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peter-3 avatar image
peter-3 asked

35w - 16w = 136w ?

screenshot-2022-07-29-191752.pngHi, trying to workout the logic of dc loads , So my 2 mppt controllers are generating only 35 watts now it is starting to go dark , my shunt says that 16 watts is being to the battery which means that 19 watts is being used somewhere , so why 136 watts ?

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1 Answer
nickdb avatar image
nickdb answered ·

Have you got a wiring diagram? Chances are something is bypassing the shunt.

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peter-3 avatar image peter-3 commented ·
I've checked that I haven't made a mistake , Battery to the shunt , the other end of the shunt to a busbar with the mppt chargers and inverter , So all loads have to go do through the shunt .
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marekp avatar image marekp peter-3 commented ·

@peter@peter247.co.uk

Are you sure that those three measurements are from the same moment in time?

Also where is the power needed for inverter to run.

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peter-3 avatar image peter-3 marekp commented ·

it is now dark and their isn't anything coming with the mppt controllers 0 watts , the shunt says -13 watts which is my inverter , but the dc loads now say 131 watts .

and it's been over 130 watts for over a day with a 13 watt real load , if you look at the dc load graph it's steady with out any load .

But the historical data says 0.02 kwh each hour so wouldn't that show 0.13kwh if it was monitoring that load from the battery or solar ?

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marekp avatar image marekp peter-3 commented ·
@peter@peter247.co.uk

How is this DC load measured?

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peter-3 avatar image peter-3 marekp commented ·
You tell me ?

The battery to the shunt ( to battery ) from the shunt ( to load ) to a busbar with controllers and my 24v 1200va inverter.

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marekp avatar image marekp peter-3 commented ·
@peter@peter247.co.uk

Apart from Inverter do you have any DC loads?

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peter-3 avatar image peter-3 marekp commented ·
no only the inverter is a load , but where would this wattage come from ? , it can't come from the battery or mppt charger ?
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