advice on my choices

[Buzz]

Hello, I have a 5th wheel trailer and I want to power my system through solar. we usually go to full hookup sites but not this year. I have done a whole lot of reading and have arrived at the following components:
2- coleman 12 volt 100 watt panels connected in series
1 ysolar tracer mppt 30a 12v 24v auto switching charge controller
1 royal power 1500 watt 24 volt d/c to 120 volt a/c invertor
1 go-power ts-30 auto transfer switch

I have 2 deep cycle 12 volt batteries and I will be hooking them up in series to get 24 volts. The auto transfer switch is so I can hard wire the inverter to my breaker panel and when I connect to shore power it will switch to that. Does this sound like I have all my "ducks in a row" ? Suggestions?? Thanks in advance

Wayne

[Sunking]

You have some big issues.

To start is why use antiquated Coleman panels?

Anyway a 200 watt panel system can only support a 24 volt 80 AH battery with a 10 amp MPPT Controller and a 300 watt Inverter.

To support a 1500 Watt Inverter requires a 24 volt 500 AH battery, with a 60 Amp MPPT Controller, and 1000 watt minimum solar panel.

[Buzz]

I went overkill on the inverter and the controller in case i want to add more later on. basically we would be using a few lights at night and maybe watch a movie or 2 and run the water pump for a minute or 2 to do dishes. There would be virtually no draw during the day. Would the 200 watt 24 volt system I have picked out keep my batteries charged up?

[Sunking]

I went overkill on the inverter and the controller in case i want to add more later on. basically we would be using a few lights at night and maybe watch a movie or 2 and run the water pump for a minute or 2 to do dishes. There would be virtually no draw during the day. Would the 200 watt 24 volt system I have picked out keep my batteries charged up?

Depends on the AH capacity, plus the unknown of how much you really use. A 200 Watt panel will support a 24 volt 60 to 100 AH battery. So if you are in that range and do not go into charging deficit that part is fine. The issue is a 24 volt battery 60-100 AH battery can only support 180 to 300 watt Inverter.

The problem is the battery cannot supply the high amounts of current above 10 to 15 amps for any meaningful time. The voltage will sag causing the Inverter to trip off line from under voltage when there is nothing wrong. Won't necessarily hurt the battery or Inverter, it is just a mismatch.

Now what it will force you to do is use at least 4 AWG wire between the battery and Inverter with a 80 Amp fuse. Here is a link that can help you with wire size. Keep wire losses to 3% or less. That is determined by Distance and Fuse Size

[Buzz]

I can estimate about 500 to 800 watts per day use so that being said, what would you recommend I use for components. I have purchased the 2 100 watt panels but have not purchased anything else. My batteries are 12 volt 770 cca 105ah deep cycle batteries. Thanks

[ewarnerusa]

Will there be some other component installed to get your 24V back down to 12V for operating all of the RV appliances? Furnace, refrigerator, water pump, lighting, slide motors if you have them, emergency trailer brake, exhaust fans, etc.? I believe it is bad practice to just tap into 1/2 of a series battery setup. Any type of converter replacement since the OEM one is only capable of charging a 12V system from shore power?

[Buzz]

I have another deep cycle that runs the 12 volt system.

[SunEagle]

I have another deep cycle that runs the 12 volt system.

Now I am confused.

You have a 24volt system going to an inverter that you want to be connected to a transfer switch that allows you to either power your loads from the Grid or from that 24volt inverter, and now you say you have another 12volt system.

How do you plan on wiring that system into the other 24volt (possibly not legal) system?

[Buzz]

I have 1 12 volt battery running the factory rv 12 volt system, and then I have 2 12 volt batteries connected in series to the inverter and through a switch to the breaker panel. 2 separate systems.

[SunEagle]

I have 1 12 volt battery running the factory rv 12 volt system, and then I have 2 12 volt batteries connected in series to the inverter and through a switch to the breaker panel. 2 separate systems.

Ok. I wasn't sure if they were part of the same system or totally isolated from each other.

I have an RV that uses a transfer switch that allows me to run it from "shore power" or the on board generator. I am not sure if you need to have an automatic transfer switch but something that will allow you to use either "shore power" or the solar/battery system through the inverter.

The problem with most battery inverters is that they are not set up to hard wire them to a transfer switch or circuit breaker panel. Most have a place to plug in an extension cord. What you are doing may be dangerous if you use and extension cord or wire that is smaller then what your inverter can deliver in amps.

[ewarnerusa]

If it wasn't for your 24V inverter, I would say scrap the dual unmatched systems and replace the 3x12V batteries with 2x6V in series and hook everything else to that. Your single 12V battery for the camper isn't going to last very long while off grid camping, you'll need to recharge it and it would be a shame to have a solar array that isn't wired up to do that.

EDIT: maybe some type of transfer switch out of the charge controller to switch between the single 12V and 2x12V series setup? Since the controller can auto detect between 12 and 24V. Then you can charge each system independently. I'm not sure how well the auto detection works though and I'm sure the 12V system won't like a hit of 24V if the controller takes time to transition.

[Buzz]

I would definitely make an appropriate cable to go from the inverter to the transfer switch to accommodate the current. 10 guage probably. It won't have to go too far, probably 12 feet.

[SunEagle]

If it wasn't for your 24V inverter, I would say scrap the dual unmatched systems and replace the 3x12V batteries with 2x6V in series and hook everything else to that. Your single 12V battery for the camper isn't going to last very long while off grid camping, you'll need to recharge it and it would be a shame to have a solar array that isn't wired up to do that.

EDIT: maybe some type of transfer switch out of the charge controller to switch between the single 12V and 2x12V series setup? Since the controller can auto detect between 12 and 24V. Then you can charge each system independently. I'm not sure how well the auto detection works though and I'm sure the 12V system won't like a hit of 24V if the controller takes time to transition.

You would have to disconnect the CC from your panels before switching to a different battery voltage. The CC needs to first connect to the battery and then connect to the pv panels.

The other problem is that both your 12v & 24v battery system should have the same Ah rating or you may have too high or low charging amps from the same set of pv panels.

[ewarnerusa]

Good point on the disconnecting of CC before switching to batteries of different voltage. Ironic that I overlooked that when I'm always advocating for some type of disconnect between panels and CC for this very reason!

[Buzz]

I read that a 24 volt system is more efficient than a 12 volt system. and that the mppt controller is a better choice for reducing loss from the panels and controlling voltages. I just want a relatively simple system that is efficient and does what I need it to do.