Switching between shore / solar power

[Wygonski]

I am installing a solar system in a pop-up with stock WFCO WF-8275 converter and 12v SLA battery. Solar system has 2 x 100W panels in series to a Epever Triton 20A mppt controller.
We sometimes camp where shore power is available, and when the new solar system is installed and we are not on shore power, we will charge the battery from solar.
When not camping I would like to leave PV connected to keep the bat charged.
My question is how to wire correctly for camping with/without shore power. With shore power we will not connect the PV. Is a switch is needed in this setup at the battery? If so, does it switch the battery between converter and SC? I have 25A breaker/switch between PV and SC and between SC and the battery.

 

[sunshine_eggo]

Charging from multiple sources

One can have as many independent charging sources running concurrently as they like provided they are programmed properly for the voltage of one's battery bank. Examples (some or all at once, even multiples of a single type, different brands, etc.): Solar PV via MPPT Solar PV via PWM AC-DC...

diysolarforum.com

There is no need to disconnect your solar when on grid provided BOTH are properly configured to charge your battery.

If you insist on disconnecting, flip PV to SC breaker off.

 

[John Frum]

Typically you will have either a discrete automatic transfer switch or an inverter charger with integrated transfer switch.

If you are using a discrete transfer switch you will want to wire the converter and ats shore power feed in parralel.
The converter will its own over-current protection.

If you are using an inverter charger its much easier and arguably better.
Just disable the converter and wire like this.

ac_domain {
    |<-master_breaker<-inverter_charger<-surge_protector<-shore_power
    |->branch_breaker
    |...
}

Which are you planning inverter/charger, discrete ats or something else?

 

[Wygonski]

Charging from multiple sources

One can have as many independent charging sources running concurrently as they like provided they are programmed properly for the voltage of one's battery bank. Examples (some or all at once, even multiples of a single type, different brands, etc.): Solar PV via MPPT Solar PV via PWM AC-DC...

diysolarforum.com

There is no need to disconnect your solar when on grid provided BOTH are properly configured to charge your battery.

If you insist on disconnecting, flip PV to SC breaker off.

Thanks, that's helpful to know we don't need to worry about switching over. Most often when we camp on grid, we will pack away or leave home the PV as they are "portable", so they will be unplugged rather than switched off.

 

[Wygonski]

Typically you will have either a discrete automatic transfer switch or an inverter charger with integrated transfer switch.

If you are using a discrete transfer switch you will want to wire the converter and ats shore power feed in parralel.
The converter will its own over-current protection.

If you are using an inverter charger its much easier and arguably better.
Just disable the converter and wire like this.

ac_domain {
    |<-master_breaker<-inverter_charger<-surge_protector<-shore_power
    |->branch_breaker
    |...
}

Which are you planning inverter/charger, discrete ats or something else?

Thanks for your detailed reply. I was planning on leaving the OEM unit in place. Just so I'm clear on terms, my popup OEM power center unit has 1) AC distribution w. breakers to outlets, 2) converter generating 12v (fused) to LED lights, refrig, heater blower, 12v outlets, etc. and 3) AC-sourced charger to battery.

 

[Wygonski]

(continued) Is this OEM power center (manufacturers term) what you meant by inverter/charger? In any case there is no transfer switch (yet). I also have a small-capacity inverter (300W I believe) that's only used for charging phones when we're on solar.

 

[John Frum]

Thanks for your detailed reply. I was planning on leaving the OEM unit in place. Just so I'm clear on terms, my popup OEM power center unit has 1) AC distribution w. breakers to outlets, 2) converter generating 12v (fused) to LED lights, refrig, heater blower, 12v outlets, etc. and 3) AC-sourced charger to battery.

correct

 

[John Frum]

(continued) Is this OEM power center (manufacturers term) what you meant by inverter/charger? In any case there is no transfer switch (yet). I also have a small-capacity inverter (300W I believe) that's only used for charging phones when we're on solar.

The oem power center contains a converter which converts ac to dc.
An inverter converts dc to ac.
Special care needs to be taken to avoid a power loop when both are present.
An inverter/charger contains a charger which makes the converter redundant.
An inverter/charger also contains an automatic transfer switch.

 

[Wygonski]

The oem power center contains a converter which converts ac to dc.
An inverter converts dc to ac.
Special care needs to be taken to avoid a power loop when both are present.
An inverter/charger contains a charger which makes the converter redundant.
An inverter/charger also contains an automatic transfer switch.

Regarding the power loop, my standalone inverter takes input at the battery terminals and outputs AC at it's outlets into which I will only plug in, for example, a brick+USB cable phone charger, so no loop there, correct?

 

[John Frum]

Regarding the power loop, my standalone inverter takes input at the battery terminals and outputs AC at it's outlets into which I will only plug in, for example, a brick+USB cable phone charger, so no loop there, correct?

Just to be clear your inverter is not energizing the ac distribution panel, confirm?

 

[Wygonski]

Just to be clear your inverter is not energizing the ac distribution panel, confirm?

Yes, that's correct. Only if I plug into shore power will the AC distribution panel be live. And in that case I wouldn't plug into the inverter AC out at all, and would toggle it's switch to off.

 

[John Frum]

Yes, that's correct. Only if I plug into shore power will the AC distribution panel be live. And in that case I wouldn't plug into the inverter AC out at all, and would toggle it's switch to off.

In that case there is no risk of a power loop.