New member in southern spain - simple solar is not working how i imagined. Any ideas?

[James Jupp]

Hello everyone, after watching lots of videos on youtube and doing a bit of research, i took the plunge last summer and invested in a simple solar set up.

Theres a 200w panel on the roof of my shed, the charge controller is the 'sun yoba' 40a mppt 12v/24v that came with it. This is hooked to a 90a? New battery.

I was running 50w of led but ive changed to 2x 7w/12v and 3x ?w/12v strips (i think 2w each?) So 20w total.

Then i have a small aliexpress inverter running a small 30w/240v fan.

It all runs great during the day, the CC shows 99% / 14.3v

The problem is when it gets to 19.00 ish and theres no more sun, i will only get maybe 3 or 4 hours out of it, just running the 20w of LED lighting

It doesnt seem to run for very long until it drops to 50% battery (CC display). Is that right? Its a deep cycle 85a battery i think (i will check, its tucked away at the bottom of the shelving to keep it cooler. Inside the shed is 30 degrees right now at 13.00 this saturday 30th of may.

If anyone has any ideas for me that would be much appreciated.

 

[James Jupp]

All im looking for is to charge my power tool batteries, my phone, a small radio, the lighting. Im not even thinking of running power tools from it. I have a 240v line as well for that.

 

[boondox]

James, it sounds like something is wrong with the system. You don't say what kind of battery but I am going to guess a lead acid battery of some variety. You say it is 85 amp hours so that works out to 1,020 watt hours of storage. If it is a lead battery you don't want to pull more that 500 watt hours out of it or you will wear it our quickly. So, if you are running 20 watts of LEDs for 8 hours that will consume 160 watt hours which should be no problem for your batteries. You say you get 3-4 hours so that should only be 60-80 watt hours consumed.

So what to do? First, using a meter, find out what your actual power usage is. Monitor the battery as it charges, do you see the proper stages of charging? (bulk, absorb, float) Get the battery fully charged, disconnect everything except for your LEDs and watch the voltage. My guess is that your battery may be toast but finding out why before you buy another would be a good idea.

 

[James Jupp]

Boondox, hi, thanks for the reply.

The battery is 13 months old, deep cycle 85a lead acid solar battery (bought from marketbattery.com ) so if its goosed its going back !

Im hoping it is a bad cheap CC rather than the battery.

I will look into the specifics in the morning, i will have to research bulk, absorb & float tho.

Every morning, by 11am the CC shows 99% charged.

 

[James Jupp]

I turn everything off if it ever shows 50% on the CC - i know not to go under that.

 

[boondox]

Get a voltmeter so that you can measure what is going on. Something ain't right. Bulk, absorb and float are the three basic stages of charging for a lead battery. Here is a site with good basic info:

Battery University Homepage

Battery University™ is a free educational website offering hands-on battery information.

batteryuniversity.com

Either the battery is shot or the CC isn't working right or both. Quite often one leads to the other. Only way to know for sure is to measure it yourself.

 

[James Jupp]

12 o clock and 27 degrees, the CC says 99% and 14.5v.

I've put a single LED 12v/7w and the fan on, (With inverter) and it drops to 13.6v and 0.0a of draw (inverter is conected to the battery not the CC).

Im getting 2a going into the battery, and within 10 seconds its over 14v and at 99% again.

Perhaps im reading this CC wrong, i thought the display showed sunshine - panel - amps into the panel/panel temp - battery volts - amps coming out/% of charge left in the battery - load on/off ?

Right now after a minute or so its saying 1a in & 26 deg c, 14.2v -14.6v and 99%. It will sit like that all day - until the sun goes over then the % just keeps dropping because nothings going into the battery.

I notice that sometimes the battery fluctuates between 13.9v and spikes to 15v -15.3v : is that normal? (Pv off is set to 14.3v)

 

[James Jupp]

Is it right that im only getting 1-3 amp into the battery from a 200w panel?

After 1.5 hours (its overcast/storm forcast) the battery was down to 13.9v and it said 87%. So i turned off the inverter & fan.. Its climbed back up to 14.2v-14.4v and 99% in a matter of 60 seconds with 0-1a going in.

 

[spoofer]

I think it's your battery. 85ah will not last long....especially if you don't know your watt use.

 

[James Jupp]

Now theres no sun, nothing is going into the panel, the 7w/12v light is still on (theres nothing else being used/plugged in) and the battery is at 12.8v and 58% i dont know whats going on.

 

[James Jupp]

According to the chart on engerymatters (referenced above), over 12.7v is 100%, 12.4v is 75% and 12.2v 50% - under that is bad, - it just doesnt match with the readings from the sun yoba CC that i have?

Perhaps i havent set up the CC correctly and it thinks i have a 24v system or something ?