Questions on upgrading solar on travel trailer

[Mcstiggens]

Two inverters in split phase. If either fail, can run the other in 120V mode.
24V/2000W backup system w/separate batteries.
1 propane generator in one of the 5th wheels and 2 portable generators on site.

That's what I'm talking about. I am setting up a 250 gal propane tank that my gennies will run directly off of when needed. That's also why I want to eventually have separate systems between the shop (stationary) and trailer (portable).

 

[sunshine_eggo]

Dagnabbit... Remembered a spare 200A 8S BMS I recently got from @Rednecktek and counted up about 70 old CALB LFP cells, so 8P8S should get me about 5kWh, and I have a stack of 18 285W panels in the backyard, so plenty of PV when the time comes.

Yes. I'm a whoreder.

What is wrong with me?

The only barrier I see is talking my wife into this. Looks like it's time to test all the cells' capacities and internal resistances... *sigh*

 

[Mcstiggens]

Dagnabbit... Remembered a spare 200A 8S BMS I recently got from @Rednecktek and counted up about 70 old CALB LFP cells, so 8P8S should get me about 5kWh, and I have a stack of 18 285W panels in the backyard, so plenty of PV when the time comes.

Yes. I'm a whoreder.

What is wrong with me?

The only barrier I see is talking my wife into this. Looks like it's time to test all the cells' capacities and internal resistances... *sigh*

That's a great problem to have. (Not the part about convincing the wifey.)

 

[sunshine_eggo]

I almost never ask for anything, and I can probably spin this into a resource for a future greenhouse she has a cho for...

Amazon cart already populated...

 

[JamesRich]

I started a system in my camper this year. Its an open range 34 foot 5th wheel with two A/Cs and runs on 50 amp service. It came with generator prep package but I didn't buy a generator. I wanted to keep it simple too so went with 12 volt. I have been running a 12 volt 2000w renogy inverter in my service truck for a few years with no problems so I bought a Renogy 3000w pure sine and mounted it in the compartment meant for a generator. I tied it into the transfer switch that came with the camper. The transfer switch is meant for 240 volts input but I just jumper the L1 & L2 terminals together on the input and it works fine. I got 4 Litime batteries in parallel powering the inverter. Since I started this at the end of the summer I decided to wait till spring to install panels. For now I play with the system with just a 20 amp charger on the batteries. I camped a weekend with just an extension from a friends camper powering the charger. Ran the A/C and microwaves when needed and never ran the batteries too low but this wasn't in the middle of the summer. I connected the set of batteries as my house batteries too and turned off the factory inverter. I only try running one A/C at a time but I can run a microwave while the A/C is running.
I tested draws with a clamp on meter and as everyone says 12v is amp heavy. One A/C running draws 110 amps. Spikes over 200 on start and I've already put soft start caps in both A/Cs. One of the microwaves pulls 130 amps and so does the 120 volt hot water heater. I was just testing, I usually only run the gas on the hot water heater. I have a 12 volt fridge too so that's not a load on the inverter. 12 volt isn't as efficient but it works! I'm thinking I will only be able to mount 8 100 watt panels on the roof and still have room to walk around up there. I'll supplement with folding panels or just a small generator running a charger when I need.
So far I'm happy with the outcome. When I start a house system I'm definitely go 48 volt.
James

 

[Mcstiggens]

Thanks James for chiming in and sharing that. When you say 4 batteries? What size? Are they the 100 ah? If so, that is the same as I am starting out with (2X 200ah Litime batts). I don't need to run an A/C thankfully, just the furnace and fridge. I think I should be alright to get started. BUT now I really should look into the 24 VS 48 system. The longer this drags on, they more I realize I don't know/need to know. I hate hasty decision making.

 

[Mcstiggens]

I almost never ask for anything, and I can probably spin this into a resource for a future greenhouse she has a cho for...

Amazon cart already populated...

Good spin.

So, let's answer me this: why not do a 48V system while I'm at it? It seems like 24V really isnt more expensive or complicated than 12V. Only a step-down device is needed additionally unless I'm missing something.
So, maybe I now spend my whole day learning about 12 vs 24 vs 48 systems instead of what I am supposed to be doing. (no, can someone just tell me what to do!)
What a wabbit hole this has become.

 

[Rocketman]

For your shed install - I would go 48v. And power the trailer from this when there.

For the inside of the trailer - sometimes it is easier to stay at 12v and live with the limitations.

In my case I stayed with 12v in the MotorHome- I wanted to keep the emergency boost ability to help the chassis battery if it ever needed it. And a Multiplus 12/3000 can supply all our needs. Another limitation for me is I was stuck with the inverter at least 8 feet from the battery (much more the way the cables were ran from the factory), and the amount of rewiring would be crazy if I changed voltages.

 

[sunshine_eggo]

For your shed install - I would go 48v. And power the trailer from this when there.

For the inside of the trailer - sometimes it is easier to stay at 12v and live with the limitations.

In my case I stayed with 12v in the MotorHome- I wanted to keep the emergency boost ability to help the chassis battery if it ever needed it. And a Multiplus 12/3000 can supply all our needs. Another limitation for me is I was stuck with the inverter at least 8 feet from the battery (much more the way the cables were ran from the factory), and the amount of rewiring would be crazy if I changed voltages.

+1

 

[Mcstiggens]

For your shed install - I would go 48v. And power the trailer from this when there.

For the inside of the trailer - sometimes it is easier to stay at 12v and live with the limitations.

In my case I stayed with 12v in the MotorHome- I wanted to keep the emergency boost ability to help the chassis battery if it ever needed it. And a Multiplus 12/3000 can supply all our needs. Another limitation for me is I was stuck with the inverter at least 8 feet from the battery (much more the way the cables were ran from the factory), and the amount of rewiring would be crazy if I changed voltages.

I guess my issue now would be that I have two 12V batteries. So I can wire the two 12's in series to get 24V but how then do I achieve 48V? I'm guessing I need two more 12's to duplicate this series setup, then create 48V?

 

[sunshine_eggo]

I guess my issue now would be that I have two 12V batteries. So I can wire the two 12's in series to get 24V but how then do I achieve 48V? I'm guessing I need two more 12's to duplicate this series setup, then create 48V?

Yep

 

[Mcstiggens]

Yep

Or try to return them and purchase this bad boy.
I'm still trying to wrap my head around best-bang-for-buck when shopping battery size, between ah, 12/24/48V etc.

For instance: I'm currently out about $1100 on two 200ah 12v batts. If I double them to get 4 12v wired to make 48V, it would cost $2200-ish. But then 800ah vs 400ah rated for the rack mount 48V. only costing $1400. But I realize when comparing 12 to 24V, the AH rating is cut in 1/2 yet yields the same due to efficiency....or something to that effect.
Would love for someone to elaborate.

LiTime 48V 100Ah LiFePO4 Deep Cycle Server Rack Battery

The LiTime 48V 100Ah LiFePO4 batteries provides 4800Wh energy, perfect for home storage, off-grid and RV.

www.litime.com

 

[sunshine_eggo]

Yep. I would look at EG4 from signature solar or SOK from CurrentConnected rather than LiTime.

 

[Mcstiggens]

Yep. I would look at EG4 from signature solar or SOK from CurrentConnected rather than LiTime.

Yea, I see that they are comparable in price as well. Problem is, the 12v ones I have are Litime. So if'n I decide to go that route it will be easier to swap out with Litime (if they are willing) than to return/re-purchase. Litime does appear to have decent support however.
*edit- Okay, nevermind any of that. It was an Amazon purchase anyway, so easy to return them. I will look into your recommendations further.

Sheesh, I can getting sent back to the drawring board.

 

[sunshine_eggo]

Sheesh, I can getting sent back to the drawring board.

Better now than buying additional stuff because the initial system disappoints!

I thought sleeping on it was going to temper my interest in the stupid PowMr...

 

[Mcstiggens]

Better now than buying additional stuff because the initial system disappoints!

I thought sleeping on it was going to temper my interest in the stupid PowMr...

Well shart! It looks like I may on the hook for the return cost of these batts.

I'm pretty much not into that, what with the shipping cost going bonkers and all.

IF they are willing to accept them in exchange for the 48V at no cost for return shipping then I am stuck with Litime.

If they will not do that, then I guess I will keep them and go 24V for now. OR I could put these in the trailer and stay 12V with lot of battery power and later on, when the budget allows go for the 48v system in the shop.

 

[Rocketman]

Will those two 12v batteries work for your rv? Size, amps, , etc?

If you are staying with 12v for the RV - they may work great there.

 

[Mcstiggens]

Will those two 12v batteries work for your rv? Size, amps, , etc?

If you are staying with 12v for the RV - they may work great there.

Well yes, my original plan was to stick with 12V in the RV, add these two 200ah 12V batteries and hook in to solar panels that will be mounted to the top of my shop/shed. (but then started toying with idea of going 24V in trailer instead ).

Later on I planned to install panels on the roof of the RV.

Now I plan to go 48V in shop and plug into that when parked. I'll stay 12V in the RV, which means keeping these would be fine.
I just would have to wait a bit to do the shop power due to budget constraints.

That means, I will need to run shop power from the trailer 12V while charging from shop solar and supplementing shop duties and cloudy day charging with a generator.

But now that I'm getting all these idears and edumacation, I am eager to set up 48V after seeing the benefits in efficiency.

 

[sunshine_eggo]

But now that I'm getting all these idears, I am eager to set up 48V after seeing the benefits in efficiency.

They're not more efficient per se.

The inverters and equipment are about as efficient as the others. The benefits come from:

1) needing less copper for the same efficiency.
2) needing less MPPT charge current for a given array power.

 

[Mcstiggens]

Will those two 12v batteries work for your rv? Size, amps, , etc?

If you are staying with 12v for the RV - they may work great there.

So now it comes full circle back to this; what are the limitations to the stock Furrion 25amp charge controller that is installed on my trailer and is it worth messing with? Can I get by with it while using 400 ah battery bank running my 12v fridge, furnace, lights and periphs?

Problem is, I still need to shop for an inverter/charge controller/ and on and on it goes. So now I'm basically BACK to square one