Charge controllers?

[ohiobenz]

If my system consists of both 24vdc PV panels and a 24vdc backup generator, will this require 2 charge controllers or a charge controller for the PV array and a BP-220 to start/stop the backup generator?

 

[jonyjoe101]

The charge controller is only needed for the the panel, since its only a 24 volt panel, you only need a pwm controller, you can use mppt but it won't give you any extra amps.







Is this the bp-220 you talking about? it looks like a battery isolator.
Victron Energy BatteryProtect BP-220 (12/24V - 220A)


The BatteryProtect disconnects the battery from non essential loads before it is completely discharged (which would damage the battery) or before it has insufficient power left to crank the engine.
Feature Highlights

• 12/24V auto ranging
• Easy to program
• Special setting for Li-ion batteries and can be controlled by VE.Bus BMS
• Ultra low current consumption
• Over voltage protection
• Ignition proof
• Delayed alarm output
• Delayed load disconnect and delayed reconnect

 

[VerMonsterRV]

The charge controller is only needed for the the panel, since its only a 24 volt panel, you only need a pwm controller, you can use mppt but it won't give you any extra amps.

Are you sure about that? My understanding is that if the voltage from the panels exceed the charging voltage a MPPT controller will up the amperage regardless of if it 12v or 24v. I run a mixed system using Blue Sky networked charge controllers, one 12v (3 panels) and one 24v(2 panels) feeding a 12v battery bank. It seems to work as I can see the amperage in vs amperage out on the monitor. Why the complexity of 12v and 24v, I started with all 24v feeding the 12v bank, but some panels failed and the only replacements I could find were 12v.

 

[IdaSHO]

Regardless of actual system voltage, if you have higher charge voltage, from either a PV or a generator, an MPPT will perform more efficiently than a PWM
The charge controller does have a maximum amp output though, so somewhere in there you might max that out.
And it is my understanding that most, if not all MPPT controllers will not be harmed doing this, they will simply max out an not output an more amps.
With that said, you should be able to run on just one controller if you want.
I run 400watts of 24v panels into a 20amp MPPT controller on a 12V system, maxing it out in full sun with drained batteries.
It does fine, but simply cannot output more than 20amps safely, so thats what I get.

BTW, pretty sure what jonyjoe was referring to was a 24v generator output voltage vs a 24v PV output voltage, with regard to your vehicle system voltage.
I may have missed it, but what is the vehicle operating voltage?
running a 24V generator (or solar, or both) on a 12v system would benefit from a MPPT as it can convert the higher voltage into additional amps.
A 24V generator on a 24V system would not benefit much, if any from a charge controller, as the voltages match. Finally, a 24V PV output voltage would be considerably higher than the 24V generator output voltage.

 

[rayra]

I wouldnt' think the charge controller cares what or how many power inputs there are, as long as they are in the proper range. So 1 charge controller. But having two is good redundancy.