Markus Loeffler

I am very excited to announce that TreeHugger is now featuring my project: http://www.treehugger.com/solar-technology/unplug-solar-controller-aims-help-you-take-your-fridge-grid.html

Hello Permies,

Today my Kickstarter campaign, on which I have worked for over three years, has finally gone LIVE - and when I reach my funding goal, thousands of fridges will come off the grid, and tons of CO2 will be saved! Here is the link: http://kck.st/1dfFaIg

It is a DIY project using equipment you might already own: Solar panels, batteries, and inverter.

Please support my KICKSTARTER Campaign in any way you can - LIKE / SHARE / Chip in.

Thank you all
Markus

Hi Darren,

Can you provide drawings of your wiring as well as make & model of the used equipment?
Going with the information you have provided:

-42V seems right for panels made from 72 individual cells
-"Low voltage connection 25.2v which batteries have been as low as 24v"
>>do you mean "low voltage disconnect"? 25.2 and even 24 is to high for that value. Go for 23 - 22V.
-Question, if each solar panel is rated at 10amp x 5 = 50amp , being the regulator is only rated at 50amp would or could this be slightly undersized ?
>>50A is the short circuit current, you will never get that in a real world environment. So 50A rating is OK.

How do you know that no charging is happening thru the panels?

Markus

I have a sine wave too but they are 3-4x the cost. I am looking to keep the cost low for a working system.
I do have a well working installation with the PowerBright 24V, 900W. The problem is that all newly bought models (4 units) are failing after some days of operation. The next model up is 1500W - it looks as if that is the only option.

I just checked the Whistler website and they only seem to have 12V inverter but i would need 24V. Any other recommendations?

@Gerard: Thanks for the suggestion but pure sine is currently too pricey.

@Tom: what do you run from it. Is it connected to a fridge?

Jhonny,

if you are trying to charge the tractor that I see when clicking the link I can not recommend this setup. 45W is the manufacturers boiler plate. That value needs to be de-rated, look for the Photo Voltaic USA Test Conditions (PTC) value.
They will most likely not print this value on those type of 'low end' panels. If you are lucky you get 80% of the value: 36W effective output. To make things worse the supplied charge controller does not deliver you that power on the output side.
It will loose another 10-15% unless you purchase a rather expensive MPPT charge controller.

Long story short: you can use it for some LED lights and as a cellphone charger. The total daily energy it will be able to produce should be no more than 200Wh

Vlad,

The type of battery influences DOD lifetime cycles. Here is a brief description about what to expect.
Summarizing the article: with 50% DOD you get between 1-3 years of lifetime out of your batteries assuming you charge them up to 100% and discharge to 50% every day.
If that is the case I recommend you get a much bigger battery bank.

On the other hand you might not measure right. You need to buy a 'fuel gauge' type of SOC meter that is doing 'coulomb counting'.
As an alternative you can disconnect ALL batteries and let them sit for 24h and measure the voltage of each battery. That will also tell you if one of the batteries is bad.

As a rule of thumb: a battery healthy is full when the absorption rate is between 1-3% of its capacity. Lets say you have a 55AH battery then you would see the current drop to 0.5 - 1.5A at 28.8V.

Hi,

I am looking for a solid and reliable 24VDC MSW inverter for 120V outputting 1000W. I own a PowerBright 24V, 900W inverter which does a very good job but I recently recommended that same model to 2 friends and they both had a very bad experience: one was bad out of the box and the other died after a week of usage. So either there is a quality control issue or they did a new revision of the circuit board.

Any suggestions on good inverters?

Markus

I also think this a 'bad' idea but it looks like a town in Holland is now building a 100m long bicycle path to test the concept of solar panels in the pavement. Maybe that slight alteration into a bicycle path works better.
http://www.solaroad.nl/en/