Purpose of Load Output?

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brokenfeet asked Jul 11, '19

Purpose of Load Output?

Hi!

I have a very simple question about the load output of the Smart/BlueSolar MPPT 75/10.

My solar panel is not permanently installed. I only connect it, when the weather is appropriate. I currently have all my load connected to the battery directly (with switches). See my electrical plan attached.

Will the load output work, when there's no solar panel connected? Why should I connect to the load output at all? Is there a limit of the current that this output can provide? Would you change something about my wiring connections?

I'm having some voltage drop problems at the moment. Apparently my battery cannot keep its voltage when the fridge is swithced on. I assume in that moment the fridge draws too much current, therefore the battery voltage drops to 11.9 V (measured with the SmartSolar, at the fridge it might be worse) and the fridge turns itself off.

Thanks so much!

Brokenfeet

MPPT Controllers voltage current limit

anschlussplan-victron.png (63.4 KiB)

spannungsabfall.png (52.6 KiB)

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JohnC answered · Jul 11, 2019 at 02:24 PM

Hi BF. I think it's usefulness is limited to small loads, preferably of the resistive type. To protect the battery from being drawn down too far, and to provide a guide to what those loads might be drawing.

But it seems you're not worried about that with your 'other' loads coming off the batt directly. That's where your fridge should be coming from too.

Your fridge's influence on the batt seems temporary, so you really don't need that V-protection to annoy you.

Note that once you step up a little in the Victron range the load terminals disappear as an option. Use them as you might, but step back if your kit gives you issues with them.

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Modifications Space

Node Red Space

Answer 1 · 2019-07-11T21:23:34Z

brokenfeet answered · Jul 11, 2019 at 09:23 PM

Thanks for the info!

So I'll stick my current wiring. As other loads I only have USB chargers and my radio. But I don't worry about those killing my battery :-)

Any idea where this massive voltage drop might come from? Shitty battery?

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JohnC ♦ commented · Jul 12, 2019 at 05:11 AM

Possibly, but not necessarily. Pb's can disappoint if you load them up even just a little. Mostly it's just a matter of learning the limitations of your kit. You shouldn't see such a serious V sag if your pv was producing at the same time though. But depends on the loads. Your 80Ah (@12V) batt mightn't like even 100W drawn from it, especially in cold weather.

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brokenfeet JohnC ♦ commented · Jul 12, 2019 at 11:18 AM

Hi John! I haven't experiencing that voltage drop all the time. So I don't think that it is the Pb-Battery in general. Switching to Li-battery is just too expensive right now.

And yes, if the solar controller is providing enough voltage/current the fridge won't shut itself down....

Also, I don't camp for much longer than 2-3 days (with solar if possible), then I normallly get back on the road and charge via the booster or generator

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