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Standby current of SmartSolar charge controller MPPT 75/15 outside spec?

On my recently installed SmartSolar charge controller MPPT 75/15 I measured a standby current of 30 mA, whereas the datasheet states 25 mA at a supply voltage of 12 V.
I also observed electric sparking when connecting the charge controller to the battery, indicating a pretty high peak current even beyond the measured 30 mA.

I would like to know, if my MPPT might have e. g. internal leakages and should be replaced, or if this type of MPPT is being delivered into the market even with current consumption higher than specified.

MPPT Controllers
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Stuart avatar image Stuart commented ·


Strangely enough I have just purchased an MPPT 75/15 solar charger and am awaiting delivery. It may well be that there are large electrolytic capacitors on the battery side or in front of a switching mosfet to smooth any voltage ripple. If the capacitors are discharged fully when you make the battery connection that would explain the spark. You could test this by connecting it just to a battery then disconnect and reconnect again. If there is no spark then my money is on the capacitor theory.

With regards to the current consumption unless it gives a specification such as 30ma at 13.8V ect it is hard to know if that is out of spec. This reading will have been taken under ideal test conditions normally with the controller running in optimum conditions and settings so I would take it as a ballpark figure unless you have the data to replicate the conditions that it was measured under including what was used for the measurement and was it calibrated ect there is no way to be sure.

I am sure someone with far deeper knowledge of Victron equipment will be able to give a more detailed explanation. I am new to victron equipment myself having used EpEver charge controllers for a few years I have yet to play with the kit on a bench and discover all its quirks and how it performs ect.

I hope that is of some help until someone with a more in depth knowledge can reply.


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Paul B avatar image
Paul B answered ·

Stuarts reply is pretty well on the mark.

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plids avatar image
plids answered ·

Thanks for the clarification, Stuart. Of course it's a problem to do the measurements right at 12 V. Once the battery will be discharged to nominal voltage I will measure the current again. Higher current consumption at a higher supply voltage could be the reason.

Sparking however is observed even if the battery is disconnected and reconnected right after. I did this by pulling the fuse and re-inserting it. Don't think, that large capacitors will be discharged that fast.


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