Solar, Inverter, and Converter Operation Clarification

Ericb760 · 05-29-2019, 10:34 AM

I hope I can explain this correctly. My 89' Chieftain has an aftermarket 300W solar panel, Solar Charge Controller, and 1000W inverter installed. The PO boondocked almost exclusively, so I understand the need for solar to charge the house batteries. What I do not understand is how this works in conjunction with the coach converter, particularly the inverter on/off switch.

Am I to assume that when the inverter is OFF, the solar panels are not charging the batteries and when it is ON it is charging them?

Am I to also assume that when on shore power, the converter is charging the batteries?

I guess where I'm going with this is to avoid cooking my batteries by charging them from two different sources (solar/inverter and converter) at the same time.

My converter is probably OEM and I've read that these older units can "boil" batteries. For this reason I will soon be upgrading to a more modern converter. I just want to be sure that I am using these two systems appropriately.

In closing I summarize that the inverter should be OFF when hooked to shore power, and ON when running on house batteries.

I hope this makes sense. Thanks,

Eric

**creativepart** · 05-29-2019, 02:04 PM

The solar charge controller is just that a charge controller. It’s job is to take electricity produced by the panels and charge your batteries as needed. It needs no other charger to do it’s work. It is a charger.

Some inverters also are chargers. If yours is so equipped you might not have or need a converter at all.

On a 30-year old RV, purchased for under $5,000 I, personally, would expect that the entire solar electrical system is likely out dated, unless the PO provided details to expect otherwise.

A 30 yr old converter would certainly not be of the “smart” charger variety. And the inverter could easily be MSW rather than PSW. The solar charge controller... PWM or MPPT? That’s anyone’s guess.

**creativepart** · 05-29-2019, 02:13 PM

Quote:

Originally Posted by Ericb760

In closing I summarize that the inverter should be OFF when hooked to shore power, and ON when running on house batteries.

Yes, generally. However, when on house batteries I would only turn on the inverter when 110v power was needed. Inverters use amps when on, even if they are not powering 110v appliances.

Most current inverters have a built in transfer switch to automatically bypass the inverter function when on shore power. That said, I still turn mine off when plugged in. My inverter is also a charger. That I leave on, obviously when on shore power to charge the batteries.

Ericb760 · 05-29-2019, 02:22 PM

The solar system is two years old and consists of a EPSOLAR VIEWSTAR PWM solar charge controller. The inverter is a Renogy 1000W PSW and the solar panel is a Renogy 300W 12/24V Monocrystalline panel.

**creativepart** · 05-29-2019, 02:36 PM

Sounds like they are newer devices. The solar charge controller should be capable of charging your batteries without over charging them. A PWM charge controller applies less voltage as batteries reach full charge. A MPPT controller is more efficient and is smarter at charging. It works as a smart 3-stage charger. The PWM charger just sort of “discards” power as your batteries reach full charge

e4services · 06-05-2019, 05:28 PM

The Solar just charges the batteries.
The controller will limit the amps if it sees the voltage raise from another charging source.
This has nothing to do with the inverter, it should always be charging in sunlight.
The Inverter just draws current from the batteries 12VDC to produce 110VAC.
It will stop when 110VAC shore power is available.
Your old Converter/Battery charger just makes 12VDC AND charges the batteries if needed, when shore power is applied.
And, yes, replace it with a new COnverter/4 stage charger

Ericb760 · 06-05-2019, 07:03 PM

Quote:

Originally Posted by e4services

The Solar just charges the batteries.
The controller will limit the amps if it sees the voltage raise from another charging source.
This has nothing to do with the inverter, it should always be charging in sunlight.
The Inverter just draws current from the batteries 12VDC to produce 110VAC.
It will stop when 110VAC shore power is available.
Your old Converter/Battery charger just makes 12VDC AND charges the batteries if needed, when shore power is applied.
And, yes, replace it with a new COnverter/4 stage charger

I have deciphered a lot since I first posted this question. The inverter only powers the TV 120V outlets. The solar panel is 100W, not 300W. I definitely want to upgrade the converter to a four stage charger to avoid damaging the batteries. However, I am a bit confused as to how many amps I need from the converter. Virtually all interior 12V lighting has been upgraded to LED. The roof AC is new. The microwave oven is "newish". I'm thinking that I can get by with a 35 Amp Converter/Charger, which I can get from the "dent and ding" section of Amazon for under $100.

leadman · 06-05-2019, 10:34 PM

I had a '89 Itasca (by Winnie) that I upgraded the convertor in. I used a Progressive Dynamics as they made a unit that fit in the original housing. Made the replacement very easy. Also great customer service.

Ericb760 · 06-05-2019, 10:37 PM

Quote:

Originally Posted by leadman

I had a '89 Itasca (by Winnie) that I upgraded the convertor in. I used a Progressive Dynamics as they made a unit that fit in the original housing. Made the replacement very easy. Also great customer service.

What Amp rating did you go with and why?

leadman · 06-07-2019, 08:06 AM

I bought the only model that fit in the original. Still plugged into 30 amp service. Can't recall the model, was about 8 years ago and I sold that MH.
Their phone number is 269-781-4241.