I recently installed solar charge controller and solar panels to the inverter battery system. Here inverter also contains battery charger and other components.

So now instead of connecting inverter directly to grid power,it's connected to solar charge controller.

Inverter power plug is now connected to power output of solar charge controller. So solar charge controller decides when to give power to inverter for charging battery through grid power and when to charge battery from solar panels.

During day,solar charge controller mostly charges battery from solar panels when required solar is available and does not give power to inverter,so inverter stays on backup mode.In this way during day,solar panels charges battery and inverter discharges DC to AC providing power to appliances.

During night, solar charge controller gives power to inverter.So inverter is now in charging mode and charges battery while powering appliances directly from grid power and switching to discharging battery DC to AC when grid power is not available.

So how to stop battery charging process AC to DC through inverter from grid power in the inverter during night.

Inverter details : 12V 1450VA https://www.exideindustries.com/products/home-ups-system/exide-inverterz-gqp.aspx

Battery details : 200Ah tubular https://www.exideindustries.com/products/solar-batteries/tubular-solar-batteries.aspx

Solar panels : polycrystalline solar panels 600 Watts.

Solar charge controller details : Pulse wave modulation (pwm) 40 Amperes. Similar to this. https://www.amazon.in/UTL-Solar-Charge-Controller-Hybrid/dp/B073TJ1GR5/ref=mp_s_a_1_2?dchild=1&keywords=pwm+solar+controller+40&qid=1610387855&sr=8-2

Here is the daigram showing this setup.

Here is the daigram showing this setup


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    It would be a setting in the solar charge controller (if it exists) Commented Jan 11, 2021 at 19:06
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    @Voltage Spike This inverter has 2 modes. 1. When grid power is available, battery charging happens,also grid power is supplied to appliances. 2. When grid power is not available, inverter discharges power from battery and supplies to appliances. So how can that be a setting on solar charge controller?
    – codewiz
    Commented Jan 11, 2021 at 19:17
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    I see that they are separate, what you would need is to put a relay to shut off the mains power to the inverter (if it still can function from only battery power). You could just buy a simple smart relay or timer and use that to switch the inverter on and off with daylight. Commented Jan 11, 2021 at 19:23
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    If the solar charge controller doesn't support this feature (which it obviously doesn't), then you just simply won't be able to do it, simple as that. Nothing short of building your own charge controller circuitry will allow you to do this, because it's a really complex thing to do (the controller would have to "top up" the charge provided by the solar panels from mains). So this question really can't be answered in the scope of this site.
    – CoolKoon
    Commented Jan 11, 2021 at 19:23
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    Your solar charge controller, which you call a "Solarcon" for some reason, is the heart of your system as you can see from the diagram. From your link it is actually a UTL SMU122440. A quick web search shows that it's only sold on flea market junk sites such as Snapdeal, Amazon, Flipkart, desertcart, etc. (Amazon used to be respectable). So there may be a serious quality problem, and especially, a big support problem. That unit is doing a very big job. Commented Jan 11, 2021 at 20:30

1 Answer 1


UTL`s SMU has the capability to charge a battery that goes in deep discharge condition. It can charge the battery if the battery voltage during discharge drops up to 8V per battery.

It uses four stages to charge the battery i.e. Boost, Absorption, Float and Equalization.

This feature protects the battery from being over charged.

Read your manual how to set these thresholds.

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