Assistance on inverter requirement

[TheChamp]

The Synapse inverter plus two 180Ah omnipower batteries, all for under R16500.

BATT 12V180 OPR

12V 180AH Rechargeable Deep Cycle AGM/GEL HybriD VRLA Solar Battery 483 x 170 x 240mm 45KG - Omnipower Overview Features Specification Nominal Voltage 2V Nominal Capacity 80AH Size 483 x 170 x 240mm Rechargeable True Downloads Datasheet Download User Manual Download

www.communica.co.za

 

[Dairyfarmer]

any idea of what size inverter we’d need to see us through minimum 4hrs of load shedding ?

I have a whole thread on setting up my inverter. https://mybroadband.co.za/forum/threads/inverter-and-batteries.997062/

You just need the following formula:
volts x Ah / watts / 2 x pf = hours

Volts is your batter voltage 12, 24 or 48
Ah is the Ah of the battery 7, 9, 100, 200 , ....
watts is your load
2 is there to stop your depth of discharge below 50%
pf is your power factor or how efficient your inverter is. 85% or 95%

So if you have a 12v 102Ah battery, your load is 500w and you have a pure sine inverter:
12 x 102 / 500 / 2 x 0.95 = 1 hour 9 minutes
So for 4 hours you would need 4 batteries connected in parallel.

You need to physically measure what the appliances use. You need to know the maximum load, so use a Kill-A-Watt type device to measure the usage over a few days. It is important that you plan that ALL the devices are running all the time at full draw.

 

[Steamy Tom]

yeah, wattage requirement is purely based on what i found on the actual supplier website (eg. Samsung Q80 65" uses 200 watts.....) etc.... and that extract per product is what i found everywhere

those numbers are seriously wrong dude, you are setting yourself up for failure. there should be a sticker somewhere on all of the appliances, look for it, on the fridges they are often inside rather than on the back or side. i would expect the fridges to be more like 400W(peak) with a higher start up draw and the freezers also.

the tv is about right i would say though.

 

[Speedster]

those numbers are seriously wrong dude, you are setting yourself up for failure. there should be a sticker somewhere on all of the appliances, look for it, on the fridges they are often inside rather than on the back or side. i would expect the fridges to be more like 400W(peak) with a higher start up draw and the freezers also.

the tv is about right i would say though.

Best option is to make the effort to measure the appliances with a kill a watt / effergy.

 

[Alton Turner Blackwood]

I really don't think that your freezers use only 27 Watts each...

Even so, a good idea would be to not connect them to the inverter because it takes more than a day for a freezer to defrost

 

[johndoe1983]

yeah. go

Even so, a good idea would be to not connect them to the inverter because it takes more than a day for a freezer to defrost

good point.... they told us when we bought the fridges/freezers they will last some time before defrosting during load shedding (especially the bosch ones), unsure of the Samsung... but i'll rework it. 1 moment

 

[Academic]

3000 kva 48v victron inverter and 5kwh lithium iron battery for R70k in February. Hope that helps as bench mark.

 

[Speedster]

yeah. go


good point.... they told us when we bought the fridges/freezers they will last some time before defrosting during load shedding (especially the bosch ones), unsure of the Samsung... but i'll rework it. 1 moment

If you knock off the fridges and freezers you're at under 500W. That puts you in Mecer 720W game, and you'll need 0.5kwh of usable battery per hour. At 12V that's 42Ah per hour (remember that lead acid batteries only give 50% of their rated capacity).