I have a Victron CC 75/15 which I thought would work with a 12v or 24v battery configuration. When I have my two 12.6v/100Ah (lipo) batteries in series (24v/100Ah) the PV input on CC doesn't show charging. When battery is in parallel 12v/200Ah there is no problem. The panels, which I have tried in series and parallel, are two 100w/12v/4.25a panels. The reason I want the 24v is my inverter is 24v only. Is there a setting, other than battery 12v/24v, in the CC I am missing?
Charge controller settings?
- Thread starter Chris1979
- Start date
BentleyJ
Solar Wizard
Likely the voltage from the 2 solar panels connected in series is below the min start up threshold for 24V charging. Check the charge controller data sheet, you will find the minimum voltage for the charger to start working.
A 24V battery needs at least 27V to charge and the charge controller needs to see 3 to 5V above the charging voltage from the panels.
A 24V battery needs at least 27V to charge and the charge controller needs to see 3 to 5V above the charging voltage from the panels.
Q-Dog
¯\_(ツ)_/¯
Can you post a photo of the label on the back of the panels? Or just post ALL of the numbers?
I have tried both ways during the peak sunlight of the day and when the battery is in parallel the wattage (180w) is well over the min threshold. When batteries are in series I get 25-26 watts max. Here I a photo of specs for solar panels.
Brucey
Solar Wizard
It's not the wattage you have to look at, it's the voltage. For a nominal 24V battery that's being charged at around 27V you will need a minimum of 32V of solar input to start charging. Whereas with your 12V battery configuration a single panel can be over the required voltage of say 18-19V.
Is your 75/15 a smart unit with Bluetooth? That will show you what the panel voltage is as far as the SCC can see.
Is your 75/15 a smart unit with Bluetooth? That will show you what the panel voltage is as far as the SCC can see.
Brucey
Solar Wizard
That should work.
Q-Dog
¯\_(ツ)_/¯
It looks like you have it sorted now, but for future reference the Victron needs to see 5 volts over the battery voltage to start charging.
Also, check the battery settings in the Victron 75/15, and verify that it knows it is on a 24v battery not a 12v battery.
I seem to recall that the manual said the the first time it auto detected, but if you change battery voltages - you need to manually change it. (But I could be remembering incorrectly).
I seem to recall that the manual said the the first time it auto detected, but if you change battery voltages - you need to manually change it. (But I could be remembering incorrectly).
RCinFLA
Solar Wizard
- Joined
- Jun 21, 2020
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That's PV array voltage at least 5v over battery voltage. This should also be met at full charge absorb voltage on batteries.
It needs a couple of volts overhead to run DC to DC converter and some additional panel voltage in order for it to search for MPPT point. It has to exceed Vmp voltage to determine it found MPPT with resultant power drop off in output. Finding a 'peak' means seeing drop off either side of peak.
When minimum overhead PV array voltage is not met, but still above battery voltage, the PV charge controller will drop into 'ON-OFF' PWM mode with direct connect PV array to batteries.
Q-Dog
¯\_(ツ)_/¯
The solar array needs to be large enough to replace the power you use. The voltage doesn't really dictate the size of the array.
