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vanholladyke avatar image
vanholladyke asked

My solar MPPT shows no evidence of charging the battery?

Before I start; I apologise for being a complete moron when it comes to electrics. I must have missed that physics class at schooled. I’ve got an MPPT 75/15 with a 150w solar panel and a 110ah battery, all brand new and installed by the company who converted my van. The only real load I have had on the leisure battery is the thermo electric coolbox, which is dc load Input rated at 3, 91 A. Admittedly, the ambient temp has reached 35 degrees C daily last couple of days, so the coolbox has been grafting. However, the leisure battery died last night whilst showing around 13.5V on the app. No power to the coolbox, not even enough to turn on the lights. Now I accept that my solar isn’t big enough to power that fridge forever, especially in this heat, however the app not showing any evidence of the solar yielding any power confuses me. Surely it was grafting to keep the battery charged all day?

Ive checked the fuses, all good.
any help, guidance or layman explanations are hugely appreciated!


regards,

Jim

MPPT SmartSolar
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4 Answers
Justin Cook avatar image
Justin Cook answered ·

Hi @VanHollaDyke,

Start by checking the wiring from your controller to battery; the history shows a lower minimum battery voltage every day than is actually possible, so this is strongly indicative that you have either a bad connection, a bad breaker or fuse, or something connected incorrectly... now it's just a matter of tracking down what exactly that is.

If you have a bad connection or a half-blown fuse (which can and does happen) or perhaps a bad/knockoff breaker then the controller won't be able to pass any current through to the battery... and you don't want it to, either, since passing current through a bad connection is an invitation to disaster.

Run through your controller-to-battery wiring, checking every single crimp, fuse, breaker (make sure that they're recognized-brand breakers or fuses like LittelFuse, Zeeman, or Bussman), connection, and etc and I'm confident you'll find the source of the problem.

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dgnevans avatar image
dgnevans answered ·

Also check to make sure you have Charge enabled on the mppt.

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vanholladyke avatar image
vanholladyke answered ·

Thank you both for your answers. @Justin Cook - Bay Marine Supply USA In particular for your detailed response. I’ve just got back home and managed to check out the full circuit. I can’t find any loose/dodgy/blown/disconnected bits. It all seems connected securely and no errors on the LEDs or the app. I’m completely stumped. I would be tempted to say that it is just working very efficiently, but the history in the app tells me otherwise.

Could I be missing something? I notice on the front of the setup I have a fuse box with three blade fuses in, and LEDs that indicate when the fuse is blown (evidential when the fuse is removed). Fuses 1 and 2 indicate the red light when I remove the fuse, but fuse 3 doesn’t show the red light when I remove it. Could this be an indication of something not set up correctly? I can’t work out exactly what these fuses are for mine. Stumped!

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klim8skeptic avatar image klim8skeptic ♦ commented ·

Have you checked the fuse in the bottom of the Mppt??

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Alexandra avatar image Alexandra ♦ commented ·

@VanHollaDyke

Are you able to check the polarity if the pv cables?

The most common mistake is they are the wrong way round.

Has the unit worked at all?

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vanholladyke avatar image vanholladyke Alexandra ♦ commented ·

I haven’t seen it working at all. My history on the app says not. I’ve only had it about a month and no readings at all, until now I have just removed The fuse on the bottom and waggled a few wires to check they are connected and I’ve noticed the following on the app. Is this sign of it working? It’s not a sunny day...

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marekp avatar image marekp vanholladyke commented ·

I heard that you need minimum 5V more from panels than the battery voltage for charging to start.

https://www.youtube.com/watch?v=EVAvRs32TiE

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vanholladyke avatar image vanholladyke marekp commented ·

Very cloudy day unfortunately. I’ve put a demand onto the battery with lighting and night heater. I’ve now got fluctuating around the following image. This is certainly more activity than I have ever had before on the screen. Is this a good indication it is functioning?

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vanholladyke avatar image vanholladyke vanholladyke commented ·

Success??!

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marekp avatar image marekp vanholladyke commented ·

Success will be when your battery voltage stops going below 10.5V.

Do you have second source of charging this battery?

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vanholladyke avatar image
vanholladyke answered ·

I think the situation may have been resolved. The readings have been how I would expect them to be, for the last few days since checking all connections are good. Thank you all for your responses



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