Hi there, 

I have installed a 5KW Sunsynk, with 5.1KW BSLBATT and 6 X 455w Longi panels in a home with average daily consumption of 15KW based in Johannesburg.

 

Looking for experienced advice on how best to setup the battery charging timing from solar and grid during the day.

 

Is it best to use the battery overnight, stopping at 25% and then in the morning use the grid and solar to get it back to 100% and maintain it there all day for the night and use any excess solar power generated during the day to feed back to the grid and "reverse" the cost of using the grid to charge the battery? Does it definitely reduce your Eskom bill? Secondary question from this: Is this not the best way to use less cycles from the battery rather than charging and discharging bits and pieces on the battery all day, rather use the grid for any excess demand and feedback using the solar when available to reduce the Eskom bill?

 

Or is it best to charge the battery up from 25% to 50% then to 75% to 100% in steps during the day depending on demand patterns, allowing the sun, when available to do the heavy lifting on charging the battery while supporting your demand loads? Here you will use more cycles of the battery as once it has reached the new SOC, you could use the battery if demand exceeds, before kicking into charging to the next level again.

 

Hope that makes sense.

Hi NB,

My system and consumption is roughly double yours, so it may be applicable. I am almost 80% off grid, most days significantly more.

First step is to doubble check what is and what is not bypassed, i.e. that the CT coil is on the main incommer before any loads. Then allow export to load and prioritise load over battery.  Disable grid charge completely and enable time of use. Run down batteries to 20% overnight (you can increase this if loadshedding is announced), and step charge up during the day - I start late (after 9am, maybe even later in winter) and go up to 80% not 100%, to allow for headroom to assist with high demand times without using grid power. Despite this I average 0.9 battery cycles per day.   Remember the battery charge percentages are minimums - if there is low demand and excess solar it will go to 100% regardless of the settings.  Give it a go then paste pics of your setup and trends for more specicic advice.

Edited January 16, 20223 yr by Scubadude

1 minute ago, Scubadude said:

Hi NB,

My system and consumption is roughly double yours, so it may be applicable. I am almost 80% off grid, most days significantly more.

First step is to doubble check what is and what is not bypassed, i.e. that the CT coil is on the main incommer before any loads. Then allow export to load and prioritise load over battery.  Disable grid charge completely and enable time of use. Run down batteries to 20% overnight (you can increase this if loadshedding is aanounced), and step charge up during the day - I start late (after 9am, maybe even later in winter) and go up to 80% not 100%, to allow for headroom to assist with high demand times without using grid power. Despite this I average 0.9 battery cycles per day.   Remember the battery charge percentages are minimums - if there is low demand and excess solar it will go to 100% regardless of the settings.  Give it a go then paste pcis of your setup and trends for more specicif advice.

many thanks kind Sir!