Change absortion time of Smart Solar Charger

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carlos-colasanti asked Mar 27, '19

Change absortion time of Smart Solar Charger

Good morning.
In point 3.8 of the SMARTSOLAR MPPT 150/60 manual explains the absorption time according to the battery charge status. My Multiplus II completely discharges the batteries every night, but the next morning when the sun rises those batteries have recovered some of their voltage to something more than 50 Vcc and therefore the Smartsolar charger decides to be in absorption only about two hours. This is not enough to fully charge the batteries. Is it possible to change this configuration with the Lcd display Controller? Or I need to do that from a notebook? Thanks since now. Greetings.

MPPT Controllers battery charging

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JohnC answered · Mar 27, 2019 at 01:35 PM

Hello Carlos. You have Pb batteries I suspect, because that's how they can behave. If you still have 50V by the morning, then they are in excellent shape, And the mppt knows that and has adjusted the charge program to suit. (I assume no external influences)

Why do you think your batteries are not being fully charged? Perhaps tell us their size (Ah), and the A delivered to them when they drop back to Float, then maybe 2 hours into Float (providing Vfloat is still being maintained).

Please forgive me for not answering your question directly. But I'm not sure you need to do anything at all..

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JohnC answered · Mar 28, 2019 at 06:42 AM

Ok, I get it. What you want isn't actually possible for that length of time - yet. There is new firmware under development (should be in testing now), which should cover this. Similar issues have been reported by others, and Victron is taking it seriously. Watch for it.

For now, a workaround you could consider. Raise your Float setting to the same, or just under, your Absorb setting. Even just with a full manually set profile.

Your batts may actually be 'sick', and the longer 'Abs' time may even help them. But I'm not a battery doctor.

*Anecdote*: A friend asked me to charge up a batt that wouldn't start a V8 engine in his boat. I reported to him that it wouldn't accept a full charge, and he abandoned it to me. I left it on full charge for 3 weeks. There was still something strange about it, and it may not start a V8, but has served well as my generator start batt for 4 years. Pb's can do strange things.. :)

Greetings too from Australia to Argentina. Good luck.

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carlos-colasanti commented · Mar 28, 2019 at 11:12 AM

Thank you very much @JohnC, I appreciate your suggestion and I will try that.
I'll be looking for that new firmware.
Thanks also for your regards.
The best for you

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Answer 1 · 2019-03-27T20:12:26Z

carlos-colasanti answered · Mar 27, 2019 at 08:12 PM

Thank you very much @JohnC for your response. 

That's right, I have a batteries bank of 48 Vcc of economical Pb batteries normally used by trucks, of 180 Ah nominal, about 120 Ah real, when I can, I will buy better ones. 

They have very high internal resistance, so the consumption causes them to lose voltage and the Multiplus detects the minimum voltage configured and goes to grid when they still have some charge left, and, on the opposite side while charging, they arrive quite fast at absorption voltage, so they require a lot of time to charge well at the absorption voltage of 57.6 Vdc, as the truck alternator does (14.4 Vdc on one battery), somehow forcing the charging current. 

I have 6 panels of 305 W each, that is two sets of 3 panels in parallel with another 3, that is 1800 W, with a voltage on the Smart Solar of 120 Vdc and a maximum of about 15 A on sunny days.

I have a consumption of 3.5 KWh during hours without sun.

The solar system is dimensioned very fair, and the consumption discharges the batteries every night and the Smart Solar must complete all the load during the day. I would like those 57.6 Vcc to be on the batteries as long as possible, 8 hours if possible. Can I do that with the Smart Solar Charger? How? 

Thank you very much again. Best regards. Carlos

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