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chenderson1965 avatar image
chenderson1965 asked

Twin MPPT controller behaviour

I have two 150w panels (one is seven years older than the other), each going through its own 75/15 controller to a pair of 80ah gel batteries.


The system works fine. But I don’t understand what I’m seeing in the controller app in two scenarios in particular.


1) The older panel/charger often drops to ‘float’ when the newer one is still showing ‘bulk’. I understand why the new panel would do more of the work - but would expect the second panel to join in some of the time when the batteries can take more current. That doesn’t seem to happen nearly as much as I’d expect. At what battery charging % is it likely that the older panel/charger will drop to float?


2) Both chargers are connected in parallel at exactly the same points (battery terminal and shunt on my motorhome electrics). Usually they show the same battery voltage - but sometimes there can be more than 0.5V between the readings on each controller. Why might that be?


Thanks


Chris

MPPT Controllers
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2 Answers
Supra-Halbleiter avatar image
Supra-Halbleiter answered ·

Maybe the charge controllers have different settings. I would compare the voltages configured here: 1691086479677.png


1691086479677.png (168.0 KiB)
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chenderson1965 avatar image chenderson1965 commented ·
Thanks. I just checked and the settings are identical.
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seb71 avatar image
seb71 answered ·

The MPPT-battery wires are the same length and cross section for both MPPTs?


Your MPPTs are SmartSolar or BlueSolar?
If they are SmartSolar, you could use VE.Smart Networking, which should improve the situation.

https://www.victronenergy.com/media/pg/VE.Smart_Networking/en/index-en.html

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