Charging off generator in RV

[liamlunchtray]

So I have been slowly building out a system in a used 10 year old RV that had a factory 2000watt charger/inverter and on onboard generator.

I used a MultiPlus 12/3000/120-50 as a drop in replacement for the original charger/inverter.

Once I added some panels and batteries, I realized that that inverter only powered the outlets and wasn't wired to the AC/Fridge/Furnace. Today I redirected the shore power so it now goes:
Shore Input -> Inverter -> ATS Switch -> Converter -> Loads

Everything works OK, but the inverter is before the ATS, so when I'm on generator I'm not charging the batteries. Is there some way to get power to the multiplus to charge batteries when I'm on Generator? I feel like Im missing something obvious.

 

[Checkthisout]

So I have been slowly building out a system in a used 10 year old RV that had a factory 2000watt charger/inverter and on onboard generator.

I used a MultiPlus 12/3000/120-50 as a drop in replacement for the original charger/inverter.

Once I added some panels and batteries, I realized that that inverter only powered the outlets and wasn't wired to the AC/Fridge/Furnace. Today I redirected the shore power so it now goes:
Shore Input -> Inverter -> ATS Switch -> Converter -> Loads

Everything works OK, but the inverter is before the ATS, so when I'm on generator I'm not charging the batteries. Is there some way to get power to the multiplus to charge batteries when I'm on Generator? I feel like Im missing something obvious.

Wire the transfer switch before the inverter/charger.

It then decides if shore power or gen power feeds the multiplus.

 

[Checkthisout]

Also you lost me. How do you have an inverter and converter as shown in your circuit explanation when you ditched them both for the multiplus?

 

[jimcalf]

I'm assuming that your generator is fixed and hardwired into the ATS, as is your shore power? Then the ATS detects which is providing 120V and passes that source to the Multiplus inverter charger. Seems to me that you're bypassing the Multiplus when running the generator. The Multiplus is your battery charger, which also energizes your DC bus, which I assume is wired to your DC panel. You should disconnect the legacy converter/charger completely, as you don't need it anymore, and wire the ATS output to the Multiplus AC-In. So it would be Shore wired to ATS in 1, Generator wired to ATS in 2, Multiplus wired to ATS out. Then Multiplus DC to DC bus, which is wired to the 12V panel and then onto the 12V loads. Of course the AC-Out on the Multiplus would also be wired to the main breaker on the AC panel.

 

[liamlunchtray]

Yeah I’m starting to see where by just dropping in the Multiplus to the existing system and not starting from scratch I have made things more complicated when I was actually trying to simplify. This is a standard 30 amp class C RV with a factory inverter/charger. I dropped in the Multiplus when the factory unit died. I then added lithium/solar and a dc/dc charger for alternator charging. This all works fine unto itself.

I just tried writing this out to explain how I over complicated everything and realized I’m absolutely going to have to draw out a diagram. Ugh - we’re supposed to be heading out on Friday and I’m seeing just hiw not ready this is. Blech.

 

[John Frum]

So I have been slowly building out a system in a used 10 year old RV that had a factory 2000watt charger/inverter and on onboard generator.

I used a MultiPlus 12/3000/120-50 as a drop in replacement for the original charger/inverter.

Once I added some panels and batteries, I realized that that inverter only powered the outlets and wasn't wired to the AC/Fridge/Furnace. Today I redirected the shore power so it now goes:
Shore Input -> Inverter -> ATS Switch -> Converter -> Loads

Everything works OK, but the inverter is before the ATS, so when I'm on generator I'm not charging the batteries. Is there some way to get power to the multiplus to charge batteries when I'm on Generator? I feel like Im missing something obvious.

The Multiplus is an ATS so the legacy ATS is surplus to requirments.
Also the converter will make a power loop with the multiplus unless special care is taken to prevent it.

 

[John Frum]

The Multiplus is an ATS so the legacy ATS is surplus to requirments.
Also the converter will make a power loop with the multiplus unless special care is taken to prevent it.

The Multiplus can be easily integrated.
Starting from scratch is not required.

 

[John Frum]

Assuming you want your generator to automatically disconnect shore power you can integrate like this.

ac_domain {
                                                   A<-generator
                                                   T
    |<-master_breaker<-multiplus<-surge_protector<-S<-shore_power
    |->branch_breaker->converter(disabled)
    |->branch_breaker->branch_load
    |...
}

 

[Paul_R]

The Multiplus is an ATS so the legacy ATS is surplus to requirments.
Also the converter will make a power loop with the multiplus unless special care is taken to prevent it.

Yup.

 

[liamlunchtray]

Ok, so I realized that I need to go

Shore/Gen-> ATS-> MULTIPLUS-> panel and outlets

That leaves the converter in place powering the DC loads. I’m assuming the right change is to then remove the converter and run a fresh line from my 12v bus to the 12v section of the panel? It’s a standard parallax RV panel with the integrated converter.



My own damn fault for not drawing everything out first. I should have known better

 

[Checkthisout]

Yeah I’m starting to see where by just dropping in the Multiplus to the existing system and not starting from scratch I have made things more complicated when I was actually trying to simplify. This is a standard 30 amp class C RV with a factory inverter/charger. I dropped in the Multiplus when the factory unit died. I then added lithium/solar and a dc/dc charger for alternator charging. This all works fine unto itself.

I just tried writing this out to explain how I over complicated everything and realized I’m absolutely going to have to draw out a diagram. Ugh - we’re supposed to be heading out on Friday and I’m seeing just hiw not ready this is. Blech.

Better get started.

As others have said, it will go in place of your current transfer switch.

The transfer switch and converter will be removed.

Your old setup tapped in post-panel to avoid the issue of powering the converter with the inverter.

 

[Checkthisout]

Ok, so I realized that I need to go

Shore/Gen-> ATS-> MULTIPLUS-> panel and outlets

That leaves the converter in place powering the DC loads. I’m assuming the right change is to then remove the converter and run a fresh line from my 12v bus to the 12v section of the panel? It’s a standard parallax RV panel with the integrated converter.



My own damn fault for not drawing everything out first. I should have known better

No, not correct.

The generator and shore power will go into the multiplus's gen and shore power inlets.

The multiplus is also a transfer switch...and a nice one at that!

So you will go:

Shore power to multiplus line input.
Generator to multiplus gen input.

Multiplus 120V out to RV panel main breaker.

Multiplus 12V in/out to your batteries.

Your multiplus has some other nice features but ignore them for no so you can go camping next weekend.

Example (it has an output that is only powered when you have ac power available from shore or gen. This would be a good output to hookup to air conditioner circuit)

 

[liamlunchtray]

My multiplus only has a single 120v 3 wire input - No separate generator input. It looks like this

So I'm assuming that means I need to retain my factory ATS, no?

Thanks for everyones help!
Liam

 

[John Frum]

No, not correct.

The generator and shore power will go into the multiplus's gen and shore power inlets.

The multiplus is also a transfer switch...and a nice one at that!

So you will go:

Shore power to multiplus line input.
Generator to multiplus gen input.

Multiplus 120V out to RV panel main breaker.

Multiplus 12V in/out to your batteries.

Your multiplus has some other nice features but ignore them for no so you can go camping next weekend.

Example (it has an output that is only powered when you have ac power available from shore or gen. This would be a good output to hookup to air conditioner circuit)

It can be done either way.
The ats can be left upstream of the multiplus if he wants to hardwire his generator.

 

[jimcalf]

No, not correct.

The generator and shore power will go into the multiplus's gen and shore power inlets.

The multiplus is also a transfer switch...and a nice one at that!

So you will go:

Shore power to multiplus line input.
Generator to multiplus gen input.

Multiplus 120V out to RV panel main breaker.

Multiplus 12V in/out to your batteries.

Your multiplus has some other nice features but ignore them for no so you can go camping next weekend.

Example (it has an output that is only powered when you have ac power available from shore or gen. This would be a good output to hookup to air conditioner circuit)

Not sure what you mean by the "Multiplus Gen Input" on a 12/3000/120 Multiplus. Mine has "AC-In" and that's it. If I want to hardwire a generator, I need an ATS between the genny/shore and the AC-In to detect and route the AC source to the Multiplus.

 

[John Frum]

My multiplus only has a single input - No generator. It looks like thisView attachment 106788

So I'm assuming that means I need to retain my factory ATS, no?

Thanks for everyones help!
Liam

Yes keep the ats and integrate according to my diagram from earlier in the thread.

 

[Checkthisout]

My multiplus only has a single 120v 3 wire input - No separate generator input. It looks like thisView attachment 106788

So I'm assuming that means I need to retain my factory ATS, no?

Thanks for everyones help!
Liam

My bad.

I thought the multiplus had 2 ac inputs.

Yes, so the same still applies. The multiplus just goes in between the rv transfer switch and panel and then gets wired to batteries.

Your converter goes in the spare parts pile.

 

[liamlunchtray]

Awesome, ok. I got a full afternoon ahead of me

 

[liamlunchtray]

One last stupid question - it’s probably a 10-12’ run from my dc stuff to the dc panel. Am I just running a hot and grounding to chassis or am I running both pos and negative back to my batteries?

 

[Checkthisout]

One last stupid question - it’s probably a 10-12’ run from my dc stuff to the dc panel. Am I just running a hot and grounding to chassis or am I running both pos and negative back to my batteries?

It's up to you. Chassis ground is fine but I personally like two cables all the way back to the batteries. It takes some effort to properly clean and star washer chassis ground points.