Upgrade to next stage - What is my options?

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John asked Dec 31, '21

Upgrade to next stage - What is my options?

Hi,

I have been using the following configuration for some time but now my requirements have become larger. Can anyone point me in the direction as to what I would need now to upgrade for my newer requirements please.

Currently: Daytime requirement approx 180Watt per hour. Nighttime is approx 180watt per hour for about 3hours.

I use 4 solar panels up to 260W each (panels are 51.25Vmp 5.07A IMP) currently configured in parallel being used. I have two more of the same panels not currently being used.

2 x 120AH deep cycle batteries in parallel for 12Vdc.

1 x 300W 12vdc - 240vac inverter.

1 x Victron SmartSolar 75/15 Solar charge controller.

New Requirement:

Up to 1500 Watt max required. This will need to be for Daytime using a 700W air conditioner plus still about 180W for the computer and to be able to run for about 6 hours nighttime occasionally using the 700W air conditioner along with the computer of about 180W as well.

I am pretty sure a 1500W inverter will work for my power needs, but I am not sure what charger and battery bank size Ah I will require to ensure the batteries always get fully charged through the daytime as to allow for approx 6 hours use in the night time.

Any ideas and suggestions appreciated, please.

John.

smart solar charging behaviour

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Answer 1 · 2021-12-31T14:08:58Z

kevgermany answered · Dec 31, 2021 at 02:08 PM

You probably need to do a better total power audit. Otherwise size for 1500Wx24H. But that is probably too much, depending where you are. You need to allow for reduced panel output in winter as well.

Look at 24 or 48V batteries, this has a big effect on current and thus wiring. What voltage is the A/C? Guessing it's mains, but.

Do you want to retain or replace existing batteries? Either way you need more. If you retain, you'll have problems with unequal charging etc. Better to replace.

Your existing panels can remain connected in parallel for a 24V system. They won't handle a 48V system unless you replace the old MPPT. Makes it tempting to add a new bigger MPPT that can handle all the new panels you will need and run a 24V system. Keeping old panels on one MPPT and new panels on a new MPPT avoids panel incompatibility between old and new.

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