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okelaa avatar image
okelaa asked

MPPT RS 450/100-Tr reduces current on generator input

Why the solar charger MPPT RS 450/100-Tr reducing current to charge the battery bank, when a generator input (e.g. 9,5A) is added via Quattro 48V/5000VA ?

1680258042604.png

It happens always, even when the battery voltage is low (48,5V) and a lot of current would be required to charge the battery bank 480Ah (6 x 12V 240Ah Victron AGM deep cycle batteries).

As soon as the generator is stopped the solar charger restores the current.

In MPPT settings the maximum charge current is set to 96A.

MPPT SmartSolar
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3 Answers
Michelle Konzack avatar image
Michelle Konzack answered ·

Dou you have 6 or 8 batteries? ;-)

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okelaa avatar image okelaa commented ·

Sorry, I have 8 batteries 12V 240Ah Victron AGM deep cycle, total 480Ah.

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Alexandra avatar image Alexandra ♦ okelaa commented ·
Are they charging at the same voltage or is the inverter pushing a higher voltage?
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JohnC avatar image
JohnC answered ·

Hi @okelaa

I suspect this is very Voltage related. It appears that the mppt is backing off once it has reached Absorb, leaving the Quattro to dominate. This can happen in practice, despite the target settings for Abs (and Temp Comp) being identical. A pity your widget doesn't show V, so guessing somewhat.

To fix it, turn on DVCC so that they both see exactly the same V (maybe use the BMV's). Then drop the Quattro Abs setting slightly below that of the mppt. Over 48V, I find 0.1V enough for the mppt to assume priority, and the genset will back off first. Also make sure that the current limiting in DVCC isn't set where it too could cause undue limiting.

You mention this also happens at 48.5V, but that low a V can't happen with the charge current you're showing.


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JohnC avatar image JohnC ♦ commented ·
@okelaa

Seeing your last comment after posting, also use the STS option in DVCC, so that both see the same Temp.

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okelaa avatar image
okelaa answered ·

Thank you for most professional advice!

Here is the same chart V parameter added.

1680348169791.png


Following your instructions I set MPPT Absorption V slightly higher 57,7V and Quattro slightly lower 57,5V. So the current difference is 0,2V to see how it works. If all good, I'll reduce the difference to 0,1V.

I did set up DVCC as follows:1680345955689.png


Moreover, I am not sure if it would be even better to set up the Smart Battery Sense for V and temp reading?


JohnC - You mention this also happens at 48.5V, but that low a V can't happen with the charge current you're showing.

Yes, perhaps I exaggerated. I'll be careful with further claims and back them up with objective data.


Look forward to hearing from you.

Kind regards,



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JohnC avatar image JohnC ♦ commented ·
@okelaa

Yeh, the V addtion tio the chart is what I expected. What you've done there with the DVCC should work fine.

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JohnC avatar image JohnC ♦ JohnC ♦ commented ·
The Smart Battery Sense can't be networked via cable, and adding a bt network to a cabled one isn't recommended.
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okelaa avatar image okelaa JohnC ♦ commented ·
Great! Thank you so much, appreciate it highly!
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