the originals are losing performance), a charge controller and wiring,etc. I have a 62 Ford Falcon sitting around that would be perfect as a test mule/someday daily driver. Lighter than my new Focus, 4 doors, and no technology to get in the way. Its an idea I'd like to invest in eventually. First, I want a greenhouse and the wife wants a new kitchen. Then maybe I get to build my garage and THEN I can work on my electric car project in it...maybe...someday...

I'm in awe Nebbian. Electronics is way over my head so I wont be following you on that adventure.

Maybe you and Ryan could make these things up and sell to us Luddites.

I had to buy my backup system in parts off the shelf and that cost plenty.

Even a "simple" fall over switch i have to get from the ES 'cos you can't buy them here. To make matters worse I had to buy 2 in 2 years as they don't last long.

Note to self "got to get one of the kids into electronics"

Well it turns out I need more panels, more batteries or both.

System was at 9.6v tonight after a couple of days of cloud.

Back to the drawing board, and out with the extension cord. *sigh*

Cloud often means wind

What you need is Fisher and Paykel Smart Drive hard rubbish

Hi Nebbian,

Just catching up on your thread. Looks like you have got a good system there.

If you are looking to web enable it I would suggest you design in some data logging, if you haven't done so already. This can then be graphed and you can see the usage/trend.

You should also monitor the power coming from your panels and also from your batteries - using some power meters. A good review of some power meters can be found on the mjlorton Youtube channel:

http://www.youtube.com/watch?v=Lxv9Rozs774




Would be nice if the power readings can be logged and graphed too.

Keep up the good work.

Cheers,

Mon

Well there's your problem...

Angles that are fine in summer might not be so fine in winter. So now the bottom cells of my panel are never getting sunlight on them, which is wildly inefficient.

So after a quick trip to the big B, a bottle of wine and some help from an old friend, the panel is mounted well away from any shadows.

Hopefully my battery will recover... Might be time to put that low voltage cutoff in place.

Excellent!

That means you will soon make a solar tracker. And it will need to be on a raised frame.

Perfect.

Now I can just copy your design

[well that was easy. Even before I hit submit you have solved it ]

Ha ha I've got to finish my auto fish feeder first. How's yours going?

By the way when I first put the panel up it was quite... floppy... the thin aluminium angle barely held up the panel, and would definitely not have stood up to a normal seabreeze.

My mate suggested some wire stays, which made an incredible difference! The effect was so very marked, a graphic demonstration of triangulation.

Hi Nebbian,
On my solar experiments a hand shadow on the panels made a huge difference to the output. They might have a diode on the panel array but it only needs one cell to be shadowed and it knocks out the output of the panel. To compare someone at the same latitude I recharge a 24 amp/hr battery with a 20 watts panel and run 4 amps for one hour a day with a water feature and garden lighting. The battery is recharged well before midday.

I also have a security camera and sensor 12 volt flood lighting running on the same size battery with an 80 watt panel. It hasn't run out of charge yet despite leaving the 6 flood lights (10 watt) unintentionally left turned on for 6 hours during the day.

My panels are mounted on posts and frame angled at 32 degree to North. The structures are high enough that they get unobstructed sun all day. You are right about the flimsy solar panel frame and I suggest a strong structure so that the tempered glass does not explode. We had a 15 year old tempered glass patio table explode over the new year - we were inside and not using the table at the time and there was nothing on the table to cause the explosion. According to an architect friend previous scratches or temperature changes can cause it. It has made me very wary of tempered glass since.

My aquaponics setup is a bit overkill providing 360 watts of solar energy and it hasn't failed yet despite drawing a lot more that my other systems.

I reckon you are on the right track lifting your panels above the shadow lines. My regulators are PMW and they have a low voltage battery cutout so little chance of draining a battery enough to damage it.