Solar Panel output

I think you'll find that if you connect the unit to the battery the voltage will quickly drop to the proper level. The 20 volts would be a "No Load" voltage I imagine. That is with nothing connected to the output, other than the voltmeter.

uys

I am not a sparky either but this does not make sense.
20V is what it reads if there is no controller!
If I measure my V after the controller with no load it is 14.1V (which is the preferred laod for some batteries)
CJ

Are you sure you have a regulator attached to the panel. Perhaps you just have the output junction box? Open the cover and if there is just 3 diodes in there, its just the solar cells junction and not actually a regulator. Without seeing what you have, I would put money on there being no regulator.

Cheers

Captain

Tony Z

I have a 120 watt folding momocrystaline panel, but could not figure anything out, at first, because I was pulling up, setting up camp, putting out the panels, then attempting to measuring panel output.
Der me,.... Battery fully charged after driving most of the day,therefore would not accept from panel....conclusion, panelmworkinf fine
Still not happy, as panel only showing a series of blinking lights.

But wait, we have Technology....
Enter the Powertec MP3129 controller, hooked it into the system, disconnected the $10 controller, that came with the panels.

It has a digital display, and cycles between, PV Voltage, Battery Voltage, State of charge, Amps being delivered to Battery, and a heap of other things thet confuse me a little

Now I know exactly what the panels are doing, and when working, the panels (most I have seen from controller) can pump in 3.5 amps, and run my Engel, and keep the battery topped up.

Works a treat, amd my knowlege of solar charging has gone up from nill, to just enuf to know what is going on, sort of

Cheers
Bucky

with some of those 12/24 volt controllers the connection sequence is critical, make sure you connect positive then negative, to disconnect reverse process, eg negative then positive.
If you have the option connect to battery first then panels.

Hi All,
Just connected the solar panels to the batteries and put a multimeter on it and it read 13.1v on load taking reading of the clamps, then I checked the battery charge (disconnected)and it was 13.1 must be full charge or near to.
Hope thats ok
Thanks for all your help
Tony Z

Hi Tony, I have also just bought a 160 watt folding solar panel which came with a cheap ($14) regulator. Was not happy with this cheap reg so I bought aN MPPT regulator and all is working brilliantly now.

If you read the output of the panels they will often show 20 volts on an open circuit. i often check mine on open circuit and the open circuit amps as well with a cheap ($9) multi meter. The output of the reg will be somewhere near the 14 volt mark. and should get around 10 amps into a well drained battery. As battery voltage rises so the amps will drop back.

Unless your batteries are low you will get dissapointing readings as the regulator senses the battery is full and shuts down the input accordingly. This is normal but can be frustrating when we first get these things as we are looking for significant outputs from our newly acquired gear.

My advice is get a battery that is down quite a bit, say around 11.5 volts and try your solar on that and take some readings. You will be reassured and pleased you spent the money. This has been my experience having just gotten into solar in the last 3 weeks. My cousin down on the central cost did exactly the same thing as I have done and we have been comparing notes daily and this is what we have found. Don/t be disalussioned as it will all come out in the wash, so to speak.

The main thing is gat a good MPPT regulator. We each got one in from China for about $100 landed at our respective doors.
Hope this helps.
Bruce.

Hi Bucky, i knew nothing about solar 18 months ago either. I have just fitted a REDARC 1240 DC-DC Charger. Best move so far. You need to fit a switch to select either Solar or Vehicle charge and away you go. A bit exxy but peace of mind camping. Only other option that works that i know of is the REDARC BMS, but they cost twice the price of the 1240.
Good Luck
Macca.

Tony Z ,

Best thing to do is connect it to your batteries with a multimeter across the battery terminals -- If it goes up from your 13.1 to around 14.2 and stays there then it is fine .. IF however as I suspect it will continue onwards and upwards to a bad voltage ( disconnect at 15V if it does and then change the controller .)



Cheers

Steve