sanity check on basics

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airborne_spoon

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May 11, 2022
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USA, California
Ok so i just want to make sure i fully understand solar components and whatnot before i start buying stuff. I'm also very new to RV stuff and will be buying an RV tomorrow (Bushwhacker 10HD.)
So I'm looking at this panel for the solar (also thinking about this panel and sticking it to the curved portion of the treardrop for better aerodynamics) and from there the lines go to a charge controller... which has to be specific for lead acid or lithium? or just as long as its the right amps it doesn't matter?
power then goes to the batteries then out the the inverter and then the outlets. Is the inverter is the bit next to the fuse box? Does that have to be specific to lithium or lead acid batteries?

I'll have to wait till i get the trailer to measure the roof but i know at least one panel will fit on the roof rack, ideally I'd like to have 400w of solar going to 200-300Ah of lithium batteries.
I can do house wiring all day and car wiring is just as easy for me, but this 12v and 120v in the same system has got me a bit confused lol.
 

uchu

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Ontario, Canada
charge controller... which has to be specific for lead acid or lithium? or just as long as its the right amps it doesn't matter?


You answered your own question about the batteries. If you are getting lithium, the charger has to be lithium battery friendly.
 

airborne_spoon

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USA, California
So if i get a solar charge controller that is for lithium batteries how do i charge the batteries while on shore power? Because the way i understand the wiring, is when plugged into shore power it has a line that also charges the battery but that would be a charge line for a lead acid battery... so would i need another charge controller for while on shore power? or is there a charge controller that has an extra input leg for the shore power connection?
 

DonTom

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Auburn, CA or Reno, NV
So if i get a solar charge controller that is for lithium batteries how do i charge the batteries while on shore power?
Don't you have a converter? If that works, there is no need to think about your solar when on shore power. The converter will keep the battery charged up.

Solar is only needed for boondocking. And in some cases, it helps for long term storage. But is useless when yu have shore power if you have a working converter.

If you have a lead-acid converter on a lith battery, it just will not charge the battery to full but probably not that big of a deal to be charged to 85% SOC compared to 100% SOC. Solar has a higher voltage and can be used to charge to full.

You have the same issue when driving if you're not using a DC2DCC.

-Don- Auburn, CA
 

Gary RV_Wizard

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The converter DonTom is talking about is that shore line charger. They make models that are tuned for Lithium rather than lead acid and you could repalce the OEM converter/charger, or you can add a DC-to-DC device to transform the lead-acid charge values to lithium specs.
As I understand it, the only real problem with using a lead acid charger is that it won't fully charge a lithium battery. That may not be a problem worth solving if you have solar as well.
 

DonTom

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As I understand it, the only real problem with using a lead acid charger is that it won't fully charge a lithium battery.
The fully charged lith battery voltage is higher than the L-A converter and is also higher than the output of the vehicle charging system. But it should charge to above 80% SOC or so, I would think. Most lith batteries don't like to be left fully charged anyway (mine is an exception--the manual for my lith battery says leave it fully charged when not in use).

Solar should be able to take the lith all the way up, if you're not in a hurry. Solar can output more voltage than the lith battery.

I have a lith converter in both my RVs as well as solar. My Y2k RV has a DC2DCC so it charges the lith house battery to full as I drive. In my Y2k RV, that is the only house battery.

I have not found a need to charge my added house battery as I drive in my new RV. It gets used for only a few things--& for nothing stock. Still has the stock L-A batteries also. I did purchase a DC2DCC for my added lith also, but I never bothered to install it. I have not found a need to do such. But I leave it loose inside the RV in case I get bored someday and then want to add it.

-Don- Reno, NV
 

airborne_spoon

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USA, California
The stock converter for my trailer is made for lead acid only and i was talking to some other people with a similar model trailer and they just hit the battery disconnect when hooked to shore power so they don't have to think about at and everything 12v is running off shore power so its fine anyway and the solar can still charge the battery.
I use a 4 pin for the trailer and will not be hooking up the 12v line from the car. the only charge the lithium battery will get is from the solar. But the main drain will be the fridge which should use 50-80Ah a day and the solar panel can make up to 100Ah a day in ideal conditions so it shouldn't be an issue as it can charge while its drained.
 

John From Detroit

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Davison Michigan
It would seem to me that an MPPT controller could "Boost" the converter output voltage.

So I googled it. They do. To just over eighteen volts (A touch higher than I'd like in a 12 volt system)
But you might want to look a MPPT controllers.. See if perhaps they make one that you can limit.
There has to be a way to do the job.
 
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