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Power variation from municipality


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Hi All

I have recently installed a 5kva Mecer inverter,  6 x 300W solar panels and 4 x 110AH Monbat batteries.

I have diverted the grid input into the inverter and from there it goes into my original DB.

The problem is that the municipal power comes in at 254V and the inverter output is 230V.

Can this have a detrimental affect on my appliances if i run my inverter on SBU and it switches from grid to solar / batteries?

Regards

George 

 

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I think you have to make a distinction between various appliances.

Most electronics won't care. They have switch-mode power supplies and will simply adjust their regulations when the voltage changes. Since most of them generate a lower voltage somewhere between 5V and 30V, and you're talking about not even a 10% change in voltage (which will be reflected on the low voltage side as well), I doubt there'd be a problem.

Heating elements similarly won't care. Your kettle will take 10% more/less time to boil the water, but the switch-over itself will cause no problems at all. Incandescent lamps will go dimmer or brighter, again no harm done.

The only thing I cannot be sure of would be induction motors, such as used in refrigerators. I doubt there'd be a problem, but don't quote me on it.

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You could of course configure the inverter to make 240V instead, to decrease the difference (I assume they are configurable for this?). Because most appliances convert the energy or otherwise rely on a total amount of energy (eg kettle will use more power and boil faster, but take less time, thereby evening out at the same amount of energy), it should have no detrimental effect on the battery discharge rate, but it will lessen the perceived shock effect when it takes a 24V jump.

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Thank you Plonkster.

It is specifically one of my fridges that i am referring to.

I had the compressor replaced 3 weeks ago (2 weeks before solar installed) and now it seems to have gone again...

There are plenty of people complaining about losing their appliances in this ineptly run town i am staying in.... At least 3 power failures a month....And Eskom interruptions set to commence on 20 November due to non payment.

Thanks for the tip on increasing my inverter output.

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I speak under correction, hopefully someone will either back me up or shoot me down. Far as I know induction motors are more easily damaged by low voltage conditions than the other way round, though of course serious overvoltage issues will eventually damage them (that is of course easy to prove: It will happen some time before you reach 1000V, for sure :-) ).

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2 hours ago, plonkster said:

I speak under correction, hopefully someone will either back me up or shoot me down. Far as I know induction motors are more easily damaged by low voltage conditions than the other way round, though of course serious overvoltage issues will eventually damage them (that is of course easy to prove: It will happen some time before you reach 1000V, for sure :-) ).

I learned this many years ago in the printer industry. Voltage below 190V would damage printers quickly. 

 

@GVC The Mecer interver will output a fairly stable 230V volt even if the input fluctuates. It can take between 90V and 280V (lower and upper limits) on the AC input side. Your fridge should work fine on the 230V being supplied from the inverter. 

I suggest you install (or have installed by a qualified electrician) some surge arrestors before, and after the inverter. They're much cheaper to replace than the inverter or a fridge motor. 

And check the voltage on the fridge plug point, even if the inverter supplies the power, there could be a cable fault and the plug supplies "dirty" power. 

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Thanks guys,

It could of course be a defective compressor that was installed, it does come with a 18 month warranty.

SilverNodashi, thanks for the tip. I will definitely be installing AC surge arrestors on the AC side and will check the plug point as well.

 

 

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So the technician came and found that he had cracked some pipe when he crimped it 3 weeks ago and only the gas escaped...pheeew false alarm

Thank you for the suggestions which i will be implementing on my solar system asap.

PS. Is there any way i can log my pv output wattage as i see WatchPower only logs the voltage?

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