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Bypassing the solar charge controller?


meyerwh
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Hi everyone,

i have recently started with my own PV installation and searched the components via internet and helpful websites.

I figure out now, that i am learning it the hard way by combining components without being aware of the consequences.

Ok, enough intro.

I have two 12V 120W solar panels connected in parallel (directly on the terminals) and routed one set of cables to an 30A 12V Ecco solar charge controller. The controller has one set of terminals for the solar panel(s), one for the battery/batteries and one 12V 30A for DC loads (which i am not using). I connected two 12V 120Ah batteries in parallel to the controller and to a 12V 3000W pure sine wave inverter. I put a 16A breaker between the controller and the batteries it is loading. I also put 2 breakers after the inverter (63A earth and 16A load) before connecting to a set of 220V plugs.

The problems: the inverter draws constantly 2A on standby (no load). It is not written in the manual and i found it eventually on the internet. I have an Owl ampere meter which works via induction (don't ask me more) via magnet placed around the live wire (it is very useful and saves data every minute which can be downloaded). The Owl confirmed 2A usage at no load. Considering no solar power for 15h at night, i am loosing 30A of my battery power. I checked with the Owl the amps going from the charge controller to the batteries and found and average of about 6A (depending also on state of batteries and whether the inverter is on or not). Well, that means i would use the whole day meaning 5h sunlight just to recharge what the inverter used at night! Ok, i can switch it off but that is not the idea of the setup...

Next surprise (another praise for the Owl): the controller shuts down the power supply to the batteries when a load on the inverter exceeds 10A (including the usage of 2A of the inverter itself) drawing from the batteries! This means roughly, a constant load of 120W would prevent the controller from loading the batteries while the load is on! I could check this with a desk halogen light with two settings, one below 100W and one of about 150W: while the controller keeps on charging at the lower light setting, it stops loading the moment i switch to the brighter light setting.

Finally my question:

Can one 'trick' the controller by letting him 'see' never more than a 10A load on the inverter? How can one manipulate the live wire from controller to battery to achieve this? Is there a way to bypass this function maybe by changing settings? Or is the controller not functioning the way it should? Something wrong with my setup?

This is utterly frustrating... i hope someone has an idea.

Cheers

Wolfgang

 

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Hi

 

 

The inverter must be connected to the batteries and not the charge controller. The charge controller's load out cannot handle the inverter load.

 

Hope this is going to help solve your problem.

 

Regards

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Hi

 

 

The inverter must be connected to the batteries and not the charge controller. The charge controller's load out cannot handle the inverter load.

 

Hope this is going to help solve your problem.

 

Regards

Hi Regie,

 

thanks for your reply.

 

the inverter is connected to the batteries. I think the problem is, that the charge controller is, too. So, when the inverter draws +10A from the batteries, it will also draw it from the charge controller through the wire from battery to charge controller.

 

Regards

 

Wolfgang

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What is your plan with this system? Just a backup power supply or would you like to ues it 24/7?

 

Just remember @ 12V and 3000W you looking at 250Amp!!!

2A at 12V is only 24W, so that is really low for a 3000W invertor on standby load. It will never draw Zero amps, ok.

 

I suspect your controller is a really cheap PWM unit from a firm in JHB selling cheap crap solar suff on the web :D

Perhaps look at connecting your solar panels in series, to output a higher voltage.

Perhaps when you draw power, the voltage drops too low and the solar controller shuts down?

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What is your plan with this system? Just a backup power supply or would you like to ues it 24/7?

 

Just remember @ 12V and 3000W you looking at 250Amp!!!

2A at 12V is only 24W, so that is really low for a 3000W invertor on standby load. It will never draw Zero amps, ok.

 

I suspect your controller is a really cheap PWM unit from a firm in JHB selling cheap crap solar suff on the web :D

Perhaps look at connecting your solar panels in series, to output a higher voltage.

Perhaps when you draw power, the voltage drops too low and the solar controller shuts down?

Hi Wetkit,

 

hehehe, you are right about the cheap crap solar stuff. It is rated at 30A 12V DC load but battery loading only 10A at 12V and 20A at 24V.

 

Actually, i only want to use it to power my garage doors and roller shutter doors: power consumptions are 450W, 300W, 3x200W. These roller shutter doors only work with pure sine wave. A 1kW sine wave inverter would be to small, and i got also a rather cheap (R10,500) 12V 3kW pure sine converter from AC/DC.

 

So, actually, i would not need to worry but if i like to add a 24/7 load, i found it just disturbing that the solar charge controller stops loading if the inverter drawing more amps from the battery than 10A. It does not matter for opening/closing garage doors as this takes only 30s.

 

Connecting the panels in series (and then also the batteries, right?) is a good idea, thanks. Just wondering what to do then with my 12V inverter? (it cannot handle 24V) Can is just connect it to one battery instead of the two which are connected in series?

 

My other idea, forgive my ignorance about electronics...: can one not get a 9A relay which switches then a new circuit from controller to battery with a higher resistance??? In this way, even if the inverter draws >10A, the controller will only "see" much less and continue loading... any comments?

 

Lastly, maybe i should not waste my and your time and just buy new equipment... just not happy about spending lots of money again.

 

Regards

 

Wolfgang

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Connecting the panels in series (and then also the batteries, right?) is a good idea, thanks. Just wondering what to do then with my 12V inverter? (it cannot handle 24V) Can is just connect it to one battery instead of the two which are connected in series?

 

 

No, only do the solar panles in series.

This should give you 24V, but your solar controller should then reduce it down to 12V for the battries.

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