ana-carvalho avatar image
ana-carvalho asked

MPPT 100/20 load output reading current wrong?


I am using an MPPT 100/20 charge controller with a DC/DC Converter and a pump at the load ouput. Although this load is asking for a maximum of around 17A from the controller, the reading at the controller is 20A and it disconnects.

Could this be a defect from the product? Is it perhaps reading the current wrong or it has too high sensitivity?

Thank you for your help,

MPPT Controllerscurrent limit
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1 Answer
JohnC avatar image
JohnC answered ·

Hi Ana.

The first thing to ask is where your 17A is being read from? Confident it's correct?

'Sensitivity' may well come into it too. If you're reading the '20A' as a peak, then it may well have picked up a 'spike' and tripped. Or a start load you mightn't notice, but the mppt will.

Perhaps you're just operating just a little too close to the limit? The easy workaround is to take your load direct from the batts. In practice, this could be just a matter of switching the LOAD+ wire to the BAT+ terminal (doubled in).

Sure you'd lose the low V protection, but properly wired in with a relay could sort that.

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ana-carvalho avatar image ana-carvalho commented ·

Hi John, thank you for your answer.

Connecting the load directly to the batteries could be an option. However, if I connect it directly, will I be able to power the load with the PV?

What I mean is, if it's connected directly to the batteries, that means the PV will charge the battery first and only after will it power my load, correctly? Or will the load take the needed current and the batteries would take the excess until full?

Thank you very much for you help!

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JohnC avatar image JohnC ♦ ana-carvalho commented ·

Yes, it'll work fine. The mppt will keep going, and supply the load first before the batts. Providing you don't put the load on different batt terminals to the mppt (please don't do that).

You won't see a load reading separately though, just that of the mppt's output feeding both.

Hope this doesn't spoil the party, but you don't have to step up too much further in the Victron mppt range to see no load terminals provided at all. Nor do I see it as a fault, 'tis by design. 'Specially for you big power users.. :)

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