Using MPPT 75/15 with Charger 12V/15

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brianor asked Jan 15, '19

Using MPPT 75/15 with Charger 12V/15

Hallo,

I have the MPPT 75/15 unit installed in my 4x4 and connected the the Auxiliary battery for solar charging (using a 100W solar panel) as well as to manage the load output. Since solar may not always be sufficient in high demand situations (and/or not able to charge via alternator when stationary), I plan on connecting a BluePower 12V/15A charger to the mix where camp sites may have 220V power.

If both devices are directly connected to the battery (with the MPPT providing solar power to battery), will there be any risk when the Charger is plugged in and also providing charge to battery? Will the MPPT detect this higher charge on the battery and then go to float mode (or switch off)? Any settings I need to make on Connect App?

Thanks

Brian

MPPT Controllers battery charging charger solar

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Answer 1 · 2019-01-15T09:53:35Z

Peter Polz answered · Jan 15, 2019 at 09:53 AM

It's generally no Problem to load a voltage source(Batterie) with different current sources (BatteryCharger, SolarCharger aso) at the same time

Until reaching absorbtion both will work, after reaching absorbtion the charger with minimal higher charge voltage settings will do all the charging and the others will stop charging or charging 0A. Thats no Problem, thats normal.

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Answer 2 · 2019-01-15T10:54:41Z

brianor answered · Jan 15, 2019 at 10:54 AM

Excellent, thanks for confirming!

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brad-australia commented · Feb 02, 2019 at 12:33 AM

Will be fine, what you could do, if 240ac is available is connect a 24v 5-10a power supply to the Pv input on the MPPT and it will do all the charging,

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sparks brad-australia commented · Feb 22, 2019 at 12:25 AM

There's a potential problem if the external supply is battery-ground-referenced, I think the solar input is designed for isolated ground-floating supplies (i.e. a solar panel) and I think I've read that you can't battery-ground the solar input low voltage terminal. Awaiting answer on this currently.

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john-farquhar sparks commented · Feb 24, 2020 at 02:09 PM

HI Sparks, Did you ever get an answer to this? I am proposing to doing exactly that. i.e. connecting a mains to DC power supply and solar panels into the PV inputs on an MPPT 75/15 SCC at the same time. I'm concerned if the PV inputs need an isolated-floating ground. I think that on some MPPT controllers which have a seperate "LOAD" output, the load terminals can't share the battery ground. so possibly this is an issue?

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