100W Solar Panel & Charge controller Electrical Problem

[owen_a]

Hi everyone,

I have my 100W Solar Panel connected to my charge controller, and my 12V Leisure Battery connected as well. The problem I'm facing is that in pure daylight i'm getting around 12.4-12.0V but "+0.1-0.2" Amps. I have attached two images below showing the solar panel (brand new out the box), and the charge controller values which it is showing when in operation. I have no load as I have turned this off via the charge controller (It is digital).

Charge Controller WITH Values - here

Solar Panel - here

Solar Panel Technical Specification (Electrical Values) - here

Any ideas?

Thanks.

[Sunking]

Yeah it is behind glass and inside attenuating 90% of the current (power). Just as well put it in the garage and let it collect dust.

[russ]

Hi Owen - Have you tried it in direct sun? Not just behind a double pane window?

[owen_a]

Thanks. I brought it outside resting directly facing the sky on two chairs. I plugged in the charge controller and saw it was producing 1A at 12.9V. This still seems very low for what it is rated at. Would I see it producing a lot more power at its current rating if it was sunny? Or should it be outputting a lot more than the values I stated?

Hi Owen - Have you tried it in direct sun? Not just behind a double pane window?

I tried it in direct sun the other day and my 500W Inverter was drawing 12.3V at 5.5A when powering a computer alone with a 250W power supply. The battery information on the Charge controller was showing "12.3V AND -1.2A" during this.

[Sunking]

Depends on the state of charge of the battery. Put it in full sum and put a load on it of of say 200 to 300 watts and see what it does.

[owen_a]

Depends on the state of charge of the battery. Put it in full sum and put a load on it of of say 200 to 300 watts and see what it does.

Next time I have sun here in Britain, I'll sure give it a shot.

[Sunking]

Next time I have sun here in Britain, I'll sure give it a shot.

That explains a lot. Solar panels are current power sources and current output is directly proportional to sun light input. You Brits are not know for sun tans. At least not real sun tans. Last time I can remember hearing about a sunny day in Britain was May 7 1945.

[PNjunction]

Aside from the lack of a lot of sun, what exactly IS that charge controller and it's ratings? Are you using default options that may not be applicable to your setup?

And generally, a reminder that charge controllers usually need to see the *battery* attached first to get it's brain together, and then attach the panel last. Do it the other way around and sometimes controllers can go dumb. Just something to look into.

[thastinger]

Last time I can remember hearing about a sunny day in Britain was May 7 1945.

...unless you were German that is

[PNjunction]

Thing is, without knowing the load requirements we are shooting in the dark.

But to just have a go at it in the UK with limited solar insolation calls for LOTS of solar power, and if using a leisure battery, at least an AGM rather than flooded to take advantage of an AGM's greater charge acceptance. Time to get a decent charge is the enemy here.

That existing panel with a pwm controller is only capable of 5a charge under the best of conditions. If you only have 3 hours of solar-insolation per day (solar insolation being different from visible daylight as being the hours when sun is strong enough to actually do some good from a solar panel standpoint), we're talking 15a recharge ability per day.

And while this is an ultra-simple and not very accurate calculation, assuming you wanted to keep the battery healthy by not discharging it past 50% DOD each day, and getting to a full charge in 3-4 hours, then I'd be looking at a 35ah AGM battery max. If your existing leisure battery is larger than this, then like most of us when we start out we kill our batteries with "deficit-charge", ie never getting a full charge and thence walking the capacity down by sulfation.

Whether your loads will only survive for 15 minutes or 15 hours with a 35Ah AGM depends on how much current they pull.

Still, one can have a lot of fun with a quality multimeter watching this system. At the very least, add a simple quality charger like a CTEK MXS 5A charger for bad days.