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Posted

Hi all, it's been some time since I have posted here as my 3Kva off grid system seems to be ticking away nicely and doing what it is supposed to.

I have now been asked by a friend to help with installing a system at his workplace, to try to offset the high Eskom charges.  He has bought an Axpert RCT-AXMK2-5K-48V and is in the process of buying 10 x CNBM 6P330, 330W panels.  He already has 4 x 102 Ah batteries which he intends to use in the meantime while he saves for a Pylontech.  

His intention is to run off solar during daylight hours and is then happy to use Eskom at night when his load is very low.  On average his daily consumption is about 15Kw (08:00-16:00) and less than 1Kw (16:00-08:00)

Would such a setup work, and if so what does it entail to install?  Your advice would be greatly appreciated.

Thanks, Peter

Posted

15 kW? Or 15kWh(Eskom units)? Either way my layman's 2c worth of gut feeling is that his 10x330W panels are not going to really meet his goals if the Axpert doesn't blend power sources. Either way the instantaneous power consumption should be too high most of the day compared to solar production to really see a big benefit. Shortish window around midday expected. on average. I'm saying this without knowing his power usage exactly through the day, but would recommend plotting his daily power usage against expected daily power generation to see exactly how much and for how long solar production exceeds consumption.

Posted
8 hours ago, dax021 said:

His intention is to run off solar during daylight hours and is then happy to use Eskom at night when his load is very low.

I’ve got more or less a similar setup but my batteries were 120AH gel’s with six 330W panels and I managed to run just on solar most days but that’s if weather permitted. My average load is between 250W to 750W and the occasional kettle boiling. That seemed to be ok, The problem comes in when using things like dishwasher or a geyser that can draw 2.2KW for say a half an hour or longer, that is what will force your inverter to switch to utility due to low battery voltage. It will also reduce the battery lifespan as they will probably sometimes discharge more than 50% at high AH rating.

I would think splitting the DB’s essential loads to run on solar, and keep the heavy stuff away from those 102AH batteries unless you are prepared to replace batteries every year.

I recently upgraded to a pylontech battery from the the old gel’s (the gels behaved for about 15 months and than lost power) I manage to run quite successfully on solar everyday but I now keep the heavy loads away from the pylontech, my battery seldom goes below 60% it only happens when I also use the inverter at night. I am planning on adding more panels but I guess it might be a waste until I also add another pylontech. Thats just my bit of experience.

 

Posted

Thanks so far.  Yes, I should have said KWh.  His heaviest load will be a kettle, but I'm sure he can change this to gas.  Otherwise his load is an office with about 6 or 7 staff.  It is a computer retail/repair outlet.

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