New to the Forum / Intro Question RE Charge Controllers and Generators

[MechEng85]

Hi All,

I am new to the forums and wanted to first say how helpful the site has been so far just in my research. I am new to solar, so I am trying to spend 10x the time learning before I buy.

The system I am setting up is for a trailer that I leave at my remote property in AZ. The electrical requirements are minimal at this point (furnace, charging phones, etc.) but as I learn more, I plan to expand. The camper has a 4k generator as a backup, but I'd like to avoid running it in the middle of the night because the kids are cold

So far, I'm targeting about 300w worth of panels feeding 220Ah worth of batteries (AGM planned), but I am sizing the wiring for future plans to add batteries and panels as the demand increases.

My question is this....with an MPPT controller, do I need to add any sort of provision for a disconnect or transfer switch when the generator is running and powering the 120VAC - to - DC converter to avoid having dual charging sources? I would assume that the charge controller would see the increase in battery voltage and the lack of demand and pull back its charging, but I cannot find anything concrete to back this up and would rather not burn up my batteries prematurely.

Thanks in advance

[Paul Land]

Hi All,



My question is this....with an MPPT controller, do I need to add any sort of provision for a disconnect or transfer switch when the generator is running and powering the 120VAC - to - DC converter to avoid having dual charging sources? I would assume that the charge controller would see the increase in battery voltage and the lack of demand and pull back its charging, but I cannot find anything concrete to back this up and would rather not burn up my batteries prematurely.

Thanks in advance

Here U go. ags.png

[MechEng85]

Here U go. ags.png

Thanks Paul. That controller looks like it's more geared towards remote starting and stopping the generator when conditions dictate. I am fine with manually starting and stopping when needed, more so just need to know if there are any unintended consequences of running the generator when the MPPT controller is also charging the batts.

[Mike90250]

No need. A solar charge controller, will attempt to charge the batteries when the voltage is low. When the voltage rises, the batteries draw (consume) less power. I can be outside running my generator, and hear it's tone change when the sun comes out and the solar charging takes over and the generator unloads ( as the 240v charger does less work when the sun is charging)

As long as your don't over voltage the batteries, it sorts itself out pretty well. There is the odd half hour when first starting the generator, if the sun comes out full, when the batteries are quite low, they "could " take a bit of abuse from some overcharge, but I'd call it negligible because it's likely to be very infrequent.

[MechEng85]

No need. A solar charge controller, will attempt to charge the batteries when the voltage is low. When the voltage rises, the batteries draw (consume) less power. I can be outside running my generator, and hear it's tone change when the sun comes out and the solar charging takes over and the generator unloads ( as the 240v charger does less work when the sun is charging)

As long as your don't over voltage the batteries, it sorts itself out pretty well. There is the odd half hour when first starting the generator, if the sun comes out full, when the batteries are quite low, they "could " take a bit of abuse from some overcharge, but I'd call it negligible because it's likely to be very infrequent.

Thank you Mike....that's exactly what I needed to know